Polymer Based Injection Mould Cavity Inserts: An Influence on Crystallization and Thermo-Mechanical Properties of Injection Moulded Parts

Abstract

Injection moulding is a major used technology in mass production of high-quality plastic and composite parts. Once the initial costs have been paid the price per produced part is extremely low and part is then created up to million times. On the other hand, the product development process is time-consuming and costly due to preparation time. Therefore, the efficiency and similarity to real production are essential. Injection moulding into polymer injection mould cavity inserts appears to be an appropriate step in the product development process in particular concerning quickly developing additive manufacturing technologies. Though polymers are thermal insulators, therefore, cooling time is longer compared to injection into fully metal moulds. The impact of different cooling conditions is a change in the crystallization of injected material causing different mechanical properties of products. Removable injection mould cavity inserts were made from PET (Polyethylene terephthalate), PEEK (Polyether ether ketone), PSU (Polysulfone) and PTFE (Polytetrafluoroethylene). The main goal was to compare crystallization and thermo‑mechanical properties of injected PP (Polypropylen) parts into polymer cavity inserts to those injected into a steel mould.