Composites Weekly: 3D Printing Advancements in Aerospace, Medical and Automotive – Interview

composites-weekly-logo-1PADT was recently asked to do an interview with Composites Weekly  to talk about what is new in the world of Additive Manufacturing.  Host Jonathan Taylor asked some great questions and we covered a lot of important advances and what to look for in the near future.   Listen here.

inBusiness: Arizona Additive Manufacturing Committee

New Dimension
Committee to advocate manufacturing advancement

The inBusiness magazine published an article on the newly formed Arizona Additive Manufacturing Committee that we co-chair with our friends at Titan Industries under the aegis of the Arizona Technology Council. Link to the article is here:
http://inbusinessmag.com/partner-section/new-dimension#.V36QrvkrKUk

The Committee aims to meet once a month, our second meeting occurs Monday, July 11 2016 at the ASU Polytechnic Campus and is open to anyone in Arizona that works in Additive Manufacturing and has an interest in promoting its growth statewide through collaboration. For more info, connect with me on LinkedIn or send a note to info@padtinc.com and cite this blog post.

inbusiness

Denver’s Money Talk 1690: Interview on State of Manufacturing in Colorado

kdmt-logo-1PADT’s Norman Stucker joins Nathan Morimitsu from Manufacturer’s Edge to discuss the current and future state of manufacturing in Colorado.  Norman speaks to the impact of 3D Printing and how it is changing manufacturing. It is a great discussion that looks beyond the hype and shares where Additive Manufacturing is today and how it is being applied in the real world.

Listen here:

Want to learn more, email us at info@padtinc.com

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:

Webinar on Demand: Make Functional Prototypes More Economically with 3D Printed Injection Molds

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Make Functional Prototypes More Economically

With 3D Printed Injection Molds

Arad Group
3D printed injection molds created by Arad Group

One of the most dramatic impacts of 3D printing on design and manufacturing is with injection molding. Companies such as Seuffer, Unilever, Arad Group and Whale report significant savings in molding costs and production time by 3D printing injection molds to test designs before mass production and produce small quantities of custom parts.

Learn more by viewing this 60-minute webinar as Gil Robinson, Stratasys senior application engineer, explains the what, why and how of 3D printed injection molding.

The Additive Manufacturing Software Conundrum

Why are there so many different software solutions in Additive Manufacturing and which ones do I really need?

This was a question I was asked at lunch during the recently concluded RAPID 3D printing conference by a manager at an aerospace company. I gave her my thoughts as I was stuffing down my very average panini, but the question lingered on long after the conference was over – several weeks later, I decided to expand on my response in this blog post.

There are over 25 software solutions available and being used for different aspects of Additive Manufacturing (AM). To answer the question above, I found it best to classify these solutions into four main categories based on their purpose, and allow sub-categories to emerge as appropriate. This classification is shown in Figure 1 below – and each of the 7 sub-categories are discussed in more detail in this post.

Figure 1. Seven sub-categories of software that are applicable to Additive Manufacturing, sorted by the need into four main categories

Basic Requirements

1. Design Modeler

You need this if you intend to create or modify designs

Most designs are created in CAD software such as SOLIDWorks, CATIA and SpaceClaim (now ANSYS SpaceClaim).  These have been in use long before the more recent rise in interest in AM and most companies have access to some CAD software internally already. Wikipedia has a comparison of different CAD software that is a good starting point to get a sense of the wide range of CAD solutions out there.

2. Build Preparation

You need this if you plan on using any AM technology yourself (as opposed to sending your designs outside for manufacturing)

Once you have a CAD file, you need to ensure you get the best print possible with the printer you have available. Most equipment suppliers will provide associated software with their machines that enable this. Stand-alone software packages do exist, such as the one developed by Materialise called Magics, which is a preferred solution for Stereolithography (SLA) and metal powder bed fusion in particular – some of the features of Magics are shown in the video below.

Scanning & File Transfer

3. Geometry Repair

You need this if you deal with low-quality geometries – either from scans or since you work with customers with poor CAD generation capabilities

Geomagic Design X is arguably the industry’s most comprehensive reverse engineering software which combines history-based CAD with 3D scan data processing so you can create feature-based, editable solid models compatible with your existing CAD software. If you are using ANSYS, their SpaceClaim has a powerful repair solution as well, as demonstrated in the video below.

