Metal Additive Manufacturing, or Metal 3D Printing, is a topic that generates a lot of interest, and even more questions. So we held a webinar on February 9th, 2016 to try and answer the most common questions we encounter. It was a huge success with over 150 people logging in to watch live. But many of you could not make it so we have put the slides and a recording of the webinar out there. Just go to this link to access the information.
The presentation answered the fllowing common questions:
Who are PADT and Concept Laser?
How does laser-based metal 3D printing work?
Are there other ways to 3D print in metal and how do they compare?
What are the different process steps involved?
How “good” are 3D printed metal parts?
What materials and machines do you offer?
Who uses this technology today?
What is the value proposition of metal 3D printing for me?
What can I do after this webinar?
As always, our technical team is available to answer any additional questions you may have. Just shoot an email to firstname.lastname@example.org or give us a call at 480.813.4884.
Most histories of Additive Manufacturing (3D printing) trace the origins of the technology back to Charles Hull’s 1984 patent, the same year production began on the first of the Back to the Future movies. Which is something of a shock when you see 3D printing dotting the Gartner Hype Cycle like it was invented in the post-Seinfeld era. But that is not what this post is about.
When I started working on Additive Manufacturing (AM), I was amazed at the number of times I was returning to text books and class notes I had used in graduate school a decade ago. This led me to reflect on how AM is helping bring back to the forefront disciplines that had somehow lost their cool factor – either by becoming part of the old normal, or because they contained ideas that were ahead of their time. I present three such areas of research that I state, with only some exaggeration, were waiting for AM to come along.
Topology Optimization: I remember many a design class where we would discuss topology optimization, look at fancy designs and end with a conversation that involved one of the more cynical students asking “All that’s fine, but how are you going to make that?”. Cue the elegant idea of building up a structure layer-by layer. AM is making it possible to manufacture parts with geometries that look like they came right out of a stress contour plot. And firms such as ANSYS, Autodesk and Altair, as well as universities and labs are all working to improve their capabilities at the intersection of topology optimization and additive manufacturing.
Lattice Structures: One of the first books I came across when I joined PADT was a copy of Cellular Solids by Lorna Gibson and M.F. Ashby. Prof. Gibson’s examples of these structures as they occur in nature demonstrate how they provide an economy of material usage for the task at hand. Traditionally, in engineering structures, cellular designs are limited to foams or consistent shapes like sandwich panels where the variation in cell geometry is limited – this is because manufacturing techniques do not normally lend themselves well to building complex, three dimensional structures like those found in nature. With AM technologies however, cell sizes and structures can be varied and densities modified depending on the design of the structure and the imposed loading conditions, making this an exciting area of research.
Metallurgy: As I read the preface to my “Metallurgy for the Non-Metallurgist” text book, I was surprised to note the author openly bemoan the decline of interest in metallurgy, and subsequently, fewer metallurgists in the field. And I guess it makes sense: materials science is today mostly concerned with much smaller scales than the classical metallurgist trained in. Well, lovers of columnar grain growth and precipitation hardening can now rejoice – metallurgy is at the very heart of AM technology today – most of the projected growth in AM is in metals. The science of powder metallurgy and the microstructure-property-process relationships of the metal AM technologies are vital building blocks to our understanding of metal 3D printing. Luckily for me, I happen to possess a book on powder metallurgy. And it too, is from 1984.
At PADT, we’re as big of a fan as anyone of the cool, trendy software and IT companies that run up billion dollar valuations in Silicon Valley and keep us all entertained and productive with their latest apps and platforms.
But as an engineering product and services company, we’re hardware geeks at heart and one of our favorite conferences is coming up quick. It’s the Aerospace, Aviation, Defense and Manufacturing (AADM) Conference hosted by the Arizona Technology Council and Arizona Commerce Authority on March 3 at the Hilton Scottsdale Resort.
Arizona has a rich history in this sector. TechAmerica’s 2014 Cyberstates Report ranks Arizona fourth nationwide for jobs in the space and defense systems manufacturing industry, employing more than 8,300 people. Industry giants such as Raytheon, Honeywell, Boeing, Lockheed Martin and General Dynamics all have a big presence here. Luke Air Force Base, Fort Huachuca and the Yuma Proving Ground all provide ideal places for testing and flying in our cloudless skies and more than 300 days of sunshine.
