JPH03230914A - Mold-registering mechanism of mold device - Google Patents

Abstract

PURPOSE:To obtain the mold-registering mechanism which suppresses the effect of the displacement due to the thermal expansion of a mold by a method in which fitting holes are provided in the central position in the direction of the porting face of at least three side walls in the four side walls which constitute the outer wall-surface of a mold, and the standard pins which position the mold by fitting the pins into the fitting holes are provided on a holding frame. CONSTITUTION:A mold 14 is placed on a holding frame 10, and the mold is positioned on the holding frame as that the standard pins 16, 38, 39 of the holding frame are fitted into the fitting holes 60, 62, 64 of the mold. Since the fitting holes are provided in the central positions of at least three side walls in the four side walls of the mold, the central position of the mold is specified from the position of three fitting holes, and the mold is registered to the holding frame by using the central position of the mold as standard. Then the mold is heated at high temperature and the mold is thermally expanded in all directions, while the central position of the mold is assumed as standard. Lead frames 66, 68, 70, 72 are placed on prescribed positions of the mold and are sealed in the mold. Accordingly, the displacement due to the thermal expansion of the mold becomes the position-error relative to the lead frame. Consequently the position error relative to the lead frame may be suppressed to half or less. The property of the molded product with the lead frame which has high density is improved.

Description

DETAILED DESCRIPTION OF THE INVENTION (Field of Industrial Application) The present invention relates to a mold positioning mechanism for a molding device in which a removable mold is installed.

(Prior Art) A molding device for enclosing a lead frame in a mold accurately positions and fixes a mold at a reference position. After the mold is fixed, a lead frame having a guide through hole is inserted into the guide pin of the mold, and the upper mold is pressed and sealed in the mold.

Conventionally, a method for positioning a mold for this mold is performed as follows. As shown in FIG. 4, when the mold is positioned and fixed to the holding frame of the molding device, the two blocks 102 and 104 are fixed to the holding frame so as to come into contact with the two adjacent side walls 100a and 100b. There is. The mold 100 consists of these two blocks 102.
The positioning is performed so that the inner wall surface of 104 and the side walls 100a, 100b are in contact with each other. Once the positioning is completed, the mold 100 is fixed at that position by tightening bolts or the like.

Therefore, the reference position is where the inner wall surfaces of blocks 102 and 104 intersect (point A in FIG. 4).

After that, the mold is heated to a high temperature (approximately 180℃) to melt the molding material.
°C). And lead frame 106a
~106d is placed at a predetermined position on the mold by a transfer mechanism, and is pressed between the upper mold and molded.

(Problems to be Solved by the Invention) However, the mold positioning mechanism of the above molding device has the following problems.

When the mold 100 is attached to the molding device, the mold is at approximately room temperature, but when mold encapsulation is repeated, the temperature is always quite high (approximately 180"C), and therefore the mold expands thermally, causing the mold to initially close. A positional deviation has occurred from the set state.In other words, if the two side walls 100a and 100b of the mold are brought into contact with the inner wall surfaces of the blocks 102 and 104 and aligned, as in the conventional example shown in FIG. When the mold 100 thermally expands, it expands toward the side that is not in contact with both blocks 102 and 104.

Therefore, although there is no positional displacement due to thermal expansion at point A in the figure,
The positional displacement at point B is maximum, and B
If the positional displacement at the point is ΔX and ΔY, then the positional displacement at the 0 point is ΔX/2 and ΔY/2.

On the other hand, the lead frame is placed at an accurate position using the center point C of the parting surface of the mold as a reference by the transfer mechanism.

Therefore, due to thermal expansion, lead frames 106a to 10
A relative positional error occurs between 6d and the mold 100, and this positional error is large at the lead frame position near the B point because the positional displacement of the mold 100 is large toward the B point.

Recent lead frames have become extremely dense, so it is necessary to set the lead frame to the mold at a high density, and the inner diameter of the guide through hole is relative to the outer diameter of the guide pin of the mold. By reducing the margin, mutual positional deviation is suppressed as much as possible. Therefore, if there is a large positional error at point B as described above, the guide pins will not fit into the guide through holes of the lead frame accurately when setting the lead frame in the mold, and the lead frame will not fit into the mold. It may be set at an angle.

Thereafter, when the upper mold and the lower mold are pressed together, the lead frame that is stopped midway is forcibly pressed, and the shape of the through hole is deformed. Even in this post-molding process, the lead frames are positioned based on the through holes, so each lead frame with a deformed through hole cannot be accurately positioned.
This may cause defective products. There is a problem in that such a large positional error of the mold affects the quality of the molded product.

SUMMARY OF THE INVENTION Therefore, an object of the present invention is to provide a mold positioning mechanism that suppresses the influence of positional displacement due to thermal expansion of a mold.

