The second stop on our trip around the Southwest for Stratasys’ new J750 Full Color 3D Printer was in fantastic downtown Salt Lake City. This device is reinventing 3D printing, and we are showing it off in person so people can see it up close along with holding incredible parts it makes in their hands.
The 3D Printing community in Utah is very mature and the attendees were mostly very experienced users of many different additive manufacturing technologies. So we focused on real world applications for the J750 as well as other Stratasys systems.
We were fortunate enought to have a customer, Ultradent, present the fantastic ways that they use their FDM and Polyjet printers to make prototypes, tooling, and production parts.
As is usual in this type of an event, the discussion between and after presentations are the best part. People from Aerospace, sporting goods, medical devices, and consumer products swapped stories, suggestions, and tips.
It was also a family affair. with Jame Barker’s latest family addition was in attendence to help spread the word on the value of 3D Printing with Stratasys solutions:Beyond the little guy, the other hit of the afternoon was the J750. As seasoned additive manufacturing profesionals they see the incredible leap forward this machine represents – truly reinventing 3D Printing and opening up a huge range of oportunities.
Denver was the first stop on a trip around the Southwest for Stratasys’ new J750 Full Color 3D Printer. We are showing this machine that is reinventing 3D printing off in person so people can see the device up close and hold the incredible parts it makes in their hands.
The Denver event was hosted by St. Patrick’s Brewery in Littleton, right down the street from PADT’s Colorado Office. Several customers and PADT employees gave talks on how to better use 3D Printing, including a presentation from Mario Vargas on the new Stratasys J750.
On top of all of that, local radio station KDMT, Denver’s Money Talk 1690, did a live broadcast from the event. Radio Waves have huge collection of radio stations. You can listen in here. Again, PADT employees and customers talked about 3D Printing as well as the new Stratasys J750.
We also made the local paper, check that out here.
According to some, the novelty of 3D printing has been wearing off — its mentioned in daily conversations, used on Grey’s Anatomy episodes, incorporated in high school and college classes. Most iPhone-wielding millennials know what it is and how it works. It’s not a “new thing” anymore, right?
Coming to Denver, Salt Lake City, and Phoenix — Phoenix Analysis & Design Technologies (PADT) invites you to be one of the first to meet the Stratasys J750 3D Printer: the latest introduction in the portfolio of PolyJet 3D Printers. The Stratasys J750 is the first-ever full-color, multi-material system, which finally addresses the frustration of designers who want realistic models but have to contend with inconsistent color results and rough finishes from current technology.
Unlike other 3D printers currently in existence, the Stratasys J750 can operate with five different colors: cyan, magenta, yellow, black and white — all of the primary colors in the CMYK color process, just like day-to-day 2D full-color printers. The Stratasys J750 also achieves very fine layer thicknesses, enabling high surface quality and the creation of models and parts with very fine, delicate details, where current 3D printers usually result in relatively rough surface finishes.
What does this mean for those who use 3D printing? The Stratasys J750 not only delivers incredible realism but it’s also the most versatile 3D printer available. Designers and producers can say goodbye to the days of adopting multiple 3D-printing technologies and still resorting afterwards to extensive post-processing, such as sanding, painting and bonding.
Before the Stratasys J750, no single 3D printer could deliver full color, smooth surfaces and multiple materials. Now, however, you can print realistic prototypes, presentation models, Digital ABS injection molds, jigs, fixtures, educational and promotional pieces, production parts – or all of the above, with one system.
The Stratasys J750 even goes one step past versatile, simultaneously being the fastest, simplest, and easiest 3D printer to use. The printer includes several user-requested upgrades, such as server functionality, six-material capacity, and even three print modes that are suitable for different priorities: high speed, high mix and high quality. Additionally, where some 3D printing processes must run in a dedicated facility due to the possible hazard of the materials, chemicals and post-processing steps involved, the Stratasys J750 3D Printer uses a clean, easy process, with no hazardous chemicals to handle.
The Stratasys J750 is one choice among an ever-growing array of 3D printers in the marketplace. But its capabilities and versatility make it more than just a 3D printer; It’s a solution-maker.
In other words, Stratasys has just invented 3D printing. Again. PADT’s 3D Printing team can help you pick the best printer for your job and provide you with one-on-one engineering and prototype support.
If you’re at all interested in technology, you won’t want to miss this printer’s big coming-out day.
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.
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.
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.
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.
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.
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 f represents the cross-sectional area fraction of the contours.
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.
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.
