Plastic article or earthenware shaping or treating: apparatus – Distinct means to feed – support or manipulate preform stock... – Opposed registering coacting female molds
Patent
1993-09-07
1994-10-25
Nguyen, Khanh
Plastic article or earthenware shaping or treating: apparatus
Distinct means to feed, support or manipulate preform stock...
Opposed registering coacting female molds
249102, 264272170, 425183, 425185, 425186, 425190, 425192R, 425544, 425568, 425569, B29C 4502, B29C 4518, B29C 4526
Patent
active
053583965
DESCRIPTION:
BRIEF SUMMARY
BACKGROUND OF THE INVENTION
1. Field of The Invention
The invention relates to a multi-functional mould convertable from transfer mould to injection mould, particularly for encapsulating chips placed on lead frames, comprising mutually movable mould halves on the mutually facing surfaces of which cavities are arranged for receiving chips for encapsulating, means for ejecting finished product out of the mould, runners for the passage of encapsulating material to the cavities and a feed opening in one of the mould halves for admitting encapsulating material.
2. Description of the Prior Art
Such a mould is known from Modern Plastics, vol. 47, no. 07, Jul. 1970, Lausanne CH, pages 102-104; R. Paci "Now it's easy to convert from transfer to injection moulding".
Chips arranged on lead frames are normally encapsulated with material by means of the so-called transfer method. An example of such a method and device suitable therefor is described inter alia in the European patent application No. 89.203003.2. With this known method and device a pellet-like piece of encapsulating material is placed in a space suitable for this purpose, pressure is applied on the pellet by means of a plunger and a temperature increase effected such that it becomes liquid and moves through runners suitable therefor to the mould cavities. Materials with a thermosetting character are used as encapsulating material.
In addition to the transfer method, encapsulating material can also be processed as is usual in injection moulding devices. Materials used herein have a thermoplastic character.
The known mould should be machined for conversion of the mould in order to have the means extended. This makes it extremely difficult and cumbersome to reconnect the mould again.
SUMMARY OF THE INVENTION
It is the object of the invention to provide a mould which can be used with both transfer devices and injection moulding devices. This is achieved according to the invention in a multi-functional mould as described in the preamble by a chamber connecting to the feed opening and extending to the cavities for replaceably receiving a chamber connected to the feed opening and extending to the cavities, whereby by only replacing an aggregate in said chamber the mould is converted from transfer moulding to injection moulding or vice versa.
The invention makes it possible by exchanging only an aggregate comprising the insert member and a mounting plate for the mould to be used as desired in a method for encapsulating according to the transfer method or in an injection moulding device. A mould for use as a transfer mould has an insert member with a bore for the passage of a plunger in addition to a mounting plate holding the member fixedly on the mould.
A mould for use as injection mould for connection to an injection moulding device has an insert member with a through-channel and a mounting plate holding the member fixedly on the mould.
The invention will be elucidated with reference to the drawing.
BRIEF DESCRIPTION OF THE DRAWINGS
FIG. 1 shows schematically the arrangement of a mould during application of the transfer method,
FIG. 2 shows the arrangement of a mould during application of the injection moulding method,
FIG. 3 shows the multi-functional mould according to the invention with dismantled parts,
FIG. 4 is a view on a larger scale along the arrow IV in FIG. 1,
FIG. 5 shows a sectional view of the multi-functional mould according to the invention during use as transfer mould, and
FIG. 6 shows a sectional view of the multi-functional mould during use as injection mould.
DESCRIPTION OF THE PREFERRED EMBODIMENT
The arrangement according to FIG. 1 shows guides 2, 3, 4 placed on a base 1 in the usual manner and control means for mutually displacing mould halves 5 and 6. In the closed situation the plunger 7 (FIG. 4) is displaced in the transfer method whereby due to the pressure exerted and the increase in temperature the pellet-like encapsulating material becomes liquid, moves through runners 9 arranged for this purpose to the chips for encapsul
REFERENCES:
patent: 2279380 (1942-04-01), Reid
patent: 4077760 (1978-03-01), Sauer
patent: 4653995 (1987-03-01), Ward
patent: 4655274 (1987-04-01), Dannoura
Rick Paci; "Modern Plastics" vol. 47, No. 7, Jul. 1970, Lausanne CH pp. 102-104; "Now it's easy to convert from transfer to injection molding".
Nguyen Khanh
Sony Corporation
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