Usually cut from a pre-hardened die, mold, or tool steel such as 4140 PH, 4340 PH, or P20, mold base frames normally separate into two sides at a parting line allowing manufactured parts to be extracted. Molding plates made from 4140 and 4340 steel, typically in the Rockwell hardness ranging from 28 - 32 to upward of 38 - 45, provide a long lifespan as they are extremely wear resistant. These steels can handle the high melting points of the composite liquids or resins poured into these forming cores. Typically, a releasing agent precedes the pouring step in order to facilitate removal of the hardened part from the mould.
Precision Grinding provides contract moldmaking services to manufacturers and job shops serving various industries such as, automotive, aerospace, and industrial applications. As the moldmaker, we are able to flame cut the plate to shape from inventory, rather than saw-cutting pre-hardened steel flats. Prior to grinding or machining 4140 steel plate, we may anneal the preliminary mold plates within our inhouse car-bottom furnace. In the case requiring cavities or core drills, the plates are then pre-ground, or rough ground to specified tolerance levels upon one of several Blanchard and Mattison grinders. Depending upon the machining required and the desired hardness, we allow for tempering and quenching in addition to providing annealing services. 4140 can be quenched and tempered up to approximately 50 Rockwell hardness.
