JPH07124988A - Plunger apparatus in transfer molding machine - Google Patents

Abstract

PURPOSE:To facilitate adjustment for aligning the axial line of a raw material feeding hole and the axial line of a plunger inserted therein in a mold and to improve durability of the plunger in a transfer molding machine. CONSTITUTION:An annular groove 21 is provided on the outer peripheral face of the apex part of a plunger 19 pushed into a raw material feeding hole and a ring body 22 tightly fitting to the raw material feeding hole is mounted in such a way that the ring body is freely movable in the right angle direction to the axial line of the plunger and a communicating hole 23 communicated with the annular groove is provided in such a way that the communicating hole is opened on the apex face 19a of the plunger.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to, for example, a transfer molding machine for molding synthetic resin parts such as mold packages for semiconductor parts, in which a raw material tablet of the synthetic resin is pushed toward a molding cavity. It relates to a plunger device for.

[0002]

2. Description of the Related Art Generally, a transfer molding machine of this type is described, for example, in Japanese Utility Model Laid-Open No. 59-9538, and is constructed as shown in FIGS. That is, a plurality of columns 2 standing upright from the table 1
The upper molding die 4 is attached to the lower surface of the fixed platen 3 fixed to the upper end of the lower plate, and the lower molding die 7 is attached to the upper surface of the movable platen 6 which is vertically moved by the main hydraulic cylinder 5 provided in the table 1. After these two molding dies 4 and 7 are matched by the operation of the main hydraulic cylinder 5, the plunger 9 is fixed in the raw material charging hole 8 formed in the upper molding die 4. By inserting the sub-hydraulic cylinder 10 attached to the upper surface of the board 3 into the raw material synthetic resin tablet A previously loaded in the raw material loading hole 8, the mating surfaces of the molding dies 4 and 7 are melted. It is adapted to be pushed into the molding cavities 4a and 7a formed in the above.

In this transfer molding machine, the raw material loading hole 8 is operated by the operation of the sub-hydraulic cylinder 10.
The diameter of the plunger 9 inserted into the raw material loading hole 8 is close to the inner diameter of the raw material loading hole 8 so that the plunger 9 is closely fitted into the raw material loading hole 8. When pushed, the molten synthetic resin is configured so as not to leak from the gap between the outer peripheral surface of the plunger 9 and the inner peripheral surface of the raw material charging hole 8.

[0004]

[Problems to be Solved by the Invention] However, in this way,
Bring the diameter of the plunger 9 close to the inner diameter of the raw material charging hole 8,
In order to closely fit the raw material loading hole 8, the sub hydraulic cylinder 10 provided with the plunger 9 and the raw material loading hole 8 are provided.
When the upper molding die 4 having the above is mounted, the axis of the plunger 9 of the sub-hydraulic cylinder 10 must be exactly aligned with the axis of the raw material loading hole 8 of the upper molding die 4. The sub-hydraulic cylinder 10 having the plunger 9 and the upper molding die 4 having the raw material loading hole 8 are configured to be attached separately, so that the sub-hydraulic cylinder 10 and the upper molding die 4 are attached.
At the time of mounting, the axis of the plunger 9 and the axis of the raw material loading hole 8 must be finely adjusted so as to be strictly coincident, and this adjustment requires a great deal of labor and a high degree of skill. Therefore, the productivity is greatly reduced.

Moreover, even if the fine adjustment is performed, the axes of the plunger 9 and the raw material loading hole 8 cannot be completely aligned with each other, so that the plunger 9 comes in partial contact with the inner surface of the raw material loading hole 8. As a result, great wear occurs on the outer peripheral surface of the plunger 9 and the inner peripheral surface of the raw material loading hole 8. In this case, the raw material loading hole 8 is
Although it is formed by fitting the bush 8a into the upper molding die 4, since the bush 8a and the plunger 9 must be frequently replaced, the replacement of these parts further lowers the productivity. In addition to this, maintenance costs increased.

In addition, the plunger 9 and the raw material loading hole 8
By not being able to perfectly match the axes of and
In the bush 9a for the plunger 9 and the raw material loading hole 8,
Another problem is that it is not possible to use a super hard alloy having excellent wear resistance. An object of the present invention is to provide a plunger device capable of solving these problems all at once.

[0007]

In order to achieve this technical object, the present invention is to "push into a raw material charging hole formed in at least one molding die of a transfer molding machine. An annular groove is provided on the outer peripheral surface of the tip of the plunger to be inserted, and a ring body closely fitted in the raw material charging hole is freely inserted into the annular groove in a direction perpendicular to the axis of the plunger. The plunger is provided with a communication hole that communicates with the annular groove so that the communication hole opens on the tip end surface of the plunger. "

[0008]

[Operation] With this configuration, at the time of the first molding operation, the ring body in which the plunger is fitted into the annular groove of the plunger is closely fitted into the raw material loading hole in which the raw material synthetic resin tablet is preliminarily loaded. Then, after melting the raw material synthetic resin tablet, by further pressing the plunger,
The molten synthetic resin is filled in the molding cavity of each molding die, at the same time, is filled in the gap between the annular groove and the ring body through the communication hole, and is cured in that state. From this, even if the axis of the plunger does not coincide with the axis of the raw material loading hole, in other words, even if there is an error between the axis of the plunger and the axis of the raw material loading hole, the raw material With respect to the plunger, the ring body closely fitted in the loading chamber can be closely fitted in the raw material loading hole, that is, the axis of the ring body is strict with respect to the axis of the raw material loading hole. It can be fixed under the condition of matching.

