“Metal Printing for the Masses” at MD&M 2018

Metal Printing for the Masses

With the arrival of the new EVO Additive Manufacturing Center came an outpouring of questions about the machine’s metal printing capability. At the 2018 Design & Manufacturing Show in Anaheim, CA, Airwolf 3D Co-Founder and CEO Erick Wolf gave a presentation entitled “Metal Printing for the Masses,” in which he explained how anyone can 3D print in metal. A transcript adapted from the presentation follows the video below.

Just to put it in perspective, we’re going to talk about the processes now, very quickly. The previous speaker, “Eric” also, was excellent. He’s clearly an expert on powder 3D printing. I am not. I come from the FDM world. And we started Airwolf 3D…geez, about six years ago now, with FDM printing and our focus at the time was ABS.

Current Types of Metal Printing

Selective Laser Sintering

There’s several different types of metal printing that we know now. The first one, a very popular one, is Selective Laser Sintering. We have, like previously discussed, a metal powder, a roller, build chamber, and laser that sinters the metal. And then we come out with the final part. Not that easy, but a general summary.

Selective Laser Sintering
A diagram of the selective laser sintering process. Photo Credit: CustomPartNet

Selective Laser Melting

We also have Selective Laser Melting where we take it up a notch and are actually melting the metal as [the part] is being made. It uses a laser also, similar process: The powder comes up, gets pushed over a build platform, a laser comes down and, layer by layer, creates the part.

Selective Laser Melting
Diagram of Selective Laser Melting. Credit: Michael Schmidt

There’s a company called Arcam that does electron beam melting, it’s a little bit stronger way of making those parts. Or a little bit, I should say, stronger beams coming down there, going through the powder, and making the parts. Rather than a laser, it’s called an “electronic beam.”

And these are all machines that are very, very expensive and they’re very, very precise. They’re high quality. EOS has a really nice display across from us and I think their machines, the E100, starts at $350,000. Great machine, beautiful metal parts. However, that’s not really what a consumer or even a small business could afford. We’re a small business, $350,000 for a machine would probably be out of the question.

Electron Beam Melting
Diagram of Electron Beam Melting.

Binder Jetting and Inkjet 3D Printing

There’s a last process called binder jetting and inkjet 3D printing. This would be X1. If anyone’s ever heard of X1, it’s where you’re going to have the metal powder and then you’re going to spray a binder over it and, layer by layer, make your part. And I encourage, if anyone’s interested in this, to get on Wikipedia and look around. There’s a ton of information about metal 3D printing, but not all of it is as clear as it should be.

Diagram of Binder Jetting and Inkjet Printing.
Diagram of Binder Jetting and Inkjet Printing.

Challenges of Metal 3D Printing

Challenges of Metal 3D Printing. Very, very expensive. The size of the machine — you’ve heard it before — these machines are giant. Then you have the material cost, which is pricey, but it’s not outrageous. It’s pricey.

But the safety. The safety is one of the things that kind of spoke out to me. It’s concerning. You know those metal particles get in the air. And I think the previous speaker spoke about this, they can become very dangerous. These metal particles float in air and can spark and ignite. I’m not sure where it was. I think it was New Jersey a couple years ago, but the whole back of a building blew out because the material wasn’t handled correctly. So it’s a dangerous process. And, yet, a lot of people want to print in metal. How many people in here want to print in metal?

[Majority of audience raises hands]

Challenges of Metal

See? And one of us has done it already. Just one, out of everybody in this room. So the idea is, can’t we bring some of this technology onto the desktop? We have been working with metal at Airwolf 3D since 2013. We’ve been making metal parts, but it’s only under a controlled environment.

The way we first did it was through metal clay. Metal clay is basically metal combined with a binder and you put a little bit of water in there and you can actually create a clay that is mostly metal. You can dispense that out of a syringe-type setup and there’s a little company — I think in Arizona — that has done this. And then you can form your part, put it in a kiln, a regular kiln that you can buy for $500, and make a metal part. However, it’s very hard to reproduce the process. You can see all the Buddha’s on my desk that have been made with this process and they’re all just a little bit different.

So that was a process that was tempting to say, “Hey, we’re going to print metal!” But it really wasn’t something that we could provide to a consumer.

Metal Injection Molding

There’s this wonderful technology called metal injection molding. Metal injection molding has been around for a long time. I think one of the concepts was invented in the 50’s and it really started being commercialized in the 80’s by a company, I believe they’re called Parmatech, in California.

