Medical Device – Surgical Stapler Planetary Gear System
A sinter-hardened steel planetary gear system, featuring a carrier with an integrated sun gear and three planetary gears, earned the Grand Prize in the Medical/Dental Category for ASCO Sintering Co., Commerce, California. The system is used in multiple stacks for gear reduction in a single-use, portable, physician-operated surgical device. In addition to the integrated pinion gear, the carrier includes three posts that extend above the flange with a 2-to-1 length-to-diameter ratio. Proprietary press mechanisms were required to achieve the post density, as well as a proper post-to-flange bond. The carrier is pressed, sintered, and tempered to net shape.
The part had originally been fabricated as an assembly of a powder metallurgy (PM) part and wrought posts. By integrating the posts to the flange through advanced PM manufacturing techniques, and by the elimination of a secondary heat-treating operation through the use of modern sinter-hardening materials, the new part design achieved a 60% cost reduction. The part is an outstanding example of a PM medical application, unique in that it is not made of stainless steel nor fabricated through metal injection molding.