JPS61297033A - Electric discharge machine - Google Patents

Abstract

PURPOSE:To eliminate wait time and enhance the processing accuracy by putting a pump control device and a heating control device in operation simultaneously a certain preset while prior to start of the electric discharge processing and by furnishing a timer to actuate heater and a processing liquid circulating pump. CONSTITUTION:A processing liquid circulating pump control device and a processing liquid temp. control device are put in operation simultaneously at a preset time prior to start of electric discharge processing, and a timer is furnished to actuate a processing liquid circulating pump P2 8 and a heater 7. The timer is actuated at the preset time before electric discharge processing to operate the processing liquid circulating pump P2 8 and heater 7. As the processing electrode 1, a work to be processed on a fixed electrode 2 or the fixed electrode 2 is heated to the specified temp. by the heated processing liquid 3, starting the processing at the specified time can be made with processing error due to temp. variation suppressed to possible minimum. This can eliminate wait time to lead to enhancement of the processing accuracy and reduction of working processes.

Description

[Detailed Description of the Invention] [Field of Industrial Application] The present invention relates to a control circuit for an electric discharge machining device, and particularly to a control circuit having a function of being able to set the start-up time of a heater control device and a pump control device. It is related to.

[Conventional technology]

FIG. 2 is a system diagram showing a conventional electrical discharge machining apparatus. In the figure, (1) is 1 for processing! pole, (2) Fi is a fixed electrode opposite to this that holds the workpiece, and an electrode that applies current to it; (4) is a machining tank filled with machining fluid (3); electrical discharge machining is performed in this machining tank ( 4) It is carried out in the machining liquid (3) filled in the inside. (5) is a tank for storing the machining fluid (3), and (6) is a machining fluid for supplying and circulating the machining fluid (3) from the machining fluid tank (5) to the machining tank (4). Circulation pump P1, (8) is a machining fluid circulation pump for circulating the machining fluid (3) between the machining fluid tank (5) and the heater (7) that heats the machining fluid (3) to a predetermined temperature. P2
, (9) At the liquid overflow port provided on the upper side of the processing tank (4), the processing liquid circulation pump P, (6) The processing liquid is supplied from the processing liquid tank (5) to the processing tank (4). When the machining tank (4) is almost full, the machining fluid (3) is returned to the machining fluid tank (5) from the fluid overflow port through the piping, and is passed between the machining fluid tank (5) and the machining tank (4). cycle. Ql) is a liquid drain pipe for returning the machining fluid (3) from the machining tank (4) to the machining fluid tank (5) when the workpiece is taken out or installed at the completion of electrical discharge machining. .

FIG. 3 is a control circuit diagram for controlling the temperature of the machining fluid (3) among the control circuits of the electrical discharge machining apparatus shown in FIG. 2 above. In the figure, % (6) # (7) # (8) corresponds to the corresponding parts in Figure 2, I is the main switch, Q is the processing fluid circulation pump P, (6) e P
,(s).

Stop switch to stop the heater (7), 0 row is the machining fluid circulation pump P, (6), P, (8) e Start switch to start the heater (7), I is the machining fluid circulation pump P, ( 6), P2(8).

Electromagnetic contactor MC, ~3a for operating the heater (7)
This is a relay that closes contact RA through which α7)K current flows and is self-held by RA2. A protection device is provided so that electrical discharge machining is stopped when the RA is not closed.

The conventional electrical discharge machining equipment f is constructed as described above, and its electrical discharge machining is performed, for example, as follows. Turn on the main switch aO, set the workpiece on the fixed electrode (2), and move the machining electrode (1) to set a predetermined discharge gap between the machining part of the workpiece and the machining electrode (1). Adjust the interval to , turn on the start switch I, and turn on the processing fluid circulation pump P
, (6), P2 (8), Plow the heater (7).

