JPH09164548A - Resin molding device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To reduce the amount of unnecessary resin and enhance the effective utilization factor of resin by a method wherein a pot, in which a resin tablet and a plunger for pressurizing the resin tablet are inserted, communicates with a gate through a side wall adjacent to the mating surfaces of molds. SOLUTION: After the completion of the connection between a pot 24 and connecting parts 19 and 22, a plunger 26 is inserted in the pot 24. By further being pressurized, the resin tablet 25 immediately starts flowing, resulting in pouring in a cavity 15 through the connecting parts 19 and 22 and a runner 18 so as to cover the major portion on a lead frame with the resin. When the resin turns into a semi-hardened state after the resin is filled in a cavity 21, a movable block 23 is moved horizontally so as to be separated from molds 13 and 20. Then, after the top and the bottom molds 13 and 20 and separated from each other, a resin molding is unloaded from the molds 13 and 20 together with the unnecessary resin locating in the connecting parts 19 and 22. Then, the top and the bottom molds 13 and 20 and the movable block 23 are cleaned for continuing a resin molding work.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention belongs to a technical field related to a resin molding device using a resin tablet.

[0002]

2. Description of the Related Art Generally, an electronic component is mounted on a substrate, and an electrode of the electronic component body is electrically connected to an electrode or lead for external extraction so that a main portion including the electronic component body is connected. It is packaged and manufactured. FIG. 2 shows an example of a resin molding apparatus that covers the body of an electronic component in the process of manufacturing the electronic component. In the figure, reference numeral 1 is a lower mold, and a cull portion 2 is formed in a central portion of an upper surface, a plurality of runners 3 are communicated with the cull portion 2, and lower cavities 4 are formed along each runner 3 at predetermined intervals. The respective runners 3 and the lower cavity 4 are communicated with each other through a gate 5. In the illustrated example, a cross section passing through one cavity 4 from the cull portion 2 through the runner 3 is shown. Reference numeral 6 denotes an upper die which is disposed above the lower die 1 and which is relatively close to and separated from the lower die 1 and abuts the lower die 1. The pot 7 penetrates the central portion of the upper die and the lower end thereof faces the cull portion 2. The upper cavity 8 is formed so as to face the lower cavity 4. Reference numeral 9 is a lead frame on which the electronic component body 10 is mounted, and is positioned and placed on a predetermined portion on the lower mold 1. 11
Is a resin tablet placed in the pot 6 with the molds 1 and 6 holding the lead frame 9 therebetween, and 12 is a plunger for pressing the resin tablet 11. Although not shown, the upper and lower molds 1 and 6 are fixed to a fixed platen or a movable platen and heated by a heating means. In this apparatus, with the molds 1 and 6 opened, the lead frame 9 is placed on the cavity 4 of the lower mold 1.
Are positioned and arranged, the molds 1 and 6 are closed, the lead frame 9 is clamped, the resin tablet 11 is put into the pot 7, and the plunger 12 is further inserted to make the resin tablet 1
When 1 is pressurized, the resin tablet 11 is heated from the molds 1 and 6, and is pressurized by the plunger 12 to be fluidized and injected into the cavities 4 and 8 via the runner 3 and the gate 5. Since the fluidized resin undergoes a polymerization reaction and cures over time, when the injection of the resin is completed, the resin is maintained for a predetermined time, and when the resin is in a semi-cured state, the plunger 12 is pulled out from the pot 6. , Open molds 1 and 6,
A molded product in which the main part on the lead frame 9 is coated with resin is taken out.

[0003]

By the way, the cull portion 2 is made up of the resin 11 pressurized by the plunger 12 in the pot 7.
The pressure applied to is converted from the axial direction of the pot 7 to the extending direction of the runner 3 intersecting this axis. On the other hand, the depth of the cull portion 2 is determined by the opening diameter of the runner 3, but if the opening diameter of the runner 3 is reduced, the flow resistance of the resin increases, the fluidity of the resin decreases, and the resin is injected into the cavity. If the delay occurs, the curing of the resin proceeds, resulting in defective molding due to unfilling. Therefore, the opening diameter of the runner 3 is determined by the fluidity of the resin, and the depth of the cull portion 2, that is, the minimum value of the capacity of the cull portion is determined. The resin remaining in the cull portion 2, the runner 3, and the gate 5 is discarded as unnecessary resin, but the amount of the resin remaining in the cull portion 2 is large and the total amount of the unnecessary resin including the residual resin in the runner 3 and the gate 5 is large. And the effective utilization rate of the resin was about 10% to 50%, and there was much waste. Further, since the resin 11 fluidized in the pot 7 advances in the radial direction of the pot 7 and flows into the runner 3, only a part of the pressure by the plunger 12 is applied to the resin in the runner 3.
A large amount of force is required to drive the plunger 12, which is a constraint in reducing the size of the device. In order to solve such a problem, one resin tablet 11 is not used for resin molding of one or a plurality of lead frames 9 as a whole, but a plurality of molding portions in one lead frame 9 are formed. A so-called multi-plunger type resin molding device for molding with one resin tablet 11 has been put into practical use to improve the resin utilization rate and to reduce the driving force of the plunger, but the resin utilization rate is still 40 to 70. %, Further improvement was desired.