Improving Performance Through Analysis

4. Topology Optimization

You need this if you stand to benefit from designing towards a specific objective like reducing mass, increasing stiffness etc. such as the control-arm shown in Figure 2

Topology optimization applied to the design of an automobile upper control-arm done with GENESIS Topology for ANSYS Mechanical (GTAM) from Vanderplaats Research & Development and ANSYS SpaceClaim
Figure 2. Topology optimization applied to the design of an automobile upper control-arm done with GENESIS Topology for ANSYS Mechanical (GTAM) from Vanderplaats Research & Development and ANSYS SpaceClaim

Of all the ways design freedom can be meaningfully exploited, topology optimization is arguably the most promising. The ability to now bring analysis up-front in the design cycle and design towards a certain objective (such as maximizing stiffness-to-weight) is compelling, particularly for high performance, material usage sensitive applications like aerospace. The most visible commercial solutions in the AM space come from Altair: with their Optistruct solution (for advanced users) and SolidThinking Inspire (which is a more user-friendly solution that uses Altair’s solver). ANSYS and Autodesk 360 Inventor also offer optimization solutions. A complete list, including freeware, can be availed of at this link.

5. Lattice Generation

You need this if you wish to take advantage of cellular/lattice structure properties for applications like such as lightweight structural panels, energy absorption devices, thermal insulation as well as medical applications like porous implants with optimum bone integration and stiffness and scaffolds for tissue engineering.

Broadly speaking, there are 3 different approaches that have been taken to lattice design software:

I will cover the differences between these approaches in detail in a future blog post. A general guideline is that the generative design approach taken by Autodesk’s Within is well suited to medical applications, while Lattice generation through topology optimization seems to be a sensible next step for those that are already performing topology optimization, as is the case with most aerospace companies pursuing AM technology. The infill/conformal approach is limiting in that it does not enable optimization of lattice structures in response to an objective function and typically involves a-priori definition of a lattice density and type which cannot then be modified locally. This is a fast evolving field – between new software and updates to existing ones, there is a new release on an almost quarterly, if not monthly basis – some recent examples are nTopology and the open source IntraLattice.

Below is a short video demo of Autodesk’s Within:

6. Analysis

You need this if you do either topology optimization or lattice design, or need it for part performance simulation

Basic mechanical FE analysis solvers are integrated into most topology optimization and lattice generation software. For topology optimization, the digitally represented part at the end of the optimization typically has jarring surfaces that are smoothed and then need to be reanalyzed to ensure that the design changes have not shifted the part’s performance outside the required window. Beyond topology optimization & lattice design, analysis has a major role to play in simulating performance – this is also true for those seeking to compare performance between traditionally manufactured and 3D printed parts. The key challenge is the availability of valid constitutive and failure material models for AM, which needs to be sourced through independent testing, from the Senvol database or from publications.

Process Development

7. Process Simulation

You need this if you would like to simulate the actual process to allow for improved part and process parameter selection, or to assess how changes in parameters influence part behavior

The real benefit for process simulation has been seen for metal AM. In this space, there are broadly speaking two approaches: simulating at the level of the part, or at the level of the powder.

  • Part Level Simulation: This involves either the use of stand-alone AM-specific solutions like 3DSIM and Pan Computing (acquired by Autodesk in March 2016), or the use of commercially available FE software such as ANSYS & ABAQUS. The focus of these efforts is on intelligent support design, accounting for residual stresses and part distortion, and simulating thermal gradients in the part during the process. ANSYS recently announced a new effort with the University of Pittsburgh in this regard.
  • Powder Level Simulation: R&D efforts in this space are led by Lawrence Livermore National Labs (LLNL) and the focus here is on fundamental understanding to explain observed defects and also to enable process optimization to accelerate new materials and process research

Part level simulation is of great interest for companies seeking to go down a production route with metal AM. In particular there is a need to predict part distortion and correct for it in the design – this distortion can be unacceptable in many geometries – one such example is shown in the Pan Computing (now Autodesk) video below.

A Note on Convergence

Some companies have ownership of more than one aspect of the 7 categories represented above, and are seeking to converge them either through enabling smooth handshakes or truly integrate them into one platform. In fact, Stratasys announced their GrabCAD solution at the RAPID conference, which aims to do some of this (minus the analysis aspects, and only limited to their printers at the moment – all of which are for polymers only). Companies like Autodesk, Dassault Systemes and ANSYS have many elements of the 7 software solutions listed above and while it is not clear what level of convergence they have in mind, all have recognized the potential for a solution that can address the AM design community’s needs. Autodesk for example, has in the past 2 years acquired Within (for lattice generation), netfabb (for build preparation) and Pan Computing (for simulation), to go with their existing design suite.

Conclusion: So what do I need again?

What you need depends primarily on what you are using AM technologies for. I recommend the following approach:

  • Identify which of the 4 main categories apply to you
  • Enumerate existing capabilities: This is a simple task of listing the software you have access to already that have capabilities described in the sub-categories
  • Assess gaps in software relative to meeting requirements
  • Develop an efficient road-map to get there: be aware that some software only make sense (or are available) for certain processes

In the end, one of the things AM enables is design freedom, and to quote the novelist Toni Morrison: Freedom is not having no responsibilities; it is choosing the ones you want.”  AT PADT, we work with design and analysis software as well as AM machines on a daily basis and would love to discuss choosing the appropriate software solutions for your needs in greater detail. Send us a note at info@padtinc.com and cite this blog post, or contact me directly on LinkedIn. .