Then, the machining fluid (3) circulating through the machining fluid tank (5) and the heater (7) is heated to a predetermined temperature. This heated machining fluid (3) circulates between the machining fluid tank (5) and the machining tank (4). ) to heat the workpiece, the processing electrode (1), the fixed electrode (2), and the processing tank (4) to a predetermined temperature. After waiting for the temperature to reach a predetermined temperature, a start switch (not shown) of the electrical discharge machining apparatus is turned on, and the machining electrode is moved automatically or manually to perform electrical discharge machining. At this time, the workpiece set on the anode is eroded by the pulsed arc discharge and processed into a predetermined shape. When electrical discharge machining is completed, turn off the stop switch (not shown) on the main body of the electrical discharge machining device, turn off the stop switch a, and open the cock of the pipe Ql to drain the machining fluid (3). Return to step 5) and take out the workpiece. Electric discharge machining is performed in the same manner as above.

[Problem that the invention seeks to solve]

However, in the conventional electrical discharge machining equipment as described above, before starting electrical discharge machining, machining fluid (3) is supplied from the machining fluid tank (5) into the empty machining tank (4) and electrical discharge machining is immediately started. However, if you start electrical discharge machining immediately with machining fluid (3) in the machining tank (4), the machining fluid (3), machining electrode (1), workpiece, fixed electrode (2), etc. In addition, the temperature around the discharge gap and the temperature of other parts change over time, so it is difficult to perform electric discharge machining by converting the thermal expansion and thermal effects. This was a hindrance to electrical discharge machining.

Therefore, when starting electric discharge machining, the machining fluid (3) heated to a predetermined temperature by the heater (7) is circulated between the machining tank (4) and the machining fluid tank (5), and the machining electrode (1) is heated to a predetermined temperature by the heater (7). ), the workpiece, the fixed electrode, and its surroundings have to wait until the temperature reaches an allowable predetermined temperature.

This invention was made to solve this problem, and when starting electric discharge machining, the machining electrode (1), the workpiece, the fixed electrode (2), the machining fluid (3), and the It is an object of the present invention to enable electrical discharge machining to be started at a predetermined time, instead of waiting until something that has a strong influence reaches a predetermined temperature.

[Means for solving problems]

The present invention, which achieves the above objects, includes a machining electrode for performing electrical discharge machining, and a fixing device that faces the machining electrode and holds the workpiece facing the machining electrode while passing a current through the workpiece. An electrode, a machining tank that accommodates these electrodes and a workpiece, a machining fluid supplied to the machining tank to a level at which the machining electrode is immersed, and a machining fluid tank for storing the machining fluid. A machining fluid circulation pump that supplies and circulates the machining fluid from the machining fluid tank to the machining tank, a pump control device that controls the machining fluid circulation pump, and a heater that heats the machining fluid to a predetermined temperature. , in an electric discharge machining apparatus equipped with a heater control device for controlling the heater, and a control circuit for operating these, the pump control device and the heating control device are operated from a time set before the start of electric discharge machining. The present invention is characterized in that a timer is provided to operate the machining fluid circulation pump and the heater at the same time.

[For production]

A timer is provided that simultaneously operates the machining fluid circulation pump control device and machining fluid temperature control device from the time set before the start of electrical discharge machining, so that the machining fluid circulation pump and heating device operate. The machining fluid circulation pump and heating device are operated from a preset time, and at that time, the machining electrode, workpiece, and fixed electrode are heated to a predetermined temperature by the heated machining fluid. Even if electrical discharge machining is started at a certain time, machining errors caused by temperature changes are suppressed to a minimum.

〔Example〕

FIG. 1 is a control circuit diagram showing one embodiment of the present invention;
6) ~(8), (11) ~(IT)RA, ~
RA2C is completely the same as the control circuit diagram of the conventional electric discharge machining apparatus described above. Moreover, FIG. 2 is a system diagram showing the electric discharge machining apparatus according to the present invention, and is the same diagram as the conventional electric discharge machining apparatus.

