PODCAST: Large-scale 3D printing with GE Additive’s X Line

Posted On May 24, 2021 By Protolabs

Let’s say you need a huge part with tons of complexity. One of your best options to get it done right is 3D printing. Protolabs has some of the largest 3D printers on the planet, the GE Additive X Line series. Explore the history of large-format 3D printing and how to design your parts for best results on these machines. Guest: Marques Franklin, GE Additive Customer Success Technical Account Manager.

Additional Links

> GE Additive Website

> Metal 3D Printing

> Designing Larger Parts for X Line Printing

Podcast Transcription

Steve Konick: Hi and welcome to The Digital Thread, Protolabs’ podcast that looks at new trends in manufacturing technologies and strategies, cool products and companies that are pushing boundaries with innovative ideas along the way will also give you some design tips to improve how you and your manufacturer work together. I'm your host, Steve Konick, thanks for checking us out. There's that overused phrase, go big or go home, and when it comes to 3D printing, what do you do when you need the kinds of complex and organic geometries, that 3D printing offers, but your parts have to be really super huge. At Protolabs, we turn to our GE Additive XLine printers. Joining us today to talk about 3D printing on a huge scale is Marques Franklin, who has the longest title of any person I've met, GE additive customer success technical account manager. It is a sentence unto itself. Welcome to The Digital Thread, Marques.


Marques Franklin: Thank you, Steve. I appreciate that.

Steve Konick: Let's start off with a bit of history. Additive manufacturing started as a prototyping technology, but times have really changed and we've seen a shift from small- and medium-sized parts to much, much, larger applications and also from prototyping to end-use. So how did that come about?

Marques Franklin: So, as you said, plastic printing has been around since the early-1980s. And in the mid-1990s, there was an institute called the Fraunhofer Institute in Germany which started doing melting of metals. And so that's just developed from prototype into, you know, working in a lab, to more and more companies trying to turn it into a production-type system. And so here at GE, we recognize the significance of being able to take complex parts that consisted of multiple pieces and turn them into one single piece. For instance, the CFM fuel nozzle was GE's first part where we went from 18 parts down into one part. And so it allowed us to get complex shapes, but also simplify the geometry and the manufacturing process for a cost advantage.

Steve Konick: And you said it started with plastics initially and moved on to metals, what was the trigger that made someone decide, you know what, we could probably do this with metals?

Marques Franklin: You know, I think it's like with anything, everyone is always trying to push the boundaries of what can be done. And when people saw all the advantages of plastic printing, they said, well, man, if only we could do this in metal, that would take this to the next level. And a star was born.

Steve Konick: And now we have plastics, we have metals of various sorts. And we'll talk about that in just a little bit. The XLine printers are really about large, large format. Just how big is it with these printers? Are we talking—you can print a part that's cantaloupe-size, or basketball-size, or like a Yugo, or what? What can you get out of them?

Marques Franklin: We're not quite at the Yugo point to sort of put things into perspective. The build platform on the XLine is 800mm long by 400mm in depth by 500mm tall. So, roughly you mentioned basketballs. Imagine you had two basketballs side by side, that’s a general frame of reference.

Steve Konick: And that is huge, no question. So that's the size of the part that you're going to get if you want to go all out and really hit the limits of what the XLine printer can do for you.

Marques Franklin: Yes.

Steve Konick: What actually happens inside the printer as it creates a part?

Marques Franklin: Yes. So it starts out where you have a flat plate in a similar material of what you're trying to print. So, for instance, if you're trying to print in Cobalt, chrome or Inconel 718, maybe you have a stainless steel plate that is just bare metal. All right. And that is in what is known as your build chamber. OK, and then right next to that, you have this bin that is filled with this powdered material that I mean, it could be anywhere from think of it's kind of like flour or sugar. But the size of those particles, it's anywhere from like 15 to 63 microns. And then what happens is we take this let's say you wanted to make a coffee cup, so to speak, and we take this coffee cup and slice it into a bunch of different layers, almost like a loaf of bread. But think vertically. All right. And so then what we do is on that bare plate, we take some of the powder from the—we call it the dosing chamber—spread it real thin over the plate. And then we take essentially the bottom of that coffee cup, that first slice of bread, that cross-section. And then we take these lasers and we just blast them powder until we melt it.

