FDM printed part with surface texture added in SolidWorks 2020.

Printing 3D Texture on FDM 3D Printed Parts – it can be done!

While many examples exist of impressive texturing done on 3D printed Stratasys PolyJet printed parts (some wild examples are here), I have to admit it took me a while to learn that true texturing can also be added to Stratasys Fused Deposition Modeling (FDM) parts. This blog post will walk you through adding texture to all faces or some faces of a solid model, ready for FDM printing. You, too, may be surprised by the results.

I know that complex texturing is possible in a graphics sense with such software packages as Rhino, PhotoShop, Blender and more, but I’m going to show you what you can achieve simply by working with SolidWorks, from Rev. 2019 onwards, as an easy starting point. From there, you can follow the same basic steps but import your own texture files.

Example of Stratasys FDM part set up to print with a checkerboard surface texture. (Image courtesy PADT Inc.)
Example of Stratasys FDM part set up to print with a checkerboard surface texture. (Image courtesy PADT Inc.)

SolidWorks Texture Options

First off, let’s clarify some terms. Texture mapping has existed for years and strictly speaking creates a 2D “texture” or pattern. If I were to wrap that imagery around a 3D CAD model and print it on, say, a PolyJet multi-color 3D printer, I’d get a 3D part with a flat or perhaps curved surface decorated with a multi-color “picture” such as a map or a photo of leather. It could conform, but it’s still basically a decal.

A 3D texture instead is more properly referred to as Bump Mapping (not to be confused with …..too late….bit mapping). Bump mapping interprets the color/contrast information of a 2D image such that it renders light and shadow to give the illusion of a 3D part, while remaining in 2D. Taking this concept one step further, 3D CAD software such as SolidWorks can apply rules that convert white, black and grey shades into physical displacements, producing a kind of tessellated topology mapping. This new information can be saved as an STL file and generate a 3D printed part that has physical, tactile variations in material height across its surface. (For a detailed explanation and examples of texture versus bump-mapping, see the GrabCAD Tutorial “Adding Texture to 3D Models.”)

For FDM parts, you’ll get physical changes on the outer surface of the part that appear as your choice of say, a checkerboard, an arrangement of stars, a pebbly look or a series of waves. In the CAD software, you have a number of options for editing that bump map to produce bigger or smaller, higher or lower, finer or coarser variations of the original pattern, prior to saving the model file as an STL file.

Stepping through SolidWorks 3D Texturing

The key to making this option work in SolidWorks 3D CAD software (I’m using SolidWorks 2020), is in the Appearances tab. Here are the steps I’ve taken, highlighting the variety of choices you can make. My example is the Post-It Note holder I described in my PADT blog post about advanced infill options in GrabCAD Print.

  1. Open Post-It note CAD file, select Solid Bodies (left menu) and select Appearances (in the right toolbar).
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  1. Expand Appearances and go all the way down to Miscellaneous, then click to open the 3D Textures folder.
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  1. Scroll down to choose one of the more than 50 (currently) available patterns. Here, I’ve chosen a 5-pointed star pattern.
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  1. I dragged and dropped that pattern onto the part body. A window opens up with several choices: the default is to apply the pattern to all faces:
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However, you can mouse over within that pop-window to select only a single face, like this:

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  1. When you’ve applied the pattern to either all faces or just one or two, you’ll see a new entry in the left window, Appearances, with the subheading: 5-pointed Star. Right-click on those words, and choose Edit Appearance:
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Then the Appearances window expands as follows, opening by default to the Color/Image tab:

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In this pane, if desired, you could even Browse to switch to a different pattern you have imported in a separate file.

  1. Click on Mapping, and you’ll see a number of “thumb wheel” sliders for resizing the pattern either via the wheel, clicking the up/down arrows, or just entering a value.

Mapping: this moves the pattern – you can see it march left or right, up or down. I used it to center the stars so there aren’t any half-stars cut off at the edge.

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Size/Orientation: You can also try “Fit width to selection” or “Fit height to selection,” or experiment with height and width yourself, and even tilt the pattern at an angle. (If you don’t like the results, click on Reset Scale.) Here, I’ve worked with it to have two rows of five stars.

  1. Remember I said that you can also make the pattern higher or lower, like a change in elevation, so that it stands out a little or a lot. To make those choices, go to the Solid Bodies line in the Feature Manager tree, expand it, and click on the part name (mine is Champfer2).

In the fly-out window that appears, click on the third icon in the top row, “3D Texture.” This opens up an expanded window where you can refine the number of triangular facets that make up the shape of the selected texture pattern. In case you are working with more than one face and/or different patterns on each face, you would check the box under Texture Settings for each face when you want to edit it.

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Here is where you can flip the pattern to extend outwards, or be recessed inwards, or, if you brought in a black/white 2D pattern in the first place, you can use this to convert it to a true 3D texture.

I’ll show you some variations of offset distance, refinement and element size, with exaggerated results, so you can see some of the possible effects:

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In this first example, the only change I made from the default was to increase the Texture Offset Distance from 0.010 to 0.200. The stars are extending out quite visibly.

Next, I changed Texture Refinement from 0% to 66.7%, and now you can see the stars more distinctly, with better defined edges:

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Finally, I am going to change the Element size from 0.128 to 0.180in. It made the star edges only slightly sharper, though at the expense of increasing the number of facets from about 24,000 to 26,000; for large parts and highly detailed texturing, the increased file size could slow down slicing time.

  1. To make sure these textured areas print, you have to do one more special step: Convert to Mesh Body. Do this in the Feature Manager by right-clicking on the body, and selecting the second icon in the top row, “Convert to Mesh Body.” You can adjust some of these parameters, too, but I accepted the defaults.
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  1. Lastly, Save the file in STL format, as usual.

At my company, PADT, my favorite FDM printer is our F370, so I’m going to set this up in GrabCAD Print software, to print there in ABS, at 0.005in layers:

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You can definitely see the stars popping out on the front face; too bad you can also see two weird spikes part-way up, that are small bits of a partial row of stars. That means I should have split the face before I applied the texture, so that the upper portion was left plain. Well, next time.

Here’s the finished part, with its little spikes:

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And here’s another example I did when I was first trying out a checkerboard pattern; I applied the texture to all faces, so it came out a bit interesting with the checkerboard on the top and bottom, too. Again, next time, I would be more selective to split up the model.

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NOTE: It’s clear that texturing works much better on vertical faces than horizontal, due to the nature of the FDM layering process – just be sure to orient your parts to allow for this.

For More Information on Texturing

SolidWorks offers a number of tutorials on the texturing set-up process, such as http://help.solidworks.com/2019/english/solidworks/sldworks/c_3d_textures.htm, and Shuvom Ghose at GrabCAD gives even more details about what to expect with this process in his post https://grabcad.com/tutorials/how-to-3d-texture-your-parts-for-fdm-printing-using-solidworks-2019

There will also be a general Stratasys webinar on The Benefits of 3D Printing Physical Textures on July 29 at 9am PT.

Commercial aircraft companies are already adding a pebble texture to flight-approved cosmetic FDM parts, such as covers for brackets and switches that keep them from being bumped. If you try this out, let us know what texture you chose and send us a photo of your part.

PADT Inc. is a globally recognized provider of Numerical Simulation, Product Development and 3D Printing products and services, and is an authorized reseller of Stratasys products. For more information on Stratasys printers and materials, contact us at info@padtinc.com.

The Mini-EUSO (Extreme Universe Space Observatory), now flying in the International Space Station on the Russian Zvezda module. 3D printed brackets made from Stratasys Ultem 9085 holds photo-multiplier sensors in place. (Image courtesy Italian National Institute for Nuclear Physics (INFN))

3D Printing for Space: FDM Materials on Real Missions

UV sensor section of the Mini-EUSO (Extreme Universe Space Observatory) telescope, now flying in the International Space Station on the Russian Zvezda module. The bracket to mount photo-multiplier detectors above the flat focal plane was 3D printed on a Stratasys F450 system from space-qualified Ultem 9085 filament.
 (Image courtesy Italian National Institute for Nuclear Physics (INFN))
UV sensor section of the Mini-EUSO (Extreme Universe Space Observatory) telescope, now flying in the International Space Station on the Russian Zvezda module. The bracket to mount photo-multiplier detectors above the flat focal plane was 3D printed on a Stratasys F450 system from space-qualified Ultem 9085 filament.
(Image courtesy Italian National Institute for Nuclear Physics (INFN))

What a cool time to be involved in space-based projects, from the recent, stunningly successful manned Space X launch that linked up with the International Space Station (ISS), to the phase 1, unmanned Northrop Grumman/Lockheed Martin Artemis OmegA launch planned for a Spring 2021 debut. In between these big-splash projects are the launches of hundreds of small satellites, whether a 227 kg Starlink or a 1 kg CubeSat. (According to the Space Surveillance Network of the United States Space Force, there are more than 3,000 active satellites currently in orbit.)

One common thread that runs through many of these technology achievements is the use of 3D printed polymer parts, not just as manufacturing tools and fixtures but as flight-certified, end-use components. Applications already in use include:

– Enclosures, casings and covers for bus structures, avionics and electrical systems

– Mounting/routing brackets and clips for wire harnesses

– Barrier structures that separate different on-board experiments

The number and variety of these applications may surprise you, particularly as demonstrated with Stratasys fused deposition modeling (FDM) printed parts made from one of two currently selected materials: Ultem 9085 and Antero ESD (Antero 840CN03). (Tune in for the Stratasys webinar on this topic, Thursday, July 23, at 10am CDT, Additive Manufacturing Applications and Materials for Space.)

Tough, lightweight, space-ready materials

If ever an industry needed light-weight parts, it’s the space industry. Every kilogram loaded onto a rocket demands a physics-determined, expensive amount of fuel to create the thrust that will push it against Earth’s gravity. In addition, most components are one-of-a-kind or low volume. No wonder engineers have worked for decades to replace dense metals with effective, lighter weight polymers.

Those polymers must meet stringent requirement for mechanical behavior:

  • High strength-to-weight ratio
  • Heat resistant up to 320F/167C
  • Chemically resistant to various alcohols, solvents and oils
  • Flame-retardant
  • Non-outgassing

Add to this the need to work in a form that is compatible with additive manufacturing, and the number of material options goes down. However, there are two filaments that have made the grade.

Ultem 9085 is a polyetherimide (PEI) thermoplastic developed and marketed in raw form by SABIC. Stratasys uses strict quality control to convert it into filament that runs on its largest industrial printers and also offers a certified grade that includes detailed production test-data and traceable lot numbers.

Stratasys Ultem 9085 parts have been certified and flown on aircraft since 2011 and have been key components in spacecraft beginning in 2013, such as onboard the Northrop Grumman Antares vehicles typically used for resupplying the ISS.  An unusual project that has used Ultem 9085 parts is MIT/NASA Ames Research Center’s Synchronized Position Hold, Engage, Reorient, Experimental Satellites (SPHERES). Various iterations of these colorful nano-satellites (looking like volley-ball-sized dice) have floated inside the ISS since 2006, with an initial goal of testing the algorithms and sensors required to remotely control the rendezvous and docking in weightlessness of two or more satellite-type structures.

Since then many different versions have been built and delivered to the astronauts of the ISS; both high school and college students have been heavily involved in designing experiments that test physical and mechanical properties of materials in microgravity, such as wireless power transfer. In 2014, the “Slosh” project used Ultem 9085 parts to help connect the units to investigate the behavior of fluids such as fuel sloshing between containers.

