JPS6156823A - Electrode feeding control in electric discharge machine - Google Patents

Abstract

PURPOSE:To achieve rational electrode feeding control in electric discharge machine by detecting the voltage across the gap of electrodes and comparing with a referential level and stopping or moving the electrode. CONSTITUTION:An operator will set the machining conditions Ip, Ton, Toff, etc. through input section 21 then said conditions are set in CPU23 and discharging energy providing unit 27 while stored in memory 25. CPU23 will operate the referential voltages Vref1, Vref2 on the basis of said machining conditions and provide to a unit 27 having a machining condition detector and electrode feeding direction deciding means. Memory 25 is storing values corresponding with unit movement DELTAX optimal for various machining conditions while a unit 23 will retrieve the memory 25 on the basis of the setting machining conditions to decide the movement DELTAX which is provided to the unit 27 in motion command pulse generator thus to determine the referential voltages Vref1, Vref2 and the unit movement DELTAX automatically.

Description

DETAILED DESCRIPTION OF THE INVENTION a. Field of Industrial Application This invention relates to an electric discharge machining apparatus, and more particularly to a method of controlling the feed of an electrode in an electric discharge machining apparatus.

b. Conventional technology In electric discharge machining, the gap between the tool electrode and the workpiece (hereinafter referred to as the electrode gap) widens as machining progresses, so in order to keep this electrode gap constant, an electric or hydraulic servo mechanism is generally used. It is used.

In this case, the 'F1 electrode gap is detected indirectly by sensing the average voltage across the electrode gap, and by comparing this average voltage with a separately determined /Cl quasi-voltage, the electrode gap corresponding to the reference voltage is determined. This means that it has been adjusted. Also, when moving the electrode using a servo such as 414, 1. - When the command is J:, the amount of movement to move the electrode forward or backward (
(hereinafter referred to as unit movement amount) is generally constant.

Problems to be Solved by the Invention As mentioned above, conventionally, the electrode gap is indirectly detected by the average voltage of the electrode gap, and a servo mechanism is used to adjust this average voltage to the reference voltage. However, the average voltage across the electrode gap is the pulse interval width TO, rest time TO or
It is a function of r, and changes depending on their relative magnitude. Therefore, the reference voltage is Ton, Tor
It should be set in consideration of working conditions such as r.

In addition, if the servo (electronic) is to be moved due to the structure, etc.,
It is generally accepted that the unit movement speed of the electrode should be small for finishing machining and sharp for rough machining.

The purpose of this invention is to improve the problems of the prior art as described in Section 11a, and to provide a more rational electrode feed control method for electrical discharge machining equipment that meets the machining conditions. .

d. Means for Solving the Problem In order to accomplish the above object, the present invention calculates a reference voltage across the electrode gap based on set processing conditions, and detects the voltage across the electrode gap; The gist of the 1111 configuration is that the detected voltage of the electrode gap is compared with the reference voltage of a) a) small gap between the electrodes, and the electrodes are made to stand still or move.

e. Effect This invention is configured as described above, and in electrode feed control, the reference voltage of the electrode gap, which is a reference for comparison, is calculated from the set machining conditions, so that an accurate reference voltage that matches the machining conditions is calculated. Electrode feeding control is performed by.

f　　　　　　　　　　1 row Next, an actual MG example of the present invention will be explained based on the drawings.

FIG. 1 is a block diagram of an electrode feeding device 1 using the present invention. As shown, the electrode gap 3 formed by the tool electrode and the workpiece is adjusted by a DCC servomorph. A tachogenerator (TG) 7 and an engine (E) 9 are attached to the morph axis.The voltage generated by the tachogenerator (TG) 7 is adjusted to the command speed by a speed control servo amplifier 11. The rotational speed of the servo motor is controlled until the difference between the two becomes approximately zero.

The encoder pulse of encoder (E) 9 is (2-phase signal)
is output at fixed angle intervals in proportion to the rotation angle of the servo motor 5, so it is guided to the deviation counter 15 along with the motor rotation command pulse output from the movement command pulse generator 13, and the deviation between both pulses is calculated. Be taken. Ii; Since the output of the difference counter 15 is equal to the deviation between the command angle of the movement command pulse generator and the rotation angle of the servo motor, D/
The A converter 17 converts it into an analog voltage, and the PID calculator (
(not shown), the command speed of the speed servo system is controlled, and the servo motor 5 is rotated until the output of the deviation counter 15 becomes zero.

The machining state detection and electrode feeding direction determining device 19 detects the machining state of the electrode gap 3 and also controls the advancement of the electrode, which will be described later.
It determines whether the vehicle is stationary or backward, and outputs the determination result to the movement command pulse generator 13. This feed direction determination device detects the average voltage vav of the electrode gap, and the reference voltages vref+ and Vr determined by the processing conditions.
cr2 (no-load voltage > Vrer 2 > Vrer l
) and the average voltage Vav, and V av > V
Advance the electrode when rcf 2, and VrcJ 2 >V
When av>Vrer 1, stand still, Vav<Vre
When r+, it is necessary to make decisions such as retreating.

In this case, the reference voltage Vref and Vrcr2 are determined as follows. Assume that the discharge energy is given by a constant rectangular voltage pulse, the pulse duration is TOn, the pause time is TO'[, the average voltage of the electrode gap in TOn is Ton=a, and the average voltage of the electrode gap in Torr is Let the average voltage be Toff=b.

