JP3418264B2 - Lead frame depressing apparatus and control method therefor - Google Patents

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a lead frame depressing apparatus and a control method thereof, and more particularly to a lead frame depressing apparatus and a control method thereof capable of performing depressing with high accuracy.

[0002]

2. Description of the Related Art As a depressing device for a lead frame, a depressing device provided with an upper die and a lower die for pressing the lead frame to depress it is known.

Of these, the upper mold is held by a ram movable in the vertical direction, and the ram is driven by a hydraulic drive mechanism or a crank drive mechanism.

[0004]

As described above, in the conventional depressing machine, the ram holding the upper die is driven by the hydraulic drive mechanism or the crank drive mechanism, but when the hydraulic drive mechanism is used. Since the pressing force of the ram is controlled, a bottom dead center stopper for the upper die is provided to control the bottom dead center of the ram in order to adjust the amount of depressing. However, when the bottom dead center stopper for the upper die is provided in this manner, the shape of the die becomes complicated, which causes a cost increase. In addition, when adjusting the amount of depressing in the production preparation stage, it is necessary to adjust the position of the bottom dead center stopper for the upper mold in units of microns, or by inserting a spacer between the upper and lower stoppers. Requires a considerable amount of work, which reduces the utilization rate. Furthermore, when the amount of depressing is adjusted by the bottom dead center stopper for the upper die, there is a problem that it is difficult to perform highly accurate adjustment.

On the other hand, when the ram is driven by the crank drive mechanism, the position of the bottom dead center can be adjusted, but the resolution of the bottom dead center adjustment is coarse, so that there is a problem that high precision adjustment is difficult. In addition, in order to adjust the position of the bottom dead center, the adjustment must be performed using a mechanical tool, which reduces the operating rate. Further, when adjusting the position of the bottom dead center stopper or adjusting the bottom dead center position by sandwiching a spacer between the upper and lower stoppers, the crank drive mechanism may be damaged.

When the lead frame is subjected to high precision depressing, the ram is 0.1 to 1 at the bottom dead center of the ram.
It is necessary to stop for about a second, but there is a problem that the crank drive mechanism cannot stop the ram at the bottom dead center. Further, when the crank drive mechanism is used, there is a problem that the rising speed and the falling speed of the ram cannot be controlled arbitrarily.

The present invention has been made in view of the above points, and a lead frame depressing apparatus and a lead frame depressing apparatus capable of highly accurately depressing a lead frame without using a stopper or the like. The purpose is to provide a control method.

[0008]

The invention according to claim 1 is
Upper die and lower die for pressing and depressing the lead frame, ram for holding the upper die and pressing it against the lower die, servo motor for driving this ram, and pressing of the ram Find the force sensor that detects the force and the pressure detection point that starts to detect the pressing force based on the signal from this force sensor, and determine the point where the ram descends from this pressure detection point by the prescribed downset machining amount at the bottom dead center. And a controller for driving and controlling the servo motor according to the bottom dead center information.

According to a second aspect of the present invention, an upper die and a lower die for pressing the lead frame to perform depressing, a ram that holds the upper die and presses it against the lower die, and this ram. A servo motor for driving the ram, a force sensor for detecting the pressing force of the ram, and a point where the pressing force reaches a predetermined load based on a signal from the force sensor is set as the bottom dead center. A lead frame depressing apparatus, comprising: a controller for driving and controlling a servo motor.

According to a third aspect of the present invention, an upper die and a lower die for pressing the lead frame to perform depressing, a ram that holds the upper die and presses it against the lower die, and the ram. In the method of controlling the leadframe depressing apparatus, which comprises a servomotor for driving the ram and a force sensor for detecting the pressing force of the ram, the pressure of the ram that starts to detect the pressing force based on the signal from the force sensor. A step of obtaining a detection point, a step of obtaining a point where the ram descends from the pressure detection point by a predetermined downset machining amount as a bottom dead center, and a step of driving and controlling a servo motor based on the bottom dead center information, A method for controlling a lead frame depressing apparatus, comprising:

According to a fourth aspect of the present invention, an upper die and a lower die for pressing the lead frame to perform depressing, a ram that holds the upper die and presses it against the lower die, and this ram. In a method for controlling a lead frame depressing apparatus including a servo motor for driving a ram and a force sensor for detecting the pressing force of the ram, a point where the pressing force reaches a predetermined load based on a signal from the force sensor. Is a bottom dead center, and a step of driving and controlling a servomotor based on the bottom dead center information is provided, the lead frame depressing apparatus control method.

[0012]

According to the first and third aspects of the present invention, a pressure detection point at which the pressing force of the ram is detected based on a signal from the force sensor is determined, and the ram is downsized by a predetermined amount from the pressure detection point. The bottom dead center position (information) can be obtained with high accuracy because the point where the is descending is obtained as the bottom dead center. Next, by driving and controlling the servomotor based on this bottom dead center information, a large number of lead frames can be sequentially depressed with high accuracy between the upper die and the lower die.