Steve Konick: (Laughing) Great!

Marques Franklin: And then we take the chamber, move it down by a layer thickness, move the powder chamber up, spread a little more powder on the top of it and that’s the second cross-section. And we'll take that and will melt that with the lasers. And we keep doing that until we get to the top of the part. And so your dose chamber is empty because you slowly moved your powder over to your build chamber. You've melted the shape that you want, and then we have to take the machine and vacuum all the powder out. So one of the nice things about the XLine is the whole powder circuit is encapsulated in the machine. And what I mean by that is you have a big silo that holds thousands of pounds of powder. And what happens is over the course of the build, as you're emptying your dose chamber, it actually has a feature where it will automatically refill the dose chamber while you're building. And that's also what enables us to print for days or weeks on end because the machine just keeps adding powder to it.

Steve Konick: What ensures that the platform doesn't just collapse? How do you get that kind of precision where it just moves that one layer, that micron of thickness or whatever it is to be able to attach the next layer?

Marques Franklin: So that is part of the internal workings of the machine. There are certain features in there that allow us to move microns at a time with some of the structures and motors and lifts that we have designed into the machine. And we check that multiple times during the quality inspections of the machine development with lasers and other internal devices. And so we're pretty confident that when we say move 50 microns, you're moving 50 microns.

Steve Konick: What are some of the challenges that are inherent in producing large parts?

Marques Franklin: What we've seen is sometimes large parts are very complex and one of the things you have to consider are support structures. For instance, do you have overhangs on that part that may start small at the base and then grow out wider as you move up in the and then we call it the Z-direction or the height direction. Other things to consider are the thermal shift of the part over time. You know, if you're printing something that large, you're probably printing for weeks. Sometimes when you start out with a small part, you're putting all of this laser energy into a built platform and heating it up. But then as you move further and further away, that platform is going to cool while up top you're still putting in laser energy into the part. And so you've got shrinkage in warping that you have to consider over time.

Metal 3D-printed part
Large metal 3D-printed parts, like this thrust chamber, are often used for aerospace applications.

Steve Konick: So, 3D printing is the technology that we're talking about, but it competes with other technologies that are out there as well. What are some comparisons you can make to something like machining or casting? Is there an advantage to 3D printing in that sense?

Marques Franklin: Yes. So with casting, you know, some of the things you have to consider are if you have like an internal surface and an external surface and you have like a mold that's on the inside, how are you going to get that mold out? You know, with subtractive manufacturing where you're using a mill to remove material, you know, you don't always have the ability to have, like, internal passages in complex paths and stuff like that. So that's definitely an advantage of additive manufacturing. Things that you also have to consider, though, is with the complexity comes, you know, sometimes you can't manufacture as quickly as you can with subtractive manufacturing. So it tends to be more expensive than subtractive. But we expect as we develop more and more innovations in the field that those prices will come down. We'll start printing faster, you know, materials will grow. And so we'll be able to branch into more and more markets. So in my opinion, it's a matter of time.

Steve Konick: 3D printing started off as something that hobbyists tried out, but it seems like over the years it's become a really complex process and it requires some specialized manufacturing training.

Marques Franklin: I know people when they first started getting into the industry, thought that 3D printing was going to be a lot easier than it truly is, but it's like anything in manufacturing. If you go back to like a milling machine, you can look up feeds and speeds for a certain mill size. That's just common knowledge now. And right now in the additive industry, our equivalent to feeds and speeds are laser power and how fast the laser moves over a part. And a lot of that is still being determined. And so it's not like a printer where you go at home and you hook it up to your computer and you push print and you've got this 2D representation of whatever you wanted. There's a lot of development and a lot of thought and trial and error that comes into creating new shapes. Now, the advantage of Protolabs is they've seen all kinds of different structures and so they have an idea of what works and what doesn't work. And so I'm assuming that when they see things from different customers, they can easily say, let's tweak this a little bit, maybe you should consider this or consider that. And so I definitely see how they can help accelerate the process for someone that's got this crazy idea that they're just trying to turn into a 3D actual shape.

