在铸型中,往往用粘结剂把型砂粘合起来,从而获得足够的湿强度,以确保尺寸稳定性和加强型砂密实化。这样,既能防止金属液渗漏,又可保持充分的透气性,有利于气体外逸。铸型各个横向和纵向的表面必须匀实,才能得出尺寸精确的铸件,从这个意义上说,粘结剂起着一定的促进作用。另一方面,粘结剂本身却妨碍了砂粒的运动,使密实程度有所降低。 In the mold, the binder is often used to bond the sand to obtain sufficient wet strength to ensure dimensional stability and to enhance sand compacting. In this way, both to prevent metal liquid leakage, but also to maintain adequate air permeability, is conducive to gas escape. In all, the horizontal and vertical surfaces of the mold must be solidified in order to obtain a dimensionally accurate cast piece, in the sense that the binder plays a role of promotion. On the other hand, the binder itself hinders the movement of the sand and reduces the degree of densification.