More recently, in May 2020, Italian researchers at the National Institute for Nuclear Physics (INFN) relied on Ultem 9085 to build several final parts in its ultraviolet telescope that is now operating onboard the ISS. Called the Mini-EUSO (Extreme Universe Space Observatory), this piece of equipment is one element of a multi-component/multi-year study of terrestrial and cosmic UV emissions, and is now mounted in an earth-facing window of the ISS Russian Zvezda module.

Scientists involved in the Mini-EUSO noted that 3D printing saved them a lot of time in the development and manufacturing process of custom brackets that attach photo-multiplier detectors to the top and bottom of the focal surface, permitting modifications even “late” in the design process. Their use also saved several kilograms of upload mass.

The Mini-EUSO (Extreme Universe Space Observatory), now flying in the International Space Station on the Russian Zvezda module. Upper photo: Close-up of the 3D printed Ultem 9085 brackets (in red) used to mount detector units to the top and bottom edges of the focal plane (blue/purple squares). (Image courtesy Italian National Institute for Nuclear Physics (INFN))
Left: 3D printed Ultem 9085 face-plate added to Mini-EUSO detector bracket. Right: Final unit with electronics included, installed in the complete Mini-EUSO instrument housing. (Images courtesy Italian National Institute for Nuclear Physics (INFN))

The Mini-EUSO (Extreme Universe Space Observatory), now flying in the International Space Station on the Russian Zvezda module. Upper photo: Close-up of the 3D printed Ultem 9085 brackets (in red) used to mount detector units to the top and bottom edges of the focal plane (blue/purple squares). Lower left: 3D printed face-plate added to bracket. Lower right: Final unit with electronics included, installed in the complete Mini-EUSO instrument housing. (Images courtesy Italian National Institute for Nuclear Physics (INFN))

Electrostatic Dissipative PEKK: Antero ESD

Although Ultem 9085 has proven extremely useful for many space-based applications, for certain applications even more capability is needed. The search was on for an electrostatic dissipative filament that also displayed great chemical, mechanical and flame/smoke/toxicity properties. NASA Goddard Spaceflight Center became the driving force behind Stratasys’ subsequent development of Antero ESD (Antero 840CN03), a filament based on the already successful Antero 800NA.

Both Antero products are based on polyetherketoneketone (PEKK), a high-strength, chemically resistant material; in addition, the ESD version is loaded with carbon-nanotube chopped fibers providing a moderately conductive “exit path” that naturally dissipates any charge build-up during normal operations. It also prevents powders, dust or fine particles from sticking to the surface.

NASA first flew Antero ESD parts in 2018 in the form of brackets holding fiber optic cables smoothly in place. This was inside the climate-change monitoring satellite called Ice, Cloud and land Elevation Satellite-2 (ICESat-2). The satellite was built and tested by then Northrop Grumman Innovation Systems, now part of Northrop Grumman Space Systems; the instrument itself is called the Advanced Topographic Laser Altimeter System (ATLAS), a space-based LIDAR unit. Built and managed by NASA Goddard Space Flight Center, this satellite monitors such data as changes in polar ice-sheet thickness.

A Stratasys Antero ESD (Antero 840CN03) 3D printed part (the black curved bracket holding fiber-optic cables) is shown toward the back of NASA’s Advanced Topographic Laser Altimeter System (ATLAS) instrument. This device was launched in 2018 and operates onboard the Ice, Cloud and land Elevation Satellite-2 (ICESat-2) satellite. (Image courtesy NASA)

A Stratasys Antero ESD (Antero 840CN03) 3D printed part (the black curved bracket holding fiber-optic cables) is shown toward the back of NASA’s Advanced Topographic Laser Altimeter System (ATLAS) instrument. This device was launched in 2018 and operates onboard the Ice, Cloud and land Elevation Satellite-2 (ICESat-2) satellite. (Image courtesy NASA)

Counting Down for Launch

An even bigger Antero ESD application – bigger in multiple ways – is waiting in the wings for its debut, comprising sections of the Orion module designed and built by Lockheed Martin Space Systems. This spacecraft will eventually carry astronauts to the Moon and beyond as part of NASA’s Artemis program, with the first un-crewed, lunar-orbit launch scheduled for Spring 2021.

The Orion craft’s docking hatch cover is made entirely from sections printed in Antero ESD. Six pie-shaped sub-sections with intricate curves and cut-outs fit together forming a one-meter diameter ring with a central hole. (If Ultem 9085 had been used, the parts would have needed a secondary coating or nickel-plating to deflect static charge, making the Antero ESD option very attractive.)

Ready, set, print, launch!

Overall view and close-up of Orion spacecraft six-piece hatch cover, 3D printed in Stratasys Antero 840CN03, a carbon-nanotube-fiber filled PEKK thermoplastic with ESD properties. The complete cover diameter is approximately one meter. (Image courtesy Lockheed Martin Space Systems)

Overall view and close-up of Orion spacecraft six-piece hatch cover, 3D printed in Stratasys Antero 840CN03, a carbon-nanotube-fiber filled PEKK thermoplastic with ESD properties. The complete cover diameter is approximately one meter. (Image courtesy Lockheed Martin Space Systems)

PADT Inc. is a globally recognized provider of Numerical Simulation, Product Development and 3D Printing products and services, and is an authorized reseller of Stratasys products. For more information on Stratasys printers and materials, contact us at info@padtinc.com.

Top Ten Additive Manufacturing Terms to Know

The world of additive manufacturing, or 3D printing, is constantly evolving. The technology was invented less than 35 years ago yet has come a long way. What began as a unique, though limited, way to develop low-end prototypes, has exploded into a critical component of the product development and manufacturing process with the ability to produce end-use parts for critical applications in markets such as industrial and aerospace and defense.

To help our customers and the larger technology community stay abreast of the changing world of additive manufacturing, we launched a glossary of the most important terms in the industry that you can bookmark here for easy access. To make it easier to digest, we’re also starting a blog series outlining ten terms to know in different sub-categories.

For our first post in the series, here are the top ten terms for Additive Manufacturing Processes that our experts think everyone should know:

Binder Jetting

Any additive manufacturing process that uses a binder to chemically bond powder where the binder is placed on the top layer of powder through small jets, usually using inkjet technology. One of the seven standard categories defined by ASTM International (www.ASTM.org) for additive manufacturing processes.

Digital Light Synthesis (DLS)

A type of vat photopolymerization additive manufacturing process where a projector under a transparent build plate shines ultraviolet light onto the build layer, which is against the transparent build plate. The part is then pulled upward so that a new layer of liquid fills between the build plate and the part, and the process is repeated. Digital light synthesis is a continuous build process that does not create distinct layers.

Direct Laser Melting (DLM) or Direct Metal Laser Sintering (DMLS)

A type of powder bed fusion additive manufacturing process where a laser beam is used to melt powder material. The beam is directed across the top layer of powder. The liquid material solidifies to create the desired part. A new layer of powder is placed on top, and the process is repeated. Also called laser powder bed fusion, metal powder bed fusion, or direct metal laser sintering.

Directed Energy Deposition (DED)

An additive manufacturing process where metal powder is jetted, or wire is extruded from a CNC controlled three or five-axis nozzle. The solid material is then melted by an energy source, usually a laser or electron beam, such that the liquid metal deposits onto the previous layers (or build plate) and then cools to a solid. One of the ASTM defined standard categories for additive manufacturing processes.

Fused Deposition Modeling (FDM)

A type of material extrusion additive manufacturing process where a continuous filament of thermoplastic material is fed into a heated extruder and deposited on the current build layer. It is the trademarked name used for systems manufactured by the process inventor, Stratasys. Fused filament fabrication is the generic term.

Laser Powder Bed Fusion (L-PBF)

A type of powder bed fusion additive manufacturing process where a laser is used to melt material on the top layer of a powder bed. Also called metal powder bed fusion or direct laser melting. Most often used to melt metal powder but is used with plastics as with selective laser sintering.

Laser Engineered Net Shaping (LENS)

A type of direct energy deposition additive manufacturing process where a powder is directed into a high-energy laser beam and melted before it is deposited on the build layer. Also called laser powder forming.

Material Jetting

Any additive manufacturing process where build or support material is jetted through multiple small nozzles whose position is computer controlled to lay down material to create a layer. One of the ASTM defined standard categories for additive manufacturing processes.

Stereolithography Apparatus (SLA)

A type of vat photopolymerization additive manufacturing where a laser is used to draw a path on the current layer, converting the liquid polymer into a solid. Stereolithography was the first commercially available additive manufacturing process.

Vat Polymerization

A class of additive manufacturing processes that utilizes the hardening of a photopolymer with ultraviolet light. A vat of liquid is filled with liquid photopolymer resin, and ultraviolet light is either traced on the build surface or projected on it. Stereolithography is the most common form of vat photopolymerization. The build layer can be on the top of the vat of liquid or the bottom. One of the ASTM defined standard categories for additive manufacturing processes.

We hope this new blog series will help to firm up your knowledge of the ever-evolving world of additive manufacturing. For a list of all of the key terms and definitions in the additive manufacturing world, please visit our new glossary page at https://www.3dprinting-glossary.com/. The glossary allows you to search by terms or download a PDF of the glossary in its entirety to use as a reference guide.

We also know that there are a ton of experts in our community with knowledge to share. If you notice a term missing from our glossary or an inaccurate/incomplete description, please visit the suggestions page at https://www.3dprinting-glossary.com/suggest-a-correction-clarification-or-new-term/ and drop us a note.

Subscribe to the PADT blog or check back soon for the next installment in our series of “Top Ten Terms to Know in Additive Manufacturing.” We also welcome your feedback or questions. Just drop us a line at here.

Example of full color part with mapped image, created from 3MF file format brought into GrabCAD Print and printed on a Stratasys PolyJet 3D printer. (Image courtesy GrabCAD)

3MF Printing Format Comes to GrabCAD Print

Example of full color part with mapped image, created from 3MF file format brought into GrabCAD Print and printed on a Stratasys PolyJet 3D printer. (Image courtesy GrabCAD)

Example of full color part with mapped image, created from a 3MF file-format brought into GrabCAD Print and set up to print on a Stratasys PolyJet 3D printer. (Image courtesy GrabCAD)

What is the 3MF format? How does it differ from the standard STL format? And what can you do with it, especially if your 3D printers run GrabCAD Print software from Stratasys?

For most designers, engineers and users involved in 3D printing, regardless of the 3D CAD software you use, you save (convert) your model to print as an STL format file. A lot has been written about it, including a PADT post from back in 2012 – and STL-wise, things really haven’t changed. This format approximates the native CAD solid model as a closed surface comprising small triangles of various shapes and sizes. STL has been the standard since the AM industry began, and although different CAD packages use different algorithms to create the mesh, for the most part, it’s worked pretty well.

A Sample STL File Segment

However, an STL file is simply a large text file listing the Cartesian coordinates for each vertex of the thousands of triangles, along with info on the normal direction:

Sample code from saving a CAD model in STL format.

A modest number of large triangles produces relatively small files but doesn’t do a good job of reproducing curves (think highly faceted surfaces); conversely, big files of many small triangles produce much smoother transitions but can take a long time to process in slicing software.

And, perhaps the biggest negative is that an STL file cannot include any other information: desired color, desired material, transparency, internal density gradient, internal fine structure or more.

What is 3MF?

In early 2015, Microsoft and a number of other major corporations including Autodesk, Dassault Systèmes, HP, Shapeways and SLM Group created a consortium to address these issues. They decided to overhaul a little-used file format called the 3D Modeling Format (3MF), to make it support highly detailed 3D model information and be more useful for 3D printing and related processes.

