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.

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.

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.

Introducing TPU 92A – The latest FDM material from Stratasys

PADT is excited to announce the release of the latest FDM material from Stratasys: TPU 92A.
Thermoplastic Polyurethane (TPU) is a type of elastomer material, known for its flexibility, resilience, tear resistance, and high elongation. It’s a highly process-able material which makes it ideal for additive manufacturing.
TPU 92A is an elastomeric material that is ideal for prototyping highly functional, large, durable, complex elastomer parts. 

This material brings the benefits of an elastomer to the accurate and easy-to-use F123 3D Printer. Combined with soluble support, it lets you create simple to complex elastomer parts, and through printing on the F123 Series gives product developers more tools to expand their prototyping capabilities with reliable accuracy.
Curious to learn more about the unique properties that make TPU 92A such a great option for prototyping?Schedule a meeting to see the material for yourself.Click the link below to start a conversation with PADT’s resident material experts, in order to discuss the capabilities of this Thermoplastic Polyurethane material, and how your company can benefit from using it.

Don’t miss this unique opportunity, schedule a meeting today!

Don’t compromise your composite tooling design – Streamline your Sacrificial tooling with FDM

FDM Sacrificial Tooling: Using Additive Manufacturing for Sacrificial Composite Tool Production

Additive manufacturing has seen an explosion of material options in recent years. With these new material options comes significant improvements in mechanical properties and the potential for new applications that extend well beyond prototyping; one such application being sacrificial tooling.

Traditional composite manufacturing techniques work well to produce basic shapes with constant cross sections. However, complex composite parts with hollow interiors present unique manufacturing challenges. However, with FDM sacrificial tooling, no design compromise is necessary.

Download the white paper to discover how FDM sacrificial tooling can dramatically streamline the production process for complicated composite parts with hollow interiors.

This document includes insight into:

  • Building for optimal results
  • Consolidating composites
  • Finding application best fits

Best practices for composite tooling with additive manufacturing

Additively Manufactured: Best Practices for Composite Tooling with 3D Printing

The advanced composites industry has a continual need for innovative tooling solutions. Conventional tooling is typically heavy, costly and time-consuming to produce. New applications, product improvements and the demand for faster, lower-cost tool creation challenge composite product manufacturers to innovate and remain competitive.

The use of additive manufacturing (or “3D printing”), and specifically FDM, for composite tooling has demonstrated considerable cost and lead time reductions while providing numerous other advantages such as immense design freedom and rapid iteration, nearly regardless of part complexity.

Download the white paper to learn more about the various advantages and capabilities of composite tooling with additive over traditional manufacturing methods, and discover the best practices for ensuring that your composite tooling process is efficient as possible.

This document includes best practices for:

  • Testing and characterization
  • Tool Design, Production, & Use
  • Analyzing results

Discover the benefits of using additive manufacturing for composites

Introduction to Additive Manufacturing for Composites

Additive manufacturing encompasses methods of fabrication that build objects through the successive addition of material, as opposed to subtractive methods such as CNC machining, that remove material until a final shape is achieved. Composite fabrication is one of the most original forms of additive manufacturing.

Whether the process involves wet lay-up, hand lay-up of prepreg materials, or automated fiber placement (AFP), methods of composite manufacture are distinctly additive in nature, building up to final part forms typically one layer at a time. However, the nature of additive manufacturing has been revolutionized with the advent of the 3D printing industry.

Strong, resilient, fiber-reinforced thermoplastics. Lightweight, low-cost composite tooling. Explore these and other characteristics and benefits of additively manufactured composites in the e-book “Introduction to Additive Manufacturing for Composites.”

This e-book covers:

  • Current applications for composite fabrications
  • Comparison of printed and conventional tooling
  • Characteristics of printed mold tooling

 

Getting to Know PADT: Stratasys 3D Printer Sales and Support

 This post is the eleventh installment in our review of all the different products and services PADT offers our customers. As we add more, they will be available here.  As always, if you have any questions don’t hesitate to reach out to info@padtinc.com or give us a call at 1-800-293-PADT.

When it comes to delivering accurate, robust, and feature-rich additive manufacturing, commonly called 3D Printing, to professional users, one brand of systems stands above all the rest: Stratasys. For over a decade PADT has been a reseller of these outstanding machines in the four-corners states of Arizona, Colorado, New Mexico, and Utah. In fact, our leadership position in the Additive Manufacturing space is built on the foundation of our sales and support history with Stratasys.

Stratasys, The World Leader in Additive Manufacturing

There is one simple reason why Stratasys is the world leader in Additive Manufacturing systems and why so many of our customers keep buying Stratasys systems: They Work.  The whole point of 3D Printing is that you can go from a computer model to a real part as quickly and easily as possible. Stratasys has created a complete set of hardware, material, and software to make that happen.  For hardware, they offer two additive manufacturing technologies: FDM and PolyJet.

