US4900485A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Method and apparatus for transfer molding
Assignee: Fujitsu Ltd
•
Filing: 1988-07-21
•
Granted: 1990-02-13
•
Expires: 2008-07-21
Abstract
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.
Inventors
- 👤 Yoji Murakami
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-09 11:22
CPC Classifications
B; B29; B29C; B29C45/00; B29C45/17; B29C45/76; B29C45/77; B29C45/02; B29C2045/025
Claims Analysis
Total Claims: 20
Claim 1
Independent Claim
188 words
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.
Claim 2
Dependent Claim
188 words
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.
Claim 3
Dependent Claim
22 words
The method according to claim 1, wherein said means for detecting said internal pressure in said pot comprises a pressure sensitive element.
Claim 4
Dependent Claim
19 words
The method according to claim 2, wherein said control means comprises a control unit and a hydraulic pressure controller.
Claim 5
Dependent Claim
13 words
The method according to claim 3, wherein said thermosetting resin is epoxy resin.
Claim 6
Dependent Claim
13 words
The method according to claim 3, wherein said thermosetting resin is silicone resin.
Claim 7
Dependent Claim
15 words
The method according to claim 3, wherein said pressure sensitive element is a strain gage.
Claim 8
Dependent Claim
191 words
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.
Claim 9
Dependent Claim
191 words
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.
Claim 10
Dependent Claim
15 words
The apparatus according to claim 7, wherein said detecting means is a pressure sensitive element.
Claim 11
Dependent Claim
21 words
An apparatus according to claim 7, wherein said detecting means is provided in said plunger means near the end surface thereof.
Claim 12
Dependent Claim
15 words
The apparatus according to claim 8, wherein said pressure sensitive element is a strain gage.
Claim 13
Dependent Claim
21 words
The apparatus according to claim 9, wherein said detecting means is provided in a cavity formed centrally in said plunger means.
Claim 14
Dependent Claim
35 words
The apparatus according to claim 11, wherein said detecting means further comprises a converter located in said cavity in said plunger means which is operatively connected between said pressure sensitive element and said control means.
Claim 15
Dependent Claim
22 words
An apparatus according to claim 7, wherein said detecting means is provided in the mold near said resin, opposite said plunger means.
Claim 16
Dependent Claim
19 words
The apparatus according to claim 7, wherein said control means comprises a control unit and a hydraulic pressure controller.
Claim 17
Dependent Claim
32 words
The apparatus according to claim 7, wherein said detecting means is provided in said plunger means near said end surface thereof and in said mold near said resin, opposite said plunger means.
Claim 18
Dependent Claim
14 words
The apparatus according to claim 7, wherein said driving means is a hydraulic press.
Claim 19
Dependent Claim
13 words
The apparatus according to claim 16, wherein said thermosetting resin is epoxy resin.
Claim 20
Dependent Claim
13 words
The apparatus according to claim 16, wherein said thermosetting resin is silicone resin.
References Cited (Backward Citations)
CA637097A
Cited
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1993-02-12 | 1993-08-14 | 1994-02-13 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1997-02-12 | 1997-08-14 | 1998-02-13 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 2001-02-12 | 2001-08-14 | 2002-02-13 | $7700.00 | Window Closed / Lapsed |