Electron Beam Melting Machine Raises R&D Bar for Additive Metal Manufacturer
An Arcam A2 machine shows great potential for creating precision, near net-shape parts for medical and aerospace applications.
Morris Technologies, Inc. (now GE Aviation) (www.geaviation.com), an innovator in additive metal manufacturing, recently acquired an Arcam A2 electron beam melting (EBM) machine that will enhance its product offerings by making the EBM technology available to its customers in aerospace, medical, and other industries. The contract manufacturer has offered its clients direct metal laser sintering (DMLS) and other additive technologies since 1994.
Initially, Morris Technologies will be focusing on building geometries from titanium with the EBM machine. The company also plans ongoing testing of other alloy powders and will introduce other options as appropriate. "The Arcam A2 is a complementary technology to our existing DMLS additive manufacturing machines, and will allow us to offer additional capabilities and solutions for our customers," says Greg Morris, the CEO of Morris Technologies. "Coupled with our extensive, world-class machining and finishing technologies, we believe that we can offer cost and time savings for a number of customer geometries and projects."
The Arcam A2 builds functional metal parts layer by layer using metal powder. The powder is then melted by a powerful electron beam to the exact geometry dictated by a 3D CAD model. Parts are built in vacuum at elevated temperatures, resulting in stress-relieved parts with material properties better than cast and comparable to wrought material.
Based in Cincinnati, Ohio, Morris Technologies, Inc. specializes in end-to-end product development, from engineering to prototyping to low-volume manufacturing. The company's heavy investments in research and development have enabled MTI to evolve into a leader in additive-metal manufacturing processes and advanced technologies by offering new materials and developing new hardware. According to Steve Rengers, vice president of advanced technologies and manufacturing, MTI has a dedicated group of scientists and technicians responsible for the advancement of additive metal technologies.
"Process parameter development is one of their primary functions," Rengers said in an email to Design2Part Magazine. "While AM equipment manufacturers are able to develop and qualify widely used materials, many customers seek niche materials for their complex geometries. Morris Technologies is typically a faster option and gives North American sources a domestic resource for these R&D activities. Generally, customers request existing alloys in powdered form and wish to develop the machine settings, process parameters, and post-build thermal treatments to yield final parts that meet wrought properties."
Greg Morris recently spoke with D2P, providing an in-depth perspective on how EBM and DMLS technology complement each other during prototyping, engineering, and production processing.
D2P: How does the Arcam A2 complement the company's existing DMLS additive manufacturing machines?
Greg Morris: The Arcam machine's EBM (electron beam melting) technology is interesting for a few reasons, and it has some differences from the laser-based systems, like DMLS (direct metal laser sintering). The Arcam technology uses an electron beam power source of about 3,500 watts; whereas, the laser-based technologies are typically 200 to 400 watts. The Arcam machines use a magnetic field to direct the beam. One of the areas where the Arcam machine has potential is that it has a vacuum chamber. The vacuum chamber allows us to create some alloys that will be a little easier to map and get decent properties with versus in an atmospheric chamber.
The DMLS machines use nitrogen or argon, and it complements EBM technology. We look at DMLS as a very enabling technology with tremendous capabilities, but it also has limitations when it comes to certain alloys and the speed with which it can build certain types of parts. So this is where the Arcam tends to be a very nice complement to the DMLS technology. If you have a bulkier, less detailed part that doesn't require the surface finish that a DMLS part can give you, Arcam's strength is being able to build the part faster than the DMLS. The part size, geometry, and the detail resolution that DMLS covers is really a different market in many ways than what the Arcam covers. Typically, where there is less detail resolution required, the Arcam technology may be a better fit.
D2P: Has the Arcam A2 machine been installed? If so, is it already producing parts?
GM: It has been installed. We've gone through the qualification process, so we're right on target. Today we are able to accept part files and start building components. Parts for us, in our world, are typically prototype or development hardware types of parts. I would also comment that the EBM technology has already been in the United States for a while, although it's new to us. It was something that was put in place due to a very specific contract with a customer. Indeed, we are up and running with it, and we are accepting and building parts with it.
There are going to be a few overlapping types of components where an Arcam or a DMLS machine can make the same parts. But more often than not, maybe 95 percent of the time, we're going to see where they don't overlap. We do indeed look at them as complementary technology, even though some people would say they are competing technologies. They serve different markets, different niches, and different needs.
D2P: What industries and applications does your company expect to use the machine for?
GM: This machine has traditionally been very strong in the medical field. In Europe, they have some installations where they are producing medical implant parts, utilizing a [trabecular] metal structure that they grow onto the part. I would say that we see a fair amount of opportunity in the medical field. That would potentially be implants, but also instrumentation, and device types of components, like surgical devices. It could be anything from endoscopic devices to something that might be implantable in the body, outside of an actual implant. But also I would suggest that this technology would be appropriate for certain medical implants, like for hip implants.
D2P: Why is the machine good for these types of medical applications?