FDM, or Fused Deposition Modeling, is the most common technology because it is reliable, accurate and builds strong parts.  FDM was invented by Stratasys over 25 years ago and still forms the foundation of their product line.  It is a layered deposition process that melts a variety of plastics that are then extruded through a nozzle to draw the shape of each layer. From the desktop MakerBot machines to the industry favorite FORTUS 900, there is a machine that works for every need.  Recently, we have been selling a large number of F370’s to new an existing customers.  FMD systems come in a variety of sizes, speeds, costs, and most importantly, material options.  And best of all, the majority of FDM systems come with Stratasys’ patented soluble support material that makes support removal as easy as dropping your part into a cleaning system (many of which are made by PADT).

If you need greater refinement, the ability to change material, or color, then PolyJet technology is your ideal solution.  The power of PolyJet is that it uses inkjet print heads to deposit tiny dots of liquid material on a build layr. That material is then hardened with an ultraviolet lamp. What is cool is that you can have multiple inkjet print heads and therefore deposit a mix of material within a given layer. This allows you to make parts with very hard, or very soft material in the same build. Or, to mix clear and colors in the same build.  Our customers use Polyjet printers to make everything from accurate medical models of organs to molds for plastic injection molding.  No other 3D Printing technology is as versatile as the PolyJet machines from Stratasys.

The PADT Sales Experience

Lots of people sell 3D Printers. We know because we have been doing it for over fifteen years. And as the technology has become more popular, more and more people are getting into the industry.  Our experience and technically driven sales approach is why customers keep coming to PADT when they have so many choices.  Our sales team is not about this months sales goal. They are about building, and more often than not, growing our relationship with customers new and old.  We are all about understanding what you really want to get done, and then finding the right combination of Additive Manufacturing system, accessories, and software that will make it happen.

That expertise comes from the fact that we have been running a 3D Printing service since 1994.  We know the real world of Additive Manufacturing.  No other reseller can bring our expertise and experience to your aid.

Support that Goes Above and Beyond

Once you purchase a system, your journey with PADT hits full swing. Our engineers will help you install, train your users, and then be there when you need us for maintenance and repair. Or simply to answer your questions.  We recently won a series of competitive situations where customers had a choice of who to hire to support their Stratasys systems. They chose PADT over other solutions for one simple reason: we know what we are doing and we really do care.  Our team has driven through snow storms, stayed with machines late into the night, and personally shipped replacement parts just so they could get customer’s machines back online and running as quickly as possible.

Talk to PADT about your Additive Manufacturing Needs

ULA’s Kyle Whitlow demonstrates the ECS duct that was printed using FDM

Regardless of what systems you currently have, or if you don’t have any 3D Printing capability in-house, now is the time to talk to PADT.  We have never had a better offering of solutions in terms of price, performance, and variety of capability.  We are helping universities establish labs, Aerospace companies 3D Print hardware for launch vehicles, and consumer products companies shorten their design cycle.  It may be time for you to upgrade or add a new material or technology. Or maybe you just need some accessories to get more out of the equipment you have.  Regardless of where you are in your Additive Manufacturing journey, PADT is here to help you get more out of your investment.

Getting to Know PADT: 3D Printing Services

This post is the sixth installment in our review of all the different products and services PADT offers our customers. As we add more, they will be available here.  As always, if you have any questions don’t hesitate to reach out to info@padtinc.com or give us a call at 1-800-293-PADT.

If there is one service that most people connect PADT with it is our 3D Printing Services.  We have been making prototypes for companies using this ever-advancing technology since we started the company in 1994. As 3D Printing has become more popular and entered the mainstream even beyond engineering, what 3D Printing means to people has changed as well. Along with that, people’s understanding of exactly what it is we do in this area has drifted a little from what goes on. In this month’s installment of our “Getting to Know PADT” series, we will work to provide insight into what 3D Printing Services are and how they can benefit your company.

What is “3D Printing” and “3D Printing Services?”

To start, it should be called “Additive and Advanced Manufacturing and Prototyping Services, ” but people search for “3D Printing” so that is what we call it.  3D Printing is the common name for what is technically referred to as Additive Manufacturing, or AM.  Most physical parts are made (manufactured) by casting or shaping material into a shape you want, removing material from stock to get the shapes you want, and/or combining physical parts you get by the other two methods. Instead of these well-proven methods, AM creates a part by building up material one layer at a time.  That is why it is called additive – it adds layers of material to get a shape. Here is an older blog article showing the most common technologies used in AM.

The advantage of this approach is that you just need one machine to make a part, you can go straight from a computer model to that part, and you are not held back by the physical constraints of traditional processes. These features allow anyone to make a part and to make shapes we just could not create before.  At first, we only used it for prototypes before parts were made. Then we started to make tools to make final products, and now 3D Printing is employed to manufacturing end-use parts.

In the world of mechanical engineering, where 3D Printing is heavily used, we call companies that use additive manufacturing to make parts for others 3D Printing Service Bureaus or 3D Printing Service Providers. Therefore, the full process of doing manufacturing using the technology is called: 3D Printing Services.

