JPH04766B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to an electric discharge machining apparatus equipped with a sub-supporting device that assists a main supporting device for an electrode.

Electrical discharge machining equipment, which performs machining by placing a workpiece and an electrode facing each other at a predetermined distance in a machining fluid and applying a voltage pulse between the two to generate a discharge in the liquid, produces a desired shape on the workpiece. It is used in a wide range of fields because it can be processed in a short time.

Normally, during machining in electrical discharge machining equipment, the movement of the workpiece and electrode in opposing directions such as up and down is controlled by a servo to prevent abnormal arc discharge between the electrode and the workpiece. It is configured to be controlled by a control device.

However, in some cases, the above-mentioned processing feed of the electrode may not be performed accurately, and in particular, the electrode may become abnormally worn out because the processing feed under control is not performed without time delay. I have a problem. In addition, when processing a workpiece using a large electrode, the upper arm and column supporting the electrode must be enlarged, and furthermore, a drive mechanism for processing and feeding the electrode must be increased. Similarly, the output must be high, which increases the weight and increases the size of the entire device, making it impossible to control the machining feed with high-speed response.Furthermore, the center of gravity of the electrode is located at the head that supports the electrode. When it is offset from the center, an uneven load occurs, and the time lag with respect to the control signal for machining feed is large, resulting in a problem that the desired machining speed and machining accuracy cannot be obtained.

The present invention has been made based on the above-mentioned viewpoints, and its purpose is to accurately move the processing feed, etc. in opposite directions such as up and down of the electrode with little time lag, and to provide a center of gravity to the electrode. The present invention provides electrical discharge machining equipment that prevents abnormal wear of the electrodes by configuring it so that it can be operated without causing tilting of the electrodes or biasing loads even if there is bias, and that also allows the entire equipment to be made compact and lightweight. This is what we are trying to provide.

Therefore, the above purpose is to reduce the machining gap formed between the machining electrodes and the workpiece which are arranged opposite to each other.
In electrical discharge machining equipment, a voltage pulse is applied between a machining electrode and a workpiece with a machining fluid interposed between the workpiece and the workpiece to repeatedly generate a pulsed discharge, and a relative machining feed is applied between the two to perform machining. a main support device that has an electrode shank that supports a machining electrode and a drive mechanism that moves the electrode shank in its axial direction and provides machining feed to the machining electrode; and controls the operation of the drive mechanism of the main support device. a main servo controller,
A drive mechanism for moving each of the plurality of supporting arcs and the plurality of supporting arms in the axial direction of the electrode shank, which are integrally connected to the electrode shank and extend in a radially uniform manner about the axis of the electrode shank. a position detector for detecting the axial position of the electrode shank at each end of the plurality of support arms; a processing feed signal from the main servo controller and a detection signal from the position detector; This is achieved by providing an auxiliary servo controller that controls the operation of the plurality of drive mechanisms of the auxiliary support device in accordance with the above.

Embodiments of the present invention will be specifically described below based on the drawings.

FIG. 1 is an explanatory diagram showing one embodiment of the electrical discharge machining apparatus according to the present invention.

In Figure 1, 1 is the processing tank, 2 is the processing tank 1
3 is a workpiece, 5 is a machining electrode, 6 is an electrode shank, 7 is a head attached to a column of the electrical discharge machining apparatus main body (not shown) or an arm extending from the column; 30 is a main support device, 31 is housed inside the support device 30, and the electrode 5 is
main hydraulic cylinders, 32 and 3 that move up and down
3 is a sub-support device, 32a and 33a are sub-hydraulic cylinders, 32b and 33b are pistons, 32c and 33c are piston rods, 34 is an electrode shank 6
It has arms 34a, 34a, and the auxiliary hydraulic cylinders 32a and 3 are attached to the ends of the arms 34a, 34a.
A support arm is provided with holders 34b and 34b that are fitted into the tip portions of the piston rods 32c and 33c of 3a, 35 and 36 are hydraulic switching valves, 3
5a and 36a are solenoid coils, 35b and 36b are springs, 37 is a hydraulic pump, 38 is a hydraulic tank, 39 and 40 are the above-mentioned sub-support devices 32
and 33 are sub-servo controllers that control the main servo controller 47 to control hydraulic switching valves and flow rate adjustment valves (not shown) in the main support device 30, 41 and 42 are flow rate adjustment valves, 43 and 4
4 is attached to the tip portions of the auxiliary hydraulic cylinders 32a and 33a, and is located at the position of the piston rods 32c and 33c, that is, the arm 3 of the support arm 34.
Encoders 45 and 46 detect the positions of the ends of 4a and 34a, and 45 and 46 correspond to the encoders 43 and 44 described above.
This is an AD converter that converts the output into a digital signal.

Further, 29 is a machining fluid supply pipe, through which the machining fluid supplied under pressure passes through the inside of the electrode shank 6 and is supplied to the electrode 5.
It is ejected from the opening at the tip during machining.

Thus, the apparatus shown in FIG.
2 and 33 are driven by hydraulic cylinders via hydraulic switching valves, flow rate control valves, etc.

Electrode 5 attached to the tip of electrode shank 6
are opposed to the workpiece 3 with a predetermined gap therebetween, and voltage pulses are supplied between the two from a power supply device (not shown in the figure), and the machining progresses due to discharge erosion caused by this. During processing control feeding during processing, the distance between the electrode 5 and the workpiece 3 is controlled with a high speed response with little time lag, so that it is always maintained appropriately.