Metal injection molding is similar to plastic injection molding — it’s not that simple, but it’s a similar concept — rather than injecting your ABS or your polycarbonate into these molds, you’re injecting a metal matrix.

Plus, you can’t just inject metal into the mold. You start with our metal powder and then we have a binder and that binder can be a substance like Delrin, which BASF uses, it can be different types of waxes. There’s all different types of binders that can be used. The metal powder and the binder are mixed, then they’re basically put into an extruder, the granulation process, and then they come out of the end of the extruder and they’re cut into feedstock. They’re cut into pellets and the pellets look a lot like ABS pellets or PLA pellets. It’s the same concept.

The metal injection molding process. Image Credit: Finemim.com

The injection molding machine will take that feedstock, heat it up, and turn it into a green part. That green part will have, in some cases, 80% metal and 20% binder. That binder could be the POM, the Delrin, or different types of waxes, maybe a CMC. We have all sorts of different properties to it.

This part is then put into a solvent debinding tank or a thermal debind. That’s generally the way it’s done. The debinding takes most of that binder out and you’re left with this brown part.

So we’ll take that brown part and put it into a sintering furnace. After it gets sintered, you have the finished MIM part. This is a beautiful technology. It’s very expensive, though. It’s usually used for small, high-precision parts that are difficult to machine. And they’re generally done in limited quantities.

We’ve been talking to a lot of experts lately in the field and one of the latest applications is on Tesla’s. The door hinges on Tesla’s are metal injection molded. I guess it’s a more efficient way than machining or casting. Also, from what we know the processes are generally stronger than casting. You’re looking at a net part of 96-99% metal.

Applying Metal Injection Molding Technology to FFF 3D Printing

So with that said, why don’t we apply metal injection molding to FDM 3D printing? This is what we’re doing right now and we’re working with one of the metal injection molding companies called BASF. They make a product called Catamold. It’s basically a metal with a polymer (Delrin) combined. It seems like this is difficult. It’s going to cost so much money. How can you ever maintain control of the process? The reality is we print these parts on our own.

[Holds up printed gear]

3D-Printed Metal Parts
The stainless steel gears passed around by the audience at the presentation.

This part right here is stainless steel. This is 316L. That’s what BASF calls it. This is the green part that came right off the printer. We’re printing this exact same part downstairs. We’re printing this part right now. This material costs about $100 a pound. It gets sent to a sintering shop where it gets debinded and sintered. And it is really that simple.

The truth is going to come out at some point and I’m glad I had the opportunity to tell you all: This type of metal 3D printing is not complicated.

The most expensive part of it is the actual sintering. Now, there are shops — and the supply chain is very well defined for metal injection molding — there are shops that specialize in just debinding and sintering your parts. All around Southern California and obviously in different parts of the country too, metal injection molding is about a $1.2 billion industry right now.

I thought I would pass around something to show everybody because, really, it’s not more complicated than this. Now these are basic parts that we started with.

[holds up stainless steel spiked motorcycle clutch lever]

3D Printed Stainless Steel Motorcycle Clutch Lever
Custom-designed motor clutch lever printed as a sample part for the presentation.

This is not what it looks like, by the way. Is anyone here not from California? A lot of people NOT from from California! Let’s see, as a motorcycle rider in California you have to be very cautious when you’re splitting those lanes like you have to do to get to work sometimes, people tend to veer into your lane. Anyway, this is the prototype clutch lever for my motorcycle — no one’s gonna get me! We made this part in about 5 hours right on the printer, sent it to New Jersey. There’s a company that works a lot with BASF material. They have a contract with them. We just send it to them, they processed it, and I took 80 grit and 180 grit and just sanded to finish.

You can see this is a full stainless steel part right here, so I’ll pass that around. Also, we have little bitcoins. This guy is probably worth more than a real bitcoin at this point!

3D-Printed Metal Bitcoin
3D-printed metal bitcoin produced on the EVO Additive Manufacturing Center.

This is all very new, too. While the technology has been around for a long time, we haven’t been doing it very long. We’ve been doing it for a couple months and just in that small amount of time, we’ve been able to produce these parts that are perfectly flat.

I’m kind of skipping ahead, but as you’ll see downstairs with our printer — it’s an FDM printer — now it’s a high-end desktop 3D printer. It’s $8,000. I consider that high-end because I still think about it from in the garage trying to buy a 3D printer and how much these things cost. To some people that may seem really cheap. I get a lot of times, “Wow, I thought it’s $80,000!” but no, it’s an $8,000 printer.