[0004]

The present invention has been proposed for the purpose of solving the above-mentioned problems, and a cavity and a gate are provided in communication with at least one of the abutting surfaces of a pair of molds, and a pot is provided therewith. Provided is a resin molding apparatus in which the cull portion, which has been conventionally required, is substantially eliminated and the effective utilization rate of the resin is improved by arranging and connecting the mold so that its axis is substantially parallel to the gate. .

[0005]

BEST MODE FOR CARRYING OUT THE INVENTION The present invention is characterized in that the resin to be injected into the cavity formed in the abutting surfaces of the upper and lower molds is supplied from the side wall of the mold. As a result, the fluidized resin can be directly supplied from the inner end of the pot to the mold abutment surface, so that the cull portion conventionally required is substantially unnecessary, and the effective utilization rate of the resin can be significantly improved. . Further, even if a connecting portion that communicates with the cavity is formed at a position facing the pot on the side wall of the mold, by making the diameter of this connecting portion larger than the inner diameter of the pot, the inner end of the plunger can reach within this connecting portion. It can be inserted and the resin remaining at the connection can be minimized as much as possible. Further, since the moving direction of the resin by the plunger and the moving direction of the resin moving to be supplied to the cavity are the same, the pressure applied by the plunger is effectively applied to the fluidized resin, and the plunger drive device can be downsized. It is possible to downsize the device.

[0006]

