METHOD OF MANUFACTURING A PLASTIC CAMSHAFT WITH A TUBULAR METAL INSERT

摘要

A method of manufacturing a plastic camshaft having a tubular metal insert using a die assembly having a pair of aligned pins. The tubular metal insert is cut to a length slightly shorter than the length of the finished camshaft and is placed on one of the pins. The second pin is then inserted into the opposite end of the tubular metal insert during the closing of the die assembly. The pins properly align the metal insert within the mold cavity of the die assembly during injection of a surrounding plastic material which forms the remainder of the camshaft. The pins also axially compress the tubular metal insert and have tapered shoulders which bear against and slightly deform or flare the end regions of the insert. The flared ends of the tubular metal insert tightly engage the pins and prevent the formation of flash within the hollow interior of the tubular metal insert. By cutting the inserts to a length which is shorter than the total length of the camshaft, imprecision in the cutting of the insert does not result in the formation of flash adjacent the annular ends of insert. This method permits the tubular metal insert to be properly located within the mold and prevent the formation of flash during injection of molten plastic without requiring the metal insert to be precision ground.