JP2836362B2 - Mold clamping force detection method and mold clamping force detection device for molding apparatus - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method and a device for detecting a mold clamping force of a molding device used for sealing a semiconductor element with a resin.

[0002]

2. Description of the Related Art Conventionally, in order to obtain a mold clamping force of a mold at the time of mold clamping in a resin molding apparatus, a tie bar supporting a mold mounting platen is stretched at the time of mold clamping. Was. This type of mold clamping force detecting device will be described with reference to FIG.

FIG. 2 is a front view of a molding apparatus provided with a conventional mold clamping force detecting device. In FIG. 2, a tie bar penetrating portion is cut away. In the figure, reference numeral 1 denotes an upper mold, 2 denotes a lower mold which is clamped to the upper mold 1 from below, and these upper and lower molds 1 and 2 are for resin molding, and an upper platen as a fixed platen. 3, and are supported and fixed to the moving platen 4, respectively.

The upper platen 3 and the moving platen 4
The upper platen 3 is fixed to the upper end of the tie bar 5 by nuts 3a and 3b. Each of the tie bars 5 is provided so as to be parallel to each other with the longitudinal direction directed up and down, and a lower end portion thereof penetrates a lower platen 6 described later and is fixed to the lower platen 6 by nuts 6a and 6b. The movable platen 4 supporting the lower mold 2 is mounted on the tie bar 5 so as to be able to move up and down using the tie bar 5 as a guide. In FIG. 2, the tie bar through holes of the moving platen 4 are drawn larger than the actual ones so that the structure can be easily understood.

Reference numeral 7 denotes a mold clamping drive motor serving as a drive source for moving the movable platen 4 up and down. The output shaft of the motor 7 is connected to a lower platen driving ball screw 10 via a clutch 8 and a worm speed reducer 9. ing. The ball screw 10 is mounted on the lower platen 6 and is driven by a worm speed reducer 9 to rotate.
A holder 11 having a nut (not shown) screwed to the screw shaft 10a and fixed to the lower platen 6 is provided. The holder 1 is rotated by rotating the screw shaft 10a.
1 is configured to rise or fall.

That is, when the mold clamping drive motor 7 operates, the rotation of the output shaft is transmitted to the ball screw 10 via the clutch 8 and the worm speed reducer 9, and the screw shaft 10a rotates to move the moving platen 4 up and down. Become.

Numeral 12 denotes a displacement sensor for detecting a mold clamping force when the movable platen 4 rises from the state shown in the figure and the lower mold 2 and the upper mold 1 are clamped. The displacement sensor 12 is configured to detect a movement dimension of the detector 12a urged in a direction protruding from the main body portion, and is fixed to an upper end portion of the tie bar 5 with the detector 12a facing downward. The protruding end (lower end) of the detector 12a
Is in contact with the upper end of the detection rod 13 fixed to the lower end of the tie bar 5 supporting the main body. The lower end of the detection rod 13 is fixed to the lower end of the tie bar 5 via a connecting plate 14.

That is, when the movable platen 4 is further urged upward with the upper and lower dies 1 and 2 clamped, a reaction force acts on the lower platen 6 to extend each tie bar 5, and the upper end of the detection rod 13. The distance between the displacement sensor 12 and the main body of the displacement sensor 12 increases, and the detector 12a slightly projects from the main body. At this time, the displacement sensor 12 has its detector 12a
Is detected as a displacement.

[0009] 15 amplifier for amplifying a signal output from the displacement sensor 12, 16 is an arithmetic unit for calculating the clamping force from the displacement signals S ₁ output from the amplifier 15, the arithmetic unit 16 , CPU 17 and arithmetic means 18
And The CPU 17 is electrically connected to the displacement sensor 12 via the amplifier 15 and is configured to output the mold clamping force value calculated by the calculating means 18 as mold clamping force data 19 to, for example, a display (not shown). I have.

The calculating means 18 is configured to calculate a mold clamping force value by multiplying the displacement data (extension dimension of the tie bar 5) sent from the CPU 17 by a constant K, and output the value to the CPU 17. .