When you look at manufacturing, you’ll find thousands of varied companies located here that are propelling Arizona’s economy into the next era of growth. Industries leaders such as Intel, Microchip, and Frito Lay all have significant Arizona operations.
Now in its fifth year, this conference has become the gathering place for Arizona’s AADM industry. You’ll not only have a chance to hear what the big companies are up to, you’ll meet potential suppliers and customers during the interesting presentations and well-attended cocktail reception. And for as little as $750 you can get a booth space and two conference tickets – that’s a deal you won’t find in New York City! The traffic at our booth always keeps us hopping and give us the opportunity to capture great leads.
If you haven’t checked it out yet, get on it, check out the sponsorships and register now. And don’t forget to stop by the PADT booth. We’ll show you how we make innovation work!
Have an idea for a product and feel like you need a prototype.Tishin Donkersley from the Arizona Tech Beat asked me over to their offices to do a short interview and share some pointers on the subject. Take a look at the result here.
I talk about trends in the 3D Printing world that impact startups who have a need for prototypes, and share a few pointers on getting a prototype made.
While you are there, take a look around the sight. AZ Tech Beat is one of the best places to find out what is going on in the Arizona Tech Community as well as in tech in general. I especially like their gadget updates.
Metal 3D printing involves a combination of complex interacting phenomena at a range of length and time scales. In this blog post, I discuss three of these that lie at the core of the laser fusion of metals: phase changes, residual stresses and solidification structure (see Figure 1). I describe each phenomenon briefly and then why understanding it matters. In future posts I will dive deeper into each one of these areas and review what work is being done to advance our understanding of them.
Phase changes describe the transition from one phase to another, as shown in Figure 2. All phases are present in the process of laser fusion of metals. Metal in powder form (solid) is heated by means of a laser beam with spot sizes on the order of tens of microns. The powder then melts to form a melt pool (liquid) and then solidifies to form a portion of a layer of the final part (solid). During this process, there is visible gas and smoke, some of which ionizes to plasma.
The transition from powder to melt pool to solid part, as shown in Figure 3, is the essence of this process and understanding this is of vital importance. For example, if the laser fluence is too high, defects such as balling or discontinuous welds are possible and for low laser fluence, a full melt may not be obtained and thus lead to voids. Selecting the right laser, material and build parameters is thus essential to optimize the size and depth of the liquid melt pool, which in turn governs the density and structure of the final part. Finally, and this is more true of high power lasers, excessive gas and plasma generation can interfere with the incident laser fluence to reduce its effectiveness.
Residual stresses are stresses that exist in a structure after it reaches equilibrium with its environment. In the laser metal fusion process, residual stresses arise due to two related mechanisms [Mercelis & Kruth, 2006]:
Thermal Gradient: A steep temperature gradient develops during laser heating, with higher temperatures on the surface driving expansion against the cooler underlying layers and thereby introducing thermal stresses that could lead to plastic deformation.
Volume Shrinkage: Shrinkage in volume in the laser metal fusion process occurs due to several reasons: shrinkage from a powder to a liquid, shrinkage as the liquid itself cools, shrinkage during phase transition from liquid to solid and final shrinkage as the solid itself cools. These shrinkage events occur to a greater extent at the top layer, and reduce as one goes to lower layers.
After cooling, these two mechanisms together have the effect of creating compressive stresses on the top layers of the part, and tensile stresses on the bottom layers as shown in Figure 4. Since parts are held down by supports, these stresses could have the effect of peeling off supports from the build plate, or breaking off the supports from the part itself as shown in Figure 4. Thus, managing residual stresses is essential to ensuring a built part stays secured on the base plate and also for minimizing the amount of supports needed. A range of strategies are employed to mitigate residual stresses including laser rastering strategies, heated build plates and post-process thermal stress-relieving.
