| 摘要 |
A method and apparatus for rotational molding provides a mold having first and second mold components defining therebetween a mold cavity. The first mold component includes a mold insert adapted to translated toward the second mold component to an inward position in the mold cavity. The first mold component includes spring assemblies for urging the mold insert inwardly, and a latch mechanism to restrain the mold insert in the outward disposition. The latch mechanism includes a touch pad which may be struck to trigger the latch mechanism and urge the mold insert inwardly into the mold cavity. In another aspect, the invention includes a method for rotational molding that employs the rotational mold described above. With the mold insert latched in the outward disposition, the rotational mold is separated and charged with thermoplastic material, closed and sealed, and placed in a furnace and rotated biaxially. After the heating phase, while the mold assembly continues to rotate, the touch pad is struck to release the latch and cause the mold insert to move inwardly. The mold insert includes structural surfaces and features that are moved more proximate to opposed mold portions. As a result, component features that are too closely spaced to be reliably molded by prior art rotational techniques are fully formed by the mold insert in a more spaced apart relationship and brought into close spacing or impingement by movement of the mold insert. The method and apparatus may be used to fabricate a bus bumper cover.
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