Process Condition - Morphology Relationships of Micro Injection Molded Components
Marcin Debowaski, Andrew Spowage
Singapore Institute of Manufacturing Technology
Singapore

Keywords: Morphology, Micro Moulding, Microscopy

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The morphologies of molded polymer components obtained using the conventional injection molding and the micro-injection molding (MIM) process were studied and compared in the paper. In the injection stage of the injection molding process, various factors can influence the final material morphology. The morphologies at the core and skin areas of molded samples can vary significantly and are controlled by different process parameters. The skin-core morphology related to the molding process was the subject of an intensive investigation in the past three decades. In recent years due to the worldwide trends toward miniaturisation the micro molding process has been used to manufacture products of the size being a fraction of milligrams. Such sample sizes and the necessary mold dimensions imply some significantly different molding conditions, as compared to the traditional molding process. The shear rates are here much higher and the heat-transfer between the sample and the mold is different. As the molding conditions are different a different morphology should also be expected. In the present study, samples of crystalline and amorphous polymers where processed with the micro molding process as well as the conventional molding process. The process conditions, such as the injection speed and the temperature of the mold were varied to show their influence on the polymer physical structures. The specimen morphology was investigated using different kinds of microscopy including Scanning Probe Microscopy, Scanning Electron Microscopy and Optical Microscopy. X-ray spectroscopy related techniques were also employed.