Size effects on process performance and product quality in progressive microforming of shafted gears revealed by experiment and numerical modeling  

作　　者：Jun-Yuan Zheng Hui Liu Ming-Wang Fu 

机构地区：[1]Department of Mechanical Engineering,The Hong Kong Polytechnic University,Hung Hom,Kowloon,Hong Kong,People’s Republic of China [2]Research Institute for Advanced Manufacturing,The Hong Kong Polytechnic University,Hung Hom,Kowloon,Hong Kong,People’s Republic of China

出　　处：《Advances in Manufacturing》2023年第1期1-20,共20页先进制造进展（英文版）

基　　金：The authors would like to acknowledge the funding support to this research from the projects of ZE1W and BBAT from The Hong Kong Polytechnic University,the National Natural Science Foundation of China(NSFC)(Grant No.51835011);the General Research Fund(GRF)(Grant No.15223520).

摘　　要：As one of the indispensable actuating components in micro-systems,the shafted microgear is in great production demand.Microforming is a manufacturing process to produce microgears to meet the needs.Due to the small geometrical size,there are uncertain process performance and product quality issues in this production process.In this study,the shafted microgears were fabricated in two different scaling factors with four grain sizes using a progressively extrusion-blanking method.To explore the unknown of the process,grain-based modeling was proposed and employed to simulate the entire forming process.The results show that when the grains are large,the anisotropy of single grains has an obvious size effect on the forming behavior and process performance;and the produced geometries and surface quality are worsened;and the deformation load is decreased.Five deformation zones were identified in the microstructures with different hardness and distributions of stress and strain.The simulation by using the proposed model successfully predicted the formation of zones and revealed the inhomogeneous deformation in the forming process.The undesirable geometries of microgears including material unfilling,burr and inclination were observed on the shaft and teeth of gear,and the inclination size is increased obviously with grain size.To avoid the formation of inclination and material unfilling,the punch was redesigned,and a die insert was added to constraint the bottom surface of the gear teeth.The new products had then the better forming quality.

关 键 词：MICROFORMING Microprocess performance Microforming quality Size effect affected deformation behavior Die design optimization 

分 类 号：TH132[机械工程—机械制造及自动化]