Solidification structure refers to the material structure of the resulting part that arises due to the solidification of the metal from a molten state, as is accomplished in the laser fusion of metals. It is well known that the structure of a metal alloy strongly influences its properties and further, that solidification process history has a strong influence on this structure, as does any post processing such as a thermal exposure. The wide range of materials and processing equipment in the laser metal fusion process makes it challenging to develop a cohesive theory on the nature of structure for these metals, but one approach is to study this on four length scales as shown in Figure 5. As an example, I have summarized the current understanding of each of these structures specifically for Ti-6Al-4V, which is one of the more popular alloys used in metal additive manufacturing. Of greatest interest are the macro-, meso- and microstructure, all of which influence mechanical properties of the final part. Understanding the nature of this structure, and correlating it to measured properties is a key step in certifying these materials and structures for end-use application.
Phase changes, residual stresses and solidification structure are three areas where an understanding of the fundamentals is crucial to solve problems and explore new opportunities that can accelerate the adoption of metal additive manufacturing. Over the past decade, most of this work has been, and continues to be, experimental in nature. However, in the last few years, progress has been made in deriving this understanding through simulation, but significant challenges remain, making this an exciting area of research in additive manufacturing to watch in the coming years.
Direct Laser Melting systems have made fantastic improvements in the last five years or so, making 3D Printing of metal parts a reality. The accuracy and strength of the finished parts rivals cast parts in the same material, but with the advantages of Freeform Fabrication. In fact, everywhere we go, people have questions about Metal 3D Printing.
So we decided to hold a webinar to answer those questions all at once. Our manufacturing team, lead by Dhruv Bhate, PhD, will share with you what we have learned while working to develop our own metal 3D Printing capability and while consulting with many of our customers as they acquired their own systems.
When: February 9, 2016
11:00 am MST / 10:00 am PST
If you would like to attend, or would like to receive a link to a recording of the event, please register here.
We look forward to sharing this exciting information with all of you.
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.
Colorado is a major contributor to the space industry, and they are quickly adopting 3D Printing to keep costs down and get to space faster. In this article, “Colorado Companies Bringing Space Costs Down to Earth” the DBJ explores how automation and 3D Printing can have a big impact on cost and schedule. Many of the companies sighted in the article are PADT customers, and PADT’s very own Norman Stucker was quoted extensively for the article.
The recent explosion of interest in 3D printing has been fascinating to engineers like myself that have been using what we call Additive Manufacturing as a standard tool for over two decades. It is easy to dismiss the interest of the general public and the media as hype and trendiness. But doing so would be a mistake. It is a big deal, but not for the reasons that most people think. “Why is 3D Printing Such a Big Deal” explains what the real power is behind 3D Printing.
As our final contribution to the AZ Tech Council and PBJ’s TechFlash Column for year, we shared how “3-D Printing Hits Major Milestones in 2015.” The article give our picks for what was significant with Additive Manufacturing for the Materials, Medical, Manufacturing, Military, and Mainstream aspects of the business.
The 3-D industry had a typical year in 2015. Of course, when it comes to 3-D printing, “typical” means lots of change, growth and innovation. It’s always hard to tell which of the year’s innovations will have the biggest impact on the future, but that doesn’t take the fun out of forecasting.
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.
Fused Deposition Modeling (FDM) is the most widely used 3D printing technology today, ranging from desktop printers to industrial scale manufacturing tools. While the use of FDM for prototyping and rapid tooling is well established, its use for manufacturing end-use parts in aerospace is a more recent phenomenon. This has been brought about primarily due to the availability of one material choice in particular: ULTEM. ULTEM is a thermoplastic that delivers compliance with FAA FAR 25.853 requirements. It features inherent flame retardant behavior and provides a high strength-to-weight ratio, outstanding elevated thermal resistance, high strength and stiffness and broad chemical resistance (official SABIC press release).
During an industry scan I conducted for a recent research proposal PADT submitted, I came across several examples of the aerospace industry using the FDM process to manufacture end-use parts. Each of these examples is interesting because they demonstrate the different criteria that make FDM preferable over traditional options, and I have classified them accordingly into: design opportunity, cost and lead-time reduction, and supply complexity.
Design Opportunity: In this category, I include parts that were primarily selected for 3D printing because of the unique design freedom that layer-wise additive manufacturing offers. This applies to all 3D printing technologies, the two examples below are for FDM in ducts.
