JPH0825100A - Operating method of press - Google Patents

Abstract

PURPOSE:To provide an operating method for obtaining a fine cut shape in a mechanical press using a servomotor. CONSTITUTION:A ram 13 of the press which is driven with a servomotor 7 is moved at a prescribed speed from the top dead center position of an effective stroke and approached to the surface of a work. After completion of the approaching stage, the work is plastically worked by continuously accelerating the ram starting from the approaching speed. After completion of the working stage, the ram 13 is stopped at the bottom dead center position for a preset time. After completion of the stop stage, the ram 13 is upward moved from the bottom dead center position at a prescribed speed slower than the moving speed in the cutting stage.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an operation control method for a pressing apparatus suitable for trimming or bending a thin plate such as a semiconductor lead frame.

[0002]

2. Description of the Related Art In punching and bending a semiconductor lead frame, a hydraulic press has been conventionally used as a measure against noise. However, due to the recent trend toward higher densities in semiconductors, the clean conditions for the manufacturing process are becoming more and more stringent, and from this relationship, instead of hydraulic presses, which have factors that obstruct clean conditions such as oil smoke, Type press is used (Japanese Patent Laid-Open No. 3-334).
No. 39).

[0003]

In the above-mentioned conventional mechanical press, operation control is performed so that the ram moving speed during processing is slower than the ram moving speed during approaching. However, during the cutting work in the press, there is a problem that sagging or burrs are likely to occur on the cut surface of the work piece (workpiece) if the work is performed at a slow speed. It is an object of the present invention to provide an operating method capable of obtaining a clean cutting shape in a mechanical press using a servo motor, focusing on such a point.

[0004]

In order to achieve the above-mentioned object, the present invention relates to the operation cycle of a mechanical press using a servomotor, and a ram having a tool arranged at the tip end of an effective stroke. An approaching step of moving the workpiece from the top dead center position at a predetermined approaching speed to approach the surface of the work; a machining step of continuously accelerating the approaching speed to plastically work the work piece after completion of the approaching step; After the end, the stopping step of stopping the ram at the bottom dead center position for a preset time, and the separation step of moving the ram upward from the bottom dead center position at a constant speed slower than the moving speed in the cutting step after the stopping step is completed. It is characterized by being composed of and.

[0005]

In the present invention, since the ram moving speed during machining is set to be faster than the ram moving speed during approaching and separating, the fracture surface at the cutting surface of the work is reduced,
You can get a beautiful cut surface without sagging or burrs.

[0006]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS FIG. 1 shows an embodiment of the present invention, FIG. 1 is a graph showing the locus of movement of the ram of the present invention, and FIG. , Fig. 3
Is a front view of the main part. This mechanical press machine (1) has a structure in which the input shaft (2) and the output shaft (3) have a common shaft core.
This reducer (4) has its (4) input shaft (2)
The connecting plate (5) is attached in such a manner that it projects to the front side. And the output shaft is also attached to this connecting plate (5).
The servo motor (7) is attached with (6) protruding to the front side, and the output shaft (6) of this servo motor (7) is connected to the input shaft (2) of the speed reducer (4) by the timing belt (8). It is connected. That is, the output shaft (6) of the servo motor (7) is in parallel with the input shaft (2) of the speed reducer (4) and in the same direction.

Further, the output shaft (3) of the speed reducer (4) is connected to the crank shaft (9) supported by bearings (8) and (8) together with both shaft cores. Specifically, the crankshaft (9)
A connection hole (9j) is bored at one end of the shaft, and the output shaft (3) of the speed reducer (4) is fitted into the connection hole (9j) for keying.
This crankshaft (9) has a disk-shaped crank arm (1
(0), a connecting rod (12) is connected to the crank arm (10) through a crank pin (11), and a ram (13) is attached to the connecting rod (12) at its proximal end. It is connected in 14).

The ram (13) is a mounting plate for incorporating the mechanical press device (1) into a transfer processing device or the like.
Linear bearings (1) provided in guide holes (16) of (15)
The outer peripheral surface of the tip is regulated by 7), and the arrow X indicates according to the rotation of the crankshaft (9) by the rotational driving force of the servomotor (7) while being regulated by the linear bearing (17). It is designed to move forwards and backwards. In addition,
An oil seal (18) is provided at the tip of the guide hole (16) to prevent the lubricant from flowing out of the case.