That is, the electrode shank 6 has two arms 34.
a, 34a, and a holder 34 at each end thereof.
A support arm 34 to which holders 34b and 34b are attached is fixed, and the respective holders 34b and 34b are fixed.
The piston rods 3 of the auxiliary hydraulic cylinders 32a and 33a are attached to the upper wall of the processing tank 1.
2c and 33c so that they are horizontally in the same plane.

Furthermore, encoders 43 and 44 are attached to the tip portions of the auxiliary hydraulic cylinders 32a and 33a.
The positions of the piston rods 32c and 33c are constantly detected, and the detected values are converted into digital signals by AD converters 45 and 46, and then sub-servo controllers 39 and 4
Enter 0.

Therefore, when the main servo controller 47 sends a drive signal to the hydraulic switching valve and flow control valve (not shown) of the main support device 30, the sub servo controller 39
and 40 to send drive signals to the hydraulic switching valves 35 and 36 and flow rate adjustment valves 41 and 42 that operate the sub-support devices 32 and 33. Hydraulic switching valves 35, 36 and flow rate adjustment valve 41 that received this signal,
42 is an auxiliary hydraulic cylinder 32a based on the above signal.
and 33a to move the piston rods 32c and 33c up and down, the support arm 34 is moved up and down via the holders 34b and 34b, and the main support device 30
The sub-support devices 32, 33 are synchronized with the machining feed by
Processing feed is also performed by. In addition, the weight of the electrode 5 and the deviation of the center of gravity of the holders 34b, 3
The inclination of 4b with respect to the horizontal plane is detected by encoders 43 and 44, which are position detectors. The sub-servo controllers 39 and 40 operate the hydraulic switching valves 35 and 36 and the flow rate adjustment valves 41 and 40 in response to this inclination detection signal.
42 to move the pistons 32b, 32b so that the holders 34b, 34b attached to the ends of the arms 34a, 34a and fixed to the piston rods 32c, 32c are always located in a horizontal plane. Therefore, due to the operation of the sub-support devices 32 and 33, the feed load on the main hydraulic cylinder 31 is reduced by the feed load on the sub-hydraulic cylinders 32a and 33a, and the center of gravity of the machining electrode 5 is aligned with the electrode shank. Even if the machining electrode 5 is deviated from the axis of the machining electrode 6, the machining electrode 5 is always held in the correct posture without tilting, and there is no biased load on the main support device, so machining feed can be carried out smoothly and with good responsiveness. At the same time, highly accurate machining can be performed.

Since the present invention is configured as described above, when the electric discharge machining apparatus according to the present invention is used, it is possible to perform machining in the opposite direction to the workpiece, such as above and below the electrode, regardless of an increase in the weight of the electrode or a deviation in the center of gravity. Movement such as feeding can be performed smoothly with good response without causing biased loads, and the machining electrode can be prevented from tilting to perform highly accurate machining, and the entire device is compact. Moreover, it can be configured to be lightweight.

It should be noted that the present invention is not limited to the embodiments described above.

That is, for example, in this embodiment, the electrodes are moved by a hydraulic cylinder, but the drive mechanisms for the main support device and the sub-support device are each configured by a feed screw mechanism whose rotation is controlled by a motor. You may also do so. As for other mounting positions and methods of the electrode and hydraulic cylinder, for example, three or four or more sub-supporting devices may be arranged and operated so that the supporting position of the main supporting device is the center of equilibrium without any biased load. Alternatively, the method of supplying the machining fluid and the method of controlling each part can be freely changed in design within the scope of the object of the present invention, and the present invention encompasses all of them.

[Brief explanation of drawings]

FIG. 1 is an explanatory diagram showing one embodiment of the electrical discharge machining apparatus according to the present invention. DESCRIPTION OF SYMBOLS 1... Processing tank, 2... Load stage, 3... Workpiece, 30... Main support device, 5... Electrode, 6...
Electrode shank, 7... Head, 32, 33... Sub-support device, 34... Support arm, 47... Main servo controller, 32a, 33a... Sub-hydraulic cylinder,
35, 36... Hydraulic switching valve, 35a, 36a...
Solenoid coil, 35b, 36b... Spring, 39, 40... Sub-servo controller, 41, 42
...Flow rate adjustment valve, 43, 44...Encoder, 4
5,46...AD converter.

Claims (1)

[Claims] 1. A voltage pulse is applied between the machining electrode and the workpiece with machining liquid interposed between the machining electrode and the workpiece that are arranged opposite to each other. In electrical discharge machining equipment that performs machining by repeatedly applying a pulsed discharge and applying a relative machining feed between the two, an electrode shank that supports a machining electrode and the electrode shank are moved in their axial direction. a main support device that has a drive mechanism and provides machining feed to a machining electrode; a main servo controller that controls the operation of the drive mechanism of the main support device; a sub-support device having a plurality of support arms extending in a radially uniform shape around the center, a drive mechanism for moving each of the plurality of support arms in the axial direction of the electrode shank, a position detector that detects the axial position of the electrode shank at the end, and operation of a plurality of drive mechanisms of the sub-supporting device in response to a processing feed signal from the main servo controller and a detection signal from the position detector. An electrical discharge machining device comprising: a sub-servo controller for controlling the servo controller. 2. The electric discharge machining apparatus according to claim 1, wherein the drive mechanism of the main support device and the plurality of drive mechanisms of the sub-support device are constituted by hydraulic cylinders. 3. The electric discharge machining apparatus according to claim 1, wherein the drive mechanism of the main support device and the plurality of drive mechanisms of the sub-support device are constituted by a feed screw mechanism whose rotation is controlled by a motor.