JP3166405B2 - Mold for transfer molding - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a transfer molding die used for sealing a semiconductor element provided on a lead frame with a resin.

[0002]

2. Description of the Related Art Conventionally, as a transfer molding die of this type, a plurality of cavities, one pot for heating and melting a resin tablet supplied from the outside, and a resin melted in the pot are supplied to each cavity. And a driving mechanism for driving the plunger, a one-pot type plunger has been used. By the way, in this one-pot transfer mold, if the number of cavities is increased in order to improve productivity, the amount of resin charged in the pot increases, and it takes time to melt the resin. Also, the length of the melting passage from each of the cavities to the respective cavities becomes extremely non-uniform, which causes variations in the pressure and temperature of the resin before filling into each of the cavities. In addition, there is a problem that the quality of the molded product in each cavity varies. Therefore, in order to solve this problem, a multi-pot type transfer molding die is provided in which a plurality of pots are provided to reduce the amount of resin melted in each pot and to make the length of each resin passage as uniform as possible. It has been developed.

[0003]

In the above multi-pot transfer molding die, a large number of plungers moving through the die are detachably connected to a pressing plate of a drive mechanism. The plungers can be simultaneously moved by moving the pressing plate by fluid pressure or the like. Therefore, when it becomes necessary to replace the plunger, it is necessary to disassemble the mold and release the connection state with the pressing plate, but this work is troublesome and the workability is extremely poor. There's a problem.

The present invention has been made in view of the above circumstances, and has as its object to eliminate the need to disassemble the mold, to easily replace only the plunger, and to replace the plunger. An object of the present invention is to provide a transfer molding die that can be smoothly and reliably performed.

[0005]

In order to achieve the above-mentioned object, the present invention provides a method comprising: forming a plurality of cavities between a pair of molds; providing a plurality of pots respectively communicating with the cavities; A plurality of plungers for extruding the tablets loaded into the pots into the cavities are provided, and in a transfer molding die for simultaneously pressing and driving these plungers, each of the plungers is An approaching / separable pressing plate is connected via an attaching / detaching mechanism. In the attaching / detaching mechanism, a mounting tool is provided on the pressing plate, and a mounting recess for mounting the plunger is formed in the mounting tool, and In the ingredients,
A locking tool is provided that can approach and separate in the radial direction with respect to the plunger mounted in the mounting recess, and a movable cylinder is provided on the mounting tool so as to be movable in the axial direction. An accommodating portion for retreating the locking tool outward from the plunger is formed in the cylinder, and the locking tool is urged by the moving cylinder toward the mold from the pressing plate. Is mounted on the plunger.

[0006]

According to the transfer mold of the present invention,
When replacing the plunger mounted in the mounting recess of the mounting tool, the pressing plate approaches the mold and the moving cylinder is pressed against the mold to move against the urging force of the resilient member. The cylinder was shifted to the pressing plate side along with the mounting tool, the locking tool was retracted to the accommodating portion in the moving cylinder, and after the pressing of the locking tool against the plunger by the moving cylinder was released, the cylinder became movable. Pull out the plunger from the mounting recess of the mounting tool to the mold side and replace it.

[0007]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the present invention will be described below with reference to FIGS.

In these figures, reference numeral 10 denotes an upper die, and the upper die 10 is provided so as to be vertically movable relative to a lower die 20. In the upper mold 10 and the lower mold 20, the mold plates 102, 202 are provided on the base plates 100, 200 via the spacers 101, 201, respectively, and the mold supports 103,
203, and these mold supports 103, 20
3. Center dies 104 and 204 and product dies 105 and 205
Are fitted, and these molds 104, 105,
Protruding mechanisms 106 and 206 for releasing the solidified resin and the molded product in the resin passage from the molds 204 and 205 are provided, while the base plate 200, the protruding mechanism 206, and the mold plate 2 are provided.
02, the mold support 203 and the center mold 204 are provided with a large number (2 rows × 8 = 16) of pots 207.