Thank you for reading!

3D Printed Molds Save Time and Money for Specialty Lighting Company

Western Technology is a manufacturer of specialty lighting solutions that cater to a variety of highly specialized industries such as aviation, oil and gas, and maritime.  Their products are used in a variety of environments making it important that the design is both versatile and functional.

In their Utah office, they have been successfully utilizing a Stratasys PolyJet 3D Printer to create polyurethane molds.  By using 3D printed molds, they have been able to save both time and money over traditional manufacturing methods.

Western Technology’s 3D Printed Toggle Mold

 “Below is a pictorial of how we’ve used our new 3D printer to develop and create polyurethane parts. The parts we are producing in this mold are used to trigger a magnetic sensor inside a sealed aluminum box. Each part has a magnet and aluminum insert cast inside.” Lyal Christensen at Western Technology

The mold was printed using a Stratasys Objet 500 Connex 1 printer in a Vero Blue material (standard plastic).  This is the final result after support material has been removed.

WT1

The mold is comprised of two halves that each have 3 different parts to create this Polyurethane mold.  Below one side is shown in an un-assembled view.

WT2

Steel pins are press fit into the 3D printed part with ease to help with locating the magnets in the correct location.  Also you can see that the part has a gloss finish to it.  The parts were printed in the glossy mode which helps in minimizing the amount of support material needed to print the parts.

WT3

Inserts and Magnets are added to the mold along with a Urethane mold release agent.  The Aluminum inserts are held in the right place by screws that keep the inserts suspended so that the Urethane can engulf all sides of it.

WT4

The clamped mold then has the Urethane fed into it which is poured at room temperature.  Once all of the cavities are filled, the mold is left to cure at room temperature for just under one hour.  Using this technique, they are able to complete 6 or 7 sets per day.

WT5

The following morning the screws and the insert bridge are removed.

WT6

The mold is pried apart using a flathead screwdriver at specific cutout locations that were printed into the mold.  With a simple turn of the wrist, this mold is easily separated.

WT7

There is a little bit of flash which can easily be removed.  These parts are almost ready for the customer.

WT8

The parts are cut away and are ready for de-flashing and finishing.

WT9

At Western Technology, Lyal estimates this mold would have cost $2,000+ to manufacture in just man hours.  They were able to get 400+ parts out of this mold and are still using it.

If you would like to learn more about how to implement 3D Printing into your processes to save time and money, contact us at sales@padtinc.com.

Simulation Driven Product Development with Free Form Fabrication

am-topo-prezo-titleJoining Two of PADT’s Favorite Things: Simulation and 3D Printing

Recent advances in Additive Manufacturing (3D Printing) have removed barriers to manufacturing certain geometry because of constraints in traditional manufacturing methods. Although you can make almost any shape, how do you figure out what shape to make. Using ANSYS products you can apply topological optimization to come up with a free-form shape that best meets your needs, and that can be made with Additive Manufacturing.

A few months ago we presented some background information on how to drive the design of this type of part using ANSYS tools to a few of our customers.  It was a well received so we cleaned it up a bit (no guarantee there all the typos are gone) and recorded the presentation.  Here it is on YouTube

Let us know what you think and if you have any questions or comments, please contact us.

Selective Laser Sintering (SLS) Additive Manufacturing Service is Back on Line at PADT

sls-sinterstation-padt-2Everyone needs a vacation. After over 15 years of service our Sinterstation 2500Plus needed some facility upgrades  and machine updates. That work is now done and our SLS system is back up and running and better than ever, producing parts for customers who have come to count on its unique capabilities.

sls-housing-bracket-1Selective Laser Sintering (SLS) is a process that uses a high power laser to fuse a bed of powdered material together, sintering the loose powder into solid geometry. It is one of the more mature and robust 3D Printing processes available and is especially well suited for making large strong parts.

We currently run Nylon 11 and Glass Filled Nylon 12 in our machine which has a build volume of 13″ x 11″ x 16.5″ and a layer thickness of 0.004″

sls-sinterstation-cleaning-padt-1Few service providers have as much experience as PADT with this system, we have been using it for over 15 years. During that time we have upgraded almost every component and during the recent downtime, the system was fully calibrated and tuned for maximum precision and performance. We are also experts on how to post process the parts that come out of this machine, including painting and other coatings.

Just a Part of 3D Printing at PADT

PADT features 3D Printing services using Stratasys FDM and PolyJet technologies, making precision parts with a wide variety of materials and colors. We also offer Stereolithography (SLA) Additive Manufacturing services along with soft tooling and injection molding consulting.

