摘要：分析使用Pro/E软件设计注射模时塑件公差采用基孔制与基轴制会导致成型零件不合格的问题,提出并验证采用对称公差解决问题的办法,并用实例演示不同情况下塑件建模时为取得对称公差的具体操作过程,对使用Pro/E软件设计注射模的成型零件具有重要作用。

摘要：Tolerance is imperative for seamless integration of CAD/CAM(Computer Aided Disignd/Computer Aided Manufacture) which is just a text attribute and has no semantics in present CAD systems. There are many tolerance types, the relations between which are very complicated. In addition, the different principles of tolerance make study of tolerance difficult; and there may be various meanings or interpretation for the same type of tolerance beeanse of the literal definition. In this work, latest unambiguous mathematical definition was applied to study, explain and clarify: ( 1 ) the formation and representation of tolerance zone, and (2) the formation and representation of variational elements ; after which, the mathematical models of syrmmetry of different tolerance principles and different interpretations were derived. An example is given to illustrate the application of these models in tolerance analysis.