Metal additive manufacturing is on the march, but despite growing interest, technologies remain slow, expensive, and limited in what they can produce. Brent Balinski spoke to Carnegie Mellon University Professor Jack Beuth about what’s being done to change this, and what to expect from 2017.
The excitement towards metals AM in recent years has been hard to miss, and this was especially the case last year.
According to the highly-regarded annual Wohlers Report, year-on-year global sales of machines able to 3D print in metals were up 75.8 per cent in 2013, 54.7 per cent in 2014, and 46.9 per cent in 2015 (topping 800 units sold in the year).
Last year things seemed to reach fever pitch, with General Electric’s announcement in September that it intended to buy two European machine manufacturers for $US 1.4 billion: Sweden’s Arcam and Germany’s SLM Solutions.
(The purchase of SLM didn’t go ahead, though GE turned its attention to another German company, Concept Laser. It now owns a three-quarter stake in both Arcam and CL.)
GE’s acquisition moves were a sure sign that things have gotten serious. It’s also great news for a set of technologies that – while promising – definitely need refining to achieve mainstream adoption in manufacturing.
GE’s investment is also particularly significant due to the size of metal 3D printing companies being nowhere near that of the 125-year-old US industrial conglomerate. R&D budgets and efforts have thus been limited and focussed on shorter-term projects, and innovations have tended to be incremental, according to Dr Jack Beuth, Professor of Mechanical Engineering and Director of Carnegie Mellon University’s NextManufacturing Center. Beuth has been on the engineering faculty for CMU (located in Pittsburgh) for a quarter-century, and researching 3D printing for over two decades.
“GE can afford to think on a bigger scale about where the AM machines need to be in, say, ten to 20 years,” Beuth told Manufacturers’ Monthly regarding the significance of the acquisitions.
Perhaps the biggest development in the last year, however, is that there is an interest in metals AM from nearly every company making metal components, he offered. Previously this was concentrated within aerospace. The automotive world is tipped to be the next big adopter.
Beuth’s NextManufacturing Center (which includes the likes of GE, Alcoa and Bosch among its collaborative members) is attacking the issue of adoption from multiple angles.
The group aims to assist in bringing things to the mainstream through improvements in areas including process variables (geometric designs, but not printing processes, can be readily tweaked right now), the variety of powders that can be used, and monitoring capabilities. These and other areas are currently highly limited.
Read on to learn more about the state of the art, what needs to be done to bring metals 3D printing to a greater number of users, and what 2017 might bring.
MM: One of the things that I’ve noticed in the last year or two has been the overall disappointment by machine manufacturers in the consumer market for polymers versus the interest around metal additive manufacturing. Are you able to give a comment on this?
Dr Jack Beuth: Our experience is similar to what you describe. We have seen some interest in polymer additive manufacturing (AM) from our NextManufacturing Center Consortium members and from industrial and government laboratory visitors. Most of that interest relates to new processes with increased build rates or new materials with enhanced properties for existing processes. Those members are not involved in the consumer market involving the so-called maker machines. However, the level of interest in metals AM is extremely strong (an order of magnitude greater than for polymers) and is continuing to increase. The excitement is across the board, from industry to academics (with many fundamental, yet immediately relevant, topics to explore) to government (understanding certification of aerospace components, for instance).
MM: What was the most interesting development that you saw in metal AM in 2016? Were GE’s acquisition moves the most notable?
Beuth: The GE acquisition of laser and electron beam powder bed machine manufacturers was very aggressive and was definitely a highlight for the industry. However, we were expecting something like this for a while. The current companies making metals AM machines are not large and it was only a matter of time before a large corporation made a move on one or more of them. The impact could be significant, in that the small size of machine manufacturers has limited their ability to do long-range R&D on advancing their processing capabilities. The AM processes have changed significantly over the past two years, but the changes have largely been incremental. A company like GE can afford to think on a bigger scale about where the AM machines need to be in, say, ten to 20 years, and then deploy resources to achieve those goals.
I think the biggest development we have seen over the past year has been a transition from primarily aerospace companies interested in metals AM to nearly every company that makes metal components having an interest. In particular, there is a strong interest in where the processes are going in the next five to ten years. Research that we are doing in the NextManufacturing Center is helping to define and enable some of the next developments in metals AM. For instance, we are helping to greatly increase the range of powders that can be used in AM machines. We are also pioneering the capability to locally control microstructure in AM fabricated parts.
MM: Could you please tell me what you expect to see in 2017? What excites you about the year ahead?
Dr. Beuth: I would not be surprised to see more acquisitions in the metals AM space. In addition to machine manufacturers, powder companies (supplying powder for the AM machines) and software companies (in the process planning and design areas) could be targets.
In academia, Carnegie Mellon University is making strong moves to integrate metals additive manufacturing into undergraduate and graduate programs. There are significant logistical challenges to this but we expect other universities to follow this path as well.
In industry, we see the automotive industry to be the next major user of metals AM technologies, following the example set by the aerospace industry. Overall, I think the growth of AM in companies outside of aerospace may be the biggest development in 2017.
MM: What is the current state of the art in process monitoring for metal AM? How are you and your team attempting to move things along?
Beuth: The extent of process monitoring and process feedback control in existing metals AM machines is very limited. In some ways it is amazing the quality of parts that can be built by the current machines which are not monitoring key aspects of the process (such as how well the powder is being spread and how well the powder particles are being fused). However, this is a significant area of current research and it is likely to be a key research area for ten or more years. For example, here at Carnegie Mellon University we have developed an automated system based on machine vision and machine learning for identifying errors in powder spreading during part fabrication. That system is now used every time we build a part and is extremely helpful in diagnosing whether or not a failed build was caused by a spreading problem or some other processing issue.
MM: Another aspect of NextManufacturing’s work I think readers would like to learn about is the microstructure manipulation techniques developed, which are being transferred to your industrial partners. I understand if you can’t talk specific applications among users, but if you could please talk about the technology and the potential, that would be excellent.
Beuth: We have demonstrated how to control grain size spatially within parts for laser and electron beam powder bed AM processes and two alloy systems. The methods are extendable to other processes and alloys. This is opening up the capability to design microstructure and mechanical properties such as strength and ductility with location within a component. For example, one would typically want small grain sizes and high strengths in regions of a part subjected to high stresses. In contrast, one might want more ductility (a higher strain at failure) in other regions of a part by specifying large grains. Our research is showing how to do this and we expect that within five years, industry will be employing these techniques.