Core Production For Iron Components
Cores define the internal space inside of iron castings while the mold defines the outside shape of the casting. Northern Iron and Machine produces cores using two processes. The phenolic urethane process is performed on a IMF Disco 3500 and a Simpson ABC 6 system. Shell cores are produced on Redford shell machine systems.
Both processes require use of a core box die. The die creates a negative impression of the desired core shape. Our cores are primarily made of silica sand similar to how molds are made.
But unlike molds when using the phenolic urethane process for making cores, a three part binder is mixed with sand and blown into the core box via compressed air.
By comparison, shell cores are produced somewhat the same as phenolic urethane cores but the sand is mixed with a resin that reacts to heat. During the manufacture of shell cores, the die is heated and the sand mixture is blown into the core box. The heat causes the resin to harden and the core to cure.
After a core has been produced, it may be coated with a core wash then sent through a forced air oven for curing. The core wash process improves the surface finish of the final casting while preventing undesirable iron penetration into the mold.
During mold production, the cores are set in place prior to setting the two mold halves (cope and drag) that are closed.