Steve Konick: And so from a designer perspective, it's really about that flexibility to be able to do really anything and everything that you can imagine. That's really the advantage.

Marques Franklin: Yes, I saw someone print a ball within a ball. And when it reminded me of a time in my undergrad when I was creating this 3D model with electrons in a 3D program, and I was like, oh, because I modeled it, I can make it. But at the time, there was no way to create this geometry. And when I took it to a manufacturing house to make this, they looked at me like I was crazy. But now, you know, it is totally possible. So you can think outside the box a little bit more. There are still limits, right? Because you got to think about, OK, so now I've got all this powder and can I get all this powder out? But definitely it changes the game for a lot of industries.

Steve Konick: And speaking of limitations from a designer or engineer’s perspective, what are some of the things they need to take into account in their CAD models as they think about using 3D printing?

Marques Franklin: A lot of it is transitions between shapes and such. For instance, if you're building directly off of your build platform, right? And let's say you're building a box to keep things simple, well, certain materials don't like sharp corners. And when you think about the thermal stresses in the weight versus the part and you have a sharp corner, then that is a stress intensification factor that says, please crack here. So as opposed to just having a sharp corner, maybe you put a radius in that corner, built the part a little bit taller, and then cut the part off when you cut it off the platform at a higher level than right at the platform. So when you think about overhangs, so let's say you're building at a 45-degree and now you want to flatten that out. And so then the question is, do I need supports or do I not need supports? What rate can I tell that to minimize the need for support so that I don't have to worry about that later when I am removing materials? The other thing that we've seen in the past when talking about supports is can you fully remove them after you cut the part off the platform? So if you go from a small shape to a large sheet and there're supports that bloom out in the middle of that, are you going to have enough wiggle room or can you get a tool in there to remove the supports? So things like that.

Steve Konick: Well, then how do you remove a complex part from the printer without destroying it? Is wire EDM a good solution?

Marques Franklin: So what happens is now you've got this part that is stuck to a plate and it's in this machine. So first thing you do is you vacuum all of the powder out as much as you can and then you have to lift this plate out of the machine with the crane. And then now you have to remove this part from the plate or separate the part from the plate. Now, some people can make it support that kind of breakaway, but you've got to be careful with those because they can be a little temperamental during the building process. So a much easier way is just have a solid connection to the plate. But to remove that now, you have to cut it away, so I know with the wire EDM, it is basically a thin wire that uses an electric current. I do believe that goes down the wire. And it's like a—it’s like a hot knife. And you set the platform up in this machine and then this wire just precedes down the length of the platform until the part is completely separated. And so it's like a hot knife through butter.

Steve Konick: Nice. So is there a best way to design a support structure?

Marques Franklin: Definitely: Spacing of the support structure, do they have enough to actually tie the part to the platform? What is the connection of the support to the actual part? I think of this example where we had a machine that was printing titanium and the designer didn't really connect the supports to the part. And so we're watching it build. We're watching it built and—we’re amazing! We're creating greatness! Look at it print! And then all of a sudden inside the machine—BOOM—powder goes everywhere.

Steve Konick: (Laughing).

Marques Franklin: It's like LeBron James like claps his hands together and powder goes off through the air. And we're like…

Steve Konick: Exactly.

Marques Franklin: …What the heck happened right there? And we go back and we're reviewing the video and we realize that the supports were just barely hanging on for dear life there. Like, I got the part! I got the part! And then the part was like, no, you don't.

Steve Konick: (Laughing)

Marques Franklin: And then like, let's go in, throws powder up all over the glass and it ruins the part because now the part is sticking up. And when the re-coater comes across, it's like a freight train and hits the part. And then we're like, OK, designer guy, you're going to have to rethink this.

Steve Konick: Man, that has to be embarrassing. (Laughing) Well, let's take a look at the process from the point of view of a person who's running an XLine printer. Are there things you have to think about when you use different materials?

