JPH01115515A - Controller for electric discharge machine - Google Patents

Abstract

PURPOSE:To improve machining accuracy and efficiency, in a controller for electric discharge machine where control is made according to recognition result of inter-pole voltage, by making machining control properly corresponding to the type of selected machining mode. CONSTITUTION:A controller recognizes machining condition through a machining condition recognizing circuit 9 based on an output signal from an inter-pole voltage detection circuit 8 for detecting the voltage between an electrode 1 and a work 2, then operates a machining control circuit 13 properly corresponding to the recognition result and carries out machining control. A recognition device 9 in the controller lecognizes machining condition of normal discharge A, arc discharge B, shortcircuit C and abnormal average D, and outputs signals. 9A-9D which are fed to a high speed processing line 11 and a controller 10. The controller 10 provides an operation mode command to the machining control circuit 13 according to a machining mode selected through a machining mode selector 12 from such machining modes as interpolation, interpolation rolling, plane rolling, electrode rotation and the like and operates the machine.

Description

[Detailed description of the invention] [Industrial application field].

The present invention relates to a control device for an electric discharge machine that identifies a machining state by detecting a voltage between machining electrodes and controls machining appropriately according to the identification result.

[Conventional technology]

Conventionally, there have been various types of devices of this type. For example, abnormal machining conditions such as arc discharge, short circuit, no discharge, or average value abnormality may cause devices that control the pulse width and pulse energy of machining pulses, or control the direction and speed of machining feed to fail. there were.

Conventional equipment can perform linear interpolation, circular interpolation, interpolation oscillation,
Regardless of the type of machining mode selected, such as plane swing, certain predetermined control is performed at a certain abnormal machining state.

[Problem that the invention seeks to solve]

However, with such conventional equipment, as mentioned above, machining is controlled uniformly regardless of the type of machining mode, so depending on the selected machining mode and machining conditions, machining accuracy may increase, but machining efficiency may decrease. There were problems in that the value could go down, or vice versa, or even both could be damaged.

The present invention has been made in order to solve the above-mentioned problems, and is an electric discharge machine for electrical discharge machines that can control machining more appropriately depending on the selected type of machining mode and improve machining accuracy and machining efficiency. The purpose is to provide a control device.

[Means for solving problems]

The present invention operates a machining control circuit according to a selected machining mode, and when controlling machining based on a machining state identification result, machining is controlled in an operation mode preset according to the type of the selected machining mode. It is something.

[Effect]

The optimal operation mode for each combination of machining modes such as linear interpolation, circular interpolation, interpolation oscillation, plane oscillation, and electrode rotation, and machining conditions such as normal discharge, arc discharge, short circuit, average value abnormality, and no discharge ( Each control such as machining pulses, machining feed, and electrode retraction, and the combination of control contents) are determined through experiments, and the machining is controlled by the controller in accordance with these. As a result, normal discharge efficiency is increased in any machining mode, and machining accuracy and machining efficiency can be improved at the same time.

〔Example〕

Hereinafter, the present invention will be described in detail with reference to the drawings. FIG. 1 is a block diagram showing an embodiment of the control device for an electric discharge machine according to the present invention, in which 1 is an electrode for machining, 2 is a workpiece placed opposite to the electrode 1, and 3 is a power source for machining. It is. 4 is a pulse circuit that sets the pulse energy applied between the electrode 1 and the workpiece 2 (between the electrodes) by the power source 3, and controls the on-pulse width, off-pulse width, pulse voltage, pulse current, etc. 5 is a feed motor for electrode 1 (Z-axis motor); 6.
7 is a feed motor (X, Y-axis motor) for the workpiece 2; 8 is a gap detection circuit that detects the voltage between the gaps; 9 is an output signal from the gap detection circuit 8 (a voltage waveform between the gaps); ) is a machining state identification circuit that identifies the machining state. As shown in FIG. It identifies the machining state (that there is one) and outputs identification result signals 9A to 9D. In other words, signal 9A is generated for normal discharge A, signal 9B is generated for arc discharge B, signal 9C is generated for short circuit, and signal 9D is generated for average value abnormality for each individual interpole pulse. Output.

These signals 9A to 9D are respectively supplied to a high-speed processing line 11 (a line for immediately performing processing control according to the processing state identification result) and a controller 10. The controller 10 controls a machining control circuit according to a machining mode (selected machining mode) selected by a machining mode selector 12 that selects any machining mode from among machining modes such as interpolation, interpolation oscillation, plane oscillation, and electrode rotation. An operation mode selection command 14 is given to 13 to activate it. Further, the controller 10 is
Identification result signal 9 given from the processing state identification circuit 9
Based on A to 9D, the processing control circuit 13 is operated via the normal processing line 15 as follows. That is, the optimum operation mode for various combinations of the selected machining mode type and the machining state identification results, in other words, the operation mode that can increase the normal discharge rate without reducing machining efficiency, is determined in advance through experiments, and the operation mode is then Processing control circuit 1
Activate 3.

