注塑件脱模阻力计算改进

On Improving Calculation of Ejection Resistance of Injection Moulding

讨论了一般情况下脱模阻力计算公式的简化，引入了两个简化系数。分析了几种特殊情况下的脱模阻力，导出了一项附加脱模阻力计算公式，也引入了一个简化系数。以表格形式列出了几个简化系数与有关参数的函数关系，便于实际应用。

China's injection mouldings have been increasing in weight and empirical estimate of ejection resistance has to be replaced with calculated estimate. Available chinese calculationformulas need to be simplifed and several special cases require a sizable additional ejection resistance term in the calculation formula.Existing formulas for calculating ejection resistance of thin wall injection moulding ofcircular cross-section and rectangular cross-section are eqs. (3) and (5) respectively. Wesimplify eqs. (3) and (5) into eqs. (8) and (9) respectiyely.Existing formulas for calculating ejection resistance of thick wall injection moulding ofcircular cross-section and rectangular cross-section are eqs. (4) and (6) respectively. Wesimplify eqs. (4) and (6) into eqs. (11) and (12) respectively.Three special cases are dealt with.Only one special ease is shown in Fis2. For ail threecases, ejection resistance needs to be calculated with eq. (16). In eq. (16), Q Is the ordinaryejection resistance, calculable with eqs. (8), (9) or eqs. (11), (12) as the case may be. Thesizable additional ejection resistance term for all three cases is kd (Qd +Q. f)in eq. (16).