Additive manufacturing (AM) is a hot topic in manufacturing. Many aerospace companies are making large investments in this technology. GE is spearheading applications of metal AM in gas turbine engines. A fuel injection nozzle made by the powder-bed 3D printing method is slated to fly in 2016 on the newest GE Leap Engine (Fig. 1). Many more AM applications are on the verge of becoming reality.
Forgers are interested in how this new technology could affect them and their customers. While capable of producing complex parts with good mechanical properties, AM is still expensive and can’t compete with forgings for high-volume orders. In the near term, the most likely forging-related applications are in rapid prototyping and tooling. In both cases, the volumes are small (often just a few parts). Since AM does not require tooling, it can be very competitive under these circumstances.
To explore these applications, the Forging Industry Educational & Research Foundation (FIERF) has been funding exploratory studies at Case Western Reserve University, a FIERF Magnet School in Cleveland, Ohio. Tooling has been an area of research at Case for many years. The university has been awarded a few projects by America Makes, the recently established National Additive Manufacturing Innovation institute.
Among them is a project on the repair of die-casting tooling utilizing AM. This activity has also led to a new project on the repair and enhancement of forging tooling, which is supported by the Forging Defense Manufacturing Consortium’s PRO-FAST program. This project will enhance forging dies by laser cladding the surface with a layer of heat-resistant alloys such as Waspaloy, Stellite and Inconel. The performance of the dies will be monitored in production.
A FIERF-supported project has been investigating enhancement of tools for warm forging applications. Another FIERF project at Case is comparing mechanical properties of identical parts fabricated by forging and powder-bed 3D printing. Some of these parts are illustrated in Figure 2. The forged parts are made in high volume out of carbon steel. These parts are shown after machining in Figure 2. A maraging steel had to be used for the 3D printing process to match the mechanical properties.
A detailed analysis of the costs associated with the two processes placed the break-even point at about 450 parts. In other words, since no tools are required for 3D printing, it will cost less to use this process if no more than 450 parts are required. Facilitated by FIERF funding, these research projects are exposing students to forging technology and often lead to future employment in the forging industry.
Engineering students at Case are gaining valuable manufacturing experience by working on these projects. Nicole Corbin, a student who worked on the tooling repair project, just graduated and accepted employment at Lincoln Electric in Cleveland. Another student, Sonny Li, did a co-op at PCC’s Wyman Gordon Forging plant in Cleveland. Sonny’s senior project compared mechanical properties of laser-deposited to wrought IN718. The results of these projects are reported at the biannual forging technical conferences.
Provided by professor David Schwam, Department of Materials Science and Engineering at Case Western Reserve University. Professor Schwam is a Magnet School Professor and research partner of the Forging Foundation.