摘要
文章介绍了气流冲击造型的发展史。阐述了气冲紧砂过程中型砂的运动;各种气压和压力随时间的变化;并以型砂紧实状态图形式表示了在气冲紧砂过程中任一时刻砂柱中压力波和型砂紧实的状态。还分析了气流速度与压实比压的关系;二次气压的升压速度、冲击阀阻流面积的增长速率、砂型高度、一次气压大小等因素对冲击紧砂效果的影响;以及在生产实践中采用同步吹气法、二次冲击紧砂提高模样深凹处及高模样与砂箱内壁间砂型紧实度等问题。
The paper describes the deve- lepment of air impact molding technology and expounds the movement of the molding sand during the process of compact sand by air impact, and changes of the air pressure and compression force with the time. The pressure wave and the compacting state of molding sand in the sand post at any instant during the process of compact sand by air impact are expressed with the feature of the diagram of the compacting state of molding sand, Besides, factors affecting the effect of compact sand by impact such as. the relation of air speed and specific molding pressure; the speed of boost pressure of the secondary air pressure; enhancing the rate of choked flow area of the impact valve; the height of sand mold; the amount of first pressure, etc. have been analysed, However, problems on enhancing the compactness of sand mold at the deep concavity of the pattern and between the high pattern and the inside wall of the flask by using of synchronizing air blow in production practice and compact sand by secondary impact have also been discussed.
