JPS6144528A - Electric discharge machine - Google Patents

Abstract

PURPOSE:To sufficiently obtain the pumping effect due to the vertical movement of an electrode by installing an electrode vertical-movement position controller for setting either of the starting position or the completion position of the electrode vertical movement at the lowest point in work. CONSTITUTION:As for an electric discharge machine, an apparatus for setting the completion position of the vertical movement of an electrode at the lowest point in work has a linear scale 47 for detecting the present position of a working electrode 1 on the side of the working electrode 1, and among the detection signals during electric discharge work, the lowest-point position of the electrode is memorized into a peak hold circuit 49, and that position and the present position of the electrode are compared in a comparator 51, and when the both values coincide with each other, a signal for stopping the vertical movement of the electrode is outputted into an electrode controller 35 from the comparator 51. In other words, since the working electrode 1 always stops at the lowest position in the work, the pumping effect of the electrode in working liquid increases, and working chips in the gap between the electrodes can be speedily removed.

Description

[Detailed Description of the Invention] a. Field of Industrial Application ゛The present invention relates to an electric discharge machining device, and more particularly, to an electric discharge machining device equipped with a control device for the start position and end position of an electrode during vertical movement. .

b. Conventional technology: Electrical discharge machining equipment generally uses ;JO in an insulating machining fluid.
The machining electrode and the workpiece are placed facing each other, and a pulsed electric discharge is generated to melt and remove the surface of the workpiece to perform the desired machining. It consists of a servo drive device that can be adjusted freely, a processing power source, etc.

By the way, in electrical discharge machining, machining debris melted and removed from the workpiece is scattered in the machining fluid, and if the electrode gap becomes clogged with machining debris, the discharge condition deteriorates and tends to shift to abnormal discharge. Debris is typically removed by suction, jets, or the like. However, in cases where suction or jet treatment is difficult, such as electric discharge machining in a blind hole, the machining process is usually progressed by rapidly moving the electrode up and down (electrode jump operation) to remove machining debris.

C0 Problems to be Solved by the Invention As mentioned above, processing waste is removed by the bombing effect caused by the vertical movement of the electrode, but this effect differs depending on the start and end positions of the vertical movement of the electrode. That is,
When the electrode moves up and down from the lowest point of machining, the pumping effect is great and removal of machining debris is good, but when the electrode moves up and down from the middle position of machining, the pumping effect is small and the machining Debris removal is poor. Furthermore, even when the electrode is moved up and down from an intermediate position during machining, if the end of the up-and-down movement is at the lowest point of machining, the pumping effect is large and the removal of machining debris is good.

Means for Solving Problem d3 In view of the above points, this invention always sets the start position of the vertical movement of the electrode to the lowest point of machining, or sets the end position of the vertical movement of the electrode to the lowest point of machining. The gist of the configuration is that an electrode vertical movement position control device is provided to bring the electrode to the lower point.

01 Function Since the structure is as described above, a sufficient pumping effect due to the vertical movement of the electrodes can be obtained, processing debris in the electrode gap is effectively removed, and the electrode gap quickly returns to its normal state. , transition to or continuation of abnormal discharge can be prevented.

f. Example Next, an example of the present invention will be described based on the drawings. FIG. 1 is a block diagram of an electric discharge machining apparatus using the present invention. In this electrical discharge machining apparatus, a machining electrode 1 and a workpiece 3 face each other, forming an electrode gap 5. The processing electrode 1 is driven by a motor 7. A processing power source 9, a current control resistor 11, and a switching cable 1 that generates processing pulses in the electrode gap 5 are installed at both ends of the processing power source 1 and the workpiece 3.
3 series circuits are connected in parallel. Said switching element 13 is controlled by a pulse generator 15. Further, a detection resistor 17 is connected to both ends of the machining electrode 1 and the workpiece 3 to detect the voltage between the machining electrodes 1 and the workpiece 3. A discharge state determining device 19 (using the discharge machining device disclosed in Patent Application No. 59-003658 of 1982) is connected between the detection resistor 17 and the workpiece 3.

