JPS6120718A - Transfer molding equipment with low-temperature runner and method thereof - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

BACKGROUND OF THE INVENTION The present invention relates generally to transfer molding of multi-plastic molded articles, and more particularly to transfer molding of multi-plastic encapsulated semiconductor devices.

Description of prior art: Prior art in O-transfer molding of multi-plastic molded products using multi-cavity metal molds! The #O embodiment provides a multi-cavity metal mold consisting of separable upper and lower mold sections, which have multiple cavities for the molded article. and a plurality of runners having a distribution device for supplying molding material to each of the individual cavities. Runners are typically
O supplying plastic molding material to multiple cavities
terminating in a common cull or P-) region used for

The upper and lower mold halves are held together by glass and the assembly is heated to cure the molding material. Since the plastic molding material, which is usually a powder, is glassed or (retted), the molding material is pretreated in the mold assembly section to make it into a liquid or semi-liquid form.Multi-cavity molds Grangers are used to force the heated molding material under great pressure into the mold's runner system for distribution into each of the IN&O molding cavities.

Among the defects θ of the above-mentioned type Q transfer molding machine O,
This includes that the molding material must be pelletized to a size commensurate with the mold O cavity and runner O volume to be used. As a result, plastic molding materials Q rather large plugs often require considerable preheating time. Since the runner is in the mold half O along with the molding cavity, the heated mold half will also harden the plastic molding material in the runner and molding cavity II. This can result in significant Of2 stick waste depending on the relative volumes of the runner and mold cavity. Also, this device cannot continuously supply molding material, and the production output is limited by the characteristics of the operation. Accordingly, there was a need to provide a method and mold part that allows continuous supply of molding material O, preferably in the form of powder O, for transfer molding of small semi-molded parts in heated multi-cavity molds.

According to one embodiment of the invention, it is an object of the invention to provide an improved O method and apparatus for transfer molding of small molded articles.

Another object of the present invention is to provide an improved mold apparatus and method for insert molding semiconductor electronic devices and integrated circuits.

It is yet another object of the invention to provide a substantially continuous supply of plastic molding material into a multi-cavity mold.
The object of the present invention is to provide an improved method and mold device that can be improved.

Yet another object of the present invention is to provide an improved method and mold apparatus that avoids the need to pelletize plastic molding materials.

According to a preferred embodiment of the present invention, the multi-cavity mold ■
The runner section is insulated from the metal mold Q cavity to provide a flow of molding material directly to the r-top section of the mold without curing the plastic in the mold Q2 runner section 0.

According to another θ embodiment of the invention, a portion of the molding apparatus 0 runner is cooled to prevent the plastic molding material from hardening in the runner apparatus θ.

According to a further embodiment of the invention, the plastic molding material is distributed through a runner sufficiently cold to prevent the molding material from curing until it reaches the cult or rout portion of the molding apparatus, where it A glass/jar and local heating device are provided to supply liquid molding material under pressure to the mold cavity.

The above and other objects, features and advantages of the present invention will become apparent from the following detailed description of preferred embodiments of the invention, particularly as illustrated in the accompanying drawings.

DESCRIPTION OF THE PREFERRED EMBODIMENTS Referring now to FIG. 1, a mold Q upper half 4 (
and the lower half 2) are shown. The mold is separated into an upper mold part 4 and a lower mold part 2 along the c+MUθ parting line in order to allow the finished molded plastic product to be extracted. Both mold halves are made of a thermally conductive metal material, such as stainless steel. Above the upper mold part 4 is an additional metal part or block 10.12 forming part of the runner 20 for feeding plastic molding material into the mold lead frame cavity. runner-200
The vertical part is block 1 with a tapered orifice.
It is made up of 5.

The runner block 10.12 has a number of runners 20 feeding the cavities of the cavity block. Each of the plurality of O runners 20θ is supplied with plastic molding material O from a central tank.

