JP2762113B2 - Electric discharge machine - Google Patents

Description

Description: TECHNICAL FIELD The present invention relates to an electric discharge machine.

(Prior Art) When performing a desired machining on a given workpiece by an electric discharge machine, in order to perform machining under the best machining conditions, it is necessary to optimize the electrical conditions for more than 10 types of machining, respectively. Must be set to a value. However, considerable experience is required to set each of 10 or more types of processing conditions to optimal values. For this reason, in the conventional apparatus, one set of processing condition data is predetermined for each of a plurality of preset reference processing conditions, and the operator sets one set of processing condition data corresponding to a desired processing condition. An operation of selecting and then changing each element to meet the specific processing conditions at that time is performed.

(Problems to be Solved by the Invention) However, the selected set of machining condition data includes as many as ten or more types, and the operator individually sets again such a large number of machining parameter data. This imposes a heavy burden on the operator, and in most cases, machining under the best conditions cannot be performed.

SUMMARY OF THE INVENTION An object of the present invention is to provide an improved electric discharge machine which can solve the above-mentioned problems in the prior art.

(Means for Solving the Problems) A feature of the present invention for solving the above problems is that a machining condition setting means for setting values of a plurality of machining parameters required for performing electric discharge machining, and at least electric discharge machining Means for setting an index value indicating the stability of electric discharge machining with respect to the speed, and substantially the value of the machining parameter set by the machining condition setting means based on the index value set by the means for setting the index value Change amount determining means for determining a change amount of at least one processing parameter contributing to realization of the index value; and correcting the value of the at least one processing parameter based on the change amount determined by the change amount determining means. Correction means, and the processing parameter values corrected by the correction means and the processing parameters set by the processing condition setting means. Means for performing electric discharge machining based on the values of machining parameters other than the modified machining parameters.

(Operation) Based on a machining condition table prepared in advance, values of predetermined machining parameters required for performing a desired machining are set by machining condition setting means, and a discharge required for machining at that time is set. An index value indicating the stability of the electric discharge machining with respect to the machining speed is set. The index value is used to determine the processing efficiency, and at least one processing parameter selected as one that substantially contributes to the realization of the index value among a plurality of processing parameters set by the processing condition setting means. On the other hand, the change amount based on the set index value is determined by the change amount determining means.

The correction unit corrects at least one processing parameter to be corrected based on the correction amount determined by the change amount determination unit. The electric discharge machining is performed in accordance with the machining parameters corrected in this way and the remaining machining parameters not corrected.

That is, the value of a set of machining parameters set by the machining condition setting means is modified so as to be suitable for the intended electric discharge machining by setting an index indicating stability with respect to the machining speed of electric discharge machining. 1 obtained
The electric discharge machining is performed according to the set of machining parameters. In this manner, the value of the processing parameter is automatically corrected according to the index value only by giving the index value without the operator performing the operation of individually correcting each processing parameter.

Hereinafter, an embodiment of the present invention will be described in detail with reference to the drawings.

FIG. 1 shows an embodiment of the wire electric discharge machine according to the present invention. The wire cut electric discharge machine 1 includes a wire cut electric discharge machine main body 2 having a known configuration,
And a control unit 3 for controlling the wire-cut electric discharge machine body 2. The control unit 3 includes a computer system, and a processing control program for processing the workpiece 21 into a desired shape is executed in the computer system, and a desired processing is performed between the wire electrode 22 and the workpiece 21. The control unit 3 outputs an X-axis control signal S _X and a Y-axis control signal S _Y for performing the relative movement. For moving respectively the machining table workpiece 21 is attached (not shown) in the X-axis direction and the Y-axis direction, the wire-cut electric discharge machine main body 2 is provided with an X-axis motor M _X and Y-axis motor M _Y cage, each of these motors M _X, M _Y is respectively controlled by the X-axis control signals S _X and Y-axis control signals S _Y, thereby the workpiece relative motion necessary for processing the wire electrode 22 was 21 Given between

The control unit 3 also includes a wire electrode 22 and a workpiece 21.
And a power supply unit for supplying a pulse voltage P for machining to an electric discharge machining gap G formed between the wire electrode 22 and the workpiece.
21 is applied. As a result, a discharge current for machining flows through the electric discharge machining gap G, and the workpiece is machined by this.