The terminal that outputs the number of abnormal discharge waveforms provided in the discharge state determination device @19 and the terminal that outputs the number of discharge waveforms when the electrode gap is in a contaminated state are connected to the m pole vertical movement command signal device 2.
1, and the logical sum of the numbers of both waveforms is output to the counter 25. The output A of the counter 25 is input to the comparator 27 and compared with the reference value B.
When it is greater than that, an H level signal is output to one input terminal of the AND element 29. On the other hand, the preset counter 31
A pulse is input from the pulse generator 15,
When the number of pulses C corresponding to the set time is counted, an H level signal is output to the other input terminals of the two AND elements. Therefore, the sum A of the number of different discharge waveforms within the set time and the number of discharge waveforms when the electrode gap is contaminated is:
If it is greater than the reference value B, the AND element 29 outputs a signal of 1-Levels to the electrode vertical movement position control device 37 of the present invention.

FIG. 2 shows an example thereof. This device is
It consists of two devices: a device whose lowest point is the start position of the vertical movement of ~, and a device whose lowest point is the same end position. The device that sets the starting position of the vertical movement of the electrode as the lowest point of machining has a resistor of 3
9. B consists of a capacitor 41, a comparator 43 and an AND element 45, and the end position of the electrode vertical movement is the lowest point of machining.
The position is 9, near scale 47, peak hold circuit 4
9 and a comparator 51.

The device that sets the starting position of the vertical movement of the electrode to the lowest point of machining is
It utilizes the correlation between the electrode gap and the voltage between the electrodes, and the voltage between the electrodes detected by the detection resistor 17 is averaged by the resistor 39 and the capacitor 41, and compared with the set voltage 1 in the comparator 43, which is smaller than Vl. Sometimes, AND
An H level signal is output to one input terminal of the element 45. The other input terminal of the AND element 45 is connected to the AND cable 2 of the electrode vertical movement command signal device.
Since the output terminal of the ANDX element 45 is connected to the electrode control device 35, the starting position of the vertical movement of the electrode is the lowest point of processing determined by V+, and a sufficient pumping effect can be obtained. can get.

The device that makes the end position of the vertical movement of the electrode the lowest point of machining is
A linear scale 47 is provided on the side of the machining electrode 1 to detect the current position of the machining electrode, and the lowest point position of the electrode is stored in the peak hold circuit 49 among the detection signals during electric discharge machining, and the position and the position of the electrode are stored in the peak hold circuit 49. The current position is compared by the comparator 51, and when the two match, the comparator 5
1, the electrode control device 35 outputs a stop signal for vertical movement of the electrode. That is, since the machining electrode always stops at the lowest point of machining, the electrode's bombing effect in the machining fluid increases, and machining debris in the gap between the electrodes is rapidly removed.

Note that this invention can be implemented in embodiments other than the examples.

0. Effects of the Invention As understood from the above explanation, this invention has the structure set forth in the claims, so it is possible to obtain a sufficient pumping effect due to the vertical movement of the electrode, and to prevent abnormal discharge. It is possible to provide a IIIi electrical processing apparatus that prevents the transition or continuation of the above.

[Brief explanation of the drawing]

FIG. 1 is a block diagram of an electric discharge machining apparatus using the present invention, and FIG. 2 is a block diagram of the present invention. (Explanation of symbols representing main parts in the drawings) 1... Machining electrode, 3... Workpiece 5... Electrode gap 13...
・Switching element 15...Pulse generator 17...
・Detection resistor 19...Discharge waveform discrimination device selection 21...Electrode vertical movement command signal device 29...AND element 35...Electrode control device 37...Electrode vertical movement position fli control device 39... Resistance 41... Capacity 43... Comparator 45...
・AND element 47...Linear scale 49・
・Peak hold circuit 51 ・Comparator (1 piece with scratches)

Claims (1)

[Claims] An electric discharge machining apparatus characterized by being provided with an electrode vertical movement position control device 37 that sets the starting position and end position of the electrode during vertical movement to the lowest point of machining of the electrode.