抽油机的曲柄铸造难度较大。1986年底我们曾试铸过两次,质量差。两次试铸曲柄共计六件,其中两件因严重粘砂和缺齿而报废,四件经清理打磨后,勉强可用,废品率达33％。因此,曲柄铸件只好由外协厂生产。 为进一步提高经济效益,1988年底,曲柄由外协厂铸造改为厂内铸造。首先对报废曲柄进行了分析,查明了存在的两个主要问题:1.曲柄齿条严重粘砂;2.齿顶部位产生冷隔和浇不 Crank pump crankshaft pumping more difficult. At the end of 1986 we had tried casting twice, with poor quality. Two trial cast crank a total of six, two of which were scrapped due to severe sticky sand and missing teeth, four clean and polished, barely available, rejection rate of 33%. Therefore, the crank casting had to be produced by the Association. In order to further improve economic efficiency, by the end of 1988, the crank was changed from foundry to casting in the factory. First of all, the scrapped crankshafts were analyzed to identify the two main problems that existed: (1) severe sticking of crank racks;