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摘要
Clamping force greatly influences the injection molding quality, particularly in molding thin-walled plastic parts. Low clamping on mold halves can easily cause flash defects in the part geometry, whereas high clamping can cause poor air venting that in turn causes a short shot. Therefore, using an optimal clamping force setting is crucial. However, traditional methods for estimating the clamping force for injection molding mainly use the total projected area of the cavity, sprue, and runner along the clamping direction multiplied with the predictive cavity pressure of a molten polymer. Because this prediction is rough, a maximal machine specification is commonly applied during practical operations. Thus, heavy loading on the machine and mold may generate defects on molded parts, cause extra energy consumption, and shorten the tool life. A strain sensor mounted on the tie bar can reveal the dynamics of the clamping force during injection molding. For example, tie-bar elongation increases during mold filling and packing when the high-pressure molten polymer acts on the mold halves. This study developed a novel searching algorithm based on information about tie-bar elongation with various clamping force settings to identify the proper clamping force value to set. An experimental verification shows that the clamping force determined using the proposed method feasibly improves the injection molding quality.
- 出版日期2017-6
