JPS60162600A - Method for controlling blanking in mechanical press - Google Patents

Abstract

PURPOSE:To decrease generation of cracking and to obtain a sheared surface having good surface roughness by controlling the operation of a motor which is a driving source for a punch and a clutch brake and applying repeatedly and finely high and low speeds to the stroke motion of the punch. CONSTITUTION:The rotation of a crank shaft 2 is braked by a brake 5 during the time since a punch 6 contacts with a blank material W until the punch ascends after blanking a blank 8 from the material W and detaches from the material W in the vertical stroke of the punch 6. Conditions are otherwise set by a setting part 11 so that the number of revolutions of the motor 1 is increased or decreased for each rotating angle of the shaft 2.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a method for controlling punching in a mechanical press.

When punching with a mechanical press, the stroke amount and stroke speed of the punch are set to the capacity that is empirically considered optimal depending on the thickness and quality of the material, but the operating conditions of the punch are inappropriate. The roughness of the sheared surface during punching becomes rough, making it impossible to perform accurate punching.This tendency is particularly high for materials that are thick or have high toughness.

This is because the material increases its deformation resistance as the cutting edge of the punch advances, and when the cutting edge bites and sag occurs and the maximum shear load is reached, the material cracks at the point where it touches the tip of the cutting edge, causing the punch to deform. This is due to the shearing mechanism of the punching process in which the cracks penetrate through the material as the cracks progress.

Furthermore, in conventional punching, if a so-called scrap-up phenomenon occurs, the next punch in continuous processing may be defective or the work must be interrupted.

In view of the above points, the present invention provides a method for controlling punching in a mechanical press, which can reduce the occurrence of cracks and realize a sheared surface with good surface roughness, and which does not cause scraps to rise. The structure of this method is that during punching with a mechanical press, while the punch is in contact with the material while making a stroke, the motor and clutch brake that are the drive source of the punch are The present invention is characterized in that the reciprocating stroke operation of the punch is repeatedly given a minute speed increase or decrease by controlling the operation of the punch.

Next, embodiments of the present invention will be described with reference to the drawings.

In the figure, l is a servo motor that is the stroke drive source for the punch in a mechanical press, and 2 is a crankshaft connected to the output end of the motor 1 with a reduction mechanism 3, a clutch 4, and a brake 5 interposed therebetween. A punch 6 for punching is attached to the shaft 2 via a connecting rod 2a.

7 is a die, 8 is a punched blank, and W is a material from which blank 8 is punched, and these constitute an example of a drawing section in a known mechanical press.

Therefore, the punching process using a conventional mechanical press is
Motor 1, clutch 4. While operating the brake 5, the punch 6 is operated to make a reciprocating stroke to punch out, for example, a blank 8 from the material W. In the present invention, a control system as described below is provided for such punching. , the operation of the motor 1, clutch 4 and brake 5 is controlled, and when the punch 6 is reciprocatingly stroked, the stroke speed is controlled in a minute range, so this point will be explained next. do.

In the figure, 9 is a rotation angle (number) detector mounted in relation to the crankshaft 2 and configured to detect, for example, 10 pulse signals per rotation angle J, and 9a is the rotation angle (number) detector 9. a rotational pulse processing unit 10 that processes a pulse signal supplied from the unit, for example, per unit rotational angle or as a current rotational angle;
is an oscillator that generates, for example, 100 pulse signals per second, 11 is the rotation speed of the crankshaft, and rotation angle (number)/
It can be set by a signal expressed in the form of unit time or time/unit rotation angle (number), or the operating conditions such as the stop position of the crankshaft, acceleration or deceleration position can be set by the rotation angle (number) of the crankshaft.
12 is a processing section that processes the signal representing the rotation speed of the crankshaft 2 set in the setting section 11 into an actuation signal for the drive section 13 of the motor 1;
The clutch 4.4 transmits a signal representing operating conditions such as the acceleration, deceleration or stop position of the crankshaft 2 set in the setting section 11, or the rotational speed of the crankshaft at these positions. This is a processing unit that processes the operation signal of the drive control unit 15 of each drive source 4a, 5a in the brake 5. When the control system is configured as an open loop control system, the rotation of the crankshaft 2 is controlled by the above system elements. and controls the operation of the punch 6.