Further, the CPU 17 comprises a calculating means 18
Mold clamping force value calculated in is configured to output a clutch release signal S ₂ to the clutch control circuit 20 when it becomes larger than a predetermined value. The clutch control circuit 20 is connected to the clutch 8, intended to control switching of the opening, the clutch 8 outputs a clutch-off signal S ₃ to the clutch 8 when the clutch release signal S ₂ is input from the CPU17 It is configured to operate to the open side.

Next, the operation of the conventional mold clamping force detecting device configured as described above will be described. First, a lead frame (not shown) or the like to be sealed with a resin is
Then, the mold clamping drive motor 7 is operated to raise the lower mold 2 together with the moving platen 4 to bring the lower mold 2 into contact with the upper mold 1.

Then, the lower mold 2 is urged toward the upper mold 1 until a predetermined mold clamping force is obtained, and the resin is filled in the mold to perform resin sealing. In order to obtain the mold clamping force, the arithmetic unit 16 calculates the amount of downward movement of the detection rod 13 (the amount of extension of the tie bar 5) detected by the displacement sensor 12.

That is, when the force (clamping force) for pressing the lower mold 2 against the upper mold 1 is increased, the tie bar 5 is extended by the reaction force, and the detection rod 13 is lowered with respect to the displacement sensor 12. The displacement sensor 12 detects the displacement. The signal output from the displacement sensor 12 is amplified by the amplifier 15, is inputted to the arithmetic unit 16 as the displacement signal S _1. In the arithmetic unit 16, the CPU 17 and the calculating means 18 calculate the mold clamping force based on a relationship in which the displacement is proportional to the mold clamping force, and output it as mold clamping force data 19 to a display or the like.

When the mold clamping force obtained in this way reaches a predetermined value, the mold clamping drive motor 7 is stopped,
It will shift to the resin sealing step.

If the result of the calculation by the arithmetic unit 16 indicates that the mold clamping force is excessive, the CPU 17 outputs a clutch release signal S ₂ to the clutch control circuit 20. As a result, the clutch 8 is operated to the release side, and the mold clamping drive torque is interrupted.

[0017]

However, if a method of detecting the displacement of the detection rod 13 which is moved by the extension operation of the tie bar 5 in obtaining the mold clamping force is employed, the extension of the tie bar 5 during mold clamping is extremely small. There is a problem that a high-precision sensor is required as the displacement sensor 12. The use of the high-precision displacement sensor 12 not only increases the cost, but also increases the error in the detection value when vibration is applied during mold clamping.

Further, if the lower mold 2 is inclined and an uneven load is applied to both the molds, the mold clamping force is not evenly distributed to each tie bar 5, so that the average load or the total load is obtained. In this case, a displacement sensor 12 is required for each tie bar 5.

Further, in the conventional mold clamping force detecting device, in order to detect that the mold clamping force has become excessive based on the calculation result of the arithmetic unit 16, it is necessary to release the clutch 8 and cut off the mold clamping driving torque. There was also a problem of delay.

[0020]

According to a first aspect of the present invention, there is provided a method of detecting a mold clamping force of a molding apparatus, wherein a movable platen is moved along a tie bar to a fixed platen side so that mold dies of both platens are brought into contact with each other. Then, the movable platen is urged toward the fixed platen to move the fixed platen against the elastic force of the elastic body attached to the tie bar, and to contact the mold at the center of the fixed platen. The subsequent movement is detected by a displacement sensor fixed to the tie bar, and the mold clamping force is obtained based on the displacement obtained from the displacement sensor.

According to a second aspect of the present invention, there is provided a mold clamping force detecting device, wherein a fixed platen of a molding device is provided movably along a tie bar, and the tie bar is provided with an elastic body for urging the fixed platen toward the moving platen. At the same time, a displacement sensor having a detection unit positioned at the center of the surface of the fixed platen opposite to the moving platen is supported, and the displacement sensor controls the mold clamping force based on the amount of movement of the fixed platen. It is connected to the required mold clamping force detecting means.

According to a third aspect of the present invention, there is provided a mold clamping force detecting device, wherein a fixed platen of a molding device is provided movably along a tie bar, and the tie bar is provided with an elastic body for urging the fixed platen toward the moving platen. At the same time, a displacement sensor having a detection unit positioned at the center of the surface of the fixed platen opposite to the moving platen is supported, and the displacement sensor controls the mold clamping force based on the amount of movement of the fixed platen. A connection between the mold clamping force detection means to be obtained and a protection means which is provided with a comparator and stops the pressurization by the moving platen pressurizing device when the displacement amount obtained by the displacement sensor becomes larger than a predetermined value. It is.