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 firstname.lastname@example.org and cite this post, or connect with me directly on LinkedIn.
For 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.
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 email@example.com to see how “We Make Innovation Work”
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.
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.
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.
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.
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.
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”).
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 (firstname.lastname@example.org).
Many of you may have seen the recent launch of an Atlas V rocket from United Launch Alliance (ULA). We are honored to have lent our expertise to ULA’s 3D Printing efforts that resulted in the use of parts on that rocket made with additive manufacturing. We will be talking about that and other ways we help the Aerospace Industry at the 32nd Space Symposium this week in Colorado Springs Colorado. Please stop by!
3D Printing Expertise from PADT Advances Aerospace Industry
Product design and development leader provides additive manufacturing support for United Launch Alliance Atlas V rocket
COLORADO SPRINGS, Colo. – April 11, 2016 – PRLog — Phoenix Analysis & Design Technologies Inc. (PADT), the Southwest’s largest provider of Numerical Simulation, Product Development, and 3D Printing services and products, is highlighting its expertise this week at the 32nd Space Symposium, the premier global, commercial, civil, military and emergent space conference.
During the symposium, PADT experts in additive manufacturing will be on hand to discuss the company’s technical expertise, logistics, sales and service capabilities in the exciting aerospace sector, which contributed to the successful launch on March 22 of a United Launch Alliance (ULA) Atlas V rocket. The Atlas V rocket made use of lightweight thermoplastic 3D printed parts, with the application of Stratasys technology supplied by PADT and consulting from PADT on how best to apply that technology to engineering, tooling, and production.
“PADT continues to be both a great supplier of both polymer and metal additive manufacturing technologies and an additive manufacturing technical consultant to ULA, supporting our Atlas V, Delta IV and future Vulcan Centaur launch vehicles,” said Greg Arend, ULA manager, Additive Manufacturing. “By consulting with PADT, we were able to understand how these technologies enhance our design and manufacturing process, saving time, money and weight. PADT’s knowledge of the use of both polymer and metal materials was instrumental in helping us achieve our success.”
In addition to supplying ULA with Stratasys’ polymer 3D Printing machines, PADT consulted with them early on andled a tour of Oakridge National Labs to help them understand the state of the art for both metal and polymer applications and produced a technological roadmap for both technologies that has largely been followed. Assisted by PADT, both companies made use of additive manufacturing for engineering prototypes, then advanced to the production of tooling for manufacturing and developed the confidence needed to move to flight hardware.
The founders of PADT have been involved with additive manufacturing since the late 1980’s and the company was the first service provider in the Southwest in 1994. Over the years, PADT has built a reputation for technical excellence and a deep understanding of how to apply various 3D printing technologies to enable real world applications. Their sales team has shown the ability to sell sophisticated engineering products to companies large and small, and to provide excellent support to their customers.
“3D Printing is not just about makers, nor is it just about engineering prototypes,” said Rey Chu, co-owner, principal and director of Manufacturing Technologies at PADT. “Every day users are creating production hardware to produce usable parts that save them time and money. Ducts for rockets are a perfect application of 3D printed parts because they are complex, low volume, and can make single parts that need to be made in multiple pieces using traditional methods.”
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
ULTEM-9085 is one of my favorite materials to 3D-print: one of the reasons is it is a high performance polymer that can and has been used for end part manufacturing (see my blog post about ULTEM in functional aerospace parts), but the other is because it is a demanding material to print, in ways that ABS, Polycarbonate and even Nylon are not. What makes it demanding is primarily that ULTEM supports are not soluble and need to be removed mechanically. An additional challenge comes from the fact that the support is best removed when the part is at a high temperature (175-195 C), which requires the use of gloves and reduces the user’s dexterity. For complex geometries with internal channels, this is particularly challenging and occasionally results in an inability to print a certain part in ULTEM-9085, which runs contrary to the design freedom this technology otherwise enables.
In this post, I accumulate what I have learned through working (and failing) on many an ULTEM-9085 job, as well as through discussions with other users, and share this here in terms of design and process guidelines. To demonstrate these guidelines, I use a recent geometry that we printed for the Arizona State University’s (ASU) SAE team for an engine intake manifold. These guidelines apply to the Stratasys Fortus platform (for Fused Deposition Modeling, or FDM) using the Insight software that accompanies these tools. The screen shots are from Insight 10.6, and a Fortus 400 was used to print the parts shown.