 

Demo-Room-Pic-1If you are using a big impersonal 3D Printing “mill” or are not sure where to get your 3D Printing done, reach out to PADT. We have been doing it since 1994 and have hundreds of happy and loyal customers.

email: rp@padtinc.com

call: 480.813.4884

or visit our Rapid Prototyping Services pages at:

www.padtinc/com/rp

sls-gear-box-1

Do you have an Internet of Things Strategy? PADT Can Help

thing-1-250w“It is not just a trend, it is a Tsunami. One day you will wake up and see a giant wave headed your way, and that wave will be the Internet of Things!”

This was the opening line from a presentation given by the VP of sales for a major engineering software company. It got my attention because it wasn’t hype or hyperbole.  He was just pointing out the obvious. Over the past two years the signs have been there. Smart devices will connected to the internet, and older devices will be made smart and then connected. Those that don’t, will no longer be competitive.

It is not all about smart thermostats. Far from it.  I went to IoT world in San Jose last week and saw a lot of people scrambling to find their solution. And a few that found them.  The best example was an older letter stamping machine, you can guess at the manufacturer, that plugged a modular device from Electric Imp in to their controller and boom – they were connected.  Some back end programming and they now had a competitive IoT device.

iot-networ-graphic-1 It is time to define and execute on your IoT strategy

When we visit customers, we will often ask them what their IoT Strategy is.  The answers vary from “we don’t really think our products have an IoT play” to existing products on the market.  The focus in the media is on consumer IoT products, but the bigger push right now is for industrial Internet, where machines used in manufacturing, energy generation, raw material extraction, and processing are smart and connected.

Customers from consumers to other companies will be requiring the benefits of IoT devices as they look to replace older hardware.  That is why every company that makes physical products needs to develop an IoT strategy.

PADT Can Help

We have been helping our customers define and implement their approach to IoT well, since before it was called the Internet of Things.  From assisting semiconductor companies that make MEMS sensors to making smart medical devices we are plugged in to what is needed to make IoT work.

iot-landing-page-padt-1A good place to start is our IoT landing page at:

www.padtinc.com/iot

There you can find some basic information about how PADT is a more comprehensive and technically capable solution then most design houses that claim to have IoT solutions.  We are uniquely qualified to make sure the “Thing” in your IoT strategy is designed and manufactured right.

pbj-phoenix-business-journal-logoWe also published a series of articles in the Phoenix Business Journal that provide some fundamental background information on the Internet of Things and how to deal with the challenges it presents:

ansys-iot-wheelSimulation can play a big role in almost every aspect of making your IoT device development faster and more productive.  PADT uses ANSYS, Inc.’s comprehensive Multiphysics simulation tool set to model everything from the chip to the embedded system software.

We highly recommend this white paper, “Engineering the Internet of Things

We also have a recording of a very popular webinar that we did: “Engineering the Internet of Things Devices with ANSYS Simulation

and this video on how ANSYS can drive your IoT Design:

For detailed examples, check out the ANSYS IoT Landing page to get a feel for why so many companies are driving their design with ANSYS simulation software:  www.ansys.com/iot

PADT-Webinar-Logo

Engineering the Internet of Things Devices with ANSYS Simulation

June 21, 2016 (Tue)
1:00 PM AZ & PDT / 2:00 pm MDT

REGISTER

Make sure you subscribe to PADT’s email list so you don’t miss future Events

Talking is the Best Approach

We hope that you find all of the material above, and the information we will provide in the coming months useful. But they are no substitute for giving us a call or sending us an email and setting up a face-to-face to talk about your IoT strategy and device development needs.  If you are doing the work in-house, we have the hardware and software tools you need to be successful. If you need outside help, you won’t find engineers with more applicable experience.

Give us a call at 1-800-293-PADT or email info@padtinc.com.

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Spinning Gears: 3D Printing Awards for 2016 AZ SciTech Festival Sponsors

SciTech-Festival-Award-2016-2For several years now PADT has 3D Printed special thank you awards for the fantastic companies that sponsor the Arizona SciTech Festival.  This year we decided to stick with the color of the Stratasys Connex3 but add some moving parts. This gear design spins around and was made as one part, we just wash the support material out of the gaps between parts.

This is a great example of going directly from a CAD model to a custom part.  Each award has the recipient’s name printed on the smaller gear.  Everything was designed in an hour or so and it took about another hour to add in the 30 or so names.  We think these may be the best awards we have made so far.

SciTech-Festival-Award-2016-1

SciTech-Festival-Award-2016-3

Here is a video showing off how they spin:

Awards are kind of simple and fun. But the same technology is applied by PADT to help our customers design and build better medical devices, rockets, aircraft engines, computers, and pretty much any physical product you can think of.  Give us a call at 1-800-293-PADT or email info@padtinc.com to see how “We Make Innovation Work”

Unexpected Joys at Rapid 2016

While much has been (justifiably) written about HP and XJet releasing new, potentially game-changing products at RAPID 2016, I wanted to write this post about some of the smaller, unexpected joys that I discovered. If I sound overly enthusiastic about the people and companies behind them, it is likely due to the fact that I wrote this on the flight back, staring out at the clouds and reflecting on what had been a wonderful trip: I own no locks, stocks or barrels in any of these companies.