The critical word in that last sentence is “full.”  Sending a computer model to a 3D Printer is just one of many steps involved in Additive Manufacturing.  When the service is employed correctly, it includes identifying the right type of additive manufacturing to use, preparing the geometry, setting parameters on the machine, printing the parts, removing supports, cleaning the parts, sanding, applying a surface finish treatment, and then inspection and shipping.  Anyone can send a part to a printer; the other steps are what make the difference between simply printing a part, and producing a great part.

What Services does PADT Offer?

Additive Manufacturing covers a wide range of technologies that create parts one layer at a time, using a variety of approaches. Some extrude, some harden, some use an inkjet print head, and still others melt material.  What they have in common is creating solid geometry one layer at a time. Each technology has its own unique set of advantages, and that is why PADT offers so many different 3D Printing technologies for our customers.  Each of these approaches has unique part preparations, machine parameters, and post-printing processes. Each with a unique set of advantages.  The key to success is knowing which technology is best for each part and then executing it correctly.

Currently, PADT’s 3D Printing Services Group makes parts for customers using the following technologies.  Each one listed has a brief description of its advantages.  See our website for more details.

Technology

Abbrv.

Advantages

Fused
Deposition Modeling

FDM

Strong parts

Easy operation

Reliability of systems

Broad material choice

Water soluble supports

Fast

Cost

Polyjet

PolyJet

Multiple materials in a single build

Broad material choices

Custom material choices

Multiple colors in single build

Water soluble supports

Accuracy

Stereolithography

SLA

Part quality

Material options

Speed

Speed

Material properties

Self supporting

Selective
Laser Sintering

SLS

Digital
Light Synthesis

DLS

Speed

Production capable

Surface Finish

Material Choices

Material properties

Orthotropic properties

Direct
Laser Melting (Metal)

DLM

Fully dense metal parts

Accuracy

Speed

Part strength

As a proud reseller for Stratasys systems, we feel strongly that the two primary technologies from Stratasys, FDM and Polyjet, are the best for customers who want to do Additive Manufacturing in-house or as a service provider. When customers need something different, they can come to PADT to take advantage of the unique capabilities found in each technology.

How is 3D Printing with PADT Better?

The difference is in what we know and how to execute the complete process.  As a provider of 3D Printing services for over 23 years, very few people in the industry even come close to the amount of experience that we bring to the table.  We also know product development and traditional manufacturing, so when a customer comes to us with a need, we understand what they are asking to do and why. That helps us make the right recommendation on process, material, and post-processing.

A few differentiators are:

  • We know our machines
  • We know our materials
  • We offer a wide range of plastic and metal materials
  • We understand post-processing
  • We understand support removal (we manufacture the leading support removal system)
  • We understand design and manufacturing
  • In-house machining, painting, and part finishing
  • In-house inspection and quality
  • Employees who are enthusiastic and dedicated to providing the right solution.

In addition to all of these things, PADT also offers On-Demand Manufacturing as a Carbon Production Partner. We combine Carbon’s DLS technology with our existing and proven manufacturing processes to provide low volume manufacturing solutions for plastic components.

We are also always looking at the latest technologies and adding what our customers need.  You can see this with the recent addition of systems from ConceptLaser, Carbon and Desktop Metal systems.

 

Next Steps and Where to Learn More

The very best way to learn more about PADT’s 3D Printing services is to have us print a part. The full experience and the final product will explain why, with so many choices, so many companies large and small count on us for their Additive Manufacturing. If you need to learn more, you can also contact us at 480.813.4884 or rp@padtinc.com.

Here are some links that you may find useful:

 

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Getting to Know PADT: Support Cleaning Apparatus (SCA) Manufacturing and Support

This is the third installment in our review of all the different products and services PADT offers our customers. As we add more, they will be available here.  As always, if you have any questions don’t hesitate to reach out to info@padtinc.com or give us a call at 1-800-293-PADT.

PADT is in the business of helping people who make products.  So most people think of us as a provider of tools and services.  What they do not know is that PADT actually has a few of its own products.  The most successful of these is our line of Support Cleaning Apparatus systems, abbreviated as SCA.  These devices are used to remove soluble support material from parts 3D printed in Stratasys Fused Deposition Modeling Systems. They are robust machines manufactured and serviced by PADT, but sold through the Stratasys worldwide sales channel. As of July of 2017, over 10,800 units have been delivered to Stratasys.

Optimized Performance for Hands-Off Part Cleaning

The Stratasys 3D Printing systems that use Fused Deposition Modeling extrude plastic through a heated nozzle to build parts one layer at a time.  There are actually two nozzles. One puts down the building material and the other a support material that is dissolved in warm water that is slightly base.  The best way to remove that support material is to put it into a warm bath where the part is gently tumbled so that the water can works its way evenly into the part.  Stratasys tried several solutions for a companion washing system and eventually came to PADT and asked if we would try our hand at building a robust and efficient system.

