Eliminate Ejector Plates
A new ejection system that eliminates the ejector plate, reduces mold height, leaves no ejector marks on parts, shortens cycle time, and allows better optimization of cooling lines comes from D-M-E Co., Madison Heights, Mich. Its Quick Strip is a standard hardware system that uses the mold-opening movement to eject the parts and mold closing to reset the ejector. The system consists of a body, “puller,” and “spoon” that mount on the stationary mold half, plus a tapered “finger” on the moving mold half. When the mold is closed, the flat spoon fits into a pocket on the moving half with a portion of the spoon machined to form a section of the edge of the part in the cavity. Two spoons form opposite edges of the part. When the mold opens, the spoons, which are attached loosely (via the puller) to the body portion in the stationary half, first move a defined stroke to remove the part from the cavity while it is stuck onto the core. (A slot in the puller allows the spoon to travel this distance from the body.) Then the spoons are pulled out of their pockets in the moving half, and they pull the part from the core. Ejection is thus a pulling rather than pushing action, and it occurs all along the edges of the part rather than at discrete points. A spring forces the spoons to tilt at the end of their travel, so they pull away from the part. The finger in the moving half guides the spoon’s travel, and the finger’s taper allows for the spoon’s tilt and guides the spoon back into molding position when the mold closes. Quick Strip can be used in single-face or stack molds. One unit can serve multiple cavities. There are no ejector guide holes to restrict cooling-channel layout.
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