(Means for solving problems) In order to solve the above problems, the present invention has the following configuration.

That is, in a mold positioning mechanism of a molding device that positions and installs a molding die having a rectangular parting surface on a holding frame, one of the four side walls forming the outer wall surface of the mold. Fitting holes are provided at central positions of at least three side walls when viewed from the parting surface direction, and the holding frame is provided with a reference pin that fits into the fitting holes to position the mold.

(Operation) The mold is placed on the holding frame, and the mold is positioned on the holding frame so that the fitting hole of the mold and the reference pin of the holding frame are fitted. Since the fitting holes are provided at the central positions of at least three of the four side walls of the mold, the center position of the mold can be identified from the positions of these three fitting holes,
The mold is aligned with the holding frame based on the center position of the mold.

Thereafter, the mold is heated to a high temperature and thermally expands in all directions with the center position of the mold as a reference. Then, the lead frame is placed in a predetermined position of the mold and sealed in the mold. Therefore, positional displacement due to thermal expansion of the mold becomes a relative positional error with respect to the lead frame.

(Example) Hereinafter, preferred embodiments of the present invention will be described.

FIG. 1 shows a mold 14 held by a holding frame 10 of a molding device.
FIG.

When the mold 14 is aligned with the holding frame 10,
Three blocks 12.20.24 are fixed facing and surrounding the three adjacent side walls of the mold. In addition, the mold 14
A gap is provided between the side wall of the mold 12 and the block 12.20.24 for the expansion of the mold 14. A reference pin 16 is fixed to the longitudinal center of the block 12 so as to protrude in the direction in which the mold 14 is attached. block 2
At the center of the longitudinal direction of the reference pin 38 is a
is provided to move the reference pin 38 from the block 20 to the mold 14.
You can take it out or put it in the direction of. Also,
The block 20 is provided with two clamp mechanisms 18, 18 near both ends for pressing and fixing the mold after the mold alignment is completed. block 24 and block 20
Similarly, there is provided a mechanism 26 for drawing out the reference pin 39 and two clamping mechanisms 18, 18. Reference numeral 28.30 denotes a guide portion fixed to be flush with the surface of the holding frame 10, and has a protruding side wall communicating with the blocks 20.24 in order to guide the mold 14 to the mounting position.

14 is a cubic mold, with a lead frame 66 on the surface.
．． 68, 70, 72 is placed and mold encapsulation is performed. The mold 14 is provided with guide pins, and the lead frame 66
．． 68, 70, and 72 are provided with through holes for penetrating and positioning the guide pins. The mold 14 has the center position of the side wall 14a in the longitudinal direction and the side walls 14b, 1 in the width direction.
4c of the reference pin 16.3 of the holding frame 10
It has fitting holes 60, 62, and 64 that fit with 8.39.

FIG. 2 is a cross-sectional view of the clamp mechanism 18.

14 is a mold, and a recess 15 is provided in the side wall thereof. A block 24 is fixed to the holding frame 10. The block 24 has a screw hole 37 into which the bolt 36 is screwed, and a through hole 33 through which the bolt 34 passes and is screwed into a screw hole 35 provided in the holding frame 10. 3
2 is a clamp piece with one end bent, and the other end is fixed to the block 24 with a bolt 36 via a spring washer 54. One bent end of the clamp piece 32 is connected to the mold 1
It is inserted into the recess 15 of No. 4. In addition, the clamp piece 32
A through hole 56 is provided in which the bolt 34 passes. The bolt 34 passes through the clamp piece 32 and the through hole 33.56 of the block 24 via the spring washer 52, and is screwed into the threaded hole 35 of the holding frame 10. At this time, since a gap 25 is provided between the block 24 and the clamp piece 32, as the bolt 34 is screwed in, the bent end of the clamp piece 34 will hold the wall surface 17 of the recess 15 of the mold 14. The mold 14 is fixed by pressing toward the surface of the frame 10.

FIG. 3 is a plan view showing the drawing mechanism 22 of the reference pin 38 provided on the block 20. The drawing mechanism 26 of the reference pin 39 provided in the block 24 also has a similar structure and mechanism. 20 is a block, which has a through hole 46 in the center in the longitudinal direction through which the reference pin 38 can be moved. Further, the block 20 is provided with an elongated hole 44 that communicates from the surface of the block 20 to the through hole 46 and is long in the direction of movement of the pin 38.

A pin 40 fixed to the pin 38 passes through the elongated hole 44 and projects onto the surface of the block 20. The movement range of the reference pin 38 is limited by the pin 40 to the range of the length of the elongated hole 44 . 48 is a plate-like piece, and has a notch 42 at one end into which the pin 40 is inserted.