The processing control circuit 13 here includes a processing pulse control circuit 13A, a processing feed and speed control circuit 13B, and an electrode retraction control switching circuit 13C. In this case, the processing pulse control circuit 13A gives a pulse control command to the pulse circuit 4 based on the given operation mode to adjust the pulse energy, and for example, turns off when the average value is abnormal (signal 9D). Control is performed such as widening the time, applying a large current pulse with a minute width in response to a short circuit (signal 9C), and applying a high voltage pulse in response to no discharge. The processing feed and speed control circuit 13B controls the feed direction (forward, backward direction) and feed speed of the electrode 1, based on the signal sent from the controller 10 via the normal processing line 15.
For example, the feeding speed is finely switched and the inter-electrode distance (discharge gap) is appropriately controlled to ensure stable discharge. The retraction control switching circuit 13C controls when the electrode 1 is retracted.
Various retreat operations (including stopping here) such as trajectory retreat, stop, and center retreat, which are set in advance according to the type of the selected machining mode, are performed. In other words, in NC electrical discharge machining, in order to perform swing machining and contouring machining, various electrode retraction methods are prepared, and the most suitable retraction method for the machining is used. This is applied when retracting the electrode according to the selected processing mode, and similarly applied depending on the type of the selected processing mode. The motor feed control circuit 16 is based on such a control circuit 13.
It receives commands such as feed speed and direction from switching circuit 13C and controls feed motors 5 to 7. Note that 17 is a position monitoring circuit.

The above operations prevent the occurrence of abnormal discharge (arc discharge, short circuit, etc.) and no discharge, and perform discharge pulse and discharge gap control to increase the normal discharge rate, thereby achieving improvements in machining accuracy and machining efficiency. .

FIG. 3 is a flowchart showing a specific example of the above-mentioned operation by the controller 10. The controller 10 first collects abnormal measurement value data (identification results) from the machining state identification circuit 9.
is accepted (step 31).

Here, the abnormal measurement value is, for example, the number of occurrences of abnormal discharges such as arc discharge or short circuit (referring to machining conditions other than normal discharge conditions and average value abnormal conditions) or the total number of such occurrences, and Measured value (this time abnormal measured value P
In step 32, it is determined whether or not N-) is larger than the previous abnormality measurement value BN.

When PN is larger than BN, the operation mode is restored to the one before the last machining control change (step 33).
If PN is smaller than or equal to N, it is determined in step 34 whether PN is larger than a predetermined value RN. RN is given by a table (not shown) created based on the machining mode and machining pulse energy, but when PN is larger than this RN,
A backward control operation determined according to the selected machining mode is selected from a table (not shown) (step 35). Next, select the machining feed rate at that time. For example, if there are many short circuits, reduce the speed, and if there are many arc discharges, increase the speed, each to a predetermined degree, and adjust the speed. It is held (updated) in place of the previous speed (step 36). Although control of machining pulses is excluded in this example, it would be beneficial to provide that control as well.

In the above-mentioned embodiment, the machining states identified by the machining state identification circuit 9 are four: normal discharge, arc discharge, short circuit, and average value abnormality, but non-discharge, etc. may be added to these.

In addition, there are methods for detecting the average value, such as applying a monitor voltage between the electrodes and constantly detecting it, and determining the average value of the machining voltage (voltage between the electrodes) without using the monitor voltage. .

〔Effect of the invention〕

As described above, according to the present invention, there is an effect that machining can be controlled more appropriately depending on the selected type of machining mode, and both machining accuracy and machining efficiency can be improved.

[Brief explanation of the drawing]

FIG. 1 is a block diagram showing one embodiment of the device of the present invention, and FIG.
The figures are diagrams showing voltage waveforms in various machining states, and FIG. 3 is a flowchart showing a specific example of the operation of the controller in FIG. 1. 1... Electrode, 2... Workpiece, 3... Processing power source,
4...Pulse circuit, 5-7...Feed motor, 8...
- Gap detection circuit, 9... Machining state identification circuit, 10...
・Controller, 12... Machining mode selector, 13.
...Processing control circuit, 16...Motor feed control circuit.

Claims (1)

[Claims] The machining state is identified by the machining state identification circuit based on the output signal of the gap detection circuit that detects the voltage between the electrode and the workpiece,
In a control device for an electric discharge machine that controls machining by appropriately operating a machining control circuit according to the identification result, there is provided a machining mode selector that selects any machining mode from among a plurality of machining modes; When operating the processing control circuit according to the selected processing mode by the machine and operating the processing control circuit based on the identification result by the processing state identification circuit, an operation mode preset according to the type of the selected processing mode is activated. A controller for an electrical discharge machine, comprising: a controller for operating the machining control circuit.