Injection Moulding Blank

With the increasing requirement of MIM precision, it is very important to analyze the relationship between shrinkage and production. Especially shrinkage, besides the correct material selection and modification, it seriously affects the quality of products. There are many factors affecting inject blanks:

1.Thickness of product wall. The wall thickness also affects the shrinkage rate. For non-crystalline resins, if the resin makes the wall thicker, the shrinkage rate will be larger, otherwise, the shrinkage rate will be smaller. For crystalline resins, wall thickness changes must be avoided. As for multi-cavity mode, if the wall thickness of the cavity is different, the shrinkage rate will also be different.

2. Reinforcement of material content. The more fibers are added, the smaller the shrinkage is. The shrinkage of injection moulding blank in flow direction is smaller than that in transverse direction. According to the difference of resin, in order to prevent distortion, the position of gate shape and number of gate must be considered.