Logo 3MF Consortium

This ongoing consortium project defines 3MF as “a set of conventions for using XML to describe the appearance and structure of 3D models for the purpose of manufacturing (3D printing).”

In developer language, 3MF is a standard package or data that follows a core specification and may include some task-specific extensions.

In user terms, a 3MF file contains some or all of the following information in ASCII format:

  • Metadata about part name, creator and date
  • Information on the mesh of triangles (yes, it still creates and uses these, but does it better for a number of reasons, one of which is that it cannot create non-manifold edges (i.e., triangles that share endpoints with more than one triangle, which confuses the printer))
  • Color information (throughout the complete part body or in sub-sections)
  • Ways to define multiple materials combined as a composite
  • Texture information – what it is and where to place it
  • Ways to assign different materials to different sections of a part
  • Ways to duplicate information from one section of a part to another section, to save memory
  • Slicing instructions

Without getting into the nitty gritty, here are just two examples of XML code lines from 3MF metadata sections:

Example code of saving a solid CAD model in 3MF format.

Meaning, information about the part number and the part color rides along with the vertex coordinates! For a deep-dive into the coding schema, including a helpful glossary, see the 3MF github site; to learn how 3MF compares to STL, OBJ, AMF, STEP and other formats, check out the consortium’s About Us page.

Exporting 3MF Files

Now, how about using all of this? Where to start? Many 3D CAD software packages now let you save solid models as 3MF files (check out your “Save As” drop-down menu to verify), but again, they can vary as to what information is being saved. For example, a SolidWorks 3MF file can generate data on color and material but does not yet support transparency.

Here are all the options that you see in SolidWorks when you click the arrow next to “Save As”:

Second step in SolidWorks for saving a file in 3MF format: check off “include materials” and “include appearance.” (Image courtesy PADT)

“Save As” window in SolidWorks 2019, where step number one is to select “.3mf” format. (Image courtesy PADT)

You can select “.3mf” but don’t Save yet. First, click on the “Options” button that shows up below the Save as File Type line, opening this window:


Second step in SolidWorks for saving a file in 3MF format: check off “include materials” and “include appearance.” (Image courtesy PADT)

You need to check the boxes for “Include Materials” and “Include Appearances” to ensure that all that great information you specified in the solid model gets written to the converted file. A good, short tutorial can be found here.

Another interesting aspect of 3MF files is that they are zipped internally, and therefore smaller than STL files. Look at the difference in file size between the two formats when this ASA Omega Clip part is saved both ways:

Comparison of file size for STL versus 3MF formats.

The 3MF-saved file size is just 13% the size of the standard STL file, which may be significant for file manipulation; for files with a lot of detail such as texture information, the difference won’t be as great, but you can still expect to save 30 to 50%.

Working with 3MF files in GrabCAD Print

Okay, so CAD programs export files in 3MF format. The other half of the story addresses the question: how does a 3D printer import and use a 3MF file? Developers of 3D printing systems follow these same consortium specifications to define how their software will set up a 3MF file to print. Some slicers and equipment already act upon some of the expanded build information, while others may accept the file but still treat it the same as an STL (no additional functions enabled so it ignores the extra data). What matters is whether the system is itself capable of printing with multiple materials or depositing material in a way that adds color, texture, transparency or a variation in internal geometry.

GrabCAD Print (GCP), the cloud-connected 3D Printer interface for today’s Stratasys printers – both FDM and PolyJet – has always supported STL and native CAD file import. However, in GCP v.1.40, released in March 2020, GrabCAD has added support for 3MF files. For files created by SolidWorks software, this adds the ability to specify face colors, body colors and textures and send all that data in one file to a PolyJet multi-material, multi-color 3D printer. (Stratasys FDM printers accept 3MF geometry and assembly structure information.)

For a great tutorial about setting up SolidWorks models with applied appearances and sending their 3MF files to GrabCAD Print, check out these step-by-step directions from Shuvom Ghose.

Example of setting up a textured part in SolidWorks, then saving the file in 3MF format and importing it into GrabCAD Print, for printing on a full-color Stratasys PolyJet printer. (Image courtesy GrabCAD)

Example of setting up a textured part in SolidWorks, then saving the file in 3MF format and importing it into GrabCAD Print, for printing on a full-color Stratasys PolyJet printer. (Image courtesy GrabCAD)

At PADT, we’re starting to learn the nuances of working with 3MF files and will be sharing more examples soon. In the meantime, we suggest you download your own free copy of GrabCAD Print to check out the new capabilities, then email or call us to learn more.

PADT Inc. is a globally recognized provider of Numerical Simulation, Product Development and 3D Printing products and services. For more information on Stratasys printers and materials, contact us at info@padtinc.com.

Varied Infill Options for CAD models brought into GrabCAD Print software for 3D Printing. (Image courtesy PADT)

GrabCAD Print Software, Part Two: Simplify Set-ups, Save Time, and Do Cool Stuff You Hadn’t Even Considered

(Edited 3 August 2020 to reflect GrabCAD Print V1.44)

You haven’t really lived in the world of 3D printing until you’ve had a part fail spectacularly due to open faces, self-intersecting faces or inverted normals. Your part ends up looking more like modern art than technical part. Or perhaps the design you have in mind has great geometry but you wish that some parts could have regions that are dense and strong while other regions would work with minimal infill.

In Part One of this blog post about GrabCAD Print software, we covered the basics of setting up and printing a part; now we’ll look at several of the advanced features that save you set-up time and result in better parts.

Behind the Scenes Repairs

Stratasys GrabCAD Print software, available as a free download, is crafted for users setting up solid models for 3D printing on Stratasys FDM and PolyJet printers. Once you’ve started using it, you’ll find one of its many useful advanced features is the automated STL file-repair option.

Imported STL file, with GrabCAD Print ready to automatically repair errors. PADT image.

Most people still create solid models in CAD software then convert the file to the industry-standard STL format before opening it in a given 3D printer’s own set-up software. Every CAD package works a little differently to generate an STL file, and once in a while the geometry just doesn’t get perfectly meshed. Triangles may overlap, triangles may end up very long and very skinny, or the vector that signals “point in” or “point out” can get reversed.

Traditionally, the 3D printer set-up program reacts to these situations by doing one of two things: it prints exactly what you tell it to print (producing weird holes and shifted layers) or it simply refuses to print at all. Both situations are due to tiny errors in the conversion of a solid CAD model to a tessellated surface.

GrabCAD Print, however, gives your file a once-over and immediately flags sections of the model in need of repair. You can see a color-coded representation of all the problem areas, choose to view just some or all, and then click on Automatic Repair. No hand-editing, no counting layers and identifying sections where the problems reside – just a click of the virtual button and all the problem regions are identified, repaired and ready for the next processing steps.

CAD vs. STL: Do So Much More with CAD

GrabCAD Print also uniquely allows users to bring in their models in the original CAD file-format (from SolidWorks, Autodesk, PTC, Siemens, etc.) or neutral formats, with no need to first convert it to STL. For FDM users, this means GrabCAD recognizes actual CAD bodies, faces, and features, letting you make build-modifications directly in the print set-up stage that previously would have required layer-by-layer slice editing, or couldn’t have been done at all.

For example, with a little planning ahead, you can bring in a multi-body CAD model (i.e., an assembly), assemble and group the parts, then direct GrabCAD to apply different parameters to each body. This way you can reinforce some areas at full density then change the infill pattern, layout, and density in other regions where full strength is unnecessary.

Here’s an example of a SolidWorks model intended for printing with a solid lower base but lighter weight (saving material) in the upper sections. It’s a holder for Post-It® notes, comprising three individual parts – lower base, upper base and upper slot – combined and saved as an assembly.

Sample multi-body part ready to bring into GrabCAD Advanced FDM. Image PADT.

Sample multi-body part ready to bring into GrabCAD Advanced FDM. Image PADT.

Here was my workflow:

1 – I brought the SolidWorks assembly into GrabCAD, assembled and grouped all the bodies, selected an F370 Stratasys FDM printer, chose Print Settings of acrylonitrile butadiene styrene (ABS) and 0.010 inches layer height, and oriented the part.

2 -To ensure strength in the lower base, I selected just that section (you can do this either in the model tree or on the part itself) and opened the Model Settings menu at the right. Under Body, I chose Solid Infill.

3 – Next I selected the upper base, chose Hexagram, and changed the Infill Density to 60%.

4 – Lastly, I selected the upper slot section, chose Sparse, and changed the Infill Density to 35%.

5 – With all three sections defined, I clicked on Slice Preview, sliced the model and used the slider bar on the left to step through each section’s toolpath. For the screenshots, I turned off showing Support Material; the yellow bits indicate where seams start (another parameter that can be edited).

Here is each section highlighted, with screenshots of the parameter choices and how the part infill looks when sliced:

Upper base set up in GrabCAD to print as Hexagram pattern, 60% infill; sliced toolpath shown at right. Image PADT.
Upper slot section set up in GrabCAD to print as Sparse pattern, 35% infill; sliced toolpath shown at right. Image PADT.

So that you can really see the differences, I printed the part four times, stopping as the infill got partway through each section, then letting the final part print to completion. Here are the three partial sections, plus my final part:

Lower base (solid), upper base (hexagram) and first part of upper slot (sparse), done as partial prints. Image PADT.
Completed note-holder set up in GrabCAD Print, Advanced FDM mode, weighted toward the bottom but light-weighted internally. Image PADT.
Completed note-holder set up in GrabCAD Print using advanced infill features, weighted toward the bottom but light-weighted internally. Image PADT.

Automated Hole Sizing Simplifies Adding Inserts

But like the old advertisements say, “But wait – there’s more!” Do you use heat-set inserts a lot to create secure connections between 3D printed parts and metal hardware? Planning ahead for the right hole size, especially if you have different design groups involved and fasteners may not yet be decided, this is the feature for you.

Sample part set up for easy insert additions, using Advanced FDM in GrabCAD Print. Image PADT.

Sample part set up for easy insert additions, using advanced, automated hole-resizing features in GrabCAD Print. Image PADT.

In your CAD part model, draw a hole that is centered where you know the insert will go, give it a nominal diameter and use Cut/Extrude so that the hole is at least the depth of your longest candidate insert. Save the file in regular CAD format, not STL. Next bring your part into GrabCAD Print and go to Model Settings in the right-hand menu.

This time, click on Face (not Body) and Select the inner cylindrical wall of your hole. Several options will become active, including Apply Insert. When you check that box, a new drop-down will appear, giving you the choice of adding a heat-set insert, a helicoil insert or creating a custom size. Below that you select either Inch or Metric, and for either, the appropriate list of standard insert sizes appears.

Automatic hole-resizing in GrabCAD Print, for a specific, standard heat-set insert. Image PADT.

Choose the insert you want, click Update in the upper middle of the GrabCAD screen, and you’ll see the hole-size immediately changed (larger or smaller as needed). The new diameter will match the required oversized dimensions for the correct (melted into place) part-fit. You can even do this in a sidewall! (For tips on putting inserts into FDM parts, particularly with a soldering iron, see Adding Inserts to 3D Printed Parts: Hardware Tips.)

Note that this way, you can print the overall part with a sparse infill, yet reinforce the area around the insert to create just the right mass to make a solid connection. The Sliced view will show the extra contours added around each hole.

Sliced view showing insert holes with reinforced walls, done in GrabCAD Print. Image PADT.
Manufacturing notes automatically created in GrabCAD Print when insert holes are resized. Image PADT.