According to the second and fourth aspects of the present invention, the bottom dead center information is accurately obtained by setting the bottom dead center at the point where the pressing force reaches the predetermined load based on the signal from the force sensor. You can Next, by driving and controlling the servomotor based on this bottom dead center information, a large number of lead frames can be sequentially depressed with high accuracy between the upper die and the lower die.

[0014]

Embodiments of the present invention will be described below with reference to the drawings. 1 to 6 are views showing a lead frame depressing apparatus and a control method thereof according to the present invention.

As shown in FIG. 1, a depressing machine 1
Reference numeral 0 is provided with an upper die 3a held by a ram 11 which moves in the vertical direction and a lower die 2b held by a ball star 12, and a punch 3a of the upper die 2a and a die 3 of the lower die 2b.
The lead frame 1 is pressed between b and depress.

A ball screw 15 is connected to the upper portion of the ram 11, and the ball screw 15 is moved in the vertical direction by a drive unit 17 which is rotationally driven by a servo motor 16. The drive unit 17 is transmitted by the servo motor 16. It is driven via the mechanism 18.

A force sensor 13 for detecting the pressing force of the ram is attached to the ram 11. This force sensor 13
A load cell amplifier 25 and a sequencer 21 are sequentially connected to the.

Further, as shown in FIG. 2, a servo motor driver 24 for driving the servo motor 16 is connected to the sequencer 21. Furthermore, the sequencer 21
Data setting console 22 and operation button 23
Are respectively connected. A data storage / processing medium 26 such as a personal computer that constitutes a control device together with the sequencer 21 is connected to the sequencer 21. The signal from the load cell amplifier 25 is the A / D of the sequencer 21.
The converter 27 is adapted to be input.

Next, the first control method of the depressing apparatus will be described with reference to FIGS. 2, 3 and 5.

First, as shown in FIG. 5, the bottom dead center stop time of the ram 11 is input to the sequencer 21 from the data setting console 22 and predetermined. Next, the moving speed of the ram 11, the downset machining amount (x), the downset machining amount correction value (y), and the top dead center position (for convenience, the top dead center position of the punch 3a) are sequentially set for data setting. Console 22
Is input to the sequencer 21 and set (see FIG. 3).
(A)).

Next, by operating the operation button 23, the sequencer 2
An operation command is input to 1, and the sequencer 21 controls the servo motor driver 24 to drive the servo motor 16. At this time, the sequencer 21 sends a predetermined number of pulses for driving the servo motor 16 to the servo motor driver 24, and the servo motor driver 24 counts the actual number of pulses of the servo motor 16 and the sequencer 21
Entered in.

By driving the servo motor 16 in this way, the ram 11 descends via the transmission mechanism 18, the drive portion 17 and the ball screw 15. This lowering of the ram 11 continues until the force sensor 13 operates.

Next, as shown in FIG. 3B, when the punch 3a comes into contact with the lead frame 1 supported by the die 3b, the force sensor 13 attached to the ram 11 detects the pressing force of the ram. This pressing force is input from the force sensor 13 to the sequencer 21 via the load sensor amplifier 25 and the A / D converter 27.

In the sequencer 21, the pressure detection point (point A) at which the force sensor 13 starts detecting the pressing force is calculated from the number of pulses from the servo motor driver 24. Next, in the sequencer 21, the sum of the predetermined downset processing amount (x) and the correction amount (y) from the pressure detection point, that is, the point where the ram 11 descends by x + y is the bottom dead center (point B) (FIG. 3).
(C)), the sequencer 21 inputs the bottom dead center information into the data storage / processing medium 26.

Next, the sequencer 21 drives the servo motor 16 by the servo motor driver 24 to return the ram 11 to the top dead center.

Next, the sequencer 21 drives the servo motor 16 by the servo motor driver 24 based on the bottom dead center information thus accumulated in the data storage / processing medium 26 and the top dead center information previously input. The ram 11 is moved up and down, and the lead frame 1 is sequentially pressed between the punch 3a and the die 3b for depressing.

In this way, the bottom dead center (point B) is obtained based on the pressure detection point (point A), and thereafter the lead frame 1 is depressurized based on this bottom dead center information, whereby a stopper or the like is used. It is possible to perform depressing processing quickly and accurately without using.

In the above embodiment, an example in which the bottom dead center is obtained in consideration of the correction amount (y) by the sequencer 21 is shown.
The correction amount (y) does not necessarily have to be taken into consideration.

Next, a second control method of the depressing apparatus will be described with reference to FIGS. 2, 4 and 6.

First, as shown in FIG. 6, from the data setting console 22, the bottom dead center stop time of the ram 11 and the ram 11 are determined.
The moving speed, the top dead center position (for convenience, the top dead center position of the punch 3a), and the predetermined pressing force (load) of the ram 11 are input to the sequencer 21.