For example, in the present invention, during the reciprocating stroke operation of the punch 6, the descending punch 6 punches the material W from just before it contacts the material W and reaches the bottom dead center, and then starts the upward stroke and the punch 6 moves toward the material W. The stroke speed of the punch 6 is slowed down in a minute range by a low frequency vibration until it separates from W, and this is done in the following manner in the above control system.

When the punching process in this press is performed under the conditions of a stroke number of 60 spm and a stroke amount of 100 mm, for example, in the vertical stroke of the punch 6,
During the period when the punch 6 contacts the material W, punches the blank 8 from the material, rises, and separates from the material W, the rotation of the crankshaft 2 is braked, for example, in units of 5 degrees of the rotation angle. These conditions are set in the setting section 11 so as to apply braking or to increase or decrease the rotation speed of the motor 1 per 5 degrees of rotation angle of the crankshaft 2.

Specifically, every time 50 pulse signals of 5 degrees are supplied from the rotation angle detector 9 from just before the punch 6 contacts the material W in the downward stroke, the drive source 5a of the brake 5 is controlled and released. Alternatively, the stroke operation of the punch 6 may be oscillatedly slowed by alternately rotating the crankshaft 2 in braking rotation and normal rotation in increments of a rotation angle of 5 degrees.

By controlling the rotation of the motor 1 at a slow speed every 5 degrees of rotation angle of the crankshaft 2, either synchronously with the operation of the brake 5 as described above or separately from the operation of the brake 5, vibrations are generated in the punch 6. Activate the stroke.

In the illustrated embodiment, in order to control the vibratory stroke operation of the punch 6 as described above by a closed loop system,
The control system was configured as shown in the figure.

In the figure, 16 is a current speed detection unit that detects the current rotational speed of the crankshaft 2 by associating the rotational pulse signal supplied from the rotational angle detector 9 with the time pulse signal supplied from the oscillator 10; Reference numeral 17 denotes a speed calculation unit that compares and calculates the current speed signal from the current speed detection unit 16 and the expected speed signal supplied from the setting unit 11, and 18 represents the expected rotation angle of the crankshaft 2 supplied from the setting unit 11. A rotation angle calculation unit that compares and calculates the signal and the current rotation angle signal supplied from the detector 9, and the deviation signals formed in these calculation units 17.18 are supplied to a processing unit 12.14. The set signal is corrected, and the corrected signal is sent to the drive unit 13. Since it is supplied to the drive control section 15, the drive section 13 due to this
, depending on the output of the drive control section 15, the brake 5, or
The operation of motors, etc. is controlled.

In this way, in the present invention, when punching with a mechanical press, the stroke-operating punch is made to perform a vibrating stroke-like motion, so that, for example, the plate thickness is large or the material is strong, so that good surface roughness can be achieved. Even with materials that are difficult to punch out, the punching process can be performed smoothly and efficiently.

Furthermore, the vibrating stroke-like action of the punch ensures that the punched blank falls downward, thereby preventing scraps from rising.

The present invention is as described above, and is extremely useful as a method for controlling the stroke operation of a punch in punching using a mechanical press.

[Brief explanation of the drawing]

The figure shows an example of implementing the method of the present invention, and is a block diagram of a control system. DESCRIPTION OF SYMBOLS 1... Motor, 2... Crankshaft, 3... Reduction mechanism, 4... Clutch, 5... Brake, 6... Punch, 7... Die, 8... Blank, 9... Rotation angle detector, 10... Oscillator, 11... Setting section, 1
2.14... Processing section, 13.15... Drive control section,
16... Current speed detection section, 17... Speed calculation section. 18...Rotation angle calculation section

Claims (1)

[Claims] During punching with a mechanical press, while the punch is in contact with the material while making a stroke, the operation of the motor and clutch brake that drive the punch are controlled to maintain a minute speed for the reciprocating stroke of the punch. A control method for punching in a mechanical press, characterized by repeatedly applying slowing and fastening.