Design of preforms for flashless forging of gear blanks

The main objective of this research is to utilize the ALPID (Analysis of Large Plastic Incremental Deformation) computer program to design forging preforms of gear blanks that are axisymmetric, with a particular emphasis on die fill in corners and flashless forging. Much of the early work was experimentally based, while current efforts are aimed at using finite element methods, similar to the study performed here.;The forging industry is looking for ways to save money by producing Net Shape or Near Net Shape forgings. A flashless forging can save from 15% to 30% of material otherwise will be scrapped during subsequent machining operations. The benefit of using the ALPID program in this research is to simulate the forging process and to watch the forged part on the screen while the forging process is in progress. A decision can then be made to further improve the forging preform. This research was devoted to the use of ALPID to rigorously study the effects of various preform slenderness ratios (length/diameter), friction factor, and other geometrical parameters of the forging dies on the hot forging of flashless simple gear blank. The actual gear blank forging was produced at Eaton Corporation. This particular gear blank possessed a lap. If a lap forms during the forging operation, the part is usually scrapped. This research also has one of its goals examining the capability of the ALPID program to predict lap formation and any other forging defects in order to improve the design of the forging preform.;The experimental part of this research was to use Plasticine to further verify the ALPID simulation results.;The results of this research provide general rules to the forging design engineer to follow in selection of preforms for gear blanks similar to the one used in this study. It also proved that the ALPID program can be very effectively utilized to verify a preform, including the ability to model a defect in the form of a lap. Moreover the 3-D Plasticine modeling agreed completely with the Alpid simulations including the prediction of a lap similar to the one formed in the actual forging provided by Eaton Corporation. It is believed that this is the first time that Plasticine was used to predict lap formation in forgings.