To document the selected choices for whoever will be doing the insert assembly, GrabCAD also generates a numbered, manufacturing-footnote that lists each insert’s size; this information can be exported as a PDF file that includes a separate close-up image of each insert’s location.

GrabCAD Print keeps adding very useful functions. Download it for free and try it out with template versions of the various Stratasys 3D printers, then email or call us to learn more.

PADT Inc. is a globally recognized provider of Numerical Simulation, Product Development and 3D Printing products and services. For more information on Stratasys printers and materials, contact us at info@padtinc.com.

GrabCAD Print Software: Part One, an Introduction

Where are you on your New Year’s resolutions? They often include words such as “simplify,” “organize” and “streamline.” They can be timely reminders to rethink how you do things in both your personal and professional lives, so why not rethink the software you use in 3D Printing?

Preparing a CAD solid model or an STL file to print on a 3D printer requires using set-up software that is typically unique to each printer’s manufacturer. For Flashforge equipment, you use FlashPrint, for Makerbot systems you use MakerBot Print, for Formlabs printers you use PreForm, and so on.

GrabCAD Print software for setting up STL or CAD files to print on Stratasys 3D printers (main screen).
GrabCAD Print software for setting up STL or CAD files to print on Stratasys 3D printers (main screen). Image courtesy PADT.

For printers from industrial 3D printing company Stratasys, the go-to software is GrabCAD Print (along with GrabCAD Print Mobile), developed for setting up both fused deposition modeling (FDM) and PolyJet technologies in new and efficient ways. Often just called GrabCAD, this versatile software package lets you organize and control prints assigned to one of more than 30 printer models, so the steps you learn for one printer transfer directly over to working with other models.

If you’ve previously used Stratasys Catalyst (on Dimension and uPrint printers), you’ll find similarities with GrabCAD, as well as some enhanced functionality. If you’re accustomed to the fine details of Stratasys Insight, you’ll see that GrabCAD provides similar capabilities in a streamlined interface, plus powerful new features made possible only by the direct import of native CAD files.  Additionally, you can access Insight within GrabCAD, combining the best of both traditional and next-generation possibilities.

Simple by Default, Powerful by Choice

GrabCAD lets users select simplified default settings throughout, with more sophisticated options available at every turn. Here are the general steps for print-file preparation, done on your desktop, laptop or mobile device:

1 – Add Models: Click-and-drag files or open them from File Explorer. All standard CAD formats are supported, including SolidWorks, Autodesk, Siemens and PTC, as well as STL. You can also bring in assemblies of parts and multi-body models, choosing whether to print them assembled or not. (Later we’ll also talk about what you can do with a CAD file that you can’t do with an STL.)

2 – Select Printer: Choose from a drop-down menu to find whatever printer(s) is networked to your computer. You can also experiment using templates for printers you don’t yet own, in order to compare build volumes and print times.

3 – Orient/Rotate/Scale Model: Icons along the right panel guide you through placing your model or models on the build platform, letting you rotate them around each axis, choose a face to orient as desired, and scale the part up or down. You can also right-click to copy and paste multiple models, then edit each one separately, move them around, and delete them as desired.

4 – Tray Settings: This icon leads to the menu with choices such as available materials, slice height options, build style (normal or draft), and more; always targeted to the selected printer. These choices apply to all the parts on the tray or build sheet.

5 – Model Settings: Here’s where you choose infill style, infill density (via slider bar), infill angle, and body thickness (also known as shell thickness) per part. Each part can have different choices.

6 – Support Settings: These all have defaults, so you don’t even have to consider them if you don’t have special needs (but it’s where, for example, you would change the self-supporting angle).

7 – Show Slice Preview: Clicking this icon slices the model and gives you the choice to view layers/tool paths individually, watch a video animation, or even set a Z-height pause if you plan on changing filament color or adding embedded hardware.

8 – Print: You’re ready to hit the Print button, sending the prepared file to the printer’s queue.

Scheduling Your Print, and Tracking Print Progress

A clock-like icon on the left-side GrabCAD panel (the second one down, or third if you’ve activated Advanced FDM features) switches the view to the Scheduler. In this mode, you can see a day/time tracking bar for every printer on the network. All prints are queued in the order sent, and the visuals make it easy to see when one will finish and another start (assuming human intervention for machine set-up and part removal, of course).

Scheduling panel in GrabCAD Print, showing status of files printing on multiple 3D printers.
Scheduling panel in GrabCAD Print, showing status of files printing on multiple 3D printers. Image courtesy PADT.

If you click on the bar representing a part being built, a new panel slides in from the right with detailed information about material type, support type, start time, expected finish time and total material used (cubic inches or grams). For printers with an on-board camera, you can even get an updated snapshot of the part as it’s building in the chamber.

Below the Scheduler icon is the History button. This is a great tool for creating weekly, monthly or yearly reports of printer run-time and material consumption, again for each printer on the network. Within a given build, you’ll even see the files names of the individual parts within that job.

Separately, if you’re not operating the software offline (an option that some companies require), you can enable GrabCAD Print Reports. This function generates detailed graphs and summaries covering printer utilization and overall material use across multiple printers and time periods – very powerful information for groups that need to track efficiencies and expenditures.

And That’s Just the Beginning

Once you decide to experiment with these settings, you begin to see the power of GrabCAD Print for FDM systems. We haven’t even touched on the automated repairs for STL files, PolyJet’s possibilities for colors, transparency and blended materials, or the options for setting up a CAD model so that sub-sections print with different properties.

For example, you’ll see how planning ahead allows you to bring in a multi-body CAD model and have GrabCAD identify and reinforce some areas at full density, while changing the infill pattern, layout, and density in other regions. GrabCAD recognizes actual CAD bodies and faces, letting you make build-modifications that previously would have required layer-by-layer slice editing, or couldn’t have been done at all.

Stay tuned for our next blog post, GrabCAD Print Software, Part Two: Simplify Set-ups, Save Time, and Do Cool Stuff You Hadn’t Even Considered, and reach out to us to learn more about downloading and using GrabCAD Print.

PADT Inc. is a globally recognized provider of Numerical Simulation, Product Development and 3D Printing products and services. For more information on Stratasys printers and materials, contact us at info@padtinc.com.

Books on Additive Manufacturing Make the Perfect Holiday Gift, of Course

It took a while for books about Additive Manufacturing to catch up with the industry; now there are at least several dozen from which to choose.
It took a while for books about Additive Manufacturing to catch up with the industry; now there are at least several dozen from which to choose.

Much as we all love and use websites, YouTube videos and blog posts (you’re reading this one, right?), there are still times when there’s nothing like a book, even if you read it on your phone or dedicated device. Books provide data, perspective and pointers to other resources, in a convenient, all-in-one format. You can dive deeply into a subject or get a fascinating overview of topics you may never have known were connected.

For the AM-lover on your holiday shopping list, consider one of the following titles:

3D Printing: Understanding Additive Manufacturing

by Andreas Gebhardt, Julia Kessler, Laura Thurn | Dec. 2018

3D Printing and Additive Manufacturing: Principles and Applications – Fifth Edition of Rapid Prototyping

by Chee Kai Chua and Kah Fai Leong | Nov. 2016

The 3D Printing Handbook: Technologies, design and applications

by Ben Redwood , Filemon Schöffer , et al. | Nov. 2017

Additive Manufacturing (Second Edition)

by Amit Bandyopadhyay (editor) and Susmita Bose (editor) | Oct. 2019

Additive Manufacturing: Applications and Innovations (Manufacturing Design and Technology)

by Rupinder Singh and J. Paulo Davim | Aug. 2018

Additive Manufacturing Change Management: Best Practices (Continuous Improvement Series)

by David M. Dietrich, Michael Kenworthy, Elizabeth A. Cudney | Feb. 2019

Additive Manufacturing: Design, Methods, and Processes

by Steinar Westhrin Killi | Aug. 2017

Additive Manufacturing for the Aerospace Industry

by Francis H. Froes Ph.D. (editor), Rodney Boyer (editor) | Feb. 2019

Additive Manufacturing: Materials, Processes, Quantifications and Applications

by Jing Zhang and Yeon-Gil Jung | May 2018

Additive Manufacturing of Emerging Materials

by Bandar AlMangour (editor) | Aug. 2018

Additive Manufacturing of Metals: From Fundamental Technology to Rocket Nozzles, Medical Implants, and Custom Jewelry (Springer Series in Materials Science)

by John O. Milewski | July 2017

Additive Manufacturing of Metals: The Technology, Materials, Design and Production (Springer Series in Advanced Manufacturing)

by Li Yang, Keng Hsu, Brian Baughman, Donald Godfrey, Francisco Medina (Author), Mamballykalathil Menon, Soeren Wiener | May 2017

Additive Manufacturing Technologies: 3D Printing, Rapid Prototyping, and Direct Digital Manufacturing (2015 Edition)

by Ian Gibson (Author), David Rosen (Author), Brent Stucker (Author) | Nov. 2014

NOTE: this was the first book written about the field that I could find, with its first edition in 2009. (If you know of one pre-2009, I’d be interested to hear about it.) SME uses this book as the reference guide for its Certification exams for AM Fundamentals and AM Technicians.

Design for Additive Manufacturing: Tools and Optimization (Additive Manufacturing Materials and Technologies)

By Martin Leary | Nov. 2019

Design for Additive Manufacturing: Guidelines for cost effective manufacturing

by Tom Page | Jan. 2012

Design, Representations, and Processing for Additive Manufacturing (Synthesis Lectures on Visual Computing: Computer Graphics, Animation, Computational Photography, and Imaging)

by Marco Attene, Marco Livesu, et al. | June 2018

Laser-Based Additive Manufacturing of Metal Parts: Modeling, Optimization, and Control of Mechanical Properties (Advanced and Additive Manufacturing Series)

by Linkan Bian (editor), Nima Shamsaei (editor), John Usher (editor) | Aug. 2017

Laser Additive Manufacturing: Materials, Design, Technologies, and Applications (Woodhead Publishing Series in Electronic and Optical Materials Book 88)

by Milan Brandt (editor) | Sept. 2016

Laser Additive Manufacturing of High-Performance Materials

by Dongdong Gu | Apr. 2015

The Management of Additive Manufacturing: Enhancing Business Value (Springer Series in Advanced Manufacturing 2018)

by Mojtaba Khorram Niaki, Fabio Nonino | Dec. 2017

Thermo-Mechanical Modeling of Additive Manufacturing

by Michael Gouge and Pan Michaleris | Sept. 2017

Other books definitely exist that have more of a hobbyist focus. This list comes from my own research and opinions and is not intended to slight any other titles. I’d be interested in expanding the list if you know of other titles with an industrial AM slant.

Happy Holiday reading!

Stratasys 3D Printing Filament: the Quality Behind OEM Sourcing

In 1925, when the automotive industry was rapidly growing in response to consumer and industrial needs, a group of independent auto parts resellers joined to form the National Automotive Parts Association (NAPA). A founding member was the Genuine Parts Company; this group later acquired a number of other NAPA stores and gave rise to ad campaigns stressing the importance of buying genuine auto parts from a well-known, trusted source.

Stratasys 3D printing filament is crafted to stringent standards, ensuring dimensional consistency and repeatable material properties. Image courtesy PADT.
Stratasys 3D printing filament is crafted to stringent standards, ensuring dimensional consistency and repeatable material properties. Image courtesy PADT.