ULA Environmental Control System (ECS) duct: As reported in a prior blog post, United Launch Alliance (ULA) leveraged FDM technology to manufacture an ECS duct and reduce the overall assembly from 140 parts to only 16, while reducing production costs by 57%. The ECS ducts distribute temperature and humidity controlled air onto sensitive avionics equipment during launch and need to withstand strong vibrations. The first Atlas V with these ducts is expected to launch in 2016.
Orbis Flying Eye Hospital aircraft duct: The Flying Eye Hospital is an amazing concept from Orbis, who use a refurbished DC-10 plane to deliver eye care around the world. The plane actually houses all the surgical rooms to conduct operations and also has educational classrooms. The refurbishment posed a particular challenge when it came to air conditioning: a duct had to transfer air over a rigid barrier while maintaining the volume. Due to the required geometric complexity, the team selected FDM and ULTEM to manufacture this duct, and installed it and met with FAA approval. The story is described in more detail in this video.
Supply Complexity: 3D printing has a significant role to play in retro-fitting of components on legacy aircraft. The challenge with maintaining these aircrafts is that often the original manufacturer either no longer is in business or makes the parts.
Airbus Safety belt holder: Airbus shared an interesting case of a safety belt holder that had to be retrofitted for the A310 aircraft. The original supplier made these 30 years ago and since went out of business and rebuilding the molds would cost thousands of dollars and be time-consuming. Airbus decided to use FDM to print these safety belt holders as described in this video. They took a mere 2 hours to design the part from existing drawings, and had the actual part printed and ready for evaluation within a week!
Incidentally, the US Air Force has also recognized this as a critical opportunity to drive down costs and reduce the downtime spent by aircrafts awaiting parts, as indicated by a recent research grant they are funding to enable them to leverage 3D printing for the purpose of improving the availability of parts that are difficult and/or expensive to procure. As of 2014, The Department of Defense (DOD) reported that they have maintenance crews supporting a staggering 31,900 combat vehicles, 239 ships and 16,900 aircraft – and identified 3D printing as a key factor in improving parts availability for these crews.
Cost & Lead-time Reduction: In low-volume, high-value industries such as aerospace, 3D printing has a very strong proposition to make as a technology that will bring products to market faster and cheaper. What is often a surprise is the levels of reduction that can be obtained with 3D printing, as borne out by the three examples below.
Airbus A350 Electric wire covers: The Airbus A350 has several hundred plastic covers that are 3D printed with FDM. These covers are used for housing electric wires at junction boxes. Airbus claims it took 70% less time to make these parts, and the manufacturing costs plunged 80%. See this video for more information.
Kelly Manufacturing Toroid housing: Kelly Manufacturing selected FDM to manufacture toroid housings that are assembled into their M3500 instrument, which is a “turn and bank” indicator which provides the pilot information regarding the rate of aircraft turn. These housings were previously made of urethane castings and required manual sanding to remove artifacts from the casting process, and also had high costs and lead times associated with tooling. Using FDM, they were able to eliminate the need to do sanding and reduced the lead time 93% and also reduced per-piece costs by 5% while eliminating the large tooling costs. See the official case study from Stratasys here.
These examples help demonstrate that 3D printing parts can be a cost savings solution and almost always results in significant lead time reduction – both of vital interest in the increasingly competitive aerospace industry. Further, design freedom offered by 3D printing allows manufacturing geometries that are otherwise impossible or cost prohibitive to make using other processes, and also have enormous benefit in overcoming roadblocks in the supply chain. At the same time, not every part on an aircraft is a suitable candidate for 3D printing. As we have just seen, selection criteria involve the readily quantifiable metrics of part cost and lead time, but also involve less tangible factors such as supply chain complexity, and the design benefits available to additive manufacturing. An additional factor not explicitly mentioned in any of the previous examples is the criticality of the part to the flight and the safety of the crew and passengers on board. All these factors need to be taken into consideration when determining the suitability of the part for 3D printing.
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.
Making injection molding tools using 3D Printing has been a long term goal for the industry. I knew the technology had advanced recently, but was really not aware how far it had come until I attended two seminars in Utah on the subject. In this post I’ll share what I learned, and share some content that goes into greater detail.
