熔模铸造在加固层的撒砂中加入一定量的谷糠,对于提高型壳的透气性和退让性有显著作用。 我们在生产插秧机的秧爪时,爪尖厚只有1毫米,宽不到1毫米。铸件由于爪尖浇不足,废品率高达70～80％。主要原因是钢水在充填型腔时,将型腔内的气体压入爪尖的空腔内。这部分气体不能很快地排出型壳外,从而产生了一定的压力,阻碍了钢水的充填。 Investment Casting in the consolidation layer of sand by adding a certain amount of bran, to improve the permeability of the shell and concession has a significant role. When we produce transplanter seedling claw, claw tip thickness of only 1 mm, less than 1 mm wide. Casting due to lack of claws, waste rate as high as 70 ~ 80%. The main reason is that when the molten steel is filling the cavity, the gas in the cavity is pressed into the cavity of the claw tip. This part of the gas can not be quickly discharged outside the shell, resulting in a certain pressure, hinder the filling of molten steel.