Each runner 20 is insulated from the upper mold part 4 and the lower mold part 2 by a heat insulating member 14, and the temperature of the runner is kept at most about ♂O while the upper mold part and the lower mold part are heated to about /70°C. Maintain at °C. The insert heating element 18 provides a high temperature temperature for maintaining the cal or f) area O temperature wLt - approximately /fj °C and supports the insert lead frame in the mold cavity Q just before the inlet O flow O section O plastic. Molding material Q facilitates heating. aisle 16
θ to prevent liquefaction and/or hardening by flowing coolant into orifice block 15t-, O molding material in runner 20 +2)
Maintain the temperature low enough to If necessary, clean the block part 10 of the runner by two or more holes.
These blocks can be separated by a 12-theta dividing line. By applying pressure or vacuum to the end (not shown) of the horizontal portion of the runner or passageway 200, plastic molding material is fed into the mold O cavity at the start of the molding cycle θ, or the inside cavity is filled with liquefied material. It is better to collect the excess after it is filled.

Referring now to FIG. 2, a section 0 of a mold apparatus similar to the apparatus shown by FIG. 1 is shown in cross-section. The upper mold half 4 and the lower mold half 2 have a main body 6 surrounding the metal inosert 8C) bit.
A large number of afternoon and evening ceremonies are held to form the ``Yabitei''. The metal @Otner Qf lock part 10.12 has a runner 20 for supplying a flow of plastic molding material to the cavity of the mold. The mold device shown in Figure 2 is
This differs from the first mold apparatus in that the block portion 10 is maintained at a cooler temperature than the upper mold 4 by providing both runner insulation material 14 and coolant passages 1612).

In this way, the runner block can be maintained at about rO<0>C while the cavity block is maintained at about /70<0>C for a considerably longer time than the apparatus of FIG. Thus, by removing only the lower part 2 of the cavity block together with the molded product after completing each trough/sphere molding cycle 1, an almost automatic or continuous molding process can be carried out. The runner block is bare when it cools down.
In its lower O position, the glass/jar 16A blocks the flow of plastic material through the orifice.

After replacing the lower part 2 of the cavity block, the granger 16At is raised and then lowered again to force a predetermined amount of plastic material into the cavity block, where the high-temperature chig element 18 is maintained at about 1 tzc. The plastic material is heated and liquefied. An f2 plunger 16A'' having a glass tick section 17 seats in the orifice to maintain high pressure during the curing portion of the cycle.

In the apparatus shown by either FIG. 1 or FIG. 2, the insulation and/or cooling means keep the runner block O temperature sufficiently low that no hardening occurs in the runner block O. In addition, since the temperature of the runner block O can be kept sufficiently low, the plastic material is not substantially melted, and in this case, the feed material is preferably θ, which is a plastic molding material that is not pelletized.

While the invention has been particularly shown and described with respect to preferred embodiments thereof, it will be apparent to those skilled in the art that changes may be made in form and detail without departing from the scope and spirit of the invention as claimed. be understood.

[Brief explanation of drawings]

Fig. 1 is a sectional view of the molded product cavity and low temperature runner device O of the fixed mold device according to the present invention, and Fig. 2 is a sectional view of the molded product cavity and the low temperature runner device O of the fixed mold device according to the present invention. FIG. 2 is a cross-sectional view of a cold runner mold apparatus with a double T-lunger. 2... Lower half of the mold, 4... Upper half of the mold, 10, 12, 15... Layer/block, 14...
...Insulation member, 20...Runner. 1st I! 1 Figure 2

Claims (1)

[Claims] 1. A mold apparatus for transfer molding of a plurality of small molded products, which is equipped with a cavity block having a plurality of molded product cavities, and a plurality of runners for supplying plastic molding material to the cavities. a block, and an insulating device between the runner block and the cavity block for maintaining the runner block at a temperature low enough to prevent the plastic molding material from curing in the runner block. A mold device characterized by: 2. A method for transfer molding a plurality of small molded articles in a plurality of cavities of a heated cavity block, wherein the temperature of the runner block is maintained substantially below the temperature of the cavity block; A transfer molding method characterized in that a plastic molding material is supplied to the cavity through a runner.