Marques Franklin: So the process is fairly similar for all materials, but there are things that you do have to consider. For instance, with aluminum our lasers can go up to a 1000 watts. When melting aluminum we can have a parameter with the laser power that's almost 950 watts. Now you try to use 950 watts with other materials and like titanium, for example, which burns very bright and very hot. And you may end up with porosity concerns and stuff like that. So one of the things that GE Additive does and Protolabs does is they come up with specific parameters for each material. How fast do they want the laser to move? How much laser power do they want when they're building, when they look at lasers moving from one side of the part to the other side? How much space do they want in between passes of the laser or what's affected by that is porosity in the part. So what happens is you can get porosity in the part that will affect your tensile properties or your physical properties. And so the parameters that are developed are converted into physical characteristics of the parts that are created. And so a lot of those require a lot of time in study in order to determine what is the correct recipe for a given material.

Steve Konick: Was there a specific market that metal 3D printing was built out for? I mean, what was the impetus to move to metals?

Marques Franklin: For instance, health care. There are companies that print, you know, skull pieces, where let's say you were in a car accident and you fractured your skull and you needed a plate in your skull. Historically, you would get some titanium, then make it roundish, kind of like a skull where now we can actually customize pieces to a person's skull that would fit a lot better. I've seen companies do the same thing with hips, which makes it more acceptable for a body geometry, so to speak, to accept things like that. We talked about fuel nozzles for the aviation industry. There are automotive industries that are looking at heat exchangers and geometries to accelerate the thermal removal of whatever fluid they're using by using intricate shapes. So there's all kinds of industries that are pushing towards using this technology.

Steve Konick: We right now 3D-print parts in Inconel 718, and we may be moving on also to stainless steel or aluminum when we add another XLine 2000R machine. So where are these materials being leveraged in the industry?

Marques Franklin: So I know there are a lot of, let's say, aerospace companies that use stainless steel parts to make parts for space. I know there are automotive companies that use the aluminum to make car parts. And so those are the two biggest that I can think of for aluminum and stainless steel.

Steve Konick: Now, I know we have a partnership, Protolabs and GE Can you tell us a little bit about that partnership?

Marques Franklin: So we've been working with Protolabs, they’ve been a fan of our machines for several years, I've been to one of their shops down in Durham and they are actually one of the largest users of GE Additive machines. And so walking it to that shop, you know, it's like, oh, we must be doing something right here. They keep buying our machines and from M2s, to MLabs to now XLines and we're happy to sell them to them. And at the same time, you know, we've leveraged Protolabs when we've had customers that have struggled with developing parts. And so we've gone to Protolabs and say, hey, can you make this part for our customer? And they're like, yep, we can do that. And so they've stepped in and helped us as we have helped them. And so it's developed into quite that partnership in my opinion.

Steve Konick: So I guess the last question is: Marques, what's coming down the pike now for GE Additive? What do people want to know more about?

Marques Franklin: Everybody wants bigger, faster. I want to print or melt more volume in any given amount of time. And so we announced a couple of years ago how we have the Atlas machine that we've developed, which is going to be one meter by one meter by one meter. We are heavily into the binder jet realm, which maybe that's a podcast for another day where you basically take a material and you spray a binder on it and it's significantly faster than the laser printing industry. But that also comes with caveats. For instance, now you're in a green state where you have to go and put the part in an oven to sinter out all the binder and such. So we're actively moving in those markets to make metal printing faster for the world and for all those creative geniuses out there to come up with anything and everything they can think of.

Steve Konick: Very cool. Hey, Marques, thank you again for being with us on The Digital Thread.

Marques Franklin: It was my pleasure. Thank you, Steve.

Steve Konick: And that's this edition of The Digital Thread, I want to thank our guest, Marques Franklin, from GE Additive for hanging out with us. And don't forget to subscribe to future Digital Thread podcasts through one of our host sites, Apple, Google or Spotify, or you can listen on our website. The Digital Thread is produced by Protolabs an international manufacturing company with locations across North America, Europe and Japan.