Design and optimization of multi-stage manufacturing process of stirling engine crankshaft

Abstract

Crankshafts are among the most important parts in internal combustion engines, of which stirling engine is a useful example. Manufacturing process of a crankshaft, is considered as a three-step forging process using preform, due to the complexity in geometry. The most challenging step of the multistage forging process is to avoid stress concentration and to create uniformity of strain by controlling metal flow. In the present study, the final part was achieved under three manufacturing processes namely: upsetting, hot and cold forging. The models used in each manufacturing process are designed by CATIA software. A finite element simulation on the basis of Cockcraft–Latham damage criterion was developed in DEFORM software. Using experiment design by Taguchi method, The optimization of manufacturing processes were carried out by MINITAB software in two steps, in which the optimization objectives are considered as force, damage and strain uniformity, and; input variables are taken as part-mold friction, pressing velocity and process temperature. In order to find the most effective parameter of each manufacturing process, analysis of variance was conducted on the results, in which, the most effective parameters in the upsetting, hot and cold forging processes were temperature, friction and temperature, respectively.