Next, as shown in FIG. 4A, an operation command is output to the sequencer 21 by the operation button 23, and the sequencer 21 controls the servo motor driver 24 to drive the servo motor 16. The ram 11 is lowered by the driving of the servomotor 16, and the ram 11 is continuously lowered until the force sensor 13 detects a predetermined load.

Next, as shown in FIG. 4B, the punch 3a comes into contact with the lead frame 1 supported by the die 3b, and then the lead frame 1 is pressed between the punch 3a and the die 3b. During this time, the pressing force of the ram 11 is detected by the force sensor 13, and the sequencer 21 calculates the point where the pressing force reaches the predetermined load W by calculating from the number of pulses from the servo motor driver 24. The point where the pressing force or the predetermined load W is set is the bottom dead center (point C), and the sequencer 21 inputs this bottom dead center information to the data storage / processing medium 26.

Next, the sequencer 21 drives the servo motor 16 by the servo motor driver 24 to return the ram 11 to the top dead center. Next, based on the bottom dead center information accumulated in the data storage / processing medium 26 and the top dead center information inputted in advance, the servo motor 16 is driven by the servo motor driver 24 to move the ram 11 up and down, and the lead frame is moved. 1 is sequentially pressed between the punch 3a and the die 3b to perform depressing.

Thus, the point where the pressing force of the ram becomes the predetermined load W is defined as the bottom dead center, and thereafter the lead frame 1 is depressurized based on the bottom dead center information without using a stopper or the like. Quick and accurate depressing can be performed.

[0035]

As described above, according to the present invention, it is possible to accurately obtain the bottom dead center based on the pressing force of the ram obtained by the force sensor in advance. Since the lead frame is sequentially depressurized between the upper die and the lower die, it is possible to perform depressurization with constant accuracy more quickly than when the position of the upper die is restricted by a stopper or the like. it can. Further, since the stopper is not used, the shape of the mold can be simplified and the cost can be reduced.

[Brief description of drawings]

FIG. 1 is a schematic view showing a depressing apparatus for a lead frame according to the present invention.

FIG. 2 is a diagram showing a control device of the depressing apparatus.

FIG. 3 is a diagram showing a first control method of the depressing apparatus.

FIG. 4 is a diagram showing a second control method of the depressing apparatus.

FIG. 5 is a flowchart showing a first control method of the depressing apparatus.

FIG. 6 is a flowchart showing a second control method of the depressing apparatus.

[Explanation of symbols]

1 lead frame 2a Upper mold 2b Lower mold 10 Depressing machine 11 Ram 13 force sensor 16 Servo motor 21 Sequencer 24 Servo motor driver 25 load cell amplifier 26 Data storage and processing media

─────────────────────────────────────────────────── --- Continuation of the front page (56) References JP-A-5-146828 (JP, A) JP-A-5-220518 (JP, A) JP-A-1-161739 (JP, A) (58) Field (Int.Cl. ⁷ , DB name) H01L 23/50

Claims (4)

(57) [Claims] 1. An upper mold and a lower mold for pressing a lead frame to perform depressing, a ram for holding the upper mold and pressing it against the lower mold, and a servomotor for driving the ram. , A force sensor for detecting the pressing force of the ram, and a pressure detection point at which the pressing force starts to be detected based on a signal from the force sensor, and the ram descends from the pressure detection point by a predetermined downset machining amount. A lead frame depressing apparatus comprising: a point which is a bottom dead center, and a control device which drives and controls the servo motor based on the bottom dead center information. 2. An upper die and a lower die for pressing and depressing a lead frame, a ram for holding the upper die and pressing it against the lower die, and a servomotor for driving the ram. A force sensor for detecting the pressing force of the ram, and a point where the pressing force reaches a predetermined load based on a signal from the force sensor is set as a bottom dead center, and the servo motor is drive-controlled by the bottom dead center information. A lead frame depressing device, comprising: a control device. 3. An upper die and a lower die for pressing the lead frame to perform depressing, a ram for holding the upper die and pressing it against the lower die, and a servomotor for driving the ram. A force sensor for detecting the pressing force of the ram, and a step of obtaining a pressure detection point of the ram that starts to detect the pressing force based on a signal from the force sensor, , A step of obtaining a point where the ram descends from the pressure detection point by a predetermined down-set machining amount as a bottom dead center, and a step of controlling the drive of the servo motor based on the bottom dead center information. Control method for depressing machine for lead frame. 4. An upper die and a lower die for pressing and depressing a lead frame, a ram for holding the upper die and pressing it against the lower die, and a servomotor for driving the ram. In a control method of a lead frame depressing apparatus including a force sensor that detects the pressing force of the ram, a point where the pressing force reaches a predetermined load is obtained as a bottom dead center based on a signal from the force sensor. A method for controlling a depressing apparatus for a lead frame, comprising: a step; and a step of driving and controlling a servomotor based on the bottom dead center information.