Summary of Guidelines:
Orient the part to eliminate supports in regions where you cannot remove them
Remove the supports as soon as the part comes out of the build chamber
Other observations: the interface of separation
1. Part Orientation
The single most important factor in simplifying support removal is part orientation. Most users of the FDM process know that part orientation determines the amount of support material consumed and also impacts the time to build the part. When working with ULTEM-9085, the additional challenge is that it is possible to design in supports that cannot be removed and will require you to scrap the job. This is especially true of internal features. While the automatic orientation feature in Insight allows you to minimize supports, it does not account for the difficulty of removing them. Thus when you are dealing with internal features, you may need to manually orient your part such that the internal features are aligned as close to the vertical as possible, and above the support angle (to be covered later).
As shown in Figure 1, for the intake manifold, I oriented the internal pipe structure close to the vertical and had to iterate a few times and verify that I had no support in the hard-to-reach areas. While I did have supports internally, they were limited to areas that were easy to access.
2. Box Supports
In a recent software upgrade, Insight added the ability to create box supports. The support structures consist of adjacent boxes instead of a continuous raster, which has the effect of allowing for easier separation of the support, though does slow down the build time. In my experience this support strategy does help with removal – the one parameter to consider here is the “Perforations” setting, though the default values were used for this part. The perforation is a layer of model material that is inserted into the support to make for easier breaking off of the support material. All cleavage surfaces in Fig. 3 are at perforation edges and you can see the building like construction with each floor distinguished by a layer of model material. When you have supports in hard to access regions, consider increasing the interval height so as to ensure you get separation at the model-support interface on the part before it occurs within the support on a perforation layer.
3. Optimize Process Parameters
While orientation will have the most significant impact on the support you need, another variable to be aware of is the “Self-Support Angle” parameter. This angle is measured from the horizontal, and represents the minimum angle of the part wall that will be built without supports. As a result, to reduce support requirements, you want this number to be as low as possible so that a greater volume of the part can be self-supported. Stratasys recommends default values, but these scale as a function of the contour width, and layer thickness, as shown in Fig. 4. The values bottom out at 40 degrees for the 0.013″ layer thickness and 43 degrees for the 0.010″ layer thickness. Thus, all other things being equal, you will be able to reduce the support needed by choosing a 0.013″ layer thickness and a 0.026″ or larger contour width. Note that both of these will impact your ability to resolve thin walls and fine features, so ensure you scan through all the tool-paths to validate that the geometry is accurately filled in.
4. Remove Supports Immediately
Supports are best removed when the model-support interface is hot. The best time to do this is right after you remove the parts from the print chamber, which is held at 195 C for ULTEM-9085. Ensure you have safety glasses on, work with thermal gloves and have a plier handy to pull out the support. In theory the parts can be re-heated again (175 C is a reasonable value for the oven), but Stratasys suggests that each re-heat cycle actually strengthens the interface, making it harder to remove. As a result, the best time to remove the supports is immediately out of the printer. Figure 5 shows the results of support removal for the intake manifold parts, including the build sheet.
5. Other Observations: the Interface of Separation
It helps to visualize what we are trying to do when we remove supports. There are two interfaces in question here, as shown in Figure 6. One is the model-support interface, the other is the support-box structure interface. We need separation at the model-support interface since removing the thin piece of interface material can prove challenging if the box supports have broken off (as happened for the piece below). What this means is as you remove support, you need to not just pull the supports but also add some peeling force that creates the separation. Once you create separation at the correct interface, you can pull the supports and should have proper cleavage.
One final point to keep in mind is that in some cases, eliminating internal supports may be impossible, as shown for a different part in Figure 7 below. The point is to eliminate the support in places you cannot reach with your pliers and get enough peeling force applied to. In the case below, I chose to have supports at the wide opening since I had adequate access to them. With practice, you will get a better sense of what supports can and cannot be removed and use that intuition to better shape your design and process layout decisions before you print.
Show your support for ASU’s Formula SAE team at their Facebook page and see a video about the endeavor here.
At a recent Lunch-n-Learn organized by the Arizona Technology Council, I had the opportunity to speak for 10 minutes on 3D printing. I decided to focus my talk on trying to answer one question: how can I determine if 3D printing can benefit my business? In this blog post, I attempt to expand on the ideas I presented there.
While a full analysis of the Return-On-Investment would require a more rigorous and quantitative approach, I believe there are 5 key drivers that determine the value proposition for a company to invest in 3D printing, be it in the form of outsourced services or capital expenditure. If these drivers resonate with opportunities and challenges you see in your business, it is likely that 3D printing can benefit you.
