一、课题的产生 (01—6A)精铸件是某产品的重要零件。产品要求较严,铸件虽给了加工余量,但对变形仍很敏感。此零件自1986年投入生产以来,铸件质量一直很低,如88年元月铸件质量统计表1所示。其主要问题有三个:1)缩孔;占废品的60％以上。2)变形:在毛坏检验时一般不易发现,但在机械加工时就暴露出来了,废品率有时高达30～40％。 First, the issue of (01-6A) casting is an important part of a product. Product requirements more stringent, although the casting gave the allowance, but the deformation is still very sensitive. Since this part was put into production in 1986, the quality of the castings has been very low, as shown in the January 1, 1988 casting quality statistics table1. Its main problems are three: 1) shrinkage; accounting for more than 60% of waste. 2) Deformation: Generally not easy to find in the gross inspection, but exposed in the machining, the rejection rate sometimes up to 30 to 40%.