| 摘要 |
PURPOSE:To minimize thermal expansion and thermal shrinkage generated in a molded form at the time of sintering, and to prevent the generation of cracking and excess residual strain in the molded form by bringing preforming pressure and the volume content of filler powder to specified relationship. CONSTITUTION:The mixture of fluororesin powder and filler powder is pre- compression-molded at specified molding pressure (Pc). The molding pressure (Pc) is represented by a function of the volume content (C) of filler powder to fluororesin powder and filler powder as shown in formula PC=K1.C+ K2[MPa]. K1 and K2 represent constants in formula, and are determined so that the density of a preform before sintering and the density of a molded form after sintering are brought to approximately equal values. The values of the constants K1, K2 differ according to the kind of fluororesin, the kind of fillers, etc., but are acquired experimentally when PTFE is used as fluororesin and polyamide fibers as fillers. |