Following that same philosophy is a good idea for users involved with industrial 3D printing (additive manufacturing/AM). How do you know your part will print consistently, and display measureable, repeatable material properties, if you can’t rely on the consistency of the AM material’s own production?

At PADT, we print the gamut of filament options on our Stratasys industrial 3D printers, from ABS and TPU to production-grade Nylons and certified Ultem ® . As both an authorized AM system reseller and service provider, we count on the quality of the materials we source for ourselves and our customers, so it’s enlightening to get a behind-the-scenes look at the Stratasys filament production-process.

Ingredients Matter

Great recipes start with the finest ingredients, right? It’s no different when you’re producing filament for demanding applications: start with qualified raw materials from reputable sources. Standard Stratasys filament (like ASA and ABS), Engineering Grade materials (including polycarbonate and Nylon 12) and most Support materials are made in Israel at one of the two Stratasys corporate offices, while the High Performance materials such as Nylon 12 Carbon-Fiber (CF), Antero and Ultem ® products are produced at the original Minnesota location.

The raw stock for 3D printing filament comes in pellet form. Image courtesy Shutterstock.
The raw stock for 3D printing filament comes in pellet form. Image courtesy Shutterstock.

Stratasys buys polymers in pellet form from chemical suppliers such as France-based Arkema, who blends the proprietary polyethyl ketone ketone (PEKK) base formula for Antero and Antero ESD materials, and SABIC who supplies the raw pellets for Ultem ® -based filaments.

Some pellets are fed directly into the filament production equipment while others are compounded like a custom pharmaceutical: mixed and blended with stabilizers and colorants, extruded as interim-stage filament, cooled and then granulated all over again into new pellet stock. (Given that FDM is an extrusion-based technology, one of the seven standard AM technologies defined by ISO/ASTM52900-15, it’s interesting that extrusion plays a key role in the material production-process itself.)

Polymer Pasta

Whether you’ve made your own fresh pasta or just watched a child crank out endless strings of PlayDoh, you can envision the next steps in filament production, starting with melting the pellets into a viscous liquid resin. Chaffee Tran, Stratasys’ Materials Product Director, explains, “Resin is (then) run through a screw extruder and forced through a die (metal perforated with precision holes), cooled as it comes out, and wound onto spools.” An optical monitor continuously checks for “ovality” of the filament as it moves past, and triggers a stop for anything out-of-round beyond tolerance. If you’ve ever struggled with a printer that jammed because of inconsistent filament diameters, you’ll understand the importance of this process requirement.

Loading bays for Stratasys F370 office-environment FDM 3D Printer. Image courtesy Stratasys.
Loading bays for Stratasys F370 office-environment FDM 3D Printer. Image courtesy Stratasys.

Filament for the Stratasys F123 plug-and-play series of printers is packaged on-site as bagged or boxed spools. Filament for the industrial printers such as the F380cf, F450 and F900 gets loaded into sealed canisters that hold larger volumes in both standard and extended capacity. For all filament types, Tran says, “We have full traceability of our finished products via serial number and manufacturing lots. This can be traced back to production documents, to link back to the production-line settings and batch lots of resin used.”

Canister of Stratasys Ultem® 9085 filament, with production documentation for traceability. Image courtesy Stratasys.

One Step Beyond: Certification

For truly demanding applications, the quality process gets kicked up another notch. Ultem ® 9085 Aerospace and Ultem ® 1010 Certified Grade (CG) are shipped with Certificates of Compliance that confirm the production parameters down to the exact machine type and location where the filament is manufactured. “Certified Ultem ® has a higher sampling rate of finished goods for various filament properties and tighter internal specification,” adds Tran.

This tightly regulated process allows Stratasys to be the only AM company offering material certified by the Aircraft Interior Solution (AIS), a process – developed in collaboration with the National Center for Advanced Materials Performance (NCAMP) – that provides the necessary tools, documentation, and training needed to guide aerospace producers down the aircraft qualification process. In order to meet the requirements aerospace manufacturers face, their parts must not only be made from the AIS certified version of the Stratasys Ultem ® 9085 material, but must also be printed on a certified F900mc Gen II system, in accordance with a string of aerospace standards documents. (For more information see details provided by NCAMP.) That’s what you call Quality Control.

For historical details about the development of standards for qualifying non-metallic materials for aircraft applications, now including the first polymer AM material, download this nine-page document, A Path to Certification:

Today's aircraft increasingly rely on non-metallic component design to save on weight and therefore fuel consumption. Certified Ultem 9085® filament from Stratasys plays a key role in supporting the design and use of 3D printed flight-qualified parts. Image courtesy Stratasys.
Today’s aircraft increasingly rely on non-metallic component design to save on weight and therefore fuel consumption. Certified Ultem 9085® filament from Stratasys plays a key role in supporting the design and use of 3D printed flight-qualified parts. Image courtesy Stratasys.

Even if your part production process is not as stringent as that demanded for the AIS program, you’ll avoid jammed drive-gears and cross-wound spools and get consistent part performance when your Stratasys printers run “genuine Stratasys” filament. Classic ABS, chemically resistant Antero, flexible TPU and new, fine-finish Diran are just some of the materials that will offer you repeatable results. Ask us for more details, and stay tuned as Stratasys launches even more options for true industrial applications.

PADT Inc. is a globally recognized provider of Numerical Simulation, Product Development and 3D Printing products and services. For more information on Stratasys printers and filaments, contact us at info@padtinc.com.

New Options for 3D Printing with Nylon Filament, Including Diran

NOTE 10/28/2019: See updated information regarding Diran extruder heads, below.

Does the idea of 3D printing parts in semi-aromatic polyamides (PA) sound intriguing? Too bad it has nothing to do with making nicely scented models – but it has everything to do with reaping the benefits of the Nylon family’s molecular ring structure. Nylon 6, Nylon 12, carbon-filled Nylon 12 and now a new, smoother Nylon material called Diran each offer material properties well-suited for additive manufacturing on industrial 3D printers. Have you tried Holden’s Screen Supply? It has the emulsions and reclaimers needed for screen printing. To get more information about 3D printers, Go through PrtWd.com website.

Stratasys Nylon 12 Battery Box
3D printed Nylon 12 Battery Box. (Image courtesy Stratasys)

Quick chemistry lesson: in polyamides, amine sub-groups containing nitrogen link up with carbon, oxygen and hydrogen in a ring structure; most end up with a strongly connected, semi-crystalline layout that is key to their desirable behaviors. The number of carbon atoms per molecule is one way in which various Nylons (poly-amines) differentiate themselves, and gives rise to the naming process.

Now on to the good stuff. PA thermoplastics are known for strength, abrasion-resistance and chemical stability – useful material properties that have been exploited since Nylon’s discovery at Du Pont in 1935. The first commercial Nylon application came in 1938, when Dr. West’s Miracle Tuft Toothbrush closed the book on boar’s-hair bristle use and let humans gently brush their teeth with Nylon 6 (then called “Exton”) fibers.

Today’s Nylon characteristics translate well to filament-form for printing with Stratasys Fused Deposition Modeling (FDM) production-grade systems. Here’s a look at properties and typical applications for Nylon 6, Nylon 12, Nylon 12 CF (carbon-fiber filled) and Diran (the newest in the Stratasys Nylon material family), as we see their use here at PADT.

When Flexibility Counts

Nylon 12 became the first Stratasys PA offering, filling a need for customized parts with high fatigue resistance, strong chemical resistance, and just enough “give” to support press (friction-fit) inserts and repetitive snap-fit closures. Users in aerospace, automotive and consumer-goods industries print Nylon 12 parts for everything from tooling, jigs and fixtures to container covers, side-panels and high vibration-load components.

3D Printed Nylon 12 bending example. (Image courtesy Stratasys)
3D Printed Nylon 12 bending example. (Image courtesy Stratasys)

Nylon 12 is the workhorse of the manufacturing world, supporting distortion without breaking and demonstrating a high elongation at break. Its ultimate tensile strength in XZ part orientation (the strongest orientation) is 6,650 psi (46 MPa), while elongation at break is 30 percent. Users can load Nylon 12 filament onto a Stratasys Fortus 380mc CF, 450mc or 900mc system.

As evidenced by the toothbrush renaissance, Nylon 6 has been a popular thermoplastic for more than 80 years. Combining very high strength with toughness, Nylon 6 is great for snap-fit parts (middle range of flexing/stiffness) and for impact resistance; it is commonly used for things that need to be assembled, offering a clean surface finish for part mating.

Nylon 6 displays an XZ ultimate tensile strength of 9,800 psi (67.6 MPa) and elongation at break of 38%; it is available on the F900 printer. PADT customer MTD Southwest has recently used Nylon 6 to prototype durable containers with highly curved geometries, for testing with gasoline/ethanol blends that would destroy most other plastics.

Prototype gas-tank made of Nylon 6, printed on a Stratasys system, using soluble support. (Image courtesy MTD Southwest)
Prototype gas-tank made of Nylon 6, printed on a Stratasys system, using soluble support. (Image courtesy MTD Southwest)

Both Nylon 12 and Nylon 6 come as black filament that prints in tandem with a soluble brown support material called SR-110. Soluble supports make a huge difference in allowing parts with internal structures and complicated overhangs to be easily 3D printed and post-processed.

Getting Stronger and Smoother

As with these first two PA versions, Nylon 12CF prints as a black filament and uses SR-110 soluble material for support; unlike those PAs, Nylon 12CF is loaded at 35 percent by weight with chopped carbon fibers averaging 150 microns in length. This fiber/resin combination produces a material with the highest flexural strength of all the FDM Nylons, as well as the highest stiffness-to-weight ratio.

Nylon 12 CF (carbon-filled) 3D printed part, designed as a test brake unit. (Image courtesy Stratasys)
Nylon 12 CF (carbon-fiber filled) 3D printed part, designed as a test brake unit. (Image courtesy Stratasys)

That strength shows up in Nylon 12 CF as a high ultimate XZ tensile strength of 10,960 psi (75.6 MPa), however, similar to other fiber-reinforced materials, the elongation at break is lower than for its unfilled counterpart (1.9 percent). Since the material doesn’t yield, just snaps, the compressive strength is given as the ultimate value, at 9,670 psi (67 MPa).

Nylon 12 CF’s strength and stiffness make it a great choice for lightweight fixtures. It also offers electrostatic discharge (ESD) protection properties better than that of Stratasys’ ABS ESD7, yet is still not quite conductive, if that is important for the part’s end-use. (For more details on printing with Nylon 12 CF, see Seven Tips for 3D Printing with Nylon 12 CF.) The material runs on the Fortus 380mc CF, 450mc or 900mc systems.

Just announced this month, Stratasys’ Diran filament (officially Diran 410MF07) is another black Nylon-based material; it, too, features an infill but not of fibers – instead there is a mineral component listed at seven percent by weight. This filler produces a material whose smooth, lubricious surface offers low sliding resistance (new vocabulary word: lubricious, meaning slippery, with reduced friction; think “lube job” or lubricant).

Robot-arm end printed in Diran, a smooth Nylon-based filament. (Image courtesy Stratasys)
Robot-arm end printed in Diran, a smooth Nylon-based filament. (Image courtesy Stratasys)

This smooth surface makes Diran parts perfect for applications needing a non-marring interface between a tool and a workpiece; for example, a jig or fixture that requires a part to be slid into place rather than just set down. It resists hydrocarbon-based chemicals, displays an ultimate tensile strength of 5,860 psi (40 MPa), and has a 12 percent elongation at break.

