一、前言 在计算三层组合凹模时一般都是以压配顺序按由外向内(即先将中间套压入外套内,再将模心压入中间套与外套的组合件内)为条件的。在实际生产中,对模心在径向采取分段组合的三层凹模采用由内向外压配的顺序,使模具加工工艺较为简便、经济。由于压配顺序的改变,在压配过盈量相同的条件下在模心内孔处产生的预加应力将随之改变,不可能达到预期的效果。本文引入附加过盈量概念对由内向外压配的三层组合凹模进行计算。文中所用主要符号如下: I. Introduction In the calculation of the three-tier combination of the die are generally pressed in order by the pressure from the outside (that is, the first intermediate sleeve into the jacket, and then die into the middle of the sleeve and the jacket of the assembly) as the condition of. In actual production, the three-layer die with radial centering in the radial direction adopts the order of press-fitting from the inside to the outside, which makes the die machining process more simple and economical. Due to the change of press-fitting sequence, the pre-stress generated in the die-core hole will be changed under the same condition of the interference-fit interference, and it is impossible to achieve the expected effect. In this paper, the concept of additional interference is introduced to calculate the three-layer composite die press-fit from the inside to the outside. The main symbols used in the text are as follows: