在铸型合箱后的分箱面或盖箱顶面与压铁之间,用铁片或斜铁塞紧的步骤称背箱。因为背箱是用铁片塞入缝隙的,所以也叫塞铁。压铁和砂箱之间的塞铁是在砂箱的背面(顶面)进行的,所以叫背箱。干型造型中,由于分型面不平或太小,分箱面之间有高度不同的间隙,如果不背箱,压铁时可能压坏砂型、砂芯,致使铸件产生砂眼、夹砂、缺肉、形状不合格,严重时报废。因此,为了增大铸型分箱面上、下砂箱的接触面积,使压铁重力主要作用在砂箱上,并在砂箱上受力较均匀,从而预防铸型 In the mold after the sub-box or box top box and the pressure between the iron, iron or oblique plug tight step back box. Because the back box is stuffed into the gap with iron, it is also called calabash. The plunger between the weight and the flask is carried on the back (top) of the flask, so called the back box. Dry-type modeling, because the sub-surface uneven or too small, sub-box between the different height of the gap, if you do not back box, the iron may be crushed sand, sand core, resulting in castings trachoma, sand, lack Meat, unqualified shape, serious scrapped. Therefore, in order to increase the sub-box mold surface, the contact area of ​​the flask, so that the main role of the weight of the iron in the sand box, and in the flask on the force more uniform, so as to prevent the mold