The protruding mechanism 106 is provided on the base plate 10.
0, and a protruding plate 106a and a holding plate 106b movably provided in the mold opening / closing direction between the pressing plate 106b and the pressing plate 106b. Template 102, mold support 1
03 and the protruding pins 106c, 106d, and 106e penetrating the center mold 104 or the product mold 105, and are mounted between the base plate 100 and the protruding plate 106a.
A projecting spring 106f for biasing the projecting plate 106a, a biasing device 106g movably provided on the projecting plate 106a and abutting against a base end surface of the projecting pin 106c, The shock-absorbing spring 10 provided between the plate 106a and the urging tool 106g to urge the urging tool 106g toward the protruding pin 106c
6h. The protruding pin 106c is provided to face the pot 207, and is formed in the resin mold portion 104a formed in the center mold 104.
This is for releasing the solidified resin in the mold. In the drawing, reference numeral 106i denotes the protruding plate 106a, the holding plate 1
06b and a return pin for returning the protruding pins 106c to 106e to their original positions.

The protruding mechanism 206 is connected to the base plate 20.
0 and the mold plate 202, and a protruding plate 206a and a holding plate 206b movably provided in the mold opening and closing direction, and a base end portion sandwiched between the pushing plate 206a and the holding plate 206b. Template 202, mold support 2
03 and the protruding pin 206 penetrating the product mold 205
c, 206d, provided on the protruding plate 206a,
And a projecting rod 206e for urging the projecting plate 106a, the mold plate 202 and the projecting plate 206a.
And a return spring 206f for returning the projecting plate 206a to its original position. The protruding plate 206a and the holding plate 206b
The protruding pins 206c and 206d are pushed out toward the upper die 10 by a protruding member 206g via a protruding rod 206e, and a return spring 206 is provided.
f and a return pin (not shown) sandwiched between the protruding plate 206a and the holding plate 206b, so that the upper die 10 returns to the original position.

Each of the pots 207 includes an upper pot body 207.
The lower end of a is screwed into the upper end of the lower pot body 207b, and a flange 207c is formed above the screw portion of the upper pot body 207a. A flange 207d is formed at the lower end of the lower pot body 207b. The flange portion 207d is mounted in the base plate 200, and is attached to the base plate 200 by mounting bolts 207e inserted from below the base plate 200.
It is fixed to.

A plunger 300 of the plunger unit 30 is inserted into each of the pots 207 from below. The plunger unit 30 is mounted on the base plate 2.
00, and the mounting plate 30
1 supporting plate 30 attached via spacer 302
3, four guide pins 304 provided between the mounting plate 301 and the support plate 303, and a pressing plate 306 provided on the guide pins 304 via a guide mechanism 305 so as to be movable in the mold opening / closing direction. And a tilt adjusting spring 307 provided between the pressing plate 306 and the mounting plate 301 and biasing the pressing plate 306 toward the support plate 303, and is detachable from the pressing plate 306 via a mounting member 308. The drive shaft 309 connected to the pressing plate 306 and the detachable mechanism 3
And the above-mentioned plunger 300 attached through the base 10.