The result was the SCA-1200.  Launched at the end of 2008 it met the design requirements for reliability, part cleaning time, and noise.  Over 7,000 of these systems were shipped and saw heavy usage. In fact, if you have a Stratasys FDM system there is a good chance you have an SCA-1200.  It contained a unique shower head design that was optimized with simulation, and a modular assembly that could be repaired easily in the field.

Based upon the success and lessons learned from the SCA-1200, we released the SCA-1200HT in 2014.  With the same basic form factor, this design replaced the off-the-shelf magnetically coupled pump with a simpler and more reliable custom design from PADT. The new unit also had a more pleasing visual design, several usability enhancements, and a greater temperature range. It has sold over 3,000 units and continues to be a popular system.  The latest release includes a no-temperature setting that allows it to be used to clean Stratasys Polyjet parts.

The success of both system lead to a request to look at building a larger machine that could clean more parts at one time as well as larger parts.  The SCA 3600 has three times the volume but shares many internal parts with the SCA-1200HT.  Both of the new systems are doing well in the field with even better reliability and faster part cleaning times. They are also simpler to debug and repair.

The SCA systems are sold as stand alone devices or are bundled with key Stratasys FDM machines.  You can learn more about them on our SCA page:  www.padtinc.com/sca or you can contact whoever you buy your Stratasys equipment from.

Here is a video for the SCA-1200HT that talks all about what it does:

Practicing what We Preach

One of the most rewarding aspects of designing and manufacturing the SCA family of products was that it forced us to practice what we preach. We talk to companies every day about using simulation, 3D Printing, design for manufacturing, proper product development processes, and many more things needed to get a product right.  With the SCA we were the customer. We had to Walk the Walk or stop talking the talk.

 

It has been a phenomenal experience that has made us even better at helping our customers produce their new products. We used CFD to optimize the gentle agitation design and shower head and worked closely with our vendors to minimize the cost of manufacturing.  The worst part was that when the schedule slipped, we couldn’t blame the customer (only slightly joking).  One of the best set of lessons came from doing the repair and refurbishment of systems that failed. Even though the failure rate was low, we learned a lot and were able to make improvements to future designs. Now when we sit across from a customer and talk about the design, test, and manufacture of their product, we can really say that we understand where they are coming from.

 

 

 

 

 

Learn About the New Stratasys 3D Printers and New Orleans

It was my first time visiting New Orleans. I have heard many stories of how good the food is and how everyone is really nice there so I was excited to visit this city for a business trip. Stratasys Launch 2017! There was some buzz going on about some new FDM printers that Stratasys has been working on and I was really excited to see them and hear what sets them apart from the competition. Rey Chu (Co-Owner of PADT), Mario Vargas (Manager of 3D Printer Sales), Norman Stucker (Account Executive in Colorado), and I (James Barker, Application Engineer) represented PADT at this year’s Launch.

The city did not disappoint! I ate the best gumbo I’ve ever tried. Below is a picture of it with some Alligator Bourbon Balls. The gumbo is Alligator Sausage and Seafood. Sooooo Good!!


My last night in New Orleans, Stratasys rented out Mardi Gras World. That is where they build all the floats for Mardi Gras. They had a few dancers and people dressed up festive. I was able to get a picture of Rey in a Mardi Gras costume.

After dinner at Mardi Gras World, I took Rey and Mario down Bourbon Street one last time and then we went to Café Du Monde for their world famous Beignets. Everyone told me that if I come home without trying the Beignets, then the trip was a waste. They were great! I recommend them as well. Below is picture of Mario and me at the restaurant.

As you can see we had a fun business trip. The best part of it was the unveiling of the new FDM printers! Mario and I sat on the closest table to the stage and shared the table with Scott Crump (President of Stratasys and inventor of FDM technology back in 1988). These new printers are replacing some of Stratasys entry level and mid-level printers. What impressed me most is that they all can print PLA, ABS, and ASA materials with the F370 being able to print PC-ABS. You also can build parts in four different layer heights (.005, .007, .010, and .013”), all while utilizing new software called GrabCad Print.

GrabCad Print is exciting because you can now monitor all of you Stratasys FDM printers from this software and setup queues. What made me and many others clap during the unveiling is that with GrabCad Print you no longer have to export STL files! You can import your native CAD assemblies and either print them as an assembly or explode the assembly and print the parts separately.

      

Everyone wants a 3D Printer that can print parts faster, more accurately and is dependable. You get that with the family of systems! Speed has increased big time, they are twice as fast as the Dimension line of FDM printers. Stratasys has published the accuracy of these new printers to be ±.008” up to a 4 inch tall part and then every inch past 4 inches, you add another .002”. These machines are very dependable. They are replacing the Uprint (Uprint SE Plus is still current), Dimension, and Fortus 250 machines that have been workhorses. Many of our customers still have a Dimension from 2002 when they were first launched. In addition to the 43 existing patents that Stratasys has rolled into this phenomenal product, they have an additional 15 new patents that speaks volumes as to the innovation in these 3D printers.

