LIU Hong1, YANG Zhe ren1, JIANG Lan fang2

（1. College of Mechanical Engineering, Zhejiang University of Technology, Hangzhou 310014, China;

2. Zhijiang College, Zhejiang University of Technology, Hangzhou 310024, China）

 

 

Abstract: Aiming at the problem of injection molding part was full of residual stress, taking the plastic part of automotive lamp made by Polycarbonate (PC) as an example, the stress relaxation law of plastic part under annealing process was investigated, and the formula of relaxation stress used in industry glass under annealing process was analyzed. A mathematical model of stress relaxation for the material of Polycarbonate (PC) under annealing process was presented. Adopting the experimental as a method, the residual stress of the plastic part of automotive lamp from three different annealing processes were measured by drilling hole method. According to the two sets of data from the experiment, the undetermined parameters in the mathematical model of stress relaxation were calculated, and the relationship between the annealing time, annealing temperature, residual stress before annealing and residual stress after annealing was established. And the residual stress calculated by the mathematical model was compared with the third data from the experiment. The result indicates that the error between these two sets of data is very small and the mathematical model has high accuracy and reliability.

Key words: polycarbonate (PC); residual stress; annealing; injection moldingpart