Computer Modeling for Injection Molding: Simulation, Optimization, and Control

Chapter 7: Microstructure and Morphology Simulation

Huamin Zhou

State Key Laboratory of Materials Processing and Die & Mould Technology, Huazhong University of Science and Technology, Wuhan, Hubei, China

Fen Liu

Department of Mechanical and Biomedical Engineering, City University of Hong Kong, Kowloon, Hong Kong, China

Peng Zhao

State Key Laboratory of Fluid Power and Mechatronic Systems, Zhejiang University, Hangzhou, Zhejiang, China

During the injection molding process, the polymer melt is subjected to a complex thermodynamic environment with high shear rates and rapid cooling. This thermal and stress fields vary throughout the whole spatial domain of the cavity, especially along the flowpath and across the thickness of part. As a result, an injection-molded product often shows a gradual and hierarchical variation of microstructure.

The scientific and technological interest in the study of morphology is contributed to the fact that polymer characteristics (including the mechanical, optical, electrical, chemical) are strongly dependent on the morphology of microstructure.¹ For example, crystallinity can often modify the density and stiffness of materials, and orientation will induce anisotropy in mechanical properties.

7.1 Types of Polymeric Systems

The basic predominant feature of the polymer structure is a long molecular chain or backbone. The structural arrangement, size, and chemical constitution of this molecular structure² decide the valuable physical and chemical properties ...