Stratasys Launch was a blast for me. Seeing these new printers, parts that were printed from them, and understanding why these are the best FDM printers on the market was well worth my time! I look forward to helping you with learning more about them. Please contact me at james.barker@padtinc.com for more information. If you would like to hear my recorded webinar that has even more information about the new F170, F270, and F370, here is the link.  Or you can download the brochure here.

Press Release: New 3D Printing Support Cleaning Apparatus Features Large Capacity for Stratasys FDM Systems

PADT-Press-Release-IconBuilding on the worldwide success of previous products in the family, PADT has just released the new SCA 3600, a large capacity cleaning system for removing the support material from Stratasys FDM parts.  This new system adds capacity and capability over the existing benchtop SCA-1200HT System.

A copy of the press release is below.
At the same time, we are also launching a new website for support removal: www.padtinc.com/supportremoval.

The SCA 3600 can dissolve support from all the SST-compatible materials you use – ABS, PC, and nylon. A “no heat” option provides agitation at room temperature for the removal of Polyjet SUP706 material as well. The SCA 3600’s versatility and efficient cleaning performance are built on the success of earlier models with all the features you have come to expect, in a larger and more capable model.sca_3600-3pics

Since the launch of the original SCA-1200 in 2008, PADT has successfully manufactured and supported the SCA family of products for users worldwide. Common requests from desktop SCA users were for a larger system for bigger parts, the ability to clean many parts at the same time, and the option to remove supports from PolyJet parts. The SCA 3600 is the answer: Faster, larger, and more capable.

sca-logo3-web7SCA 3600 Key Features are:

  • Removes soluble support from ABS, PC, and nylon 3D printed FDM parts
  • Removes soluble support from PolyJet 3D Printed parts
  • User-selectable temperature presets at 50, 60, 70, and 85°C and “No Heat” for PolyJet
  • User-controlled timer
  • Uses cleaning solutions from Stratasys
  • Unique spray nozzle optimizes flow coverage
  • 230 VAC +/- 10%, 15A
  • Whisper-quiet operation
  • Includes rolling cart for easy movement, filling, and draining.
  • Capacity: 27 gal / 102 L
  • Size: 42.8″ x 22.8″ x 36.5″/ 1,086 x 578 x 927 mm
  • 16” x 16” x 14” / 406 x 406 x 356 mm removable large parts basket
  • Integral hinged lid and small part basket
  • Stainless steel tub and basket
  • Over temperature and water level alarms
  • Automatic halt of operation with alarms
  • Field replaceable sub-assemblies
  • Regulatory Compliance: CE/cTUVus/RoHS/WEEE

You can download our new brochure for both systems:

SCA 3600 Spec Sheet

SCA-1200HT Spec Sheet

If you are interested in learning more or adding an SCA 3600 to your additive manufacturing lab, contact your Stratasys reseller.

Official copies of the press release can be found in HTML and PDF.

Press Release:

New 3D Printing Support Cleaning Apparatus Features Large Capacity for Stratasys FDM Systems

Offered Worldwide, the SCA 3600 is Big Enough to Handle Large 3D Printed Parts, Effortlessly Dissolving Support Material

TEMPE, Ariz., November 17, 2016 – Phoenix Analysis & Design Technologies, Inc. (PADT), the Southwest’s largest provider of simulation, product development, and rapid prototyping services and products, today introduced its new SCA3600 3D Printing Support  Cleaning Apparatus (SCA). The systems are sold exclusively by Stratasys, Ltd. (SSYS) for use with its FORTUS line of 3D Printers. The hands-free support removal technology is a huge advantage to people who use Fused Deposition Modeling (FDM) systems for their 3D Printing.

“With more than 10,000 of our benchtop SCA units in the field, we gathered a wealth of knowledge on performance and reliability,” said Rey Chu, Co-owner and Principal of PADT. “We used that information to design and manufacture a system that cleans larger parts, or multiple small parts, while keeping the speed, easy maintenance and great user experience of the benchtop system.”

A powerful upgrade over PADT’s successful SCA-1200HT and SCA-1200 support removal products that have been in use around the world since 2008, the SCA 3600 features a simpler, more user-friendly design. The new versatile SCA offers temperature choices of 50, 60, 70 and 80 degrees Celsius, as well as no-heat, that readily cleans supports from all SST compatible materials – ABS, PC and Nylon. The SCA 3600 also features a large 16” x 16” x 14” parts basket, 3400 watts of heating for faster warm-up and a wheeled cart design for mobility.

The advantages of the system were highlighted by Sanja Wallace, Sr. Director of Product Marketing and Management at Stratasys, Ltd. when she commented, “the addition of the SCA 3600 as an accessory to our very successful FORTUS systems simplifies the support removal process with increased speed and capacity for multiple large parts.”

Once parts are printed, users simply remove them from their Stratasys FDM system, place them in the SCA 3600, set a cleaning cycle time and temperature, and then walk away.  The device gently agitates the 3D printed parts in the heated cleaning solution, effortlessly dissolving away all of the support material. This process is more efficient and user friendly than those of other additive manufacturing systems using messy powders or support material that must be manually removed.

