Study on the clamping force measurement and partial load regulation technology of injection molding machine

Abstract

Tie bars are the most important parts of injection molding machine, and the partial load of tie bars will directly affect the product quality. According to the measurement of strain and stress of the tie bars, the partial load rate of tie bars was calculated, and the influence of different types of thread shape and template (mold) parallelism on the partial load rate of tie bars were analyzed. Experiments reveal that the partial load rate is changed within 0.8%–3.8%, and the partial load rate gradually decreases with the increase of the clamping forces. Besides, different types of the thread of tie bars have little influence on the partial load rate, while the parallel degree of the template (mold) has great influence on the partial load rate of the tie bars. Further experiments show that the partial load rate is located in 0.79%–1.81% when the parallelism of template (mold) is good, and the partial load rate of tie bars between 8.59%–11.46% when the parallelism of template (mold) is poor. Finally, the partial load adjustment system of tie bars were also designed to make the force of tie bars more uniform and the partial load rate can be reduced by detecting the partial load rate of the tie bar and using the closed-loop control.