On the upper surface of the mounting plate 301, two discharge grooves 301a intersecting with the plungers 300 are formed in a direction orthogonal to the mold opening and closing direction. A seal member 301b is mounted around each of the plungers 300 in both the discharge grooves 301a, and a bottom plate 301c is laid on these seal members 301b. The four corners of the pressing plate 306 are supported by the guide pins 304 while maintaining a slight clearance, and the inclination of the pressing plate 306 can be adjusted by the clearance. Further, the drive shaft 30
The upper end of 9 has a neck portion 309a formed in a small diameter, and a head portion 309c connected to the neck portion 309a and having a rectangular contact surface 309b with the pressing plate 306. And, it is constituted by an attachment 308 attached to the pressing plate 306 and the pressing plate 306,
And a storage space 31 opened in a direction orthogonal to the mold opening and closing direction.
1, a head 309c of the drive shaft 309 is mounted, and the drive shaft 30 is inserted into a mounting groove 312 which is connected to the storage space 311 and is formed in the mounting fixture 308.
Nine necks 309a are mounted. Furthermore, the attachment / detachment mechanism 310 attaches the attachment 310a to the pressing plate 306.
A mounting recess 310b for mounting the base end of the plunger 300 is formed in the mounting tool 310a, and the mounting recess 310b is mounted on the mounting tool 310a.
A plurality of communication holes 310c communicating with the plunger 300 are mounted in the communication holes 310c, and a sphere 310d that can be moved toward and away from the plunger 300 in the radial direction is mounted in the communication holes 310c. The movable cylinder 310e is provided so as to be movable in the axial direction, while the movable cylinder 3
10e, the sphere 310d is inserted into the plunger 300.
A large-diameter hole portion 310f is formed to retreat outward from the cylinder. Further, the moving cylinder 310e is urged from the pressing plate 306 to the mounting plate 301 side of the moving cylinder 310e, so that the spherical body 310d is moved to the plunger. Pressing spring 3 for pressing against mounting recess 300a formed in 300
10 g is attached.

In the transfer molding die configured as described above, when the resin tablet is loaded into the pot 207, the resin tablet is extruded by each plunger 300, so that each center mold 1 is extruded.
After the molten resin is supplied into the cavities formed between the product dies 105 and 205 through the resin passages formed in the product dies 104 and 204 and the product dies 105 and 205, a molded product is formed in the cavities. In the opening process, the protrusion mechanism 1
In addition, the projecting pins 106c, 106d, and 106e release the solidified resin and the molded product in the resin passage from the center pool 104 of the upper die 10 and the resin reservoir 104a of the product mold 105, and the projecting mechanisms 206 project. The product mold 2 of the lower mold 20 is set by the pins 206c and 206d.
From 05, the solidified resin and the molded product are released from the mold and collected. Then, when it becomes necessary to replace the plunger 300, in the mold open state, the pressing shaft 306 is brought closer to the mounting plate 301 by the drive shaft 309, and the upper end of the plunger 300 is further lowered than when the resin is injected. 20 (in FIG. 1, three plungers 30).
Positions A, B, and C of 0 indicate a state in which the resin tablet is loaded into the pot 207, a state in which the resin tablet is pushed out of the pot 207, and a state in which the plunger 300 is replaced, respectively. At this time, the mounting tool 310a to which the base end of the plunger 300 is mounted moves together with the pressing plate 306 and the plunger 300.
The moving cylinder 310e, which is externally mounted on the pressing spring 310a, comes into contact with the mounting plate 301 with the movement thereof.
Stops against the biasing force of g. As a result, the moving cylinder 3
When the position of 10e approaches the pressing plate 306 side,
Up to now, the mounting tool 31 has been moved by the inner surface of the moving cylinder 310e.
The sphere 310d, which has been pressed inward into the communication hole 310c formed in the hole 0a and pressed into the mounting recess 300a of the plunger 300, moves outward along the communication hole 310c to move inside the mounting recess 300a of the plunger 300. From the large-diameter hole 310f in the moving cylinder 310e.
Evacuate to Accordingly, the engagement state between the mounting tool 310a and the plunger 300 via the sphere 310d is released, so that the plunger 300 can be easily pulled out from the lower mold 20. Then, the new plunger 300
Is inserted into the lower mold 20, the base end thereof is mounted in the mounting recess 310b of the mounting tool 310a, and then the pressing plate 306 is lowered to lower the mounting tool 310a together with the plunger 300. Is stopped while being pressed against the mounting plate 301 to some extent, the positional relationship between the moving cylinder 310e and the mounting tool 310a changes, and the moving cylinder 31
Sphere 310d that has been retracted into large-diameter hole 310f
Is extruded from the large-diameter hole portion 310f to form the communication hole 3
10c, the mounting recess 30 of the plunger 300 is moved.
0a. Thereby, the plunger 30
0 and the mounting tool 310a are engaged, so that the plunger 30
Numeral 0 is firmly attached to the pressing plate 306 side.

