Time compression-rapid steel tooling for an ever-changing world

As the race to get a product to market increases in speed, the drive for tooling lead times to decrease will become greater. This drive in time compression in the manufacturing sector leads to unique opportunities to create tooling via non-traditional methods that dramatically reduce lead times while not sacrificing mechanical properties. Rapid tooling, fabricated at The Pennsylvania State University’s P/M Lab, uses a powder metallurgy process to combine the processing of various metals and or ceramic powders to form a tool set with tailored mechanical properties. The new process has potential uses in the automotive, toy, electronics, cosmetics, fashion, medical, packaging, and metal die casting industries, as well as significant implications for the manufacturing industry as a whole. Recent reports estimate that total profits on new products are reduced by as much as 60% by a companyʹs inability to get the product to market quickly. With increasing part complexity and requirements for long production runs, tooling has become an expensive process that requires long lead times to manufacture. This lengthens the amount of time from ‘art to part’. Rapid tooling via stereolithography (SLA), filled epoxies, etc., have been stopgap measures to produce limited prototyping runs (from 10 to 500 parts). This gives poor dimensional precision and does not allow for limited production runs of 1000+ parts. The method of producing prototype tooling with a powdered metal process has been developed that produces tooling with 1150 MPa TRS strength, hardness greater than 35 HRC and shrinkage less than 0.4%. The surface finish of the tool set as sintered is approximately 1.5–2 μm, but can be polished to approximately 0.2 μm. This tooling process manufactures production ready tooling that will perform extended cycle runs (100 000+). Manufacturing of this tooling takes 1 week and will compare favorably with production grade steel tooling. The process starts with a rapid prototyped model made by whatever RP process is desired or a machined master. For this study a Sanders rapid prototyping machine was used to fabricate the model. After the model of the tool set is made, a silicone rubber negative is cast around that model. After the silicone rubber mold is hardened, slurry of metal powders and polymers is poured into the mold to create the green tool set. The tool set is left to cool, and then removed from the silicone rubber mold. The tool set is then debound and sintered to produce a final tool set with properties approaching hardened tool steel.