[0023]

According to the first and second aspects of the present invention, the stroke at the time of mold clamping is extended by the contraction of the elastic body , and the displacement detected by the displacement sensor is increased. Further, since the displacement sensor detects the movement of the central portion of the fixed platen, a value that is substantially the average of the amount of displacement with respect to each tie bar when the fixed platen moves during mold clamping is detected.

In a third aspect of the present invention, the comparator compares the displacement detected by the displacement sensor with a predetermined value, and when the displacement is larger than the set value, the comparator operates the moving platen pressurizing device. Is stopped, the time required for the stop operation is reduced as compared with the case where the displacement is calculated by a CPU or the like and then the pressurization is stopped.

[0025]

DESCRIPTION OF THE PREFERRED EMBODIMENTS One embodiment of the present invention will be described below in detail with reference to FIG. FIG. 1 is a front view of a molding apparatus provided with a mold clamping force detecting device according to the present invention. In this figure, the same or equivalent members as those described in FIG. 2 are denoted by the same reference numerals, and detailed description is omitted.

In FIG. 1, reference numeral 21 denotes a displacement sensor for detecting the displacement of the upper mold 1 and the upper platen 3. The displacement sensor 21 is a conventional sensor except that the moving stroke of the detector 21a is larger than the conventional one. And is supported and fixed to the sensor fixing plate 22.

The sensor fixing plate 22 is fixed to the upper end of each tie bar 5 by fixing nuts 22a and 22b so as to bridge the plurality of tie bars 5. The displacement sensor 21 is arranged at the center of the lower surface of the sensor fixing plate 22. The position of the displacement sensor 21 is
The distance from the displacement sensor 21 to the tie bar 5 is the tie bar 5
The position is set to be equal every time. The position does not have to be strictly positioned at the center of the sensor fixing plate 22, and the same effect can be obtained as long as the position is near the center.

When the displacement sensor 21 is mounted on the sensor fixing plate 22 as described above, the lower end of the detector 21a of the displacement sensor 21 faces the center of the upper surface of the upper platen 3. The upper platen 3 used in the apparatus of the present invention
Is configured to be able to move up and down along the tie bar 5 using the tie bar 5 as a guide, and is supported by a stopper nut 3c screwed to the tie bar 5 to restrict downward movement.

Reference numeral 23 denotes a compression coil spring as an elastic body for urging the upper platen 3 downward. The compression coil spring 23 is connected to the upper platen 3 and the sensor fixing plate with the tie bar 5 inserted through the center thereof. It is elastically mounted between the fixing nut 22b.

That is, the upper platen 3 holds the stopper nut 3 by the compression coil spring 23 before the mold is clamped.
c to stop at the initial position. The initial position of the upper platen 3 and the sensor fixing plate 22
Is set at a position where the detector 21a of the displacement sensor 21 contacts the upper surface of the upper platen 3 before the mold clamping.

The upper platen 3 holds the lower mold 2
Is further urged upward by the lower mold 3 in a state of contact with the upper mold 1, and the upward force is applied to the compression coil spring 2.
When it exceeds the spring force of No. 3, it starts moving upward. Then, the displacement of the upper platen 3 is detected by the displacement sensor 2.
1 will be detected.

[0032] 24 amplifier for amplifying a signal output from the displacement sensor 21, 25 is a displacement signal S ₁ output from the amplifier 24, the mold clamping force detection for obtaining the table data 26 Tokara clamping force to be described later It is a CPU as a means.

The table data 26 records mold clamping force data for the displacement signal output from the displacement sensor 21. Then, the CPU25 reads out the clamping force data 27 corresponding from the table data 26 in the displacement signal S _1, is configured to output to a display (not shown) or the like it. The mold clamping force data recorded in the table data 26 is obtained by performing an experiment in which the upper platen 3 is pressurized upward by a variable pressurizing type experimental pressurizing device, and the amount of displacement of the upper platen 3 (displacement sensor The pressure is in accordance with the displacement signal output from the control signal 21.