1. Essentium Materials – Carbon Nanotubes and Microwaves to improve FDM mechanical properties
Over the past year, I have studied, written and made presentations about the challenges of developing models for describing Fused Deposition Modeling (FDM) given their complex and part-specific meso-structure. And while I worked on developing analytical and numerical techniques for extracting the best performance from parts in the presence of significant anisotropy, the team at Essentium has developed a process to coat FDM filaments with Carbon nanotubes and extrude them in the presence of microwave radiation. In the limited data they showed for test specimens constructed of unidirectional tool-paths, they demonstrated significant reduction in anisotropy and increase in strength for PLA. What I liked most about their work is how they are developing  this solution on a foundation of understanding the contributions of both the meso-structure and inter-filament strength to overall part performance. Essentium was awarded the “RAPID Innovations award”, first among the 27 exhibitors that competed and are, in my opinion, addressing an important problem that is holding back greater expansion of FDM as a process in the production space.
Website: http://essentiummaterials.com/

2. Hyrel 3D – Maker meets Researcher meets The-Kid-in-All-of-Us
I only heard of Hyrel 3D a few days prior to RAPID, but neglected to verify if they were exhibiting at RAPID and was pleasantly surprised to see them there. Consider the options this 3D printer has that you would be hard pressed to find in several 3D printers combined: variable extrusion head temperatures (room temp to 450 C), sterile head options for biological materials, a 6W laser (yes, a laser), spindle tools, quad head dispensing with individual flow control and UV crosslinking options. Read that again slowly. This is true multiple degree-of-freedom material manipulation. What makes their products even more compelling is the direct involvement of the team and the community they are building up over time, particularly in academia, across the world, and the passion with which they engage their technology and its users.
Website: http://www.hyrel3d.com/

3. Technic-Print: New Chemistry for Improved FDM Support Removal
If you manufacture FDM parts with soluble supports, keep reading. A chemist at Technic Inc. has developed a new solution that is claimed to be 400% faster than the current Sodium-Hydroxide solution we use to dissolve parts. Additionally, the solution is cited as being cleaner on the tank, leaving no residue, has a color indicator that changes the solution’s color from blue to clear. And finally, through an additional agent, the dissolved support material can be reclaimed as a clump and removed from the solution, leaving behind a solution that has a pH less than 9. Since PADT manufactures one of the most popular machines that are used to dissolve these supports that unbeknown to us, were used in the testing and development of the new solution, we had an enriching conversation with the lead chemist behind the solution. I was left wondering about the fundamental chemistry behind color changing, dissolution rates for supports and the reclaiming of support – and how these different features were optimized together to develop a usable end-solution.
Website: http://www.technic.com/techni-print-lp

 

4. Project Pan: Computationally Efficient Metal Powder Bed Fusion Simulation
I presented a literature review at AMUG (another Additive Manufacturing conference) last month, on the simulation of the laser-based powder bed fusion. At the time, I thought I had captured all the key players between the work being done at Lawrence Livermore National Labs by Wayne King’s group, the work of Brent Stucker at 3DSIM and the many academics using mostly commercially available software (mostly ANSYS) to simulate this problem. I learned at RAPID that I had neglected to include a company called “Project Pan” in my review. This team emerged from Prof. Pan Michaleris’s academic work. In 2012, he started a company that was acquired by Autodesk two months ago. In a series of 3 presentations at RAPID, Pan’s team demonstrated their simulation techniques (at a very high level) along with experimental validation work they had done with GE, Honeywell and others through America Makes and other efforts. What was most impressive about their work was both the speed of their computations and the fact that this team actually had complex part experimental validations to back up their simulation work. What most users of the powder bed fusion need is information on temperatures, stresses and distortion – and within time frames of a few hours ideally. It seems to me that Pan and his team took an approach that delivers exactly that information and little else using different numerical methods listed on their site (novel Hex8 elements, an element activation method and intelligent mesh refinement) that were likely developed by Pan over the years in his academic career and found the perfect application, first in welding simulation and then in the powder bed fusion process. With the recent Autodesk acquisition, it will be interesting to see how this rolls out commercially. Details of some of the numerical techniques used in the code can be found at their website, along with a list of related publications.