GM: It's going to serve a particular market. The properties of the EBM parts, as well as the DMLS parts, are very much wrought-like properties, so they are superior to cast properties. But the real key with any of these additive technologies is that there is so much design freedom. So you can design and grow things that are more cost effective and parts you can't make in any other way, which leads to innovation and new products.
Again, a prime example in Europe right now is an Italian company that's making acetabular cups. On the outside, they have an in-bone growth [trabecular], metal-looking lattice structure that's grown directly onto the part, which is the cup. So when it comes out of the machine, the spherical top surface is already as it needs to be to go into the body. On the inside, you would need to have the ball socket made up. So this company would simply machine the inside to get the surface finishes and tolerances that they need. They are able to grow the part with one post-operation, and have the product ready to go, versus maybe casting the cup and then going through a process of adding that in-bone growth structure on top of it.
I would also point to some wins in the aerospace industry. Once again, I point to Europe where there is an aerospace company that has been able to develop the parameters for melting Ti-aluminide (an alloy of aluminum mixed with titanium), which is inherently a very difficult alloy to cast or work with. It's a high-strength, very lightweight alloy. When casting it at foundries, I understand that the yields are pretty low.
In the EBM process, I understand that their yields are very good, maybe a mid-90% yield rate. So instead of scrapping a lot of parts, you are actually growing parts that won't be scrapped out. And the parts will be near net shape with EBM. Typically, with a lot of additive processes, what you have is net shape coming out of the machine. But more often than not, you will have certain tolerances that have to be post-machined, or other post-processes used.
D2P: Why will your company focus initially on building geometries from titanium (Ti-64) with the new machine?
GM: The reason we're starting with Ti-64 is that it's pretty much the bread and butter alloy for Arcam's EBM machine today. Ti-64 is a common titanium alloy. Ti-64, and titanium in general, happens to be one of the easier materials to work with, and the aerospace business has had pretty good success with the parameters. We feel that aerospace is an industry that should benefit greatly from this technology, like it has with DMLS. I know some universities that are trying to work on nickel-based alloys using the process.
We don't know yet how many different alloys might be a candidate for this technology, but we do know that the Ti-64 material works well and has wrought properties. It's a robust material mechanically and has good surface finishes, so we want to get our feet wet and build up our experience with Ti-64 initially. Once we feel comfortable with it, like with our DMLS alloys, we'll start to explore other alloys that customers might be interested in with EBM.
D2P: When do you think you'll start producing full-production parts?
GM: My short answer is soon. The process of validation of any new process, whether it's DMLS or EBM, or anything else, is time-consuming. The process for a customer to validate a technology and a material is also a very lengthy one. There are a lot of applications in the process of being validated, but there are not a plethora of applications that we're aware of that are already out there.
And if you are in the aerospace or medical world, these are very lengthy periods of time because you don't want a structural failure, either in an implant or something that's taking people into the sky. I am aware of medical applications where I believe people are using EBM technology for full production. I think that there will be more and more of these applications in medical and aerospace. So my short answer is it will probably be around a 12-to-18 month time frame that we can expect to find a number of production applications, just like it has been with DMLS.
D2P: By "validate the technology," do you mean that you're working directly with the aerospace and medical companies to try to come up with new technologies and types of parts for them?
GM: Yes, we work directly with the OEMs. The validation process means that if an OEM comes to us to make their products, especially if it's a critical application like an airplane engine or body part, they need to make sure that there isn't going to be a failure. So a way to do that with a new technology is to understand all of the little levers and buttons needed to lock in the process. We really have to understand all of the variables in the process that could affect the quality of the product or parts.
This is one element; the other element is 'what are the mechanical properties of the parts coming off of the machine?' Usually, this is a pretty expensive endeavor to qualify a particular material for a particular technology. So, it's not unheard of to say you'll be over a million hours to qualify a particular material off of a particular technology, like EBM or DMLS.
The reason is because we have to make hundreds of test bars, which is expensive. And then you have to machine those, and then we have to pull those test bars and cycle them if we're doing low-cycle or high-cycle fatigue testing. Therefore, it takes a lot of time and a lot of money to qualify the material and understand the properties of the material. This is the dual-edged sword of an exciting, new technology. The one side of the sword is it's enabling and disruptive, and it changes the game; the other side of it is you have to have some patience and staying power in order to make it through all of the various toll gates that customers are going to have to go through.
D2P: In that 12- to-18 month timeframe, there is so much work to do, including validating, testing and retesting, and handling changes and modifications. Is the production process the same for DMLS technology and EBM?
GM: The difference with our additive technologies is that it's a relatively new, young field. Compare it to CNC machining, which has been out there for 40 or 50 years, and manual machining that's been out there much longer; it's all very well understood. Those industries had to go through the same things. So the OEMs are very excited about what our technology can do for their business. They are working very hard to accelerate the process of validation for this technology.
I think within the next year or two, we're going to see a number of applications where additive parts are in production. By virtue of that, the feeling of risk drops dramatically and people start to see that it's not just a prototyping technology—it's a real technology that has real outcomes for real products.
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