1. Accelerating Product Development
3D printing has its origins in technologies that enabled Rapid Prototyping (RP), a field that continues to have a significant impact in product development and is one most people are familiar with. As shown in Figure 1, PADT’s own product development process involves using prototypes for alpha and beta development and for testing. RP is a cost- and time effective way of iterating upon design ideas to find ones that work, without investing in expensive tooling and long lead times. If you work in product development you are very likely already using RP in your design cycle. Some of the considerations then become:
Are you leveraging the complete range of materials including high temperature polymers (such as ULTEM), Nylons and metals for your prototyping work? Many of these materials can be used in functional tests and not just form and fit assessments.
Should you outsource your RP work to a service bureau or purchase the equipment to do it in-house? This will be determined by your RP needs and one possibility is to purchase lower-cost equipment for your most basic RP jobs (using ABS, for example) and outsource only those jobs requiring specialized materials like the ones mentioned above.
The video below contains several examples of prototypes made by PADT using a range of technologies over the past two decades.
2. Exploiting Design Freedom
Due to its additive nature, 3D printing allows for the manufacturing of intricate part geometries that are prohibitively expensive (or in some cases impossible) to manufacture with traditional means. If you work with parts and designs that have complex geometries, or are finding your designs constrained by the requirements of manufacturing, 3D printing can help. This design freedom can be leveraged for several different benefits, four of which I list below:
2.1 Internal Features
As a result of its layer-by-layer approach to manufacturing a part, 3D printing enables complex internal geometries that are cost prohibitive or even impossible to manufacture with traditional means. The exhaust gas probe in Fig. 2 was developed by RSC engineering in partnership with Concept Laser has 6 internal pipes surrounded by cooling channels and was printed as one part.
2.2 Strength-to-Weight Optimization
One of the reasons the aerospace industry has been a leader in the application of 3D printing is the fact that you are now able to manufacture complex geometries that emerge from a topology optimization solution and reduce component weight, as shown in the bracket manufactured by Airbus in Figure 3.
2.3 Assembly Consolidation
The ability to work in a significantly less constrained design space also allows the designer to integrate parts in an assembly thereby reducing assembly costs and sourcing headaches. The part below (also from Airbus) is a fuel assembly that integrated 10 parts into 1 printed part.
Nature provides several design cues, optimized through the process of evolution over millenia. Some of these include lattices and hierarchical structures. 3D printing makes it possible to translate more of these design concepts into engineering structures and parts for benefits of material usage minimization and property optimization. The titanium implant shown in Figure 5 exploits lattice designs to optimize the effective modulus in different locations to more closely represent the properties of an individuals bone in that region.
3. Simplifying the Supply Chain, Reducing Lead Times
One of the most significant impacts 3D printing has is on lead time reduction, and this is the reason why it is the preferred technology for “rapid” prototyping. Most users of 3D printing for end-part manufacturing identify a 70-90% reduction in lead time, primarily as a result of not requiring the manufacturing of tooling, reducing the need to identify one or more suppliers. Additionally, businesses can reduce their supplier management burden by in-sourcing the manufacturing of these parts. Finally, because of the reduced lead times, inventory levels can be significantly reduced. The US Air Force sees 3D printing as a key technology in improving their sustainability efforts to reduce the downtime associated with aircraft awaiting parts. Airbus recently also used 3D printing to print seat belt holders for their A310 – the original supplier was out of business and the cost and lead time to identify and re-tool a new supplier were far greater than 3D printed parts.
4. Reducing Costs for High Mix Low Volume Manufacturing
According to the 2015 Wohlers report, about 43% of the revenue generated in 3D printing comes from the manufacturing of functional, or end-use parts. When 3D printing is the process of choice for the actual manufacturing of end-use parts, it adds a direct cost to each unit manufactured (as opposed to an indirect R&D cost associated with developing the product). This cost, when compared to traditional means of manufacturing, is significantly lower for high mix low volume manufacturing (High Mix – LVM), and this is shown in Figure 6 for two extreme cases. At one extreme is mass customization, where each individual part has a unique geometry of construction (e.g. hearing aids, dental aligners) – in these cases, 3D printing is very likely to be the lowest cost manufacturing process. At the other end of the spectrum is High Volume Manufacturing (HVM) (e.g. semiconductor manufacturing, children’s toys), where the use of traditional methods lowers costs. The break-point lies somewhere in between and will vary by the the part being produced and the volumes anticipated. A unit cost assessment that includes the cost of labor, materials, equipment depreciation, facilities, floor space, tooling and other costs can aid with this determination.