Close-up of Diran's smooth surface finish. (Image courtesy Stratasys)
Close-up of Diran’s smooth surface finish. (Image courtesy Stratasys)

(Revised) For the first time, Diran also brings the benefits of Nylon to users of the Stratasys office-environment, plug-and-play F370 printer. The system works with the new material using the same extruder heads as for ABS, ASA and PC-ABS, with just a few material-specific requirements. 

To keep thermal expansion consistent across a model and any necessary supports, parts set up for Diran automatically use model material as support. A new, breakaway SUP4000B material comes into play as an interface layer, simplifying support removal. The higher operating temperature also requires a different build tray, but the material’s lubricious properties (just had to use that word again) make for easy part removal and allow that tray to be reused dozens of times.

Read more about this intriguing material on the Diran datasheet:

and contact PADT to request a sample part of Diran or any of these useful Nylon materials.

PADT Inc. is a globally recognized provider of Numerical Simulation, Product Development and 3D Printing products and services. For more information on Stratasys printers and materials, contact us at info@padtinc.com.

3D Printed Parts Create a Tricked-Out Truck

PADT’s Austin Suder is a Solidworks CAD wizard, a NASA design-competition (Two for the Crew) winner and a teaching assistant for a course in additive manufacturing (AM)/3D printing. Not bad for someone who’s just started his sophomore year in mechanical engineering at Arizona State University.

PADT's Austin Suder 3D printed these custom LED reverse-light housings in carbon fiber PLA, then added heat-set inserts to strengthen the assembly and mounting structure. (Image courtesy Austin Suder)
PADT’s Austin Suder 3D printed these custom LED reverse-light housings in carbon fiber PLA, then added heat-set inserts to strengthen the assembly and mounting structure. (Image courtesy Austin Suder)

In last month’s PADT blog post about adding heat-set inserts to 3D printed parts we gave a shout-out to Austin for providing our test piece, the off-road LED light unit he had designed and printed for his 2005 Ford F-150. Now we’ve caught up with him between classes to see what other additions he’s made to his vehicle, all created with his personal 3D printers and providing great experience for his part-time work with Stratasys industrial printers in PADT’s manufacturing department.

Q: What has inspired or led you to print multiple parts for your truck?

I like cars, but I’m on a college budget so instead of complaining I found a way to fix the problem. I have five 3D printers at my house – why not put them to work! I understand the capabilities of AM so this has given me a chance to practice my CAD and manufacturing skills and push boundaries – to the point that people start to question my sanity.

Q: How did you end up making those rear-mount LED lights?

I wanted some reverse lights to match the ones on the front of my truck, so I designed housings in SolidWorks and printed them in carbon fiber PLA. Then I soldered in some high-power LED lights and wired them to my reverse lights. These parts made great use of threaded inserts! The carbon fiber PLA that I used was made by a company called Vartega that recycles carbon fiber material. (Note: PADT is an investor of this company.)

Q: In the PADT parking lot, people can’t help but notice your unusual tow-hitch. What’s the story with that?

I saw a similar looking hitch on another car that I liked and my first thought was, “I bet I could make that better.” It’s made from ABS painted chrome (not metal); I knew that I would never use it to tow anything, so this opened up my design freedom. This has been on my truck for about a year and the paint has since faded, but the printed parts are still holding strong.

An adjustable-height "topology optimized" trailer hitch Austin designed and printed in ABS. The chrome paint-job has many passersby doing a double-take, but it's just for fun, not function. (Image courtesy PADT)
An adjustable-height “topology optimized” trailer hitch Austin designed and printed in ABS. The chrome paint-job has many passersby doing a double-take, but it’s just for fun, not function. (Image courtesy PADT)

This part also gets questioned a lot! It’s both a blessing and a curse. In most cases it starts when I’m getting gas and the person behind me starts staring and then questions the thing that’s attached to the back of my truck. The conversation then progresses to me explaining what additive is, to a complete stranger in the middle of a gas station. This is the blessing part because I’m always down for a conversation about AM; the downside is I hate being late for work.

Q: What about those tow shackles on your front bumper?

Unique ABS printed tow shackles - another conversation-starter. (Image courtesy PADT)
Unique ABS printed tow shackles – another conversation-starter. (Image courtesy PADT)

Those parts were printed in ABS – they’re not meant for use, just for looks. I’ve seen towing shackles on Jeeps and other trucks but never liked the look of them, so again I designed my own in this pentagon-shape. I originally printed them in red but didn’t like the look when I installed them; the unusual shading comes because I spray-painted them black then rubbed off some of the paint while wet so the red highlights show through.

Q: Have you printed truck parts in any other materials?

Yes, I‘ve used a carbon-fiber (CF) nylon and flexible TPU (thermoplastic polyurethane) on filament printers and a nylon-like resin on a stereolithography system.

The CF nylon worked well when I realized my engine bay lacked the real estate needed for a catch can I’d bought. This was a problem for about five minutes – then I realized I have the power of additive and engineered a mount which raised the can and holds it at an angle. The mount makes great use of complex geometry because AM made it easy to manufacture a strong but custom-shaped part.     

Custom mount, 3D printed in carbon-fiber reinforced nylon, puts aftermarket catch-can in just the right location. (Image courtesy Austin Suder)
Custom mount, 3D printed in carbon-fiber reinforced nylon, puts aftermarket catch-can in just the right location. (Image courtesy Austin Suder)

After adding the catch can to my engine, I needed a way to keep the hoses from moving around when driving so I designed a double S-clip in TPU. The first design didn’t even come close to working – the hoses kept coming loose when driving – so I evaluated it and realized that the outer walls needed to be thicker. I made the change and printed it again, and this time it worked great. In fact, it worked so well that when I took my truck to the Ford dealership for some warranty work, they went missing. (It’s OK Ford, you can have them – I’ll just print another set.)    

Just-right 3D printed clips keep hoses anchored and out of the way. ((Image courtesy Austin Suder)
Just-right 3D printed clips keep hoses anchored and out of the way. ((Image courtesy Austin Suder)

Other parts I printed in TPU included clips for the brake-lines. I had seen that my original clip had snapped off, so when I had the truck up on jacks, I grabbed my calipers and started designing a new, improved version. Thirty minutes later I had them in place.

I also made replacement hood dampeners from TPU since they looked as though they’d been there for the life of the truck. I measured the old ones, used SolidWorks to recreate them (optimized for AM), printed a pair and installed them. They’ve been doing great in the Arizona heat without any deformation.      

New hood-dampeners printed in TPU have just the right amount of give. (Image courtesy Austin Suder)
New hood-dampeners printed in TPU have just the right amount of give. (Image courtesy Austin Suder)

My last little print was done on my SLA system in a material that behaves like nylon. (This was really just me showing off.) The plastic clips that hold the radiator cover had broken off, which led me to use threaded sheet-metal inserts to add machine threading to the fixture. I then purchased chrome bolts and made some 3D printed cup-washers with embossed text for added personalization and flair.  

Even the cup-washers got a 3D printed make-over on Austin's F150: printed in white resin on an SLA system, these parts got a coat of black paint and then some sanding, ending up with a two-color custom look. (Image courtesy PADT)
Even the cup-washers got a 3D printed make-over on Austin’s F150: printed in white resin on an SLA system, these parts got a coat of black paint and then some sanding, ending up with a two-color custom look. (Image courtesy PADT)

Q: What future automotive projects do you have in mind?

I’m working on a multi-section bumper and am using the project to standardize my production process – the design, material choice, sectioning and assembling. I got the idea because I saw someone with a tube frame car and thought it looked great, which led to me start thinking about how I could incorporate that onto my truck.

When I bought my F-150, it had had a dent in the rear bumper. I was never happy with this but didn’t have the money to get it fixed, so at this point the tube-frame look came full circle! I decided that I was going to 3D print a tube-frame bumper to replace the one with a dent. I started by removing the original bumper, taking measurements and locating possible mounting points for my design. Then I made some sketches and transferred them into SolidWorks.

The best part about this project is that I have additive on my side. Typical tube frame construction is limited by many things like bend allowance, assembly, and fabrication tooling. AM has allowed me to design components that could not be manufactured with traditional methods. The bumper will be constructed of PVC sections connected by 50 ABS printed parts, all glued together, smoothed with Bondo and filler primer then painted black. This is a large project!  It will take a lot of hand-finishing, but it will be perfect.

Q: If you were given the opportunity to work on any printer technology and/or material, what would you want to try working with?

Great question! If I had the opportunity to use AM for automotive components, I would redesign internal engine components and print them with direct metal laser sintering (DMLS), one of PADT’s other AM technologies. I would try printing part like piston rods, pistons, rocker arms, and cylinder valves. Additive is great for complex geometries with exotic materials.

Go Austin! Can’t wait to see what your truck looks like when you visit over semester break.

To learn more about fused deposition modeling (FDM/filament), stereolithography (SLA), selective laser sintering (SLS) and DMLS printers and materials, contact the PADT Manufacturing group; get your questions answered, have some sample parts printed, and share your success tips.

PADT Inc. is a globally recognized provider of Numerical Simulation, Product Development and 3D Printing products and services. For more information on Insight, GrabCAD and Stratasys products, contact us at info@padtinc.com.

Adding Inserts to 3D Printed Parts: Hardware Tips plus One-Click Design in GrabCAD Print Advanced FDM

Heat-set, ultrasonic, helicoil: metal inserts are exceedingly useful when you want to add threads to a plastic part, preparing it for a strong screwed-in connection. Whether you heat up the insert and push it down into the pre-made hole (purposely melting the plastic as you do so) or tap a hole to allow a helicoil to dig into its side, you create a better grip for whatever hardware you eventually install. Inserts are especially useful for parts that will be assembled and disassembled multiple times.

Here at PADT, Inc., we thought we’d research the different installation approaches and demonstrate several ways to use inserts in FDM 3D-printed parts (be sure to check out the short video further on). Our awesome intern-turned-employee Austin Suder had already designed and printed some LED light boxes for off-roading with his truck, so we used his parts for our tests and demos. (Stay tuned – we’ll soon be featuring a whole variety of Austin’s automotive upgrades in an upcoming PADT post.)

For a classically milled plastic part, you plan ahead by drilling a slightly undersized hole that is enlarged as the heated insert is pushed into place. For a 3D printed part (let’s say ABS), you plan ahead in a similar way, using the hole dimensions given on any insert data-sheet. However, to get the best anchor against torque-out and pull-out, holes in 3D printed FDM parts need multiple material contours around them. You don’t want to melt through a thin wall into the infill region, and you don’t want weird bulges on the exterior if the hole is close to an edge.

An LED light box for off-road automotive lighting.
An LED light box for off-road automotive lighting, showing sections ready for M3 heat-set inserts. Sample side part printed in white for clarity. (Images courtesy PADT)
An LED light box for off-road automotive lighting, showing sections ready for M3 heat-set inserts. Sample side part printed in white for clarity. (Images courtesy PADT)

Heat-Set versus Ultrasonic Inserts

We’ll talk about defining those beefed-up contours in a moment. First, let’s describe the difference in installing heat-set (also called heat-staked) versus ultrasonic inserts, and talk about the pros and cons of their use. Inserts can also be dropped into slightly oversized holes if you pause the printer, add the part, and continue to print over them with enough material to just trap them in place. (Note: Helical inserts require tapping and then an installation tool, and do not give quite the strength of the former two types.)

Both types of inserts may come as small as #0-80 and M2.5×0.45 up to 3/8-16 and M8x1.25 (inches and metric, respectively), depending on whether you choose tapered or straight-sided versions. Material choice typically is aluminum, brass or stainless steel, in order to provide high thermal conductivity with strength.