Metal 3D Printer
The EVO Additive Manufacturing Center has a high-temperature hot end and enclosed build chamber optimized for metal printing.

One of the beautiful things about making it with a printer like this — and you don’t have to use an Airwolf, but if you did, it would be nice [joking] — is it has a heated chamber. It has a lot of features, like if you were to somehow lose power at some point or you ran out of filament, you could always go back to where you were and restart the part. If you lost electricity, you can restart the machine and get back down on the part on where you need to be and it will finish the original part.

The enclosure and the heated chamber are really nice when you’re working with metal injection molding material because you keep the part consistent as you’re printing it. We’ll keep the chamber right about 40-50°C. The bed is only 80°C. So it’s not a whole lot different than printing PLA or ABS, believe it or not.

I’m not going to talk about potential competitors with six-figure printers, but the reality is the printing part of it is very small. Now, what’s more complicated is the debinding and sintering.

Outsourcing the Debinding and Sintering Process

The way it’s going to be sold is as a service pack. Right now we buy the material from BASF and it comes with an agreement for them to debind and sinter the material. They have it done in New Jersey. A 12-13lb roll is around $1,000. It may seem like a lot, but that’s the equivalent of five rolls of regular material. You can come down to the booth and you can pick up the roll yourself and you’ll see how heavy this thing is.

That fee — and that’s introductory pricing from BASF and they can decide differently — includes not only the material, but also the post-processing.

Debinding and Sintering for Metal Printing
Photo Credit (Left): Debinding furnace by Carbolite Gero. Photo Credit (Right): Sintering furnace by PVA TePla.

After you print out these parts — and you’ll see the green parts floating around — the green parts are not weak. They’re like a 3D-printed part. It feels like a 3D-printed part. You will package those in a bubble wrap, send them out to the contractor, they will fire them, then send them back.

There’s a lot of art in that process. And that process of debinding and sintering can be dangerous, so that’s why we’re not debinding and sintering at the house…because formaldehyde is a byproduct of that process, especially in this particular material that uses the Delrin.

There are other processes, too, where you have different gases and you need to use nitrogen. A byproduct can be hydrogen. These machines are very, very sophisticated and the way we think about this technology with the existing metals is — that’s how you want to process your part. You don’t want to be doing it in the living room.

With that said, we have a new material that we are developing right now that you will be able to process in your garage. And we should have that out in a few months — and that’s very, very exciting for us.

Benefits of MIM Printing

Benefits, just really quick, of [metal printing]:

  • It’s inexpensive, relatively speaking.
  • You don’t need molds.
  • You got simple machines, less waste — this is FDM, so there’s hardly any waste involved.
  • Strong parts — those, like I said, have 96-99% metal content in that finished part. And I challenge anyone to take that clutch handle and bang it against something. It’s incredibly strong. I broke a table at work with that handle, and you couldn’t even tell.
  • You can make complex structures.

Challenges of MIM Printing

So what are some of the challenges?

  • Converting MIM to filament. Has anyone ever tried to do that? No? Ok. This MIM powder, when you try to get it into a filament, can be kind of tricky. It’s naturally brittle. The way that BASF does it is they combine that Delrin in a certain geometry with a metal injection molding powder, so that it stays together and is smooth and flexible. It’s actually a certain way of extruding it. If you feel the material, you’ll notice it’s shiny. It almost feels like a TPU or something like that.
  • What we’re working on, too, is a direct pellet extruder, so we go straight through the extruder, down to the part and make the part. That’s our next thing on the horizon.
  • Another challenge is processing and you will have to send it out.
  • Bed adhesion, we solve that with a material called Wolfbite.
  • And, finally, your print environment, maintaining the chamber temperature — really not that much of a challenge, but in reality is something you should know.

So that is the basics. I think you’re going to hear a lot more about metal 3D printing on the desktop this year. It will be really exciting to finally make real, useful, parts with desktop metal printing.

Learn More About Metal Printing

If you would like to learn more about the metal printing capabilities of the EVO Additive Manufacturing Center referenced in Erick’s presentation, please contact us at (949)478-2933 or at info@airwolf3d.com. You also can read more about it here: Don’t Call it a 3D Printer: EVO Additive Manufacturing Center.

Industrial 3D printer
The EVO Additive Manufacturing Center With Metal Printing Capability By Airwolf 3D.