Plastic article or earthenware shaping or treating: apparatus – Distinct means to feed – support or manipulate preform stock... – Opposed registering coacting female molds
Patent
1994-06-22
1996-01-02
Nguyen, Khanh P.
Plastic article or earthenware shaping or treating: apparatus
Distinct means to feed, support or manipulate preform stock...
Opposed registering coacting female molds
249 67, 26427217, 425121, 4251291, 425544, 425556, 425444, 425DIG228, B29C 4502, B29C 4514, B29C 4540
Patent
active
054802962
ABSTRACT:
An improved transfer molding apparatus is provided for molding a preheated resin under pressure to thereby encapsulate a small element, such as a semiconductor device or package. In one aspect of the invention, the improvement consists of providing a shortened pot into which a piston is forcibly pressed to generate a flow of preheated resin in the encapsulating process, the improvement comprising the replacement of a single-element top drive plate, as found in a conventional apparatus, by a two-piece top drive plate which enables a shortening of the pot and corresponding reduction in the amount of air that would otherwise be trapped between the plunger and the resin during the process. The elimination of this air significantly reduces foaming, porosity, voids, and other defects in the cured resin which finally surrounds the electrical elements encapsulated thereby. In another aspect of the invention, a single top drive plate of a thickness comparable to that in conventional apparatus is used, the improvement being realized by forming a recess to leave a floor of relatively small thickness immediately around an upper end of the pot into which the plunger is moved to pressurize preheated resin.
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Goldstar Electron Co. Ltd.
Nguyen Khanh P.
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