For 16 years, ExOne has focused its efforts on developing additive machines for use in manufacturing. ExOne President Dave Burns explores this shift of 3D printing into additive manufacturing and how it will affect design engineers.

Leslie Langnau, Managing Editor

Before the majority of U.S. manufacturing was transferred to other countries, economics dictated that you produce hundreds to hundreds of thousands of the same item. The faster you were able to accomplish this feat, the less it ultimately cost you. Custom, one-of-a-kind products were expensive to make.

Items made on CNCs or that were injection molded had to conform to certain geometries, or had to be built into parts requiring assembly. Certain cuts, certain moves were impossible when cutting, stamping, drilling or forming parts.
Today, there is hope for the cost-effective manufacture of custom, geometrically complex parts. That hope comes from 3D printing as it matures into additive manufacturing (AM).

As recently as a couple of years ago, the idea of using the current additive technology for production-style manufacturing was a dream. Speed, reproducible accuracy and the too-small array of materials were seen as limitations not easily overcome.

These limitations are gradually disappearing as curiosity, experimentation and creative thinking are producing new machines. Thus, many in the AM industry are focusing less on prototyping and much more on how to incorporate additive machines into manufacturing.

At the recent RAPID 2015 show, I had a chance to talk with Dave Burns to discuss this shift in the AM industry. ExOne has been developing production focused AM machines since 1999.

When evaluating AM machines for production applications, many treat these machines as separate from other manufacturing machines, assuming that the production speed and material availability will inherently limit their use in manufacturing. But ExOne’s focus is different.

“We’ve been focused not on competing with other 3D printing companies,” said Burns, “but on understanding that our real competition is conventional manufacturing processes and being able to match productivity and cost with traditional process.”

As Burns noted, manufacturing plant managers track a lot of data on the manufacturing process—quality, productivity, orders in, orders out and so on. “But not one of the ones I know has a chart saying how much 3D printing they did last week. Plant managers don’t really care how much 3D printing they use, so being cool and being a 3D printing company doesn’t matter much to a plant manager.” Getting the product out the door is a plant manager’s main concern, whatever technology is used to accomplish that goal.

Burns is in favor of additive machines competing side by side with CNC and injection molding machines. ExOne’s recent introduction of Exerial exemplifies that view.

Noted Burns, some additive machines (like Exerial) are now within a few percentage points of the cost of using hard tooled automated lines. “But you get all the other advantages of 3D printing, such as complete flexibility, design freedom and a shorter supply chain, because now you can print on demand. If you hard-tool parts, then you must run 100,000 or more to amortize the cost. With additive, you need only run one part to amortize the cost because 3D printing is totally independent of volume,” he said.

Many analysts may find the news that traditional machine tool manufacturers, such as Mazak and Trumpf, plan on entering the additive market as a bit of a surprise, as well as encouraging to the additive market. For Burns, though, news of the big guys coming in was totally predictable.

“When you consider the overall size of the manufacturing industry, recently valued as a $90 billion market, the current list of additive machine vendors is too small to supply enough machines to such a huge market. That’s why it was totally predictable that more traditional machine tool vendors would have
an interest.”

The current offerings from companies like Mazak and DMG are more of a hybrid type of additive machine. Said Burns, “I think we are a long way from seeing truly additive machine tools capable of multifunction. Two recent introductions from Japan are true additive machines. They were built from scratch and were made by machine tool builders.”

A persistent idea you hear about additive machinery is that it will replace CNC machining and potentially injection molding in many applications. Experienced additive users disagree. Rather than replace an optimized process (CNC machining for example) with a relatively new process (AM), better opportunities lie with using AM to create what you have not been able to accomplish with CNCs. Therefore, do different designs and projects with AM.

Said Burns, “I see additive coexisting with traditional manufacturing operations occurring within five years. Service bureaus are already doing this.”
As companies bring manufacturing back to the U.S., AM presents interesting questions about possible changes in operations and processes, as well as design.

“Additive manufacturing, almost by definition, is a locally deployed technology,” said Burns. “You want to use it where you want parts, so what do you do now? For U.S.-based companies, additive manufacturing presents an interesting question about possible change, especially in reintroducing manufacturing to
the U.S.”

Change includes how to sequence part production. The automotive companies, for example, are exploring how AM can speed product changeover. What if you could build one part, then change to another part, and continually change parts using one machine? CNCs and injection molding systems are less flexible about part changeover than an AM machine. Plus, you can build one part on an additive machine without worrying about amortization or inventory building. You can even design the manufacturing/fabrication process such that every part coming in is synchronized within the process and assembly.

Said Burns, “We aggregate our jobs all the time. Our server is loaded with files, each one different. We print an average of 1,000 unique parts every day. The size of the parts varies. In many cases, we can print different parts simultaneously, depending on part and build size. You can’t run ten different parts on a CNC at the same time.” Such benefits are not possible with subtractive technology.

When designing for additive, it’s important to know that additive has its own “set of rules.” For example, the concept of design optimization is changing. It is no longer about whether you put an undercut in the design or not. It’s more about taking out excess weight while making the part physically stronger. While you can reduce the weight of many parts by as much as 50 to 75%, the real win may be in taking out as little as five pounds in thousands of one part that is made multiple times.

But the AM set of design rules has yet to be written. Organizations and standards bodies are working on them, but it is still very much a work in progress.