[0015]

As described above, according to the present invention, a plurality of cavities are formed between a pair of molds, a plurality of pots are respectively provided to communicate with these cavities, and the pots are inserted into these pots. A plurality of plungers for extruding the pressed tablets into the respective cavities, and a transfer plate that simultaneously presses and drives these plungers. Are connected via an attachment / detachment mechanism. In the attachment / detachment mechanism, a mounting tool is provided on the pressing plate, a mounting recess for mounting the plunger is formed in the mounting tool, and the mounting recess is formed on the mounting tool. A locking tool is provided that can approach and separate in the radial direction with respect to the plunger mounted at the place, and the mounting tool is movably moved in the axial direction. On the other hand, an accommodating portion for retracting the locking tool outward from the plunger is formed in the movable cylinder, and the movable cylinder is attached to the movable cylinder from the pressing plate to the mold side. When the plunger mounted in the mounting recess of the mounting tool is replaced, the pressing plate is formed into a mold body because a resilient member that presses the locking tool against the plunger by urging is mounted. By approaching and pressing the movable cylinder against the mold, the movable cylinder is displaced to the pressing plate side along the mounting tool against the urging force of the resilient member, and the locking tool is attached to the accommodation portion in the movable cylinder. After retracting and releasing the pressing of the locking tool against the plunger by the moving cylinder,
By pulling out the movable plunger from the mounting recess of the mounting tool to the mold side and replacing it, there is no need to disassemble the mold, only the plunger can be replaced easily, and the plunger replacement work Can be performed smoothly and reliably.

[Brief description of the drawings]

FIG. 1 is a sectional view showing one embodiment of the present invention.

FIG. 2 is a sectional view showing an example of an upper die.

FIG. 3 is an explanatory diagram of FIG. 2 as viewed from a mating surface side.

FIG. 4 is a sectional view showing an example of a lower mold.

FIG. 5 is an explanatory view of FIG. 4 as viewed from the mating surface side.

FIG. 6 is a sectional view showing an example of a plunger unit.

FIG. 7 is a view taken along line VII-VII of FIG. 6;

FIG. 8 is a sectional view of a base end of the plunger.

[Explanation of symbols]

 Reference Signs List 10 Upper mold (mold) 20 Lower mold (mold) 207 Pot 300 Plunger 306 Pressing plate 310 Attaching / detaching mechanism 310a Mounting tool 310b Mounting recess 310d Spherical body (locking tool) 310e Moving cylinder 310f Large diameter hole (accommodating section) 310g Pressing spring (elastic member)

Claims (1)

(57) [Claims] 1. A plurality of cavities are formed between a pair of molds, a plurality of pots are provided in communication with the cavities, and a tablet loaded in the pots is extruded into the cavities. A plurality of plungers are provided, and in a transfer molding die that simultaneously presses and drives these plungers, a pressing plate that can approach and separate from the mold body is connected to each of the plungers via a detachable mechanism. The attachment / detachment mechanism is provided with a mounting tool on the pressing plate, the mounting tool has a mounting recess for mounting the plunger, and the mounting tool has
A locking tool is provided that can approach and separate in the radial direction with respect to the plunger mounted in the mounting recess, and a movable cylinder is provided on the mounting tool so as to be movable in the axial direction. An accommodating portion for retreating the locking tool outward from the plunger is formed in the cylinder, and the locking tool is urged by the moving cylinder toward the mold from the pressing plate. Characterized in that a resilient member for pressing the elastic member against the plunger is mounted.