In this mechanical press device (1), the full stroke (S) of the ram (13) by the rotation of the crank arm (10) is performed.
In t), the lower movement area is formed as an effective stroke (Se), and the middle part of the effective stroke (Se) is used for cutting. And, in this mechanical press machine (1), the operation control is performed by a servo motor.
Based on the rotation of the motor obtained by the resolver (7r) attached to (7) and the current value data of the servo amplifier, speed control and torque control of the servo motor (7) are combined. During the entire stroke (St),
The upper half is a stroke for changing molds.

FIG. 1 shows the relationship between time and ram movement. The horizontal axis represents time (T) and the vertical axis represents ram stroke. The movement of the ram (13) will be described below with reference to FIG. Initially, the ram (13) is at the top dead center position (mechanical origin) determined by the mechanical mechanism shown in FIG. This position is the ram (1
It is the position where jigs are attached to the tip of 3) and work is prepared.

When the press mechanism starts operating, the ram (13)
Is the work preparation position (A) which is the top dead center of the work from the mechanical origin
Move at a preset speed. With the ram (13) stopped at the work preparation position (A), the work is set at a predetermined position on the upper surface of the lower mold, and the start switch (not shown) is operated to start the work. The ram (1
In 3), the work is moved down at a predetermined speed set in advance to a machining work starting position (B) which is separated from the work surface by a certain height. The ram moving speed (approaching speed) in the approaching process of moving the ram from the work preparation position (A) to the processing work starting position (B) is initially high, and the punch (die) attached to the tip of the ram (13) The ram movement curve is set to be a quadratic curve by setting the speed to a low speed just before the contact with the work. Here, the initial high speed is for shortening the idle time, and the low speed is set at the working start position (B) for reducing the collision noise between the punch and the work as much as possible.

When the ram (13) reaches the machining start position (B),
The moving speed of the ram (13) is switched to the high speed again, and the machining process is started. The processing speed at this time is set higher than the approach speed. When the amount of movement of the ram (13) exceeds the thickness of the work, the ram (13) is decelerated and the ram (13) moves to the bottom dead center position (C).
When the ram (13) reaches the bottom dead center position (C), the ascending and descending movement of the ram (13) is stopped for a certain period of time to maintain that state, and when the stopping process for a certain period of time is completed, the ram (13) is lowered. It moves from the dead center position (C) to the work preparation position (A) at a predetermined separation speed.

The processing start position (B) is detected by detecting the amount of movement of the ram (13) by a signal from a resolver (7r) attached to the servomotor (7). . The processing speed is controlled so that the acceleration increases linearly at a predetermined rate. Further, the separation speed of the ram is set to be slower than the processing speed, and is set to almost the same speed as the approach speed when the ram moves from the work preparation position (A) to the processing start position (B). The resolver
By using an absolute encoder instead of (7r), it is also possible to perform easier-to-use control.

[0014]

According to the present invention, the ram moving speed during machining is set to be higher than the ram moving speed during approaching and separating, so that the fracture surface at the cutting surface of the work is reduced. You can get a beautiful cut surface without sagging or burrs.

[Brief description of drawings]

FIG. 1 is a graph showing a locus of movement of a ram according to the method of the present invention.

FIG. 2 is a partially longitudinal side view showing an example of a mechanical press used for implementing the present invention.

FIG. 3 is a front view of a main part of a mechanical press.

Claims (1)

[Claims] 1. A method of operating a press machine in which a ram having a tool at its tip is driven by a servomotor via a power transmission mechanism, wherein a ram having a tool at its tip is placed on an effective stroke. An approaching process of moving from the dead center position at a predetermined approaching speed to approach the surface of the work, a machining process of continuously accelerating from the approaching speed to plastically work the work after the completion of the approaching process, and a finishing process After that, there are a stopping process that stops the ram at the bottom dead center position for a preset time, and a separation process that moves the ram upward from the bottom dead center position at a predetermined speed slower than the moving speed in the cutting process after the stopping process ends. How to operate a press machine.