More information on the systems available at www.padtinc.com/supportremoval. Those interested in acquiring an SCA 3600 should contact their local Stratasys reseller.

About Phoenix Analysis and Design Technologies

Phoenix Analysis and Design Technologies, Inc. (PADT) is an engineering product and services company that focuses on helping customers who develop physical products by providing Numerical Simulation, Product Development, and Rapid Prototyping solutions. PADT’s worldwide reputation for technical excellence and experienced staff is based on its proven record of building long term win-win partnerships with vendors and customers. Since its establishment in 1994, companies have relied on PADT because “We Make Innovation Work.” With over 80 employees, PADT services customers from its headquarters at the Arizona State University Research Park in Tempe, Arizona, and from offices in Torrance, California, Littleton, Colorado, Albuquerque, New Mexico, and Murray, Utah, as well as through staff members located around the country. More information on PADT can be found at http://www.PADTINC.com.

###

Media Contact
Alec Robertson
TechTHiNQ on behalf of PADT
585-281-6399
alec.robertson@techthinq.com
PADT Contact
Eric Miller
PADT, Inc.
Principal & Co-Owner
480.813.4884
eric.miller@padtinc.com

 

Technology Trends in Fused Deposition Modeling

A few months ago, I did a post on the Technology Trends in Laser-based Metal Additive Manufacturing where I identified 5 key directions that technology was moving in. In this post, I want to do the same, but for a different technology that we also use on a regular basis at PADT: Fused Deposition Modeling (FDM).

1. New Materials with Improved Properties

Many companies have released and are continuously developing composite materials for FDM. Most involve carbon fibers and are discussed in this review. Arevo Labs and Mark Forged are two of many companies that offer composite materials for higher performance, the table below lists their current offerings (CF = Carbon Fiber, CNT = Carbon Nano Tubes). Virtual Foundry are also working on developing a metal rich filament (with about 89% metal, 11% binder polymer), which they claim can be used to make mostly-metal parts for non-functional purposes using existing FDM printers and a heat treatment to vaporize the binder. In short, while ABS and PLA dominate the market, there is a wide range of materials commercially available and this list is growing each year.

Company Composition
Arevo Labs CF, CNT in PAEK
CF in PEEK
Fiberglass in PARA
Mark Forged Micro-CF in Nylon
CF
Fiberglass
Fiberglass (High Strength High Temperature)
Kevlar

2. Improved Properties through Process Enhancements

Even with newer materials, a fundamental problem in FDM is the anisotropy of the parts and the fact that the build direction introduces weak interfaces. However, there are several efforts underway to improve the mechanical properties of FDM parts and this is an exciting space to follow with many approaches to this being taken. Some of these involve explicitly improving the interfacial strength: one of the ways this can be achieved is by pre-heating the base layer (as being investigated by Prof. Keng Hsu at the Arizona State University using lasers and presented at the RAPID 2016 conference). Another approach is being developed by a company called Essentium who combine microwave heating and CNT coated filaments as shown in the video below.

Taking a very different approach, Arevo labs has developed a 6-axis robotic FDM process that allows for conformal deposition of carbon fiber composites and uses an FEA solver to generate optimized toolpaths for improved properties.

3. Faster & Bigger

A lot of press has centered around FDM printers that make bigger parts and at higher deposition rates: one article discusses 4 of these companies that showcased their technologies at an Amsterdam trade show. Among the companies that showcased their technologies at RAPID was 3D Platform, that showed a $27,000 3D printer for FDM with a 1m x 1m x 0.5m printing platform. Some of the key questions for large form factor printers is if and how they deal with geometries needing supports and enabling higher temperature materials. Also, while FDM is well suited among the additive technologies for high throughput, large size prints, it does have competition in this space: Massivit is one company that in the video below shows the printing of a structure 5.6 feet tall in a mere 5 hours using what they call “Gel Dispensed Printing” that reduces the need for supports.

 4. Bioprinting Applications

Micro-extrusion through syringes or specialized nozzles is one of the key ways bioprinting systems operate – but this is technically not “fused” deposition in that it may not involve thermal modification of the material during deposition. However, FDM technology is being used for making scaffolds for bio-printing with synthetic, biodegradable or bio-compatible polymers such as PCL and PLGA. The idea is these scaffolds then form the structure for seeding cells (or in some cases the cells are bioprinted as well onto the scaffold). This technology is growing fast and something we are also investigating at PADT – watch this space for more updates.

5. Material Modeling Improvements

Modeling FDM is an important part of being able to use simulation/analysis to design better processes and parts for functional use. This may not get a lot of press compared to the items above, but is a particular interest of mine and I believe is a critical piece of the puzzle going to true part production with FDM. I have written a few blog posts on the challenges, approaches and a micromechanics view of FDM printed structures and materials. The idea behind all of these is to represent FDM structures mathematically with valid and accurate models so that their behavior can be predicted and designs truly optimized. This space is also growing fast, the most recent paper I have come across in this space is from the University of Wisconsin-Madison that was published May 12, 2016.