Close-up of M3 size metric heat-set inserts to show relative size, ready for installation. (Image courtesy PADT)
Close-up of M3 size metric heat-set inserts to show relative size, ready for installation. (Image courtesy PADT)

A heat-stake machine looks like a small drill-press with a soldering-iron tip, and does ensure a perfectly vertical motion. However, the easiest insertion tool is a handheld soldering iron fitted with a flat-end heat-set tip that matches the inner diameter of the insert. Heat-set tips cost less than $20, and their benefit (compared to using just the default soldering iron tip) is that the flat head is easier to retract after the insert is completely in position. You can add package prints for that refer short run package prints.

(Left) Using a standard chisel-tip on a soldering iron to install a heat-set insert can make it difficult to get the insert in straight. (Right) Using a specialized heat-set tip gives a good vertical installation. Tips are sold to match each insert type and size (Image courtesy PADT)
(Upper) Using a standard chisel-tip on a soldering iron to install a heat-set insert can make it difficult to get the insert in straight. (Lower) Using a specialized heat-set tip gives a good vertical installation. Tips are sold to match each insert type and size. (Image courtesy PADT)                                                

A useful guide from Stratasys, “Inserting Hardware Post-Build,” suggests pre-heating the soldering iron or heat-staking press to a temperature that is approximately 170% of the glass transition temperature (Tg) of the FDM material, or work with a variable-power iron set for about 40 watts. Stratasys material data sheets list Tg values for each material.

Step-by-step Installation

To install a heat-set insert, set the metal insert on the 3D-printed part surface, centered on the hole. Tapered inserts are self-seating and make it easier to ensure the insert goes in straight, but even the straight-wall designs have a slightly smaller lead-in section to assist with alignment.

Fit the soldering-iron tip into the center of the insert, then push the insert down gently into place – you’ll feel the plastic around it starting to melt. Stop pushing when you see the insert has almost completely gone in, then pull back on the tip. Immediately place a flat aluminum plate on the insert/part area and push down until the insert is completely flush with the part surface. Alternatively, you can turn the part upside down and push the face against a table or flat plate – whatever is easiest given the part geometry.

Once you remove the soldering iron (heat source), the cooling, melted plastic reflows into the grooves, knurls and slots cut into the insert’s outer walls and solidifies. This connection is what forms the excellent grip between metal and plastic.

Finished part with insert flush to the part’s surface. (Image courtesy PADT)
Finished part with insert flush to the part’s surface. (Image courtesy PADT)

Ultrasonic installation also melts the plastic and ends up with the same result, but the process and equipment are quite different. The user (or an automated system) sets the insert in place then lowers an ultrasonic horn directly onto the metal’s surface. Ultrasonic vibrations create frictional heat, again melting the plastic, and the equipment pushes the insert down to a preset depth.

Both methods work, but unless you need the speed of automated assembly, heat-insertion is a simpler and less expensive approach. The equipment for ultrasonic insertion can be expensive, is very loud when operating, and can be harder to control. There’s also the chance that metal chips get generated and stuck in the part.

For more information comparing the two methods, see the in-depth Machine Design article, “Putting inserts in plastic parts: ultrasonic or heat?

Designing CAD Models for Inserts

The key to sizing holes to be insert-ready is to slightly undersize them. Insert datasheets provide diameter and depth information for all the standard sizes, with virtually identical values regardless of brand (one company might list a diameter as 5.2mm and another as 5.23mm but these are negligible differences for this purpose).

Two online resources are SI Inserts for Plastic and the McMaster-Carr insert webpages.

These online charts or diagrams give the minimum hole depth and diameter that must be designed into the CAD model. For tapered inserts, the mounting hole officially has its own taper, but the difference is so minimal that for most cases, a straight hole will grip the insert just fine, as shown in the figure below.

CAD part with straight-walled holes set up for adding M3 inserts (Image courtesy PADT)
Sample CAD part with straight-walled holes set up for adding M3 inserts (Image courtesy PADT)

In print set-up software such as Stratasys Insight, the recommendation is to create four to six contours around each hole that is designated for an insert. This is done by creating a Custom Group under the Toolpath heading, defining the number of contours, and selecting all the relevant holes. When you review the toolpath layer by layer you’ll see those contours show up.

One-Step Insert Set-Up in GrabCAD Advanced FDM Software

For parts printed on many Stratasys FDM printers – from the F170/270/370 Series up through the larger Fortus 380, 450 and 900 models – users can even more quickly prepare their parts for inserts using GrabCAD Print’s Advanced FDM features. Since GrabCAD Print’s set-up software works directly with CAD files, all the feature intelligence is retained, meaning the software recognizes bodies and faces, including the cylindrical sides of a hole.

As long as your part has a hole whose center is in the desired location, GrabCAD does something very cool. It lets you choose an insert from a drop-down menu then automatically resizes that hole to the correct dimensions and reinforces its perimeter with an optimized number of contours. No need to create custom groups, isolate model slices, rebuild tool paths or wonder if you added enough material.

Automated contour-creation around holes for heat-set inserts, created using Stratasys GrabCAD Print software. (Image courtesy PADT)
Automated contour-creation around holes for heat-set inserts, created using Stratasys GrabCAD Print software. (Image courtesy PADT)

Try GrabCAD Print for yourself – it greatly simplifies optimizing the contours and hole-sizing, and makes it easy to evaluate different insert sizes on-the-fly without having to edit the original CAD file.

To learn more about working with inserts in general, GrabCAD Print software and FDM printers and materials, contact the PADT Manufacturing group; get your questions answered, have some sample parts printed, and share your success tips.

PADT Inc. is a globally recognized provider of Numerical Simulation, Product Development and 3D Printing products and services. For more information on Insight, GrabCAD and Stratasys products, contact us at info@padtinc.com.

3D Printing Polymer Parts with Electrostatic Dissipative (ESD) Properties

Getting zapped by static electricity at the personal level is merely annoying; having your sensitive electronic equipment buzzed is another, highly destructive story.

Much as you’d like to send these components out into the world wearing their own little anti-static wristbands, that’s just not practical (and actually, not good enough*). During build and use, advanced electronics applications need true charge-dissipative protection that is inherent to their design and easy to achieve. However, the typical steps of painting or coating, covering with conductive tape, or wrapping with carbon-filled/aluminum-coated films incur both time and cost.

Electrostatic dissipative (ESD) polymer materials instead provide this kind of protection on a built-in basis, offering a moderately conductive “exit path” that naturally dissipates the charge build-up that can occur during normal operations. It also prevents powders, dust or fine particles from sticking to the surface. Whether the task is protecting circuit boards during transport and testing, or ensuring that the final product works as designed throughout its lifetime, ESD materials present low electrical resistance while offering the required mechanical, and often thermal and/or chemically-resistant properties.

ESD-safe fixture for testing a printed-circuit board, produced by 3D printing with Stratasys ABS-ESD7 material. (Image courtesy of Stratasys)

Combining ESD Behavior with 3D Printing

All the features that are appealing with 3D printing carry over when printing with ESD-enabled thermoplastics. You can print trays custom-configured to hold circuit-boards for in-process testing, print conformal fixtures that speed up sorting, and produce end-use structures for projects where static build-up is simply not allowed (think mission-critical aerospace applications).

Acrylonitrile butadiene styrene (ABS), that work-horse of the plastics industry, has been available as 3D printing filament for decades. Along the way, Stratasys and other vendors started offering this filament in a version filled with carbon particles that decrease the plastic’s inherent electrical resistance. Stratasys ABS-ESD7 runs on the Fortus 380, 400, 450 and 900 industrial systems, and soon will be available on the office-friendly F370 printer.

What kind of performance does ABS-ESD7 offer? When evaluating materials for ESD performance, the most important property is usually the surface resistance, measured in ohms. (This is not the same as surface resistivity, plus there’s also volume resistivity – see Note at end). Conductive materials – typically metals – have a surface resistance generally less than 103 ohms, insulators such as most plastics are rated at greater than 1012 ohms, and ESD materials fall in the mid-range, at 106 to 109 ohms.

Compared to standard ABS filament, ABS-ESD7 offers more than five orders of magnitude lower resistance, converting it from an insulator to a material that provides an effective static-discharge path to the outside world. Due to the inherent layered structure of FDM parts, the differences in properties between flat (XY) and vertical (ZX) build orientations produces a range of resistance values, with a target of 107 ohms, reflected in the product name of ABS-ESD7. Stratasys offers an excellent, easy-to-read FAQ paper about ABS-ESD7.

Printed-circuit board production tool, custom 3D-printed in Stratasys ABS-ESD7 material for built-in protection from electrostatic discharge during test and handling. (Image courtesy of Stratasys)

When ABS isn’t strong enough or won’t hold up to temperature extremes, engineers can turn to Stratasys’ ESD-enhanced polyetherketoneketone (PEKK), termed Antero 840CN03. Developed in 2016 and slated for full release in October 2019, this new filament expands the company’s Antero line of  high-temperature, chemically resistant formulations. The PEKK base material offers a high glass transition temperature (Tg 149C, compared to 108C for ABS-ESD7) while meeting stringent outgassing and cleanroom requirements. As with ABS-ESD7, the carbon-nanotube loading lowers electrical resistance values of Antero 840CN03 parts to the desirable “ESD safe” range of 106 to 109 ohm.

Setting up Parts for Printing with ESD-Enhanced Filament                                                            

Support structures in contact with part walls/surfaces can disturb the surface resistance behavior. To counter-act this condition for filament printing with any type of ESD material, users should perform a special calibration that makes the printer lay down slightly thinner-than-usual layers of support material. In Stratasys Insight software, this is currently accomplished by setting the Support Offset Thickness to -0.003; this decreases the support layers from 0.010 inches to 0.007 inches. In addition, supports should be removed (in Insight software) from holes that are smaller in diameter than 0.25 inches (6.35mm).

As more of these materials are developed, the software will be updated to automatically create supports with this process in mind.

ESD Applications for 3D Printing

Avionics boxes, fixtures for holding and transporting circuit boards, storage containers for fuel, and production-line conveyor systems are just a few examples of end-use applications of ESD-enabled materials. Coupled with the geometric freedom offered by 3D printing, three categories of manufacturing and operations are improved:

  • Protecting electronics from ESD damage (static shock)
  • Preventing fire/explosion (static spark)
  • Preserving equipment/product performance (static cling)

If you’re exploring how 3D printing with ESD-enhanced materials can help with your industrial challenge, contact our PADT Manufacturing group: get your questions answered, have some sample parts printed, and discover what filament is right for you.

PADT Inc. is a globally recognized provider of Numerical Simulation, Product Development and 3D Printing products and services. For more information on Insight, GrabCAD and Stratasys products, contact us at info@padtinc.com.

*Anti-static is a qualitative term and refers to something that prevents build-up of static, rather than dissipating what does occur


Surface Resistance, Surface Resistivity and Volume Resistivity

Surface resistance in ohms is a measurement to evaluate static-dissipative packaging materials.

Surface resistivity in ohms/square is used to evaluate insulative materials where high resistance characteristics are desirable. (Ref. https://www.evaluationengineering.com/home/article/13000514/the-difference-between-surface-resistance-and-surface-resistivity)

The standard for measuring surface resistance of ESD materials is EOS/ESD S11.11, released in 1993 by the ESD Association as an improvement over ASTM D-257 (the classic standard for evaluating insulators). Driving this need was the non-homogeneous structure of ESD materials (conductive material added to plastic), which had a different effect on testing parameters such as voltage or humidity,  than found with evaluating conductors.

