Below is a list of Core Processes manufacturers from Grand Rapids, Michigan. Core processes involve the implementation of a block or barrier around which castings are made. The use of a core in this manner allows for the creation of internal cavities and re entrant angles in solid iron castings. A core may be used to create intricate gaps or hollows such as those found in gears and engine blocks, but are also common in the production of simple parts such as cast iron window frames which require the enclosure of large openings.