How to understand polymer molecules before designing injection molds?
Plastic injection mould is the most widely used plastic mould, which can form complex and high precision plastic products.Before designing plastic injection mould, we must have some knowledge of plastic. The main component of plastic is polymer.Such as ABS plastic is three kinds of acrylonitrile, butadiene, styrene monomer by emulsion or suspension polymerization, ontology, has the better performance of three kinds of monomers and can be molded, under certain temperature and pressure injected into the mold cavity and flow deformation, and get the cavity shape, the holding out into plastic products after cooling.Polymer molecular chain structure in commonly, linear molecule chain and branched molecules considered thermoplastics, 39 and repeatable processing, cooling/heating and after heating, multiple molecular crosslinking reaction, connect into the molecular structure of mesh size plastic is usually a one-off, not repeated injection processing, thermosetting plastic that is said.Since is the chain structure, so the direction of the plastic shrinkage when processing and polymer molecule chains under the effect of stress orientation and cooling contraction is related to the flow direction than the vertical contraction.Product shrinkage is also related to product shape, gate, thermal expansion and cold shrinkage, temperature, pressure retention time and internal stress.Generally, the shrinkage rate provided in the book is quite wide. In practical application, the product's wall thickness, structure, temperature, pressure and orientation are considered.If general products do not have core support, the contraction is correspondingly larger.