5. Developing New Applications
Perhaps the most exciting aspect of 3D printing is how people all around the world are using it for new applications that go beyond improving upon conventional manufacturing techniques. Dr. Anthony Atala’s 2011 TED talk involved the demonstration of an early stage technique of depositing human kidney cells that could someday aid with kidney transplants (see Figure 7). Rarely does a week go by with some new 3D printing application making the news: space construction, 3D surgical guides, customized medicine to name a few. The elegant and intuitive method of building something layer-by-layer lends itself wonderfully to the imagination. And the ability to test and iterate rapidly with a 3D printer by your side allows for accelerating innovation at a rate unlike any manufacturing process that has come before it.
As I mentioned in the introduction, if you or your company have challenges and needs in one or more of the 5 areas above, it is unlikely to be a question of whether 3D printing can be of benefit to you (it will), but one of how you should best invest in it for maximum return. Further, it is likely that you will accrue a combination of benefits (such as assembly consolidation and supply simplification) across a range of parts, making this technology an attractive long term investment. At PADT, we offer 3D printing both as a service and also sell most of the printers we use on a daily basis and are thus well positioned to help you make this assessment, so contact us!
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
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.
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.
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.
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.
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.
As I showed in a prior blog post, Fused Deposition Modeling (FDM) is increasingly being used to make functional plastic parts in the aerospace industry. All functional parts have an expected performance that they must sustain during their lifetime. Ensuring this performance is attained is crucial for aerospace components, but important in all applications. Finite Element Analysis (FEA) is an important predictor of part performance in a wide range of indusrties, but this is not straightforward for the simulation of FDM parts due to difficulties in accurately representing the material behavior in a constitutive model. In part 1 of this article, I list some of the challenges in the development of constitutive models for FDM parts. In part 2, I will discuss possible approaches to addressing these challenges while developing constitutive models that offer some value to the analyst.
It helps to first take a look at the fundamental multi-scale structure of an FDM part. A 2002 paper by Li et. al. details the multi-scale structure of an FDM part as it is built up from individually deposited filaments all the way to a three-dimensional part as shown in the image below.
This multi-scale structure, and the deposition process inherent to FDM, make for 4 challenges that need to be accounted for in any constitutive modeling effort.
Anisotropy: The first challenge is clear from the above image – FDM parts have different structure depending on which direction you look at the part from. Their layered structure is more akin to composites than traditional plastics from injection molding. For ULTEM-9085, which is one of the high temperature polymers available from Stratasys, the datasheets clearly show a difference in properties depending on the orientation the part was built in, as seen in the table below with some select mechanical properties.
Toolpath Definition: In addition to the variation in material properties that arise from the layered approach in the FDM process, there is significant variation possible within a layer in terms of how toolpaths are defined: this is essentially the layout of how the filament is deposited. Specifically, there are at least 4 parameters in a layer as shown in the image below (filament width, raster to raster air gap, perimeter to raster air gap and the raster angle). I compiled data from two sources (Stratasys’ data sheet and a 2011 paper by Bagsik et al that show how for ULTEM 9085, the Ultimate Tensile Strength varies as a function of not just build orientation, but also as a function of the parameter settings – the yellow bars show the best condition the authors were able to achieve against the orange and gray bars that represent the default settings in the tool. The blue bar represents the value reported for injection molded ULTEM 9085.
Layer Thickness:Most FDM tools offer a range of layer thicknesses, typical values ranging from 0.005″ to 0.013″. It is well known that thicker layers have greater strength than thinner ones. Thinner layers are generally used when finer feature detail or smoother surfaces are prioritized over out-of-plane strength of the part. In fact, Stratasys’s values above are specified for the default 0.010″ thickness layer only.
Defects: Like all manufacturing processes, improper material and machine performance and setup and other conditions may lead to process defects, but those are not ones that constitutive models typically account for. Additionally and somewhat unique to 3D printing technologies, interactions of build sheet and support structures can also influence properties, though there is little understanding of how significant these are. There are additional defects that arise from purely geometric limitations of the FDM process, and may influence properties of parts, particularly relating to crack initiation and propagation. These were classified by Huang in a 2014 Ph.D. thesis as surface and internal defects.
Surface defects include the staircase error shown below, but can also come from curve-approximation errors in the originating STL file.
Internal defects include voids just inside the perimeter (at the contour-raster intersection) as well as within rasters. Voids around the perimeter occur either due to normal raster curvature or are attributable to raster discontinuities.