In FIG. 1, Ql is a switch that is turned on when the electrical discharge machining device is to be operated as a conventional electrical discharge machining device, a is a switch for supplying current to the timer wire according to the present invention, and (2OA) is a switch for supplying current to the timer wire according to the present invention. This is a contact that comes into contact during operation, and is placed in parallel with RA3 in a conventional electrical discharge machining device.

The control circuit of the electrical discharge machining apparatus according to the present invention is configured as described above, and electrical discharge machining is performed, for example, as follows. Turn on the main switch αυ, set the workpiece in the same way as in the conventional case, turn on the timer start switch (1'J), and set the timer (A) to a predetermined time in consideration of the time to start electric discharge machining. Set the time. When the set time comes, the timer (A) will operate and the contact (20
A) is closed, Huntafta M CQ 啼, ([9, (lη
is excited, machining fluid circulation buttons P, (6) I and P2 (8) are activated and machining fluid (3) is activated.
) are the machining tank (4), the machining fluid tank (5), and the machining tank (4).
and the heater (7), and the heater (7) also operates to heat the machining fluid (3), so that the machining fluid (3), machining electrode (1), workpiece, and fixed The temperature of the electrode (2) etc. is also kept constant at a predetermined temperature.

In this case, a thermometer that can be used to confirm that the temperature has reached a predetermined temperature may be installed in the machining type (4).
3) When the scheduled time reaches the predetermined temperature, press the electric discharge machining start button (not shown) to generate arc discharge from the discharge gap between the machining electrode (1) and the workpiece,
The arc melts and evaporates the workpiece and forms it into a predetermined shape. In this way, when electrical discharge machining is performed at a constant temperature, the temperature changes.

The resulting machining errors are minimized.

In the above embodiment, a sequence control circuit using a relay is used, but a program control circuit using an NC control device or the like can also be automatically started by an external timer signal. Of course, it may be configured.

〔Effect of the invention〕

As described above, according to the present invention, when performing high-precision electrical discharge machining, the circulation (including supply) of machining fluid to the machining tank is automatically performed at a preset time, so that the discharge machining can be performed automatically. Supplying machining fluid into the machining tank at the start of machining (
It is possible to ignore thermal deformation in various parts of the electrical discharge machining equipment caused by As a result, it is effective in improving processing precision or reducing the number of work steps.

[Brief explanation of the drawing]

FIG. 1 is a control circuit diagram for controlling the temperature of the machining liquid in the control circuit of an electric discharge machining apparatus according to an embodiment of the present invention, FIG. 2 is a system diagram showing the present invention and a conventional electric discharge machining apparatus, and FIG.
The figure is a control circuit diagram for controlling the machining fluid temperature among the control circuits of a conventional electric discharge machining apparatus. In the figure, (1) is a processing electrode, (2) a fixed electrode,
(3) is a machining fluid, (4) is a machining tank, (5) is a machining fluid tank, and (e). (8) is a processing fluid circulation pump, (7) is a heater, C (1)
is a timer. In addition, the same symbols in the figures indicate the same or corresponding parts.

Claims (1)

[Scope of Claims] A machining electrode for performing electrical discharge machining, a fixed electrode that faces the machining electrode and holds the workpiece toward the machining electrode while passing a current through the workpiece, A machining tank that accommodates these electrodes and the workpiece, and a machining liquid that is supplied to the machining tank to a level where the machining electrode is immersed.
a machining fluid tank for storing the machining fluid; a machining fluid circulation pump for supplying and circulating the machining fluid from the machining fluid tank to the machining tank; a pump control device for controlling the machining fluid circulation pump; a heater that heats the machining fluid to a predetermined temperature; a heater control device that controls the heater;
In an electrical discharge machining apparatus equipped with a control circuit for operating these, the pump control device and the heater control device are operated simultaneously from a time set before the start of electrical discharge machining to control the machining fluid circulation pump and the heater. An electrical discharge machining device characterized by being provided with a timer that operates.