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US 4,900,485 AGranted
Method and apparatus for transfer molding
AssigneeFujitsu Limited
InventorYoji Murakami
Life of this patent
Estimating the term…
Abstract
A transfer molding method and apparatus in which the internal pressure of a thermosetting resin in a mold is directly detected and is controlled constantly during the transfer molding.
Claims18
A transfer molding method for molding resin articles in a mold having a plurality of cavities. and a pot communicating with said cavities via a runner, said method comprising the steps of:
- (a) charging a thermosetting resin into said pot;
- (b) transferring said thermosetting resin from said pot to each of said cavities by applying pressure to said thermosetting resin by plunger means movable in said pot;
- (c) before said resin reaches said cavity, detecting internal pressure within the area defined by said pot and the end surface of the plunger directly by detecting means and controlling the pressure applied to said plunger means in response to the internal pressure detected by the detecting means so that friction between the plunger and the wall of the pot is compensated for and said internal pressure in said pot is maintained constant during said transferring step;
- and
- (d) repeating steps (a)-(c) a plurality of times, wherein the inner pressure is detected every time the transfer step is carried out and the pressure applied to the plunger is controlled so that the inner pressure during each transfer step is maintained constant.
2 more elements
A transfer molding apparatus comprising:
- (a) a mold having a plurality of cavities;
- (b) a pot communicating with each of said plurality of cavities via a runner;
- (c) plunger means movable in said pot and having an end surface for pressing a thermosetting resin charged into said pot a plurality of times;
- (d) driving means for applying a pressure to said plunger means to move said plunger, causing said resin to be transferred out of the pot, along the runner and into the plurality of cavities;
- (e) means for detecting, before said resin reaches the plurality of cavities, internal pressure within the area defined by said pot and the end surface of the plunger directly, and for generating a signal corresponding to said internal pressure;
- and
- (f) means for controlling the pressure applied to said plunger means by said driving means in response to said signal from said detecting means;
- wherein friction between the plunger and the wall of the pot is compensated for and said internal pressure is maintained constant each time said thermosetting resin is transferred from said pot to each of said plurality of cavities by the plunger.
5 more elements
Dependencies are inferred from the claim text.