Website: http://pancomputing.com/

5. FDA Participation: Regulating through education and partnership
On a different note from the above, I was pleasantly surprised by the presence of the FDA, represented by Matthew Di Prima, PhD. He taught part of a workshop I attended on the first day, took the time to talk to everyone who had an interest and also gave a talk of his own in the conference sessions, describing the details of the recently released draft guidance from the FDA on 3D printing in medical applications. It was good to connect the regulatory agency to a person who clearly has the passion, knowledge, intelligence and commitment to make a difference in the Additive Manufacturing medical community. Yes, the barriers to entry in this space are high (ISO certifications, QSR systems, 510(k) & Pre-Market Approvals) but it seems clear that the FDA, at least as represented by Dr. Di Prima, are doing their best to be a transparent and willing partner.
Website: http://www.fda.gov/MedicalDevices/ProductsandMedicalProcedures/3DPrintingofMedicalDevices/default.htm

What really makes a trip to a conference like RAPID worth it are the new ideas, connections and possibilities you come away with that you may not stumble upon during your day job – and on that account, RAPID 2016 did not disappoint. As a line in one of my favorite song’s goes:

“We’ll never know, unless we grow.
There’s too much world outside the door.”
– Fran Healy (Travis, “Turn”).

Synergy in Action, or How PADT is More than the Sum of its Parts

PADT-Company-Photo-2016-01-600wPADT talks a lot about synergy as a key strength and a key element of the value we provide to our customers. Our three departments, Manufacturing, Services, and Sales, are in constant communication, always leveraging one another’s expertise to solve problems. Strong internal relationships — a consequence of being under the same roof — precipitate easy and abundant information and resource sharing. Communication, paradigm, alignment, synergy: clear as day.

But what does any of that mean?

When a PADT product development customer meets us for the first time, he or she may be shown a slide that looks like this:

synergy-f01

Strong bilateral communication among the Product Development, 3D Printing, and Analysis groups means that the project is enriched by contributions from experts across several fields, multiplying the value we add in the development process. For instance, the product will likely someday run into a sticky problem without a clear solution. PADT can attack it from multiple angles, such as design adjustment, finite element analysis (FEA) optimization, and the iterative testing of 3D printed prototypes.

Ok, but still: what does any of that mean?

A longtime customer of PADT’s product development group recently ran into an urgent problem without a clear path to a solution. Their manufacturing partner called them and said that a particular subassembly in their design will cost three times more than expected, which would raise the price of the product above the maximum the market would bear. PADT was presented with the problem: how do we reduce the subassembly cost by 66% while maintaining overall performance, and how do we confidently select a solution in under a week?

PADT’s three engineering groups jumped in to help.

The Product Development group held a brainstorming session and came out with two adjustments to bring overall cost down. First, the subassembly of three bonded unique steel parts would be replaced by a single injection molded plastic part. This change reduces component cost to within the target, but also significantly reduces the final assembly’s structural integrity.

synergy-f02
Reduction of 3 parts to 1 part

Secondly, a plastic stiffener truss was added between components to mitigate the reduction in overall stiffness. This change adds a little assembly cost, but also significantly increases the final assembly’s structural integrity, which had been weakened by the first change.

synergy-f03
Addition of Stiffening Member

The Analysis group conducted a series of FEA simulations, first to determine the increased bending under load and second to select a material to balance the conflicting requirements for stiffness, strength, and cost. After multiple simulation iterations, it was determined that Product Development had selected a permissible path forward and that a glass-filled polypropylene provides the best combination of the three parameters.

synergy-f04
Bending under load for Material Choices 1, 2, and 3

The 3D Printing group then printed the new design for qualitative “look and feel” testing and quantitative force/deflection study. The group was able to closely match the properties of the selected material from their collection of printable filaments and top-shelf industrial printers, reproducing even the fine details — subtle fillets, radii — that boost strength but are missed with lower quality printers. Through prototype tests, it was determined that Analysis selected an appropriate material and Product Development selected an appropriate design.

In the end, PADT was able to confidently select a solution to the customer’s unique cost problem in under a week. Thanks to the synergy of three groups — Product Development, Analysis, and 3D Printing — the customer was able to stay on schedule and enter the market at a relevant price.

So how can PADT help my product?

PADT’s system for delivering services is a textbook example of synergy in action, and it represents a uniquely effective solution to your company’s product problems. Whether you’re in concept design or high-volume production, PADT will tailor-make a solution that fits your budget, schedule, and technical requirements.
Give us a call at 1–800–293-PADT or email info@padtinc.com.

PADT and ASU Collaborate on 3D Printed Lattice Research

The ASU Capstone team (left to right): Drew Gibson, Jacob Gerbasi, John Reeher, Matthew Finfrock, Deep Patel and Joseph Van Soest.
ASU student team (left to right): Drew Gibson, Jacob Gerbasi, John Reeher, Matthew Finfrock, Deep Patel and Joseph Van Soest

Over the past two academic semesters (2015/16), I had the opportunity to work closely with six senior-year undergraduate engineering students from the Arizona State University (ASU), as their industry adviser on an eProject (similar to a Capstone or Senior Design project). The area we wanted to explore with the students was in 3D printed lattice structures, and more specifically, address the material modeling aspects of these structures. PADT provided access to our 3D printing equipment and materials, ASU to their mechanical testing and characterization facilities and we both used ANSYS for simulation, as well as a weekly meeting with a whiteboard to discuss our ideas.

