The mechanical properties of an injection molded part are usually minimally affected. Some parts can have internal stresses in them. This is one of the reasons why it's good to have uniform wall thickness when molding. One of the physical property changes of an injection molded part is shrinkage. A permanent chemical property change is the material thermoset, which can't be remelted to be injected again.
The article comes from China injection mold manufacturer - Mold Best Assurance Company Limited, website is www.mbamoldanddesign.com
