Abstract: The relation between the fitting clearance of powder compacting die and the exactitude of coaxality of the compact is discussed in this paper. Through the analyses of some special examples in the preforming process, it was found that the maximum wall thickness difference of the compact is equal to the total clearance of the die, and this relation has been certificated through experiments by the author. The conclusion is that the clearance of die should be determined according to the wall thickness of the compact, and it can be calculated by the following equations:
Maximum clearance:
C_1max+C_2max ≤ △_max-ε_larger-e
Minimum clearance:
C_1min or C_2min ≥ experimental value (see Table 1)