While there are several efforts ongoing in developing design and optimization software for lattice structures, there has been little progress in developing a robust, validated material model that accurately describes how these structures behave – this is what our eProject set out to do. The complex internal meso- and microstructure of these structures makes them particularly sensitive to process variables such as build orientation, layer thickness, deposition or fusion width etc., none of which are accounted for in models for lattice structures available today. As a result, the use of published values for bulk materials are not accurately predictive of true lattice structure behavior.

In this work, we combined analytical, experimental and numerical techniques to extract and validate material parameters that describe mechanical response of lattice structures. We demonstrated our approach on regular honeycomb structures of ULTEM-9085 material, made with the Fused Deposition Modeling (FDM) process. Our results showed that we were able to predict low strain responses within 5-10% error, compared to 40-60% error with the use of bulk properties.

This work is to be presented in full at the upcoming RAPID conference on May 18, 2016 (details at this link) and has also been accepted for full length paper submission to the SFF Symposium. We are also submitting a research proposal that builds on this work and extends it into more complex geometries, metals and failure modeling. If you are interested in the findings of this work and/or would like to collaborate, please meet us at RAPID or send us an email (info@padtinc.com).

Our final poster and the Fortus 400mc that we printed all our honeycomb structures with
The final poster summarizing our work rests atop the Stratasys Fortus 400mc that we printed all our honeycomb structures on

Technology Trends in Laser-based Metal Additive Manufacturing

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Figure 1. Concept Laser’s M2 Cusing at AMUG 2016

One of the more difficult things about being at the Additive Manufacturing Users Group (AMUG) is dealing with the fact that there is more to do than you can hope to accomplish in four and a half days. So I decided to focus on two themes: laser-based metal additive manufacturing (AM); and design & simulation for AM. In this post, I focus on the former and try to distill the trends I noticed across the laser-based metal AM system manufacturers that were present at the conference: Concept Laser, SLM, Renishaw, EOS and 3D Systems (listed here in the decreasing order of the time I spent at each supplier’s booth). While it is interesting to study how 5 different suppliers interpret the same technology and develop machines around it, it is not my objective to compare them here, but to extract common trends that most suppliers seem to be working on to push their machines to the next level. For the purposes of this post, I have picked the top-of-the-line machine that each supplier offers as an indication of the technology’s capabilities: they span a range of price points, so once again this is not meant to be a comparison.

As a point of observation, the 5 key trends I noticed turned out to be all really aspects of taking the technology from short run builds towards continuous production. This was not my intent, so I believe it is an accurate indication of what suppliers are prioritizing at this stage of the technology’s growth and see as providing key levers for differentiation.

1. Quality Monitoring

Most customers of AM machines that wish to use it for functional part production bemoan the lack of controls during manufacturing that allow them to assess the quality of a part and screen for excursionary behavior without requiring expensive post-processing inspection. Third party companies like Sigma Labs and  Stratonics have developed platform-independent solutions that can be integrated with most metal AM systems. Metal AM suppliers themselves have developed a range of in-situ monitors that were discussed in a few presentations during AMUG, and they generally fall into the following categories:

  • Input Monitors:
    • Laser: Sensors monitor laser powder as well as temperature across the different critical components in the system
    • Oxygen Level: Sensors in the build chamber as well as in sieving stations track O2 levels to ensure the flushing of air with inert Argon or Nitrogen has been effective and that there are no leaks in the system
  • Output Monitors:
    • Live video: simple but useful, this allows users to get a live video stream of the top layer as it is being built and can help detection of recoater blade damage and part interaction
    • Meltpool: Concept Laser showed how its Meltpool monitoring system can be used to develop 2D and 3D plots that can be superimposed with the 3D CAD file to identify problematic areas – the video is also on YouTube and embedded below. SLM and EOS offer similar meltpool monitoring solutions.
    • Coater consistency: Concept Laser also described a monitor that captures before and after pictures to assess the consistency of the coater thickness across the build area – and this information is fed forward to adjust subsequent coater thicknesses in an intelligent manner.

Quality monitoring systems are still in their infancy with regard to what is done with the information generated, either in terms of feed forward (active) process control or even having high confidence in using the data to validate part quality. A combination of supplier development and academic and industry R&D is ongoing to get us to the next level.

2. Powder Handling

In a previous post, I touched upon the fire and explosion risks posed by metal powder handling. To lower the bar for an operator to gain access to a metal AM machine, one of the considerations is operator safety and the associated training they would need. Suppliers are constantly trying to improve the methods by which they can minimize powder handling. For a mechanical engineer, it is intriguing to see how reactive metal powders can be moved around in inert atmospheres using different strategies. The SLM 500HL uses a screw system to move the powder around in narrow tubes that stick out of the machine and direct the material to a sieving station after which they are returned to the feed area. The Renishaw RenAM 500M on the other hand uses a pneumatically driven recirculation system powered by Argon gas that is well integrated into the machine frame. Concept Laser also offers automated powder handling on the XLine 2000R, while EOS and 3DSystems do not offer this at the moment. Figure 2 below does not do justice to the level of complexity and thought that needs to go into this.

