一、前言我厂生产的JG 150混凝土搅拌机的大齿圈是一种直径较大,厚薄比较均匀的环状灰口铸铁件。牌号为HT20—40,要求加工后齿部表面不得有气孔、夹什物、缩孔等影响强度的缺陷。过去,我们是用手工或用风动捣固机捣实型砂造型工艺。由于砂型的紧实度不均匀和冒口设置不当,直接影响铸件的质量,如铸件的 I. INTRODUCTION The large ring gear of the JG 150 concrete mixer produced by our factory is a ring-shaped gray cast iron with a relatively large diameter and relatively uniform thickness. The brand name is HT20-40. It is required that the surface of the tooth surface after processing must have no defects such as air holes, clips, shrinkage holes, etc. that affect the strength. In the past, we used manual or pneumatic tamping machines to compact the sand molding process. Due to the uneven compactness of the sand mold and improper setting of the riser, it directly affects the quality of the casting, such as the casting.