Reference numeral 28 denotes a mold clamping limiter as a protection means. The mold clamping limiter 28 has a comparator. When the displacement amount indicated by the displacement signal S ₁ is larger than a predetermined value, the clutch control circuit 20 and it is configured to output an over-large clamping force detection signal S _4. Further, the clutch control circuit 20 is configured to operate the clutch 8 outputs a clutch-off signal S ₃ to the clutch 8 when the over-large clamping force detection signal S ₄ is inputted to the open side.

Next, a method for detecting a mold clamping force using the above-described mold clamping force detecting device will be described in detail. First, a lead frame (not shown) or the like to be resin-sealed is mounted on the lower mold 2 in the same manner as in the conventional apparatus, and the mold driving motor 7 is operated to raise the lower mold 2 together with the movable platen 4. Then, the lower mold 2 is brought into contact with the upper mold 1.

When the movable platen 4 is further raised in a state where the upper and lower dies are in contact with each other, the compression coil spring 23 contracts, and the upper platen 3 moves upward. At this time, the mold clamping force increases as the upper platen 3 rises against the spring force of the compression coil spring 23.

Thereafter, when the mold clamping force reaches a predetermined value, the mold clamping drive motor 7 is stopped, and the mold is filled with resin to perform resin sealing.

The CPU 25 reads the mold clamping force data corresponding to the displacement of the upper platen 3 detected by the displacement sensor 21 from the table data 26 to determine the mold clamping force.

That is, the displacement (elevation dimension) of the upper platen 3 is detected by the displacement sensor 21 and the displacement sensor 2
Signal output from the 1 is input to CPU25 is amplified as a displacement signals S ₁ by an amplifier 24. And
CPU25 compares the displacement signals S ₁ and table data 26, reads out the mold clamping force data corresponding to the displacement signals S ₁ from the table data 26.

When the mold clamping force thus obtained reaches a predetermined value, the mold clamping drive motor 7 is stopped,
It will shift to the resin sealing step.

When the displacement detected by the displacement sensor 21 is large and the mold clamping force is excessive, the mold clamping limiter 2
8, the clutch 8 is released. That is, the comparator in the mold clamping limiter 28 outputs the displacement signal S _1.
And which compares the reference signal always will output over large clamping force detection signal S ₄ to the clutch control circuit 20 when the amount of displacement exceeds a reference value. As a result, the clutch 8 is operated to the release side, and the mold clamping drive torque is interrupted.

Therefore, according to the mold clamping force detecting device according to the present invention, the stroke at the time of mold clamping is extended by the contraction of the compression coil spring 23, and the displacement detected by the displacement sensor 21 is increased. The contact clamping force is extremely small as compared with the related art. Therefore, the mold clamping force can be obtained with high accuracy without using a high-precision and expensive displacement sensor. In addition, even if vibrations are applied to the device at the time of mold clamping, the detection error is reduced by the amount of displacement.

Since the displacement sensor 21 detects the movement of the center of the upper platen 3, the upper platen 3
Is detected, a value that is substantially the average of the amount of displacement with respect to each tie bar 5 is detected. For this reason, accurate mold clamping force can be obtained even if the number of displacement sensors 21 used is one.

Further, a mold clamping limiter 2 having a comparator
If it is detected that the mold clamping force has become excessively large by 8, the time required for the stop operation is reduced as compared with the case where the displacement is calculated by a CPU or the like and then the pressurization is stopped.

In addition, as shown in this embodiment, when the table data 26 is used for obtaining the mold clamping force data, the relationship between the displacement of the compression coil spring 23 and the mold clamping force is linearly proportional. Or the displacement sensor 21
The mold clamping force can be accurately obtained even when the precision of the mold is low.

[0046]

As described above, in the method for detecting a mold clamping force of the molding apparatus according to the first aspect of the present invention, the moving platen is moved along the tie bar to the fixed platen side so that the mold dies of the two platens are paired. Then, the movable platen is urged toward the fixed platen to move the fixed platen against the elastic force of the elastic body attached to the tie bar, and the mold pair at the center of the fixed platen is moved. The displacement after contact is detected by a displacement sensor fixed to the tie bar, and the mold clamping force is obtained based on the displacement obtained from the displacement sensor. The apparatus is provided with a fixed platen of the molding apparatus movably along the tie bar, and, on the tie bar,
Attaching an elastic body for urging the fixed platen to the moving platen side, and supporting a displacement sensor in which a detection unit is positioned at the center of the surface of the fixed platen opposite to the moving platen, the displacement sensor Since the mold clamping force detecting means for obtaining the mold clamping force based on the moving amount of the fixed platen is connected, the stroke at the time of mold clamping is extended by the contraction of the elastic body , and the displacement detected by the displacement sensor is large. Become.

