Principles of polymer processing modelling

Abstract

Abstract. Polymer processing involves three thermo-mechanical stages: Plastication of solid polymer granules or powder to an homogeneous fluid which is shaped under pressure in moulds or dies and finally cooled and eventually drawn to obtain the final plastic part. Physical properties of polymers (high viscosity, non-linear rheology, low thermal diffusivity) as well as the complex shape of most plastic parts make modelling a challenge. Several examples (film blowing extrusion dies, injection moulding, blow moulding) are presented and discussed.

Scanning acoustic microscopy investigation of weld lines in injection-molded parts manufactured from industrial thermoplastic polymer

“…Changes in morphology as manifested by formation of crystalline phases were found not to have a significant effect on the elastic properties ( Ghosh et al, 2007 ). However, during the process, line welds (or knit lines) unavoidably form during the recombination, when two or more flow fronts meet in the cavity during injection moulding ( Agassant and Mackley, 2016 ). Welds comprise points of weak mechanical properties ( Nasić et al, 2018 ).…”