3D Systems recently reported the completion of comprehensive testing on the newest materials for its Figure 4 system. For some users, materials testing data is insufficient for their needs. I interviewed Marty Johnson, technical fellow, at 3D Systems about material testing and the needs of the design engineer. Listen in as Marty Johnson discusses developments in testing and how they affect prototyping and production materials.

 

Welcome to Technology Forward. I’m here today with Marty Johnson of 3D Systems, and we’re going to be talking a little bit about materials, especially in regards to additive manufacturing. Just very quickly, Marty, can you give me a little bit of background about yourself?

Marty Johnson:
Sure. I’m Marty Johnson. I’m a Technical Fellow here at 3D Systems. I’ve been here since 2007. I actually have a background in mechanical engineering, and I used to drive a lot of product development and work to create injection mold tools, different plastics and things like that. And as we started into additive manufacturing … 3D printing into additive manufacturing, let me say it that way … here at 3D Systems, we’ve come to really push into production plastics. So my background and my vision to where I look at our materials is actually from the viewpoint of a mechanical engineer more so than a material scientist.

Leslie:
Okay, perfect. Recently 3D Systems sent out news that you have comprehensive test data on materials that work with the Figure 4 system. Can you briefly go over what those tests were?

Marty Johnson:
Absolutely. So this is something we’re really passionate about. Really with the focus for production plastic, probably the two most overused words in additive manufacturing, is to really raise the bar. We’ve got a real passion to raise the standard of what do we call a production plastic. And so there’s some things that fall into that. Some of those are going to start with your mechanical properties.

So on these data sheets, we’ve totally revamped the Figure 4 mechanical properties, the entire data sheets, to look at, comprehensive consistent datasheets. So we look at mechanical properties with everything down to the detail of elongation at yield, HDT and 24-hour water absorption. We’ve added ISO data for geographies and industries that prefer the ISO data. And so we really focused in on these mechanical properties and also to be really specific to include everything that’s part of … From a mechanical engineering standpoint, it’s always in the past where you’ve been frustrating if you look at only the properties that are given that may be good. Such as when I don’t have things like 24-hour water absorption. Well if it’s not great, that might be okay, but I need to know what the number is to be able to do the design. A lot of times I can design around that.

So, we were real intentional about creating consistent, complete data sheets that have that kind of information. Everything’s conditioned per ASTM and ISO standards. And then we added to that. And so we touch on it a little bit in some of our TOUGH-BLK 20, for instance, datasheets. But then we went into production performance properties, and you’ll find those on these data sheets as well. And what you’ll find there are things like the long-term indoor and outdoor environmental stability, which are two of the things that really set you apart from a prototyping to production plastic. And then you’ll see things where it’s applicable, dielectric properties, biocompatibility, things like that.

Leslie:
Okay, interesting. So now given all of this, what would you say is the state of material development for additive manufacturing? Do we have enough materials? Too many choices? Are these choices good? Is there too much substitution and not working with the real materials? And is that even a necessity anymore?

Marty Johnson:
I think there are plenty of prototyping materials. The question is, do we have enough production type materials? And there’s very few, quite honestly. And that’s been where a lot of the focus that we’ve had is. That’s when we go back to what is a production plastic? Does it last with long-term stability? How many years does it last? If I’ve got a part with a two-year shelf life, in that two-year shelf life, I’ve got to have the same mechanical properties at that two-year point as I did two weeks after I made the parts. So we’ve got to go push for that into the production standpoint of that. So when we start looking at how many materials we have, it’s how many production materials do we have and how do we call those out? So that’s been a real push to getting to the materials that we run.

Leslie:
How far along are, or, I’m going to rephrase the question. How much time will it be before we have sufficient production materials?

Marty Johnson:
Well, I feel like we’ve got some today, and I really think that the direction that 3D Systems has taken over the last few months to really pull out and get this focus on production and move it away from prototyping with things like the long-term indoor and outdoor UV stability, with the things like the good flammability properties, the chemical compatibility. When we put all of those things together as a package, I think we’re there, and I think what we’re going to see is the things that we found to get those materials, the door’s been opened. And so there’s a real fertile ground in front of us to really push on that to get to production because one of the things you’ll see when you do an injection mold tool that some of the things you have to think about are, what is my melt flow? What are the viscosities at temperature? What’re some of the shear properties? What’s my crystallinity? And when I’m looking at that to do an injection mold tool, can I push this through a thick and thin area?

Well now when you go to additive, you remove all of those. Now when I look at my material, what do I need my material to be like? Well, I may not necessarily want an ABS material, but what I may want is a high HDT, high impact material. I may want a high modulus. And so I can start looking at the properties that I really want from an engineering application and focus on those properties a little more pointedly as opposed to having to back out to see if I can injection mold that or not.

Leslie:
It sounds like we’re shifting out of going to the brand name and looking much more specifically at the properties.

