Methods for calculating expanded size of punched hole and compression punchingtype are introduced.
简述抽孔、压缩抽型的展开时几种情况下的计算方法。
2
The test mostly analyse the film mulching hill-drop planter from two aspects: One is mechanism of duck-mouth typepunching-opener, One is analyse of metering device .
本文主要从两个方面对覆膜穴播机具进行分析：一是鸭嘴式成穴器的成穴机理；二是外槽轮式排种器的分析。
3
Punching through, the top pieces, such as the discharge of calculation to determine the type mold.