The reason for my update on this subject was a visit to PADT’s Utah office. Our two people there, Anthony Wagoner (sales) and James Barker (engineering), told me they were doing a seminar on injection molding and I should go. I figured why not, I’m in town. Maybe I’ll meet a couple of customers. Almost 30 people showed up to the Salt Lake Community College Injection Molding lab for the event. Gil Robinson from Stratasys presented a fantastic overview (included in the download package) on where the technology is, how to apply it, and gave some great real world examples. There were some fantastic questions as well which allowed us to really explore the technology
Then the best part happened when we walked into the shop and saw parts being made right there on the machine. They had recently printed a tool and were shooting polypropylene parts while we were in the classroom next door. During the hour long presentation, Richard Savage from ICU Medical was able to fine-tune the injection molding machine and good parts were popping out. As you can imagine, what followed next was they type of discussion would expect with a room full of injection molding people. “What material? How hot? What pressure? What is the cooling time? Do you use compressed air to cool it? Not a lot of flash, how hard are you clamping it? These features here, what draft did you need?” Good stuff. I got caught up in everything and forgot to grab some pictures.
I learned so much at that event that I decided to head north along the Wasatch Range to Clearfield and the Davis Applied Technology College. About the same number of people were able to make it from medical, aerospace, and consumer products companies in Northern Utah. Gil presented the same material, but this time we got some different questions so I learned a bit more about material options and some other lessons learned.
Then we visited their lab where I did remember to take some pictures:
Here is a shot of different shots that Jonathan George from DATC did to dial in the parameters. It took him about an hour, not bad for the first time using a 3D Printed tool.
The part is actually a clam shell assembly for Christmas lights, in the shape of a snow flake. Here is what they look like on the tree itself.
And here is a video they made showing the process. He was able to get 950 shots out of the tool.
In talking to attendees at both events I learned of several great applications that they were going to try, varying from medical devices for clinical trials to making rubber masking tools for surface treatments. The injection molding community in Utah is very sophisticated and forward thinking.
What I Learned
I’ll spare you the details on what we had for dinner Monday night for the Utah office holiday celebration and jump right in to what I learned.
For the right applications, you can get some very nice parts from 3D Printed tools
You do need to take the process in to account and oriented the tools facing upward in the machine, add a bit more draft than usual, and keep your pressures and temperature down when compared to metal tools.
For some parts, you can get over 1,000 shots from a tool, but most poeple are getting a couple of hundred parts.
As with any injection molding, the magic is in the tool design and setting up the right parameters on the injection molding press.
Tricky parts can be made by using metal inserts
Some machining may be required on your 3D printed tool to get it just right, but that is mostly reaming holes for ejector pins and metal inserts
Plastic is an insulator (duh) so plastic tools have to be cooled more slowly and with air.
Conformal cooling is a great idea, but some work still needs to be done to get it to work.
The mold usually fails during part ejection, so using mold release, good draft, and proper design can reduce the loading during ejection and get more parts from the tool.
The material of choice for this is DigitalABS on Stratasys Connex Machines.
There was a ton more, and you can find most of it in the download package.
The big take-away from both events was that this technology works and it really does allow you to create an injection molding tool in a couple of hours on a 3D Printer. In the time it normally takes to just get the order figured out for a machined tool (RFQ, Quote, Iterate, PO, etc…) you can have your parts.
Interested in trying this out yourself or learning more? We have put together an injection molding package with the following content:
Polyjet Injection Molding Application Brief
18 Page Polyjet Injection Molding Technical Guide
12 Page White Paper: Precision Prototyping – The Role of 3D Printed Molds in the Injection Molding Industry
3D Printed Injection Molding Application Guide from PADT and Stratasys
Presentation from Seminars
List of Relevant Videos
Four Real World Case Studies
Link List for Other Resources on the Web
We have spent some time putting all this information in one place and put it into one convenient ZIP file. Please click here to download this very useful content.
Donald Godfrey, Honeywell Engineering Fellow for Additive Manufacturing will be presenting a seminar at Arizona State University on the status of metal Additive Manufacturing (AM) within the company worldwide. This live event, being held at the ASU Polytechnic Campus in Mesa, Arizona, will be a fantastic opportunity to learn how this exciting technology is used in the real world to change the way aerospace parts are designed and made.