关于注塑件脱模力计算公式的修正

Modification of the Formula for Calculating the Demoulding Force of Injection Molded Parts

结合注塑件脱模力的计算公式,塑件收缩对模具型芯产生的包紧力与塑件对模具型芯产生的正压力出现混淆的问题,以圆筒形塑件及空心矩形体塑件为例,通过分析塑件收缩对模具型芯产生的包紧力在塑件脱模前后与塑件对模具型芯产生的正压力的变化,推导得到包紧力计算公式,说明了包紧力与正压力的区别。为了进一步分析脱模力及包紧力的变化,研究了拔模斜度α与脱模力修正系数K的关系曲线及包紧力脱模力的比p/q与脱模力修正系数K关系曲线,结果表明,在相同参数条件下,随着脱模力修正系数K的增大,拔模斜度α曲线呈线性关系,包紧力脱模力的比p/q曲线呈非线性关系。最后,根据以上研究及实际情况修正了塑件脱模力计算公式。

Introduction to the calculation of demolding force for injection molded parts based on relevant literature.The confusion between the clamping force generated by plastic part shrinkage on the mold core described in the literature and the positive pressure generated by plastic part on the mold core.Taking cylindrical plastic parts and hollow rectangular plastic parts as examples,this article analyzes the changes in the clamping force generated by plastic part shrinkage on the mold core before and after demolding and the positive pressure generated by plastic part on the mold core.The formula for calculating the clamping force was derived,and the difference between clamping force and positive pressure was clarified.In order to further clarify the changes in demolding force and clamping force,the relationship curve between the draft angleαand the demolding force correction coefficient K,as well as the relationship curve between the ratio p/q of the clamping force demolding force and the demolding force correction coefficient K,were studied.The results showed that under the same parameter conditions,as the release force correction coefficient K increased,the draft angleαcurve showed a linear relationship,while the ratio p/q curve of the clamping force release force showed a nonlinear relationship.Finally,based on the above research and actual situation,the formula for calculating the demolding force of plastic parts was revised.