Additive manufacturing brings innumerable benefits for design engineers, but determining when to use 3D printing for production parts remains a challenge. Printed components are being used in low-volume fields like aerospace, but engineers in many fields must still take a case-by-case approach to determine when parts may be a fit for the rapidly-growing manufacturing technique.
Manufacturing is being transformed by a range of printers that build parts using a variety of plastics, metals and other materials. 3D printing’s emergence is forcing more engineers to ramp up their understanding of additive processes. The new technology is increasingly seeing a transition from extremely small-volume applications like prototypes and molds, moving into higher-volume production applications. The ability to build parts in any shape instead of relying on conventional manufacturing processes gives engineers a lot of freedom.
“Additive manufacturing really opens up the design paradigm,” said Ryan Dehoff, Deposition Science and Technology Group Leader at Oak Ridge National Laboratory (ORNL). “The process constraints of conventional manufacturing are no longer there.”
Engineers who dipped their toes in the technology by designing prototypes are now beginning to explore using it for production parts. That’s worked well in aerospace, where small volumes and complex shapes produced on printers are being used in demanding areas like engines. Elsewhere, additive processes can be used to create turbine tips for utility equipment. Quantity is a key factor engineers must factor in when they make design for manufacturability decisions.
“If you’re making relatively small, complex parts in smaller volumes, it may be a good choice,” said Terry Wohlers, president of Wohlers Associates Inc. “For a surprising number of companies, manufacturing levels in the 100s or even thousands become candidates for additive processes.”
May prognosticators feel that additive processes will revolutionize the manufacturing world. That means that college students definitely need to understand the benefits and limitations while also knowing similar factors for conventional manufacturing technologies.
“Young engineers in college need to learn how it plays into the design process,” said Tim Proctor, technical leader for heavy duty engineering at Cummins. “It can be a very powerful tool for design engineers. They also need to know there’s a danger when things become fashionable, and people want to use it even if it’s not the best technology. Designers need to use the right tools.”
At present, design engineers who are considering 3D printing have a number of limitations. The technology is new, so there are still gaps that can make it difficult to utilize the printers on a global basis. One is that equipment and materials aren’t yet identical around the globe.
“Machine-to-machine reliability is improving, but it’s not perfect,” Dehoff said. “People have to be cognizant that parts made on one machine may not be identical to parts made on another machine from the same supplier.”
The design tools for additive manufacturing still don’t match the effectiveness of tools that have simplified the lives of design engineers over the past several years.
“One challenge is that the design tools are currently somewhat lacking in technology and capability,” Dehoff said.
Some observers feel that it may be a while before the base of knowledge for additive processes matures to the level of manufacturing technologies that have been used for decades. Many companies are still reluctant to share what they’ve learned. That makes it tough to create guidelines.
“There are design guidelines that go with the processes, but unfortunately, they’re not yet well documented,” Wohlers said. “A lot of people have learned on their own, companies have learned by trial and error. Often, they don’t want to share their knowledge.”
However, the stumbling blocks for 3D printing aren’t slowing growth. The Wohlers Report 2016 said that the additive manufacturing products and services worldwide grew 25.9% to $5.165 billion last year. That’s attracting a number of new suppliers. In 2015, 62 manufacturers sold industrial-grade systems, compared to 49 in 2014. That’s double the 31 companies that sold industrial systems five years ago.
As the industry matures, its role will continue to expand. Even design engineers who can’t justify the cost in high-volume applications may be able to use additive processes. One pathway to success is consolidating parts into a single assembly.
Components that are now built separately and assembled into a subsystem can sometimes be combined into a single assembly that’s built on 3D printers. That can trim handling and assembly costs, justifying the cost of converting to the new manufacturing technology. Trimming the parts count can also improve reliability. But it also takes a lot of research before consolidation can be justified.
“People are taking as many as 20 parts and condensing them into one printed component to lightweight and reduce or eliminate assembly,” Dehoff said. “That’s very interesting. However, any change depends on the components and the business case. You don’t see a huge decrease in the costs associated with higher production rates in the way you would with conventional manufacturing. For now, additive manufacturing is best utilized in low-volume, highly complex parts.”
Wohlers feels that this type of integration may be a key driver in the push to convert 3D processes from prototypes to production.
“Part consolidation takes a lot of effort and it requires a lot of knowledge about the processes,” he said. “Companies like Airbus are doing a lot with part consolidation.”
It’s not just parts consolidation that requires design engineers who understand the subtleties of manufacturing technologies. 3D printing is becoming a common tool for production, which means it will eventually be considered using the same sorts of tradeoffs that have been considered by design teams for years.
As engineers learn how additive processes work, they’ll find that many issues follow the same analysis steps that have been considered in the past. Cost will be one of the prime considerations when engineers decide how to manufacture parts. Material requirements will also be primary issues.
“Design engineers have always needed to know how manufacturing processes work, the same is true with 3D printing,” Wohlers said. “It’s just that this is new, so the knowledge base is far smaller.”