Volume resistivity is yet a third possible measured electrical property, though again better suited for true conductors rather than ESD material. It depends on the area of the ohmeter’s electrodes and the thickness of the material sample. Units are ohm-cm or ohm-m.

             

3D Printing Infill Styles – the What, When and Why of Using Infill

Have you ever wondered about choosing a plain versus funky infill-style for filament 3D-printing? Amongst the ten standard types (no, the cat infill design is not one of them), some give you high strength, some greatly decrease material use or printing time, and others are purposely tailored with an end-use in mind.

Highly detailed Insight slicing software from Stratasys gives you the widest range of possibilities; the basic versions are also accessible from GrabCAD Print, the direct-CAD-import, cloud-connected slicing software that offers an easy approach for all levels of 3D print users.

A part that is mimicking or replacing a metal design would do best when built with Solid infill to give it weight and heft, while a visual-concept model printed as five different test-versions may work fine with a Sparse infill, saving time and material. Here at PADT we printed a number of sample cubes with open ends to demonstrate a variety of the choices in action. Check out these hints for evaluating each one, and see the chart at the end comparing build-time, weight and consumed material.

Infill choices for 3D printed parts, offered with Stratasys’ GrabCAD Print software. (Image courtesy PADT Inc.)

Basic Infill Patterns

Solid (also called Alternating Raster) This is the default pattern, where each layer has straight fill-lines touching each other, and the layer direction alternates by 90 degrees. This infill uses the most material but offers the highest density; use it when structural integrity and super-low porosity are most important.

Solid (Alternating Raster)

Sparse Raster lines for Sparse infill also run in one direction per layer, alternating by layer, but are widely spaced (the default spacing is 0.080 inches/2 mm). In Insight, or using the Advanced FDM settings in GrabCAD, you can change the width of both the lines and the spaces.

Sparse Double Dense As you can imagine, Sparse Double Dense achieves twice the density of regular Sparse: it deposits in two directions per layer, creating an open grid-pattern that stacks up throughout the part.

Sparse High Density Just to give you one more quick-click option, this pattern effectively sits between Sparse Double Dense and Solid. It lays rasters in a single direction per layer, but not as closely spaced as for Solid.

Hexagram The effect of this pattern looks similar to a honeycomb but it’s formed differently. Each layer gets three sets of raster lines crossing at different angles, forming perfectly aligned columns of hexagons and triangles. Hexagram is time-efficient to build, lightweight and strong in all directions.

Hexagram
Additional infill styles and the options for customizing them within a part, offered within Stratasys Insight 3D printing slicing and set-up software. (Image courtesy PADT Inc.)

Advanced Infill Patterns (via Custom Groups in Insight)

Hexagon By laying down rows of zig-zag lines that alternately bond to each other and bend away, Hexagon produces a classic honeycomb structure (every two rows creates one row of honeycomb). The pattern repeats layer by layer so all vertical channels line up perfectly. The amount of build material used is just about one-third that of Solid but strength is quite good.

Hexagon

Permeable Triangle A layer-by-layer shifting pattern of triangles and straight lines creates a strong infill that builds as quickly as Sparse, but is extremely permeable. It is used for printing sacrificial tooling material (i.e., Stratsys ST130) that will be wrapped with composite material and later dissolved away.

Permeable Triangle

Permeable Tubular This infill is formed by a 16-layer repeating pattern deposited first as eight varying wavy layers aligned to the X axis and then the same eight layers aligned to the Y axis. The resulting structure is a series of vertical cylinders enhanced with strong cross-bars, creating air-flow channels highly suited to tooling used on vacuum work-holding tables.

Permeable Tubular 0.2 Spacing
Permeable Tubular 0.5 Spacing

Gyroid (so cool we printed it twice) The Gyroid pattern belongs to a class of mathematically minimal surfaces, providing infill strength similar to that of a hexagon, but using less material. Since different raster spacings have quite an effect, we printed it first with the default spacing of 0.2 inches and then widened that to 0.5 inches. Print time and material use dropped dramatically.

Gyroid 0.2 Spacing
Gyroid 0.5 Spacing

Schwarz D (Diamond) This alternate style of minimal surface builds in sets of seven different layers along the X-axis, ranging from straight lines to near-sawtooth waves, then flipping to repeat the same seven layers along the Y-axis. The Schwarz D infill balances strength, density and porosity. As with the Gyroid, differences in raster spacing have a big influence on the material use and build-time.

Schwarz Diamond 0.2 Spacing
Schwarz Diamond 0.5 Spacing

Digging Deeper Into Infill Options

Infill Cell Type/0.2 spacing Build Time Weight Material Used
Alternating Raster (Solid) 1 h 57 min 123.77 g 6.29 cu in.
Sparse Double Dense 1 hr 37 min 44.09 g 4.52 cu in.
Hexagon (Honeycomb) 1 h 49 min 37.79 g 2.56 cu in.
Hexagram (3 crossed rasters) 1 h 11 min. 47.61 g 3.03 cu in.
Permeable Triangle 1 h 11 min. 47.67 g 3.04 cu in.
Permeable Tubular – small 2 h 5 min. 43.95 g 2.68 cu in.
Gyroid – small 1 h 48 min. 38.68 g 2.39 cu in.
Schwarz Diamond (D) – small 1 h 35 min. 47.8 g 3.04 cu in.
Infill Cell Type/0.5 spacing Build Time Weight Material Used
Permeable Tubular – Large 1 h 11 min. 21.84 g 1.33 cu in.
Gyroid – Large 57 min. 20.59 g 1.29 cu in.
Schwarz Diamond (D) – Large 58 min. 23.74 g 1.51 cu in.

Hopefully this information helps you perfect your design for optimal strength or minimal material-use or fastest printing. If you’re still not sure which way to go, contact our PADT Manufacturing group: get your questions answered, have some sample parts printed and discover what infill works best for the job at hand.

PADT Inc. is a globally recognized provider of Numerical Simulation, Product Development and 3D Printing products and services. For more information on Insight, GrabCAD and Stratasys products, contact us at info@padtinc.com.

Seven Tips for 3D Printing with Nylon 12CF

If you’ve been thinking of trying out Nylon 12 Carbon Fiber (12CF)  to replace aluminum tooling or create strong end-use parts, do it! All the parts we’ve built here at PADT have shown themselves to be extremely strong and durable and we think you should consider evaluating this material. Get More Info here.

All large format printing for our Orlando tradeshow clients is done in house. Exhibit U is a commercial print agency located in Orlando with multiple locations nationwide. Exhibit U is known for it’s large format printing whether it’s outdoor building signage, internal wall signs. The Mimaki JFX200 2513 delivers high performance and high speed.

Nylon 12CF filament consists of black Nylon 12 filled with chopped carbon fibers; it currently runs on the Stratasys Fortus 380cf, Fortus 450 and Fortus 900 FDM systems when set up with the corresponding head/tip configuration. (The chopped fiber behavior requires a hardened extruder and the chamber runs at a higher temperature.) We’ve run it on our Fortus 450 and found with a little preparation you get excellent first-part-right results.

Forming tool printed in Nylon 12CF on a Stratasys Fortus 450 FDM printer. Build orientation was chosen to have the tool on its side while printing, producing a smooth curved surface (the critical area). (Image courtesy PADT)

With Nylon 12CF, fiber alignment is in the direction of extrusion, producing ultimate tensile strength of 10,960 psi (XZ orientation) and 4,990 psi (ZX orientation), with tensile modulus of 1,100 ksi (XZ) and 330 ksi (ZX). By optimizing your pre-processing and build approach, you can create parts that take advantage of these anisotropic properties and display behavior similar to that of composite laminates.

Best Practices for Successful Part Production

Follow these steps to produce best-practice Nylon 12CF parts:

  1. Part set-up in Insight or GrabCAD Print software:
    • If the part has curves that need a smooth surface, such as for use as a bending tool, orient it so the surface in question builds vertically. Also, set up the orientation to avoid excess stresses in the z-direction.
    • The Normal default build-mode selection works for most parts unless there are walls thinner than 0.2 inches/0.508 mm; for these, choose Thin Wall Mode, which reduces the build-chamber temperature, avoiding any localized overheating/melting issues. Keep the default raster and contour widths at 0.2 inches/0.508 mm.
    • For thin, flat parts (fewer than 10 layers), zoom in and count the number of layers in the toolpath. If there is an even number of layers, create a Custom Group that lets you define the raster orientation of the middle two layers to be the same – then let the rest of the layers alternate by 90 degrees as usual. This helps prevent curl in thin parts.
    • Set Seam Control to Align or Align to nearest, and avoid setting seams on edges of thin parts; this yields better surface quality.

2. In the Support Parameters box, the default is “Use Model Material where Possible” – keep it. Building both the part and most of the surrounding supports from the same material reduces the impact of mismatched thermal coefficient of expansion between the model and support materials. It also shortens the time that the model extruder is inactive, avoiding the chance for depositing unwanted, excess model material. Be sure that “Insert Perforation Layers” is checked and set that number to 2, unless you are using Box-style supports – then select 3. This improves support removal in nearly enclosed cavities.

3. Set up part placement in Control Center or GrabCAD Print software: you want to ensure good airflow in the build chamber. Place single parts near the center of the build-plate; for a mixed-size part group, place the tallest part in the center with the shorter ones concentrically around it.

4. Be sure to include a Sacrificial Tower. This is always the first part built, layer by layer, and should be located in the right-front corner. Keep the setting of Full Height so that it continues building to the height of the tallest part. You’ll see the Tower looks very stringy! That means it is doing its job – it takes the brunt of stray strings and material that may not be at perfect temperature at the beginning of each layer’s placement.

Part set-up of a thin, flat Nylon 12CF part in GrabCAD print, with Sacrificial Tower in its correct position at lower right, to provide a clean start to each build-layer. (Image courtesy PADT)

5. Run a tip-offset calibration, or two, or three, on your printer. This is really important, particularly for the support material, to ensure the deposited “bead” is flat, not rounded or asymmetric. Proper bead-profile ensures good adhesion between model and support layers.

6. After printing, allow the part to cool down in the build chamber. When the part(s) and sheet are left in the printer for at least 30 minutes, everything cools down slowly together, minimizing the possibility of curling. We have found that for large, flat parts, putting a 0.75-inch thick aluminum plate on top of the part while it is still in the chamber, and then keeping the part and plate “sandwiched” together after taking it out of the chamber to completely cool really keeps things flat.

7. If you have trouble getting the part off the build sheet: Removing the part while it is still slightly warm makes it easier to get off; if your part built overnight and then cooled before you got to it, you can put it in a low temp oven (about 170F) for ten (10) to 20 minutes – it will be easier to separate. Also, if the part appears to have warped that will go away after the soluble supports have been removed.

Be sure to keep Nylon 12CF canisters in a sealed bag when not in use as the material, like any nylon, will absorb atmospheric moisture over time.

Many of these tips are further detailed in a “Best Practices for FDM Nylon 12CF” document from Stratasys; ask PADT for a copy of it, as well as for a sample or benchmark part. Nylon 12 CF offers a fast approach to producing durable, custom components. Discover what Nylon 12CF can mean for your product development and production groups.

PADT Inc. is a globally recognized provider of Numerical Simulation, Product Development and 3D Printing products and services. For more information on Nylon 12CF and Stratasys products, contact us at info@padtinc.com.