(Usually, a is set to 30V and b is set to about 5V.) Assuming that the discharge is occurring under ideal conditions, and assuming that the average voltage across the electrode gap is T avo, then 7avo = (a xTo
n+b xTorr ) / (Ton+Toff >
becomes. Base #=Lightning voltage rer I, Vrcr2 is
This vavO and the following relationship vror I <vavO<
Vrer 2, processed yarn f
't-Ton, it changes depending on ToH.

The movement command pulse generator 13 outputs a movement command pulse at fixed intervals C1 based on detection of the machining state and forward, stationary, and backward commands from the electrode feeding direction determining device 19. Medium shift J fast △ corresponding to the movement command pulse output here
× means C can be changed depending on processing conditions. for example,
Under finishing machining conditions where the lightning energy is small, △× is made small, and under rough machining conditions, it is made concise to increase machining efficiency.

The reference voltages Vrel' + and Vrcr 2 described above
and x to instep movement suspension are calculated or searched and automatically set by the central processing unit (CPU), and then
Input unit (MD I) 21 shown in block diagram in the figure;
Central processing unit <CPt, In 23, memory 25, and discharge energy supply device (equipped with electrode feed υj equipment)
The explanation will be given using an electric discharge machining apparatus consisting of 27.

First, the operator sets processing conditions (I p , Ton, To, etc.) using the input unit (MID) 21.

These machining conditions are set in the central processing unit 23 and, via the central processing unit 23, in the discharge energy providing device 27, and are also stored in the memory. The central processing unit 23 calculates the reference voltages vrerl and Vrer2 from the set processing conditions,
The machining state is detected and outputted to the discharge energy supply device 27, which is equipped with one electrode feeding direction determination device. Also memory 2
5 stores the optimal corresponding value of Δ× for various additions: 11 conditions, and the central processing unit 23 searches the memory 25 to determine the value of Δ× according to the set machining conditions.
× is determined, and the discharge energy 1, which is equipped with the movement command pulse generator 13, is placed in the clam 27 and then output in the evening. 1
By setting the machining conditions by the operator, it is possible to automatically set the standard voltages Vror, , Vrer 2 and the movement amount ΔX.

Effects of the Invention As can be understood from the above explanation, the present invention has the configuration described in the claims, so that the movement of the electrode can be made more rational by using the reference voltage of the electrode gap that matches the processing conditions. A method for controlling electrode feeding in an electrical discharge machining apparatus can be provided.

[Brief explanation of drawings]

FIG. 1 is a block diagram of an electrode feed control 1211 device that utilizes the present invention, and FIG. 2 is a block diagram of an electric processing machine that utilizes the present invention. (Explanation of symbols that do not represent the main parts in the drawings) 1... Electrode feed control'!A position 3... Electrode gap 5... DC servo motor 7... Tacho generator 9... Encoder 11... Speed control servo amplifier. 13... Movement command pulse generator 15... Deviation counter 17... D/A converter 19... Machining state detection, electrode feeding direction judgment device 21
...Input section (MDI) 23...Central processing unit (CPIJ) 25...Memory 27...Discharge energy supply device agent Patent attorney Yasu Miyoshi Otoko: Mei Figure 1 Figure 2 Procedures Correction power November 2z, 1980 Manabu Shiga, Commissioner of the Patent Office1, Indication of the case Japanese Patent Application No. 176633/19832, Name of the invention M Electrode feed control method for electrical processing equipment 3.7+i Case of a person who makes a correction Relationship with Patent applicant address (residence) 200 Ishida, Isehara City, Kanagawa Prefecture Name (
Name) AMADA Co., Ltd. Representative: Ten 1) Akira Mitsuru 4, Agent address: 1-2-3 Toranomon, Minato-ku, Tokyo 105
@Toranomon Dai- Building 5th floor 5, Subject of amendment (1) Detailed description of the invention column for specification, 6, Contents of amendment (1) At the beginning of the first line of page 2 of the Memorandum, [gap (hereinafter ``What is the electrode gap?'' is corrected to ``The gap state (hereinafter referred to as the electrode gap) is''. (2) On page 2, page 211 of the same page, the phrase [because . (3) In the fourth line of page 2, the phrase ``In this case, the gap between the electrodes is'' should be corrected to ``In this case, the gap between the electrodes is''. (4) Page 3, lines 10 to 11, page 3, line 17
In lines 181j to 181j and page 3, line 19, "reference voltage" is corrected to "base! ((voltage and unit shift! between II and II"). Page 1st line ~ II; 1st page 2nd line, rPI
``Followed by D extractor (not shown),'' was deleted. (6) In page 6, line 15, 1], the phrase "varies depending on processing conditions" is corrected to "depending on processing conditions (varies automatically"). (7) Page 7, line 8 ( In 7 and 1, correct rM[DJ to MDIJ.

Claims (2)

[Claims] (1) Based on the set processing conditions, calculate the reference voltage of the electrode gap, detect the voltage of the electrode gap, compare the detected voltage of the electrode gap with the reference voltage of the electrode gap, and stop the electrode. Alternatively, a method for controlling electrode feed of an electrical discharge machining device, characterized by causing the electrode to move. (2) An electrode feed control method for an electric discharge machining apparatus according to claim 1, characterized in that the unit movement amount of the electrode is set based on machining conditions.