FIG. 1 shows an embodiment of the present invention. In the figure, 13 is a lower mold supported by a base 14, 1
Reference numeral 5 denotes a runner which is formed along a straight line of a portion adjacent to the side wall of the upper surface (abutting surface) of the lower die 13 and which guides the fluidized resin. In the illustrated example, a cross section that intersects the runner 15 is shown. Reference numeral 16 denotes a large number of cavities formed along the runner 15 in correspondence with the planned exterior portion of the lead frame 17,
Indicates a gate that connects the runner 15 and each cavity 16. The inner end of 19 communicates with the runner 15, and the outer end of the mold 1
3, a lower connection portion that opens to the side wall of 3 and communicates with a pot to be described later,
Reference numeral 20 denotes an upper mold, which is moved above and below the lower mold 13 so as to move up and down relatively and collide with each other. 21 is a lower mold 13 on the lower surface of the upper mold 20.
Upper cavity formed facing the cavity 16 of
Reference numeral 22 is an upper connecting portion formed to face the lower connecting portion 19 of the lower mold 13, and the upper and lower connecting portions 19 and 22 are the upper and lower molds 1.
They are polymerized by abutting 3, 20 so that the outer end opens to the side wall and the inner end communicates with the runner 18. This connection 1
9 and 22 are cavities having the same diameter from the outer end to the middle, and the diameters from the middle to the inner end are reduced. 23 is arranged to face the side wall where the connecting portions 19 and 22 of the abutted dies 13 and 20 are opened,
On the base 14 that supports the lower mold 13, a movable block that comes close to and separates from the side wall penetrates the pot 24 at a position facing the openings of the connecting portions 19 and 22. 25 is a resin tablet supplied in the pot 24, 26
Indicates a plunger that pressurizes the resin tablet 25. Although not shown, a drive source such as a hydraulic cylinder that applies a pressure to the plunger 26 via the rod 27 is fixed at a fixed position on the base 14. Although not shown, the base 14 and the upper mold 20 are fixed to a fixed platen and a movable platen, respectively, and heated by a heating means. The operation of this device will be described below. First, the upper and lower molds 13 and 20 are opened, the movable block 23 is separated from the molds 13 and 20, and the plunger 26 is pulled out from the movable block 23. In this state, the lead frame 17 is positioned and placed on the lower mold 13. Then, the lower die 13 and the upper die 20 are made to abut against each other, and the lead frame 17 is clamped. Meanwhile, the resin tablet 25 is inserted into the pot 24 of the movable block 23. After the upper and lower molds 13 and 20 are integrated, the movable block 23 is immediately moved toward the side walls of the upper and lower molds 13 and 20, and at least the end surface of the pot 24 is connected to the connecting portion 19,
22 is connected airtightly. During this time, the resin tablet 25 is heated and is in a state of being easily fluidized. Pot 24
When the connection between the connection parts 19 and 22 is completed, the plunger 26 is inserted into the pot 24 and further pressurized, the resin tablet 25 immediately starts to flow and flows into the runner 18 from the connection parts 19 and 22 and the cavity 15 The resin is coated on the main part of the lead frame. After the resin is filled in the cavities 16 and 21, this state is maintained for a certain period of time to proceed with the curing of the resin, and when the resin is in a semi-cured state, the movable block 23 is horizontally moved to move from the molds 13 and 20. Let go. After that, the upper and lower molds 13 and 20 are separated, and the connection portions 19 and 2 are separated.
Molded resin mold 13 with unnecessary resin located in 2,
After taking out from 20, the upper and lower molds 13 and 20 and the movable block 23 are cleaned, the above operation is repeated, and the resin molding work is continued. As described above, according to the present invention, since the fluidized resin can be directly supplied from the inner end of the pot 24 to the abutting surfaces of the molds 13 and 20, the conventionally required cull portion is substantially formed. It becomes unnecessary, and by making the diameter of the connecting portions 19 and 22 larger than the inner diameter of the pot 24, the inner end of the plunger 26 can be inserted into the connecting portions 19 and 22, and the resin remaining in the connecting portions 19 and 22 can be removed. Since it can be minimized as much as possible, the effective utilization rate of the resin can be greatly improved, and specifically, the utilization rate can be increased to 80% or more. Further, by setting the diameter of the connecting portions 19 and 22 to be larger than the inner diameter of the pot 24, even if the resin remaining in the connecting portions 19 and 22 projects into the pot 24, the connecting portions 19 and 22 and the pot 24 are Since no resin waist is formed between
When separating the movable block 23 from the upper and lower molds 13 and 20, no resin chipping occurs. Furthermore, since the moving direction of the resin by the plunger 26 and the moving direction of the resin moving to be supplied to the cavities 16 and 21 coincide with each other, the pressure applied by the plunger 26 is effectively applied to the fluidized resin, Even if the driving force is reduced, the resin can be actually injected into the cavities 16 and 21, the driving device of the plunger 26 can be downsized, and the device can be downsized. The present invention is not limited to the above-described embodiment. For example, a plurality of sets of cavities 16 and 21 are communicated with a runner 15 and resin is not supplied from the runner 15 pot 24, but one pot is used. 24 sets of cavities 1
It may correspond to 6, 21. In addition, a movable block 23 is provided on each side surface of the molds 13 and 20 each having a polygonal planar shape.
May be opposed to each other, or the mold 13 and the movable block 2 may be arranged.
The upper mold 2 divided so as to face the cavity 16 on the lower mold 13 while rotating the base 14 that supports the upper mold 2
It is also possible to place 0 and rotate the molds 13 and 20 to perform the resin molding work. Further, engaging parts that engage with each other are provided on the respective facing surfaces of the movable block 23 and the upper and lower molds 13 and 20, and by this engagement, the upper and lower molds 13 and 2
0 mold clamping property and movable block 23 and upper and lower molds 13, 2
It is also possible to improve the adhesion between 0s.

[0007]

As described above, according to the present invention, the amount of unnecessary resin can be reduced and the effective utilization rate of resin can be improved. Further, the plunger drive mechanism can be downsized, and the entire apparatus can be downsized.

[Brief description of the drawings]

FIG. 1 is a side sectional view of an essential part showing an embodiment of the present invention.

FIG. 2 is a side sectional view showing an example of a conventional resin molding device.

[Explanation of symbols]

 13 Lower Mold 15 Runner 16 Lower Cavity 18 Gate 19 Connection (Lower Connection) 20 Lower Mold 21 Upper Cavity 22 Connection (Upper Connection) 23 Movable Block 24 Pot 25 Resin Tablet 26 Plunger

Claims (4)

[Claims] 1. A cavity and a gate are provided so as to communicate with at least one of the abutting surfaces of a pair of molds, a shaft is disposed substantially parallel to the abutting surfaces of the mold, and a resin tablet and the resin tablet are pressed. A resin molding apparatus, wherein a pot into which a plunger is inserted is communicated with a gate from a side wall adjacent to an abutting surface of the mold. 2. The resin molding apparatus according to claim 1, wherein the diameter of the communicating portion communicating with the pot on the upper and lower mold side walls is set to be larger than the inner diameter of the pot. 3. The resin molding apparatus according to claim 2, wherein the inner end of the plunger is driven so as to project from the inner end of the pot into the communicating portion. 4. A runner for guiding a resin is formed at a portion adjacent to a side wall on a die abutment surface, a plurality of cavities are formed along the runner, and each cavity and the runner are connected by a gate. The resin molding apparatus according to claim 1, wherein the runner and the pot are communicated with each other.