NOVEL V/P TRANSFER ACTUATION METHOD AND INJECTION MOLDING STRATEGY AND THEIR COMPARISON TO TRADITIONAL METHODS

摘要

The use of one novel and three well-known injection strategies were investigated to determine the effect on variation in part weight for each when variation in material viscosity and check ring leakage were introduced to the process.In addition,a comparison was made of the use of traditional screw position,cavity pressure sensing,and a novel switch closed by the melt front to actuate v/p transfer with each of the processing strategies.Velocity to pressure transfer when the part was not quite full (2-stage,pack with second stage),after the part was packed with a fast velocity (2-stage,pack with first stage),and after the part was packed with a slow velocity (3-stage) were the well-known injection strategies evaluated.The novel strategy was a modified 3-stage where the v/p transfer was actuated after the first velocity (as in 2-stage,pack with second stage) and the pack velocity was set as the limit during the first profile of the second stage of injection.It was found that the modified 3-stage process reduced variation compared to traditional 3-stage and that the novel switch used to detect the flow front was the most consistent method to actuate v/p transfer.