Thus, any constitutive model for FDM that is to accurately predict a part’s response needs to account for its anisotropy, be informed by the specifics of the process parameters that were involved in creating the part and ensure that geometric non-idealities are comprehended or shown to be insignificant. In my next blog post, I will describe a few ways these challenges can be addressed, along with the pros and cons of each approach.
The Chief Science Officer program is a program for 6th-12th grade students to represent their school in STEM. And what better way is there for them to identify themselves then with 3D Printed name badges? The program’s sponsors, the AZ SciTech Festival offer a training retreat for the kids who get elected as their school’s CSO and we all thought introducing design and 3D Printing would be a great activity.
As part of the 2015 Fall CSO Institute, PADT’s Jeff Nichols joined local designer and artist John Drury to spend some time with the kids explaining how to work with logos and shapes to convey an idea, and how to design for 3D Printing. The kids worked out their own design and sent it to PADT for printing.
We converted their sketch into a 3D Model, starting in Adobe Illustrator. The sketch was traced with vector geometry and then a generic name was added. This was then copied 144 times and each name was typed in, with a few extras. This step was the only boring part.
The design worked great because it is a simple extrusion with no need for support material. The outline of their names were exported as DXF from Illustrator and then imported onto the 3D Model and extruded up to make a solid model of a badge. This was then copied to make a badge for each student. Then the names were imported and extruded on the patterned badges.
STL files were then made and sent off to one of our Stratasys FDM 3D Printers. The FDM (Fused Deposition Modeling) process extrudes an ABS plastic filament, and you can change material during the build. So, to add a bit of contrast, we changed the filament color after the base of the design was done, making the logo and student names stand out. The final results came out really nice.
This project was a lot of fun because we were able to work with the students. They got what John and Jeff taught them and did a great job. We know they will be placed with pride on back backs and jackets across Arizona.
To learn more about the CSO program, visit their website: http://chiefscienceofficers.org/ Check out the blog. Some of these kids can really write well and their insight into Science, Technology, Math, and Education is insightful.
Every once in a while a customer hits a home run with Additive Manufacturing, and United Launch Alliance had done that with their application of Stratasys technology to the production of flight-ready components for their rockets. They were able to leverage 3D printing to take one component from 140 parts to 16, reducing the risks associated with creating the assembly, the piece part costs, and the assembly cost. And PADT is proud to say we were partners in this effort with ULA and Stratasys.
If you are not familiar with ULA, they are the worlds premier launch service company in the US. It is a joint venture of Boeing and Lockheed that launches the majority of military and civilian payloads that are sent in to space. True "rocket scientists" who are headquartered down the street from PADT's Littleton Colorado office. They just released a ton of information on how they are using the Stratasys devices they acquired through PADT as an example of what the technology can achieve.
Here is a picture from Stratasys of one of ULA's structural engineers, Kyle Whitflow, holding an ECS duct they created on the Stratasys Fortus 900mc they purchased through PADT:
Stratasys just released a great video on how ULA is using the technology. This is a great example of the right people, using the right technology, in the right way:
You can also read the official press release here.
We are highlighting his application as a way to let people know that 3D Printing is not just about makers, nor is it just about engineering prototypes. Every day users are creating production hardware to produce usable parts that save them time and money. Ducts for rockets are a perfect use of the technology because they are complex, low volume, and can make single parts that need to be made in multiple pieces using traditional methods. This application also highlights the power of the material choices available to users of Stratasys FDM technology. ULA is using ULTEM 9085 for these ducts because it is durable, lightweight, and can stand up to the heat of the launch event.
Those of you familiar with the process will notice the dots on the duct. Those are target dots for 3D scanning. ULA took the technology one step further and scan the completed hardware to make sure the manufactured part is within specifications.
The team at ULA has been a pleasure to work with. They saw the promise of Additive Manufacturing but dealt with it like the seasoned professionals that they are. They started by making engineering prototypes, then as they got a feel for the technology they switched to the production of tooling for manufacturing. They have now developed the confidence needed to move to flight hardware. In addition to supplying the machines, PADT consulted with ULA early on, touring their manufacturing facilities to better understand their needs and taking them to see how others are using FDM for manufacturing. We were fortunate enough to even be invited to attend the launch of their Orion spacecraft from Florida as their guest.
We are very excited about the additional uses ULA and other companies will develop in the near future for Additive Manufacturing.
If you want to know more, or would like to have PADT help you in the same way we assisted ULA, please reach out or email email@example.com. If you need promotional services or banners (e.g., to buy Thanksgiving banners online) – feel free to contact us.