Q. Molding methods according to the method of making a mold?

Following are the molding methods according to the method of mold making:

• Open mold method: the method is suitable for making molds for flat products. Products like floor plates, grills, railings, weights are cast by this method.

• Floor molding or bedding: in method: this method is used for making molds of products which are very large in size and for which the foundry floor sand bed is used as a drag. Large size green-sand molds, skin-dry sand molds, are made by this method.

• Bench molding: Bench molding is carried out on a working bench using small size flasks and hence the method is suitable for making small molds. The molder works while standing. Green-sand molds, and skin-dry sand molds can be made by this method.

• Plate molding: It employs a metallic pattern consisting of a flat plate with portions of a pattern permanently attached on both sides of the plate. Molds for several identical parts of small size can be made using a number of patterns.

• Pit molding: Large castings that may not be accommodated in mold boxes are molded in pits made by digging the molding floor. The pit is lined with bricks or concrete and the desired shape of the mold is given by using a pattern. The bottom of the pit carries a well rammed layer of cinder to allow escaping of gases during casting.