Equipment that builds metal products up using powders and lasers instead of milling away unwanted material is evolving rapidly. It lets product designers create unusual shapes while reducing development time and costs. That’s enough to gain the attention of top executives.
“Additive manufacturing has huge advantages from a cost standpoint,” said Pratt & Whitney's President David Hess. “It also eliminates the time needed to develop tooling.”
The ability to create parts without waiting for tooling is a key benefit, especially in prototype systems where alterations are common. P&W first used additive fabrication for prototypes, helping build up confidence in the reliability of components created by fusing powdered metals by hitting them with lasers.
“Initially, we focused on development programs. It lets you get to test quickly,” said Tom Prete, Engineering Vice President at P&W. “Now we’re starting to see the benefits on the production side.”
P&W has flight tested components made from additive manufacturing on the PurePower PW1500G and PW1200G engines that will power Bombardier's CSeries jets. They are much simpler to make than conventional solutions.
“In the manifold, there are various tubes that are currently made of several parts that we braze together,” Prete said. “With additive processes, we can grow these 3-D features, eliminating the need for complex fabrication and brazing. That dramatically changes our costs and time to market.”
The technology appears poised to see significantly more use in coming years. Danny DiPerna, Vice President of Module Centers & Operations at P&W, noted that the company has internal programs, and it’s also working with outsiders.
In April, P&W partnered with the University of Connecticut to establish an additive manufacturing laboratory that will focus on metal structures. P&W invested more than $4.5 million in the P&W Additive Manufacturing Innovation Center.
The move is part of an overall trend within P&W to ensure that designers create parts based on the company’s manufacturing capabilities. Design teams now include employees from many different departments, which also ensures that manufacturing personnel understand the intent of designs.
“In the old days of developing products, engineers used their best knowledge of manufacturing processes,” DiPerna said. “Now we have integrated product development processes and integrated product development teams, with operations, manufacturing, and many other personnel all linked in part of the design process.”
Market analysts expect additive processes to see solid growth. Plastic components have been used in aircraft bodies for a while, and other engine makers are also moving metal parts from prototype to production components.
“A lot of aerospace companies are looking at this long and hard,” said Tim Caffrey, Associate Consultant at Wohlers Associates. “Production quantities in aerospace are a good match for additive parts; they often don’t have the high volume to justify the high cost of tooling.”
As additive programs expand, engine designers are learning how additive processes can benefit them. Additive processes give engineers more freedom to innovate while bringing significant cost benefits.
“It changes the idea of what you can design; you can do curved passages so you get the most efficient components,” DiPerna said. “On certain components costs drop around 30%.”
This decrease in production costs pales compared to the savings that can be gained in prototype and testing environments. Short turnaround times are extremely beneficial in this phase.
“During development, if the engine has to be shut down a week while you wait for a part, it can cost in the seven figures if you count everything,” Prete said. “With additive parts, there are times when you can go from the sketch of a part to a functioning part in less than a week. It only takes 18-30 hours to do additive processing for many of the parts we’ve done.”
Prete also noted that P&W is taking many steps to ensure that the additive parts meet or exceed the strength and reliability levels of conventional metal components.
“We do a lot of work characterizing the powders, specifying materials, the size of the particles, etc.,” he said. “For laser sintering, you have to understand the heat and the laser current, as well as the time to let the part cool before you hit it again with the laser.”