JPH11123600A - Forming controller for servo press - Google Patents

Abstract

PROBLEM TO BE SOLVED: To detect the fluctuation factor of the machining precision of a product, which occurs during forming, and to maintain the forming precision of the product by correcting the fluctuation factor immediately during the forming. SOLUTION: By detecting a touch point where a punch 10 has been abutted on a material 11 when a slide 9 has been lowered by the rise of the current of the servomotor of the servo press, and also detecting the position of the slide 9 at that time by a scale detector, a distance between the slide and the material is calculated. And, by judging that an elongation Δt caused by the thermal expansion of the punch 10 has generated, and by correcting the bottom dead point of the slide 9 by Δt during the forming, the forming precision is maintained.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a servo press forming control device which uses a servomotor capable of numerical control as a drive source and moves a slide up and down by a screw mechanism, and is effective when it is desired to improve the product accuracy of press forming. .

[0002]

2. Description of the Related Art For example, there is a servo press shown in FIG. 6 in which a servomotor capable of numerical control is used as a drive source, and a rotation amount of the servomotor is controlled as a vertical movement amount of a ram by a screw mechanism. FIG. 6 shows that the amount of elevation of the ram 1 is determined by the amount of rotation of the electric motor 2, and the amount of rotation of the electric motor 2 is controlled by the current of the motor drive 4 numerically controlled by the central processing unit 3, and the encoder 5 directly connected to the electric motor 2. Thus, the ascending position and the descending position of the ram 1 are detected. The ascending limit and descending limit of the ram 1 are determined by an ascending limit switch 6A and a descending limit switch 6B to prevent overrun.
The ram 1 is moved up and down according to the ascending position and the descending position of the ram 1 set and inputted from the operation panel 7.

[0003]

The electric press 8 described above.
Can move the ram 1 up and down with high accuracy in accordance with the set up position and the down position of the ram 1, but the vertical position of the ram 1 is detected by the encoder 5 detecting the rotation of the motor 2 driving the ram 1. Therefore, it is not possible to detect that a punch of a mold expands and expands due to heat generated by press working, for example, when the press work is performed continuously. Therefore, there is a drawback that it is not possible to prevent a substantial change in the processing accuracy of the product due to a substantial change in the position of the ram 1, that is, expansion and contraction of the frame of the press machine in addition to the mold.

SUMMARY OF THE INVENTION An object of the present invention is to solve the above-mentioned problems, to detect a cause of a variation in the processing accuracy of a product generated during molding, and to correct immediately during the molding to maintain the molding accuracy of the product. An object of the present invention is to provide a molding control device for a servo press.

[0005]

SUMMARY OF THE INVENTION In order to solve the above-mentioned problems, the present invention relates to a servo press forming control device for applying a servo motor capable of numerical control as a drive source to raise and lower a slide. By detecting the fluctuation of the motor current, the upper die provided on the slide detects the touch point where the upper die abuts on the material, and determines the vertical position of the slide and the material at this touch point to determine the slide position. Correct and maintain the molding accuracy of the product.

In a servo press forming control device that uses a servo motor capable of numerical control as a drive source and applies a vertical movement to a slide via a screw mechanism, a vertical position of the slide is detected and an electric position signal is output. A galvanometer that is provided in a circuit of a current supply to a servomotor and detects and outputs a motor current, and a galvanometer that generates a current for controlling the rotation of the servomotor during molding and generates a current. From the fluctuations in the motor current output by the controller, the electrical touch signal of the upper die of the slide contacting the material is determined, and a slide position correction signal for the material is output based on the electrical position signal of the scale detector at that time. An NC control device is provided for detecting a relative vertical position change between the slide and the material to correct the bottom dead center position of the slide.

[0007]

1 to 5 show an embodiment of a servo press forming control apparatus according to the present invention. In FIG. 1, a case where a recess 12 having a forming amount t is formed in a material 11 by a punch 10 provided on a slide 9 will be described, and the gist of the present invention will be described. As shown in the left diagram of FIG. 1A, when the slide 9 descends and the distance between the slide 9 and the material 11 at the touch point where the punch 10 contacts the material 11 is 305.00 mm, FIG. As shown in the right figure of a), the slide 9 reaches the bottom dead center, and the slide 9 and the material 1
The interval between the two was set to 300.00 mm, and the depression 12 formed in the material 11 was set to the molding amount t.

As shown in the left diagram of FIG. 1B, the punch 10 is expanded by the thermal expansion generated by the heat generated by the molding by a length Δt, and the punch 9 is expanded by the heat generated by the molding.
When the distance between the slides 9 reaches 305.01 mm and the slide 9 reaches the bottom dead center and the distance between the slide 9 and the material 11 becomes 300.00 mm as shown in the right diagram of FIG.
The recess 12A of the material 11 has a molding amount t + Δt,
The depression 12A becomes deeper by 01 mm.

