利用数学方法，推导不对称公差标注与对称公差标注间的转换公式。
The transfer formula between asymmetric tolerance marking and symmetric tolerance marking is deduced by the mathematical method.
并进一步推导对称公差标注时尺寸链的计算公式，从而简化尺寸链计算。
The process dimension chain is calculated by the dimension chain calculating formula of symmetric tolerance marking.
并进一步推导对称公差标注时尺寸链的计算公式，从而简化尺寸链计算。
Further, the dimension chain calculating formula is deduced when symmetric tolerance marking is used, so that the dimension chain calculating is simplified.
应用推荐