Conclusion

Judging by media hype, metal 3D printing and 3D bioprinting are currently dominating the media spotlight – and for good reasons. But FDM has many things going for it: low cost of entry and manufacturing, user-friendliness and high market penetration. And the technology growth has no sign of abating: the most recent, 2016 Wohlers report assesses that there are over 300 manufacturers of FDM printers, though rumor on the street has it that there are over a thousand manufacturers coming up – in China alone. And as the 5 trends above show, FDM has a lot more to offer the world beyond being just the most rapidly scaling technology – and there are people working worldwide on these opportunities. When a process is as simple and elegant as extruding material from a hot nozzle, usable innovations will naturally follow.

Fused Deposition Modeling (FDM) Properties: A Micromechanics Perspective

Have you ever looked at the mechanical properties in an FDM material datasheet (one example shown below for Stratasys ULTEM-9085) and wondered why properties were prescribed in the non-traditional manner of XZ and ZX orientation? You may also have wondered, as I did, whatever happened to the XY orientation and why its values were not reported? The short (and unfortunate) answer is you may as well ignore the numbers in the datasheet. The longer answer follows in this blog post.

FDM_01

Mesostructure has a First Order Effect on FDM Properties

In the context of FDM, mesostructure is the term used to describe structural detail at the level of individual filaments. And as we show below, it is the most dominant effect in properties.

Consider this simple experiment we did a few months ago: we re-created the geometry used in the tensile test specimens reported in the datasheets and printed them on our Fortus 400mc 3D printer with ULTEM-9085. While we kept layer thickness identical throughout the experiment (0.010″), we modified the number of contours: from the default 1-contour to 10-contours, in 4 steps shown in the curves below. We used a 0.020″ value for both contour and raster widths. Each of these samples was tested mechanically on an INSTRON 8801 under tension at a displacement rate of 5mm/min.

As the figure below shows, the identical geometry had significantly different load-displacement response – as the number of contours grew, the sample grew stiffer. The calculated modulii were in the range of 180-240 kpsi. These values are lower than those reported in datasheets, but closer to published values in work done by Bagsik et al (211-303 kpsi); datasheets do not specify the meso-structure used to construct the part (number of contours, contour and raster widths etc.). Further, it is possible to modify process parameters to optimize for a certain outcome: for example, as suggested by the graph below, an all-contour design is likely to have the highest stiffness when loaded in tension.

FDM-02

Can we Borrow Ideas from Micromechanics Theory?

The above result is not surprising – the more interesting question is, could we have predicted it? While this is not a composite material, I wondered if I could, in my model, separate the contours that run along the boundary from the raster, and identify each as it’s own “material” with unique properties (Er and Ec). Doing this allows us to apply the Rule of Mixtures and derive an effective property. For the figure below, the effective modulus Eeff becomes:

Eeff = f.Ec + (1-f).Er

where  represents the cross-sectional area fraction of the contours.

FDM-3

With four data points in the curve above, I was able to use two of those data points to solve the above equation simultaneously and derive Er and Ec as follows:

Er = 182596 psi
Ec = 305776 psi

Now the question became: how predictive are these values of experimentally observed stiffness for other combinations of raster and contours? In a preliminary evaluation for two other cases, the results look promising.

FDM-4

So What About the Orientation in Datasheets?

Below is a typical image showing the different orientations data are typically attributed to. From our micromechanics argument above, the orientation is not the correct way to look at this data. The more pertinent question is: what is the mesostructure of the load-bearing cross-section? And the answer to the question I posed at the start, as to why the XY values are not typically reported, is apparent if you look at the image below closely and imagine the XZ and XY samples being tested under tension. You will see that from the perspective of the load-bearing cross-section, XY and XZ effectively have the similar (not the same) mesostructure at the load-bearing cross-sectional area, but with a different distribution of contours and rasters – these are NOT different orientations in the conventional X-Y-Z sense that we as users of 3D printers are familiar with.

fdm-5

Conclusion

The point of this preliminary work is not to propose a new way to model FDM structures using the Rule of Mixtures, but to emphasize the significance of the role of the mesostructure on mechanical properties. FDM mesostructure determines properties, and is not just an annoying second order effect. While property numbers from datasheets may serve as useful insights for qualitative, comparative purposes, the numbers are not extendable beyond the specific process conditions and geometry used in the testing. As such, any attempts to model FDM structure that do not account for the mesostructure are not valid, and unlikely to be accurate. To be fair to the creators of FDM datasheets, it is worth noting that the disclaimers at the bottom of these datasheets typically do inform the user that these numbers “should not be used for design specifications or quality control purposes.”

If you would like to learn more and discuss this, and other ideas in the modeling of FDM, tune in to my webinar on June 28, 2016 at 11am Eastern using the link here, or read more of my posts on this subject below. If you are reading this post after that date, drop us a line at info@padtinc.com and cite this post, or connect with me directly on LinkedIn.