Therefore, as shown in the left diagram of FIG.
The punch 10 expanded by thermal expansion by the length Δt is
The touch point in contact with the surface of the slide 9 is detected by a galvanometer 19 described later, and the vertical position of the slide 9 at that time is measured by a scale detector 20, and the distance between the slide 9 and the material 11 is 3
As soon as it is determined that the lower dead point of the slide 9 is 0.01 mm, the lower dead point of the slide 9 is corrected by 0.01 mm.
As shown in the right diagram of FIG.
By setting the distance between them to 300.01 mm, the material 11
The recess 12 is defined as a molding amount t, and the molding accuracy is maintained. These controls are performed by the NC control device 17. NC
The control device 17 can maintain the molding accuracy within 0.01 mm by correcting each time the correction amount reaches the minimum control amount of the NC control, in this embodiment, 0.01 mm.

The amount of expansion and contraction due to thermal expansion is determined by the punch 10
Not only in each part of the servo press,
If the distance between the slide 9 and the material 11 is calculated in the NC controller 17 from the measurement of the height of the slide 9 by the scale detector 20, the error in the molding accuracy due to the expansion and contraction of each part of the servo press can be corrected together.

FIG. 2 is a flowchart of the molding process described with reference to FIG. 1. The contents are clear with reference to the description of FIG.

FIGS. 3 and 4 show the configuration of the servo press 13 and its control device. Frame 1 of servo press 13
The slide 9 which is guided up and down by the guide 4 is driven by a servomotor 16 via a screw mechanism 15. The drive of the servo motor 16 is controlled by a current supplied from the NC control device 17. The current circuit 18 is provided with a galvanometer 19 for detecting a current value, and outputs the detected current value to the NC device 17A of the NC control device 17 as shown in FIG. N
The C device 17A outputs a preset NC signal, and the driver 17B outputs a current corresponding to the NC signal to drive and control the servomotor 16.

The frame 14 of the servo motor 13 is provided with a scale detector 20 corresponding to the stroke range in which the slide 9 moves up and down, for example, a linear scale capable of measuring the length in minute units, and measures the amount of movement of the slide 9. ing. The electrical position signal transmitted by the scale detector 20 is
It is input to the NC device 17A.

FIG. 5 shows a motor speed diagram B and a motor current diagram C of the servo motor 16 corresponding to the slide motion diagram A. The slide 9 descends according to the slide motion diagram A, and the motor current rises at the touch point P where the punch 10 of the slide 9 contacts the material 11 shown in FIG. Motor current fluctuates.

3 and 4, the galvanometer 19 detects that the motor current has risen at the touch point P shown in FIG. 5, and this electric signal is sent to the NC unit 17 of the NC control unit 17.
A, the distance between the slide 9 and the material 11 is calculated from the electrical position signal of the slide 9 input from the scale detector 20 at that time, and the difference from the initial set value is determined as a correction fee, The preset bottom dead center position of the slide 9 can be immediately corrected during molding, and molding accuracy can be maintained. The minimum unit of correction is determined by the minimum unit of the transmission signal of the NC device 17A, and can be variously determined as necessary.

[0016]

As is apparent from the above description, according to the present invention, the upper die attached to the slide is moved between the slide and the material based on the touch point where the upper die abuts the material supplied on the lower die. Since the distance is calculated and the correction amount is determined, a correction amount including expansion and contraction of the press structure due to heat generated in molding can be obtained. Therefore, the error that occurs is not limited to the expansion and contraction of the mold,
Compensation can be made comprehensively.

[Brief description of the drawings]

FIG. 1 is a diagram for sequentially explaining the gist of the invention in one embodiment of the present invention.

FIG. 2 is a flowchart of a molding process shown in FIG. 1;

FIG. 3 is a block diagram of a servo press.

FIG. 4 is a main part diagram of a control circuit of the servo press.

FIG. 5 is an explanatory view of an operation in molding.

FIG. 6 is an explanatory view of a conventional example.

[Explanation of symbols]

9 is a slide, 10 is a punch, 11 is a material, 12, 12
A is a depression, 13 is a servo press, 14 is a frame, 1
5 is a screw mechanism, 16 is a servo motor, 17 is an NC control device, 17A is an NC device, 17B is a driver, 18 is a circuit, 19 is a galvanometer, 20 is a scale detector, t is a molding amount, and Δt is elongation. , P are touch points.

Claims (2)

[Claims] An apparatus for controlling the forming of a servo press, in which a servomotor capable of numerical control is used as a drive source to apply a vertical movement to a slide, detects a fluctuation in the motor current of the servomotor during the forming, thereby forming an upper mold provided on the slide. A servo press characterized by detecting a touch point in contact with a material, judging a vertical relational position between the slide and the material at the touch point, correcting the slide position, and maintaining product molding accuracy. Molding control device. 2. A forming control device for a servo press, in which a servomotor capable of numerical control is used as a drive source and a vertical movement of a slide is carried out via a screw mechanism. A scale detector that outputs a signal, (b) a galvanometer that is provided in a circuit of a current supplied to the servomotor and detects and outputs a motor current, and (c) rotation control of the servomotor during molding. And an electric touch signal indicating that the upper die of the slide is in contact with the material from the fluctuation of the motor current output by the galvanometer, and an electric position signal of the scale detector at that time. And an NC controller for outputting a correction signal of the slide position with respect to the material based on the position of the slide. Forming control device of a servo press and corrects bottom dead center position of the id.