Further, near the other end, there is a through hole through which the screw 50 passes,
The plate piece 48 is rotatable around the center of the screw 50. The rotation range of the plate-like piece 48 is controlled by the pin 40.
It is limited to a length range of 4. A screw 50 passes through a through hole in the plate-like piece and is screwed into a screw hole in the block 20.

Next, a method for attaching the mold 14 to the holding frame 10 will be explained.

First, before installing the mold 14 in FIG. The screw 50 is screwed in and fixed so that it does not protrude from the side wall. Further, the reference pin 39 is similarly prevented from protruding from the side wall of the block 24 by the drawing mechanism 26.

Next, the mold 14 is moved to the guide portion 28 with the side wall having the fitting hole 60 that fits the reference pin 16 facing toward the block 12.
Place it on top of 30. The mold 14 is moved as it is until the fitting hole 60 and the reference pin 16 are fitted. Then, the mounting position of the mold 14 is finely adjusted so that the fitting holes 62 and 64 of the mold 14 are in positions where they can fit with the reference pins 38 and 39, respectively.

Next, in order to fit the reference pin 38 into the fitting hole 62, the reference pin 50 of the turnout mechanism 22 is loosened, the plate piece 48 is rotated toward the mold 14, and the reference pin 38 is removed from the block 20. It is made to protrude and fit into the fitting hole 62. Similarly, the pin 39 is fitted into the fitting hole 64 by adjusting the turn-out mechanism 26.

Next, the four clamp mechanisms 18.18.18.18 provided on the block 20.24 clamp the mold 1 as follows.
Fix 4 in that position. Clamp piece 3 as shown in Figure 2.
The bent end of the clamp piece 32 is inserted into the recess 15 of the mold 14, so when the bolt 34 is screwed in, the bent end of the clamp piece 32 holds the wall surface 17 of the recess 15 and holds the frame 10.
Press the surface in the 1- direction. In this way, the four clamp mechanisms 1
The mold 14 can be fixed to the holding frame 10 by screwing in the port 34 of 8.18.18.18. Side walls 14a, 14b, 14c of mold 14 and block 1
A gap is provided between the side walls of 2, 20, and 24 so that they do not come into contact even when the mold 14 expands.

By aligning and fixing the mold 14 to the holding frame 10 as described above, the mold can be aligned to the holding frame 10 using the center position of the mold specified from the fitting hole 60, 62, 64 as the reference position. , the positional displacement due to thermal expansion of the mold 14 is the orthogonal Y-axis passing through the center, and if the overall positional displacement about the Y-axis is ΔX and ΔY, respectively, then the middle ris
L is (0,0), and the maximum displacement from the center is (ΔX/2.ΔY/2). Therefore, when point A is used as the reference as in the conventional example shown in Fig. 4, the maximum positional displacement is ΔX
, ΔY), but with the mechanism of the present invention, the maximum positional displacement can be suppressed to a small value of (ΔX/2, ΔY/2).

Therefore, when the lead frames 66, 62, 8, 70, 72 are placed at predetermined positions, the relative positional error with respect to the mold 14 can be suppressed to less than half. That is, when the lead frame is placed on the mold by the transfer mechanism and the guide pin of the mold is inserted into the through hole of the lead frame, the lead frame is not locked in the middle of the guide pin.

Although various preferred embodiments of the present invention have been described above, the present invention is not limited to the above-mentioned embodiments, and it goes without saying that many modifications can be made without departing from the spirit of the invention. .

(Effect of the invention) The maximum positional displacement due to thermal expansion of the mold is the maximum displacement when the mold is aligned with the intersection of adjacent side walls as the reference, since thermal expansion occurs in all directions with the center position of the mold as a reference. This is half of the positional displacement.

Therefore, the relative positional error with the lead frame can be suppressed to less than half, which has the effect of improving the quality of molded products of high-density lead frames.

[Brief explanation of drawings]

Fig. 1 is a plan view showing the mold installed in the holding frame of the mold encapsulation device, Fig. 2 is a sectional view of the clamp mechanism, Fig. 3 is a plan view showing the pin delivery mechanism, and Fig. 4 is FIG. 2 is a plan view showing a conventional mold alignment mechanism. 10... Holding frame, 14... Mold, 14a
, 14b, 14c -- at least three side walls,
i 6, 38.39...Reference pin, 60.62.6
4... Fitting hole.

Claims (1)

[Scope of Claims] 1. In a mold positioning mechanism of a molding device that positions and installs a molding die having a rectangular parting surface on a holding frame, the parting surface serves as an outer wall surface of the mold. Fitting holes are provided at central positions of at least three of the four side walls when viewed from the parting surface direction, and the holding frame is provided with a reference pin that fits into the fitting holes to position the mold. A mold positioning mechanism for a molding device, characterized by: