用质量损失函数解尺寸链

Solution to the Dimensional Chain with Using the Quality Loss Function

依据田口玄一的质量工程学理论，建立尺寸链封闭环的质量损失函数，考查各组成环与封闭环之间的函数关系，导出尺寸链的反计算、正计算、中间计算的公式。反计算时，考虑封闭环的用户极限，用户损失和每个组成环的工厂损失，分别求出它们的工厂容差和公差。正计算是反计算求得每个组成环的公差之后，按照尺寸的分布规律和概率论原理求出封闭环的公差。中间计算时对未知组成环公差的决定不受已知组成环公差的制约。

According to Genichi Taguchi′s theory,we construct the closed loop quality loss function of the dimensional chain,examine the functions between the closed loop and every compositive loop of the chain and present the formulas of the dimensional chain′s calculation.Within inverse calculation,every compositive loop work allowance is calculated respectively.Direct calculation resolves the closed loop tolerance in view of every other one′s distribution and probability theory.The calculation of the unknown compositive loop′s tolerances are independent of other compositive loop′s tolerances.