Therefore, the mold clamping force can be accurately obtained without using an expensive and high-precision displacement sensor.
Cost can be reduced. In addition, even if vibration is applied to the device during mold clamping, the detection error is reduced by the larger displacement amount, so that malfunction does not occur due to vibration.

Further, since the displacement sensor detects the movement of the central portion of the fixed platen, a value which is substantially the average of the displacement amount with respect to each tie bar when the fixed platen moves during the mold clamping is detected. For this reason, even if only one displacement sensor is used, the mold clamping force can be accurately obtained.

According to a third aspect of the present invention, there is provided a mold clamping force detecting device, wherein a fixed platen of a molding device is provided movably along a tie bar, and the tie bar is provided with an elastic body for urging the fixed platen toward the moving platen. At the same time, a displacement sensor having a detection unit positioned at the center of the surface of the fixed platen opposite to the moving platen is supported, and the displacement sensor controls the mold clamping force based on the amount of movement of the fixed platen. Since the mold clamping force detection means to be sought and the protection means for stopping the pressurization by the moving platen pressurizing device when the displacement amount obtained by the displacement sensor provided with the comparator becomes larger than a predetermined value, A comparator compares the amount of displacement detected by the displacement sensor with a predetermined value, and when the amount of displacement becomes larger than the set value, the comparator stops pressurizing the moving platen pressurizing device. Since thereby, time required for displacement of the stop operation compared with the case of stopping the pressurization after processing by the CPU or the like is shortened.

Therefore, according to the mold clamping force detecting device according to the third aspect of the present invention, when the mold clamping force becomes excessive, the stopping operation is promptly performed, so that safety can be enhanced.

[Brief description of the drawings]

FIG. 1 is a front view of a molding apparatus provided with a mold clamping force detection device according to the present invention.

FIG. 2 is a front view of a molding apparatus provided with a conventional mold clamping force detecting device.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Upper mold 2 Lower mold 3 Upper platen 4 Moving platen 5 Tie bar 7 Mold clamping drive motor 21 Displacement sensor 23 Compression coil spring 25 CPU 28 Mold clamping limiter

──────────────────────────────────────────────────続 き Continuation of the front page (51) Int.Cl. ⁶ identification symbol FI H01L 21/56 H01L 21/56 T // B29L 31:34 (58) Field surveyed (Int.Cl. ⁶ , DB name) B29C 45 / 02,45 / 14 B29C 45/64-45/68 B29C 45/76 -45/84 B29C 33/20-33/24 B22D 17/26

Claims (3)

(57) [Claims] The moving platen is moved along the tie bar to the fixed platen side to bring the molds of both platens into contact with each other, and then the moving platen is urged toward the fixed platen side to be mounted on the tie bar. The fixed platen is moved against the elastic force of the elastic body , and the displacement of the center of the fixed platen after contact with the mold is detected by a displacement sensor fixed to the tie bar. A mold clamping force detecting method for a mold forming apparatus, wherein a mold clamping force is determined based on a displacement amount obtained from a mold. 2. A fixed platen of a molding apparatus is provided movably along a tie bar, and an elastic body for urging the fixed platen toward the movable platen is mounted on the tie bar. Indicates that a displacement sensor having a detection unit positioned at the center of the opposite surface is supported, and that the clamping sensor is connected to mold clamping force detecting means for determining a clamping force based on the amount of movement of the fixed platen. Characteristic mold clamping force detection device. 3. A fixed platen of a molding apparatus is movably provided along a tie bar, and an elastic body for urging the fixed platen toward the movable platen is mounted on the tie bar. Supports a displacement sensor having a detection unit positioned at the center of the opposite surface.This displacement sensor is provided with a mold clamping force detecting means for obtaining a mold clamping force based on the moving amount of the fixed platen, and a comparator. A mold clamping force detecting device, comprising a protection means for stopping pressurization by a moving platen pressurizing device when a displacement amount obtained by a displacement sensor becomes larger than a predetermined value.