Sand molds used in sand casting are classified into three types: clay green sand, clay dry sand, and chemically hardened sand according to the binder used in the sand and the way it builds its strength. No-bake sand is foundry sand that is used in the casting process to add resin and other curing agents to make the sand mold harden by itself. It is mainly used in the foundry industry.
No-bake is a casting process that involves the use of chemical binders to bond the molding sand. Sand is conveyed to the mold fill station in preparation for filling of the mold. A mixer is used to blend the sand with the chemical binder and catalyst. As the sand exits the mixer, the binder begins the chemical process of hardening. This method of mold filling can be used for each half of the mold (cope and drag). Each mold half is then compacted to form a strong and dense mold.
A rollover is then used to remove the mold half from the pattern box. After the sand has set, a mold wash may be applied. Sand cores, if required, are set into the drag and the cope is closed over the cores to complete the mold. A series of mold handling cars and conveyors move the mold into position for pouring. Once poured, the mold is allowed to cool before shake-out. The shake-out process involves breaking the molded sand away from the casting. The casting then proceeds to a casting finishing area for riser removal, casting finishing and finalization. The broken pieces of molded sand are further broken down until the sand is returned to grain size. The sand can now be either reclaimed for reuse in the casting process or removed for disposal. Thermal reclamation is the most efficient, complete method of no-bake sand reclamation.
Post time: Jul-04-2021