Marty Johnson:
I think so. But you’re still going to have some alignment there because there are still things that you’ll see with your polypropylenes and your ABS’s, and other materials. But it’s aligning on the actual properties that get you the application that’s going to be the big driver.

Leslie:
Okay. So that was one of the important factors to look for. So are there some other important factors in materials testing? What are the kinds of things that design engineers need to know that they don’t already know?

Marty Johnson:
I’ll tell you one big thing that we’ve been a stickler for, and you’ll see this in the new datasheets, and I don’t think we’ve made a big enough deal on this, is on the Figure 4 technology, these materials, the way they print, we have isotropic properties. And that’s a big deal because if I’ve got a part that does not have good properties in Z that you normally see in additive manufacturing, then I’m real constrained in the terms of how I set up that part. Yet now you can go in and if I’ve got the same part in X, Y, and Z, and I can get those same properties, I can stack up 15 parts in one print and get the same properties across those 15 parts. So now my throughput has gone 15 times the part that I had where I had to lay it down in XY that took my whole build area. So now I can push on that quite a bit to get those isotropic properties and to get multiple parts that are the same.

Leslie:
Okay. Do you have an idea as to when developers will have sufficient information for design engineers?

Marty Johnson:
I think this is the information that’s coming out. This is the stuff that we’ve announced that we’re coming … and there’s some information there now, but you still need to know the details. And really part of it, and I look at it a different way. What are the hurdles that we have to remove in order that a design engineer looks at additive as a production plastic and not a prototyping plastic? For instance, UL flammability. If I’ve got a UL 94 HB rating, then that tells me that it may be a minimum that I use on a consumer product, which happens quite often. If it doesn’t at least have an HB rating, then it may still be considered a prototyping material. In fact, there are products that I’ve worked on myself that you could not use a plastic that didn’t have a minimum HB rating.

Chemical compatibility. We used the USCAR2 and ASTM spec for chemical compatibilities and ran those through suites of those hydrocarbon automotive fluids and these detergents and cleaners and put those and track the properties across so that an engineer can look at that and say, “Hey, now that I know that I’ve got a sodium hypochlorite in my cleaner, which one of these materials can I use that it’s not going to affect,” and we can go and look at that. So that’s more removing a hurdle. If it’s there, they might not have considered that. Or dielectric properties is another one. Before spending 4,000 hours on a life test to get some of these longer electrical testing. Then maybe if I don’t know what those dialectical properties are upfront, I may never even pick that plastic up. So it’s removing those hurdles so that we can get those into engineers’ hands for adoption for production.

Leslie:
Very interesting. So now what about all the amazing hybrid materials that can be developed using additive manufacturing? Some of the technologies that can do this. What will it take to instill confidence in engineers about these materials?

Marty Johnson:
I think we have to step into it. I’ll tell you the real kicker. One of the first things, when I work with a customer, is how long before this part goes brittle. That’s one of the first questions that people will ask because that’s been one of the warts we’ve had to carry, if you will, from additive manufacturing. And by having these materials engineered for long-term stability … and when I say that we’re talking about measuring things in years, I’m talking about indoor stability out to eight years, trying to keep between plus or minus 20% of my initial properties going out or where I’ve got things for two years. So by measuring those in years, that moves you quite a bit away from that prototyping. So when you start into hybrids, if I’ve got hybrids but they only last me three months, it’s not a real step forward. I think I’ve got to go the other way. How do I get something can get long term and then start bringing those materials into hybrids to get some of these more exotic properties that people are looking at.

Leslie:
Very interesting. Yeah, that all makes good sense. Did you want to add something to this conversation that I have not addressed or asked? Is there an important point that needs to be made for the design engineer?

Marty Johnson:
I think for a design engineer, when I put my design engineer hat on and I’m sitting there looking at what plastic do I choose, I really want to see the whole picture. And the more that you’ve taken out the hurdles that you’ve removed from where I can see that. Things like tensile at yield, HDT water absorption, are these industry-standard testing? And that’s a real big deal because there’s a lot of material providers, in general, will tease and trick customers too much in this industry. And when that happens and a customer picks up a material and they go run this thinking they’re going to get production and all of a sudden three months down the road, it falls apart, well then not only does the customer lose and not only does the provider of that material lose, but as an industry, we take a black eye. So as an industry- I think we’ve got to be transparent in our materials and quit trying to make the decisions for design engineers. Let’s give a comprehensive set of data to the design engineer and let them … They’re very smart people … Let them go in and make the decisions themselves. Whether they need to design around this deficiency or do they accept it or do they choose another material. But I think we’ve got to get to the point where we’re transparent with the customers on what the data is, a comprehensive set of data, and trust the customer to make the right choices and allow them to design and pick their plastic as opposed to us push that to them in another way.

Leslie:
Very good points. So those are all the questions that I had, Marty. I appreciate your time.

Marty Johnson:
Thank you very much. I appreciate it. If you can tell, I always like talking about this stuff. We’re in a really good place right now, so just excited for what’s in front of all of us to move this forward.