一台新的金属型制成之后,便进行第一次试铸。但是,在金属型加温以后,往往因为配合太紧,不能开合型。或者,浇注几件之后,越来越紧,以致不能继续浇注,被迫停止试铸,把金属型返回制模车间,修整合型间隙,这项工作通常叫做放间隙,有时,如此反复达 After a new metal was made, the first trial cast was made. However, after the metal type heating, often because of the match is too tight, can not open and close type. Or, after pouring a few pieces, tighter and harder so that casting can not be continued, it is forced to stop the trial casting, return the metal to the molding shop, and trim the fit gap, which is usually called play clearance and sometimes so repeatedly