[0009]

Therefore, according to the present invention, it is only necessary that the axis of the plunger and the axis of the raw material loading hole substantially coincide with each other, and it is not necessary to strictly match both axes with each other as in the conventional case. The number of steps required for this can be greatly reduced, and productivity can be improved.
In addition, even if there is a deviation between the axis of the plunger and the axis of the raw material loading hole, the ring body of the plunger can be fitted accurately and closely in the raw material loading hole, and this durability can be improved. Therefore, it is possible to drastically reduce productivity and maintenance costs due to replacement of parts, and the bush for forming the raw material loading hole and the ring body are made of a super hard alloy excellent in wear resistance. In addition, it has the effect of further improving its durability.

[0010]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT An embodiment of the present invention will be described below with reference to the drawings of FIGS. In this figure, reference numeral 11 denotes a fixed table, and an upper molding die 14 is attached to the lower surface of a fixed platen 13 fixed above the fixed table 11 via a plurality of columns 12, while the table 11 is A movable platen 16 that moves up and down by a main hydraulic cylinder 15 provided in
The lower molding die 17 is attached to the upper surface of the.

A bush 18a having a raw material loading hole 18 therein is fitted in the upper molding die 14, and the mating surfaces of both the molding dies 14 and 17 communicate with the raw material loading hole 18. The molding cavities 14a and 17a are formed to be recessed. In addition, on the upper surface of the fixed plate 13,
A sub-hydraulic cylinder 20 equipped with a plunger 19 that is pushed into the raw material loading hole 18 is attached.

An annular groove 21 is formed on the outer peripheral surface of the tip end of the plunger 19, and the annular groove 21 is formed.
The ring body 2 closely fitted in the raw material loading hole 18
2 is attached so that the ring body 22 can freely move in a direction perpendicular to the axis of the plunger 19, while the communication hole 2 communicating with the plunger 19 in the annular groove 21.
3, the communication hole 23 is the tip surface 19a of the plunger 19.
To make a hole.

In this embodiment, the plunger 1
The annular groove 21 is formed by screwing the locking block 19c with the flange 19b onto the tip of the groove 9, and the communication hole 23 is formed in the locking block 19c.
Is provided, and the ring body 22 is easily attached to the plunger 19. Further, one or a plurality of seal grooves 22a are formed on the outer peripheral surface of the ring body 22.

In this structure, at the time of the first molding operation, the ring body 22 in which the plunger 19 is fitted in the annular groove 21 of the plunger 19 is inserted into the raw material loading hole 18 in which the raw material synthetic resin tablet A is loaded in advance. 1
8, so that the raw material synthetic resin tablet A is melted, and then the plunger 19 is actuated by its sub hydraulic cylinder 20.
Push it in further.

Then, the molten synthetic resin is used to form the molding cavities 14a and 17a in both molding dies 14 and 17.
At the same time as filling the inside, as shown in FIG.
After passing through 3, the gap between the annular groove 21 and the ring body 22 is filled and cured in that state. Therefore, as a result, the axis of the plunger 19 is aligned with the raw material loading hole 1
8, even if there is an error between the axis of the plunger 19 and the axis of the raw material loading hole 18, even if it does not match the axis of the raw material loading chamber 18, the ring body closely fits in the raw material loading chamber 18. 22 in a state in which the ring body 22 can be closely fitted to the plunger 19 in the raw material loading hole 18, that is, the axis of the ring body 22 is strictly aligned with the axis of the raw material loading hole 18. It can be fixed under the condition that

In the above embodiment, the plunger 19 is
Although the case where the plunger 19 is operated by the sub-hydraulic cylinder 20 is shown, the plunger 19 may be configured to be operated by an electric motor. Further, according to the present invention, the raw material charging hole is provided in the lower molding die, Alternatively, it goes without saying that the present invention can also be applied to the case where both molds are provided.

[Brief description of drawings]

FIG. 1 is a partially cutaway front view of a transfer molding machine according to an embodiment of the present invention.

FIG. 2 is an enlarged view of a main part of FIG.

FIG. 3 is a sectional view of the tip of the plunger.

FIG. 4 is a partially cutaway front view of a conventional transfer molding machine.

FIG. 5 is an enlarged view of a main part of FIG.

[Explanation of symbols]

 11 Fixed Table 12 Support 13 Fixed Plate 14 Upper Mold 15 Main Hydraulic Cylinder 16 Movable Plate 17 Lower Mold 14a, 17a Mold Cavity 18 Raw Material Loading Hole 18a Bush 19 Plunger 19a Plunger Tip 20 Sub-hydraulic Cylinder 21 Annular groove 22 Ring body 23 Communication hole

Claims (1)

[Claims] 1. An annular groove is provided on an outer peripheral surface of a tip end portion of a plunger which is inserted into a raw material loading hole formed in at least one of the molding dies of a transfer molding machine, A ring body closely fitted in the raw material loading hole is mounted in the annular groove so that the ring body can freely move in a direction perpendicular to the axis of the plunger. A plunger device in a transfer molding machine, characterized in that a communication hole communicating with the plunger is provided so that the communication hole opens on the tip end surface of the plunger.