Metal Injection Molding in the aerospace industry

Technical innovations and advanced materials add to Metal Injection Molding’s appeal

Following the early successes for Metal Injection Molding in the late 1970s (see below), the technology has found a number of applications in the aerospace sector, including high performance engine components, seatbelt parts, latches and fittings, spray nozzles and vane adjustment levers, to name just a few.

Metal Injection Molding in the aerospace industry

A PW1524G during testing in West Palm Beach (Photo © Pratt & Whitney)

Whilst the majority of current MIM aerospace applications will inevitably remain confidential, Pratt & Whitney announced in 2015 that its PurePower® PW1500G engines include Metal Injection Moulded components, as well as being the first to feature entry-into-service jet engine parts produced using Additive Manufacturing.

There has in recent years been a renewed interest from the aerospace sector in using Metal Injection Molding to manufacture superalloy components for use in critical aero engine applications.

Primary MIM materials for aerospace applications include stainless steels (316L, 410, 420, 17-4 PH, 13-8 PH), superalloys (Hastelloy X, Inconels 625, 713C and 718, Nimonic 90, and Udimet 700) and variants.

Titanium alloys TiAl and Ti-6Al-4V are also used and MIM’s ability to produce complex, high volume, high performance titanium components offers attractive possibilities to reduce aircraft weight.

 

Aerospace seatbelt component

Metal Injection Molding in the aerospace industry

Fig. 27 Metal Injection Molded low alloy steel seat belt component manufactured by MimEcrisa SA, Spain

A high-strength Metal Injection Moulded seatbelt component for the aerospace sector is shown in Fig. 27. This 90 g complex shaped part is produced from an Fe7Ni0.6C steel alloy which, after heat treatment, provides a tensile strength greater than 1200 MPa.

Typically, a part of this size (80 mm diameter) and weight would be outside the conventional size range for MIM parts. Thanks to the part’s complexity, however, Metal Injection Moulding was able to provide the most cost-effective solution.

 

Valve holder

A small MIM component for the giant A380 Airbus is the valve holder. The parts were previously made from pressed metal, small machined pillars, washers, nuts, etc, using 22 items, which have been replaced by just two MIM parts.

Metal Injection Molding in the aerospace industry

Fig. 28 Valve holder parts from the Airbus A380

The MIM 316L stainless steel components hold a de-icing valve and the one-piece MIM parts have recesses in the tops of the pillars, which are used for riveting a plastic micro-switch into place.

Massive cost savings were achieved, not just for the cost of the parts, but also in assembly time and the cost of ordering and stocking the individual parts.

 

Airliner flap screw

MIM’s earliest successes were in the aerospace sector. Dating from 1979, this 50.8 mm diameter ring shaped part was used in the flap mechanisms of Boeing 707 and 727 airliners, as well as the German VFW 614 transport aircraft.

Metal Injection Molding in the aerospace industry

Fig. 29 This airliner flap screw seal, from 1979, was an early success for Metal Injection Moulding (Courtesy Parmatech Inc, and MPIF)

In addition to corrosion resistance, the part was reported to have outstanding properties as a result of its high density, which was over 96% of theoretical.

The part was made of pure nickel with a complex configuration featuring a unique internal discontinuous thread.

 

Rocket burner system

Metal Injection Molding in the aerospace industry

Fig. 30 Rocket burner system, dating back to 1979. (Courtesy Parmatech Inc, and MPIF)

These niobium alloy components, again dating back to 1979, were used in a Rocketdyne rocket thrust system.

The large 150 mm long thrust chamber was moulded in one piece, while the injector part, of an extremely complex geometry, was moulded in two pieces, which were subsequently electron beam welded together.

 

Next page: Applications: Consumer Products

 

 

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As well as an extensive MIM and CIM industry news section, this 104-page issue includes the following exclusive articles and reports:

  • Threat or opportunity? The MIM industry as a partner, a target and a market for metal AM
  • WORLDPM2018 Congress: Global MIM markets show healthy growth
  • Ceramic Injection Moulding and Ceramic Additive Manufacturing side by side: Opportunities and challenges
  • Euro PM2018: Innovations in Metal Injection Moulding highlighted in Bilbao
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