Figure 2. Two different automated powder handling systems in use in metal AM machines

One of the limitations of automating powder handling is the ability to change materials, which is very hard to impossible to do with high enough confidence with these systems. As a result, their use is limited to cases where one machine can be dedicated to one material and efficiency gains of powder handling can be fully realized. The jury is still out on the long term performance of these systems, and I suspect this is one area that will continue to see improvements and refinements in subsequent model releases.

3. Multi-Laser Processing

In the quest for productivity improvement, one of the biggest gains comes from increasing the number and power of available lasers for manufacturing. In my previous experience with laser based systems (albeit not for this application), an additional laser can increase overall machine throughput by 50-80% (it does not double due to steps like the recoater blade movement that does not scale with the number of lasers).

The suppliers I visited at AMUG have very different approaches to this: SLM provides the widest range of customizable options for laser selection with their 500HL, which can accept either 2 or 4 lasers with power selection choices of 400W or 1000W (the 4 laser option was on display, YouTube video from the same machine in action is below) – the lasers of different powers can also be combined to have two 400W and two 1000W lasers. Concept Laser’s XLine 2000R allows for either 1 or 2 1000W lasers and their smaller, M2 machine that was showcased at AMUG has options for 1 or 2 lasers, with power selection of 200W or 400W. EOS, Renishaw and 3D Systems presently offer only single laser solutions: the EOS M 400 has one 1000W laser, Renishaw’s RenAM 500M has one 500W laser and the ProX DMP 320 from 3D Systems has one 500W laser.

There are a few considerations to be aware of when assessing a multi-laser machine: Each laser drives an increase in machine capital cost. But there is another point of note to remember when using multi-laser systems for manufacturing that centers around matching process outputs from different lasers: laser-to-laser variation can be a dominant source of overall process variation and can drive a need to calibrate, maintain and control both lasers as if they were independent machine systems. Additionally, development of  a process on one particular laser power (100W, 400W, 500W, 1000W) may not scale easily to another and is something to remember when developing a long term strategy for metal AM that involves different kinds of machines, even if from the same supplier.

4. Software Integration

Renishaw spent a significant amount of time talking about their easy-to-use QuantAM software which is designed to integrate Renishaw process parameters and part processing information more tightly and allow for seamless process parameter development without needing third part software like Magics. Additive Industries announced in their presentation at AMUG that they had just signed an agreement with 3DSIM to integrate their support design software solution into their MetalFab1 machine. Software integration is likely to be an increasing trend especially around the following areas:

  • Improving support design methods and reducing its empirical nature and reducing the material, build time and support removal costs associated with them as well as eliminating the need for iterative builds
  • Increasing process options available to the user (for example for the outer skin vs the inner core, or for thick vs thin walls)
  • Simplifying the development of optimized process parameters for the user working on new materials
  • Integrating design and process optimization to increase effective part performance

In a future blog post, I will look specifically at the many design and simulation tools available around AM and how they are connected today even if not well-synergized.

5. Modular System Architectures

In a list of mostly evolutionary changes, this is the one area that struck me as being a step-change in how this technology will make an impact, even if it will be felt only by larger scale manufacturers. Concept Laser and Additive Industries are two companies that delivered presentations discussing how they were approaching the challenge of revolutionizing the technology for true production and minimizing the need for human touch. Common to both is the notion of modularity, allowing for stacking of printing, powder removal, heat treating and other stations. While Additive Industries are developing a flow resembling a series production line, Concept Laser have taken the more radical approach of having autonomous vehicles delivering the powder bed to the different stations, with travel channels for the vehicles, for the operator and for maintenance access (Figure 3). Both companies expect to have solutions out by the end of this year.

Figure 3. Concept Laser’s “Factory of Tomorrow” features swim-lanes for operators and for autonomous vehicles that will deliver powder and parts from one module to another

Concluding Thoughts

It is an interesting time to be a manufacturer of laser-based metal 3D printers, and an even more interesting time to be a consumer of this technology. The laser-material interaction fundamentals of the process are now fairly well-established. Competitors abound both in existing and emerging markets with machines that share many of the same capabilities. Alternative technologies (E-Beam melting, deposition and jetting) are making strides and may start to play in some applications currently dominated by laser-based technologies. A post early-adopter chasm may be around the corner. This will continuously drive the intense need to innovate and differentiate, and possibly also lead to a merger or two. And while most of the news coming out of conferences is justifiably centered around new process technologies (as was the case with Carbon’s CLIP and XJET’s metal nanoparticle jetting at AMUG this year), I think there is an interesting story developing in laser-based powder bed fusion and can’t wait to see what AMUG 2017 looks like!