Thanks for reading!

~

Two related posts:

Constitutive Modeling of 3D Printed FDM Parts: Part 2 (Approaches)

In part 1 of this two-part post, I reviewed the challenges in the constitutive modeling of 3D printed parts using the Fused Deposition Modeling (FDM) process. In this second part, I discuss some of the approaches that may be used to enable analyses of FDM parts even in presence of these challenges. I present them below in increasing order of the detail captured by the model.

  • Conservative Value: The simplest method is to represent the material with an isotropic material model using the most conservative value of the 3 directions specified in the material datasheet, such as the one from Stratasys shown below for ULTEM-9085 showing the lower of the two modulii selected. The conservative value can be selected based on the desired risk assessment (e.g. lower modulus if maximum deflection is the key concern). This simplification brings with it a few problems:
    • The material property reported is only good for the specific build parameters, stacking and layer thickness used in the creation of the samples used to collect the data
    • This gives no insight into build orientation or processing conditions that can be improved and as such has limited value to an anlayst seeking to use simulation to improve part design and performance
    • Finally, in terms of failure prediction, the conservative value approach disregards inter-layer effects and defects described in the previous blog post and is not recommended to be used for this reason

ULTEM-9085 datasheet from Stratasys - selecting the conservative value is the easiest way to enable preliminary analysis
ULTEM-9085 datasheet from Stratasys – selecting the conservative value is the easiest way to enable preliminary analysis

  • Orthotropic Properties: A significant improvement from an isotropic assumption is to develop a constitutive model with orthotropic properties, which has properties defined in all three directions. Solid mechanicians will recognize the equation below as the compliance matrix representation of the Hooke’s Law for an orthortropic material, with the strain matrix on the left equal to the compliance matrix by the stress matrix on the right. The large compliance matrix in the middle is composed of three elastic modulii (E), Poisson’s ratios (v) and shear modulii (G) that need to be determined experimentally.

Hooke's Law for Orthotropic Materials (Compliance Form)
Hooke’s Law for Orthotropic Materials (Compliance Form)

Good agreement between numerical and experimental results can be achieved using orthotropic properties when the structures being modeled are simple rectangular structures with uniaxial loading states. In addition to require extensive testing to collect this data set (as shown in this 2007 Master’s thesis), this approach does have a few limitations. Like the isotropic assumption, it is only valid for the specific set of build parameters that were used to manufacture the test samples from which the data was initially obtained. Additionally, since the model has no explicit sense of layers and inter-layer effects, it is unlikely to perform well at stresses leading up to failure, especially for complex loading conditions.  This was shown in a 2010 paper that demonstrated these limitations  in the analysis of a bracket that itself was built in three different orientations. The authors concluded however that there was good agreement at low loads and deflections for all build directions, and that the margin of error as load increased varied across the three build orientations.

An FDM bracket modeled with Orthotropic properties compared to experimentally observed results
An FDM bracket modeled with Orthotropic properties compared to experimentally observed results

  • Laminar Composite Theory: The FDM process results in structures that are very similar to laminar composites, with a stack of plies consisting of individual fibers/filaments laid down next to each other. The only difference is the absence of a matrix binder – in the FDM process, the filaments fuse with neighboring filaments to form a meso-structure. As shown in this 2014 project report, a laminar approach allows one to model different ply raster angles that are not possible with the orthotropic approach. This is exciting because it could expand insight into optimizing raster angles for optimum performance of a part, and in theory reduce the experimental datasets needed to develop models. At this time however, there is very limited data validating predicted values against experiments. ANSYS and other software that have been designed for composite modeling (see image below from ANSYS Composite PrepPost) can be used as starting points to explore this space.

Schematic of a laminate build-up as analyzed in ANSYS Composite PrepPost
Schematic of a laminate build-up as analyzed in ANSYS Composite PrepPost

  • Hybrid Tool-path Composite Representation: One of the limitations of the above approach is that it does not model any of the details within the layer. As we saw in part 1 of this post, each layer is composed of tool-paths that leave behind voids and curvature errors that could be significant in simulation, particularly in failure modeling. Perhaps the most promising approach to modeling FDM parts is to explicitly link tool-path information in the build software to the analysis software. Coupling this with existing composite simulation is another potential idea that would help reduce computational expense. This is an idea I have captured below in the schematic that shows one possible way this could be done, using ANSYS Composite PrepPost as an example platform.

Potential approach to blending toolpath information with composite analysis software
Potential approach to blending toolpath information with composite analysis software

Discussion: At the present moment, the orthotropic approach is perhaps the most appropriate method for modeling parts since it is allows some level of build orientation optimization, as well as for meaningful design comparisons and comparison to bulk properties one may expect from alternative technologies such as injection molding. However, as the application of FDM in end-use parts increases, the demands on simulation are also likely to increase, one of which will involve representing these materials more accurately than continuum solids.