THESIS
1997
1 v. (various pagings) : ill. ; 30 cm
Abstract
The objective of this study is to develop a methodology for the determination of injection molding processing parameters for defect-free parts. The proposed methodology consists of two parts: initial setting and defect correction. The initial setting scheme uses a simplified approach to estimate the processing window within the operating region of the process. The processing window is estimated by using a set of quality criteria in conjunction with a simplified process model. The initial setting of the processing parameters is selected within the simplified processing window based on the minimum cycle time criterion. The defect correction scheme uses a qualitative approach to provide corrective actions if defects are existed after initial setting. A defect-free quality criteria is devel...[
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The objective of this study is to develop a methodology for the determination of injection molding processing parameters for defect-free parts. The proposed methodology consists of two parts: initial setting and defect correction. The initial setting scheme uses a simplified approach to estimate the processing window within the operating region of the process. The processing window is estimated by using a set of quality criteria in conjunction with a simplified process model. The initial setting of the processing parameters is selected within the simplified processing window based on the minimum cycle time criterion. The defect correction scheme uses a qualitative approach to provide corrective actions if defects are existed after initial setting. A defect-free quality criteria is developed for this purpose. The corrective actions are guided by a qualitative search algorithm in conjunction with a knowledge base for defect correction. Results are presented to verify the initial setting scheme and the defect correction scheme against numerical results of a commercial numerical simulation package C-MOLD. Results show that the initial setting scheme is able to provide a reasonable initial estimate of the processing parameters, while the defect correction scheme is able to search the processing parameters to correct the violated quality criteria. The proposed methodology is further verified experimentally for a film-gated plate with two polymers, polystyrene (PS) and polypropylene (PP). Experimental results for PS show that the initial setting scheme generates a set of defect-free processing parameters. Results for PP shows that corrective actions are necessary after initial setting, and the defect correction scheme is able to correct the defects.
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