As a signal indicating the state of electric discharge machining gap G, the discharge machining gap G occurring gap voltage V _g are fed back to the control unit 3, the gap voltage V _g is referenced in the control unit 3, the electric discharge machining gap G X axis control signal S _X and Y-axis control signal S _Y is output such that a gap width is maintained at a desired value during electric discharge machining. Since the above-described feedback control of the electric discharge machining gap width is known, a detailed description thereof will be omitted.

The wire cut electric discharge machine 1 has a machining parameter setting device 4 of a known configuration in order to set machining parameters necessary for executing the above-described operations in the control unit 3. In the machining parameter setting device 4 shown in the illustrated embodiment, respective values of ten machining parameters ON, OFF, IP, H, P, SV, SF, C, WT, and WS described below are input, respectively. be able to. The contents of each of these processing parameters are as follows.

ON: A parameter that determines the ON time of the pulse voltage P.

OFF: A parameter that determines the OFF time of the pulse voltage P.

IP: a parameter for selecting a peak value of a machining current flowing in the machining gap, and a parameter relating to a resistance value of a circuit for supplying the machining current.

V is a parameter relating to a no-load voltage. Therefore, if the current peak value is I, Is established.

H is a parameter for determining the value of the superimposed high voltage. The larger this value is, the better the so-called processing bite is.

P: A parameter for determining the ON time of the pulse voltage during unstable machining.

Is a parameter for determining a reference level to be compared with the gap voltage V _g for holding the SV ...... gap width to a predetermined value, the gap width extent that this value increases increases.

C is a parameter for determining the capacity of the capacitor connected to the processing gap, and the larger the value, the more stable the processing.

SF: A parameter that determines the feed rate of the machining table.

WT: A parameter that determines the tension of the wire electrode.

WS: A parameter that determines the feed speed of the wire electrode.

When machining is performed by the wire-cut electric discharge machine 1, an operator needs to set the values of these machining parameters with the machining parameter setting device 4. As these processing parameters, for example, a set of processing parameter values suitable for required processing may be selected from a processing condition table prepared in advance, and the selected values may be set by the processing parameter setting device 4.

Among the processing parameters input by the processing parameter setting device 4, first data D ₁ indicating the processing parameters OFF and SV which substantially affect only the processing efficiency are input to the change unit 5. On the other hand, other processing parameters having a close relationship to the finish state of machining, ON, IP, V, H , P, C, SF, WT, second data D ₂ indicating the WS is directly input to the control unit 3 The processing conditions are set according to this.

Reference numeral 6 denotes a selector for selecting the processing efficiency. In the illustrated embodiment, the processing efficiency is set to 0.6, 0.8, 1, or 1.
The configuration can be changed to four stages of 1.1, and any one of the above four processing efficiencies can be selected by operating the adjustment knob 6a. The selector 6 outputs a selection signal SS indicating the processing efficiency selected at that time.
Is input to the change amount determination unit 51 in the change unit 5.

In the change amount determination unit 51, the change amounts ΔOFF, ΔSV of the processing parameters OFF, SV are determined according to the content of the selection signal SS. In the illustrated embodiment, the processing efficiency and each change amount are determined as shown in the following table.

The change amount data ΔD indicating each change amount determined according to this table is the first data D indicating the processing parameters OFF and SV.
₁ is input to the input correction unit 52, where the values of the processing parameters OFF and SV are corrected and changed as necessary according to the change amount data ΔD. Processing parameters OFF output thus to the modification unit 52, the third data D ₃ indicating the SV, it is input to the control unit 3.

Here, in the illustrated embodiment, the processing parameter setting unit 4
Are given as integer values from 1 to n, and the value of n is appropriately determined by each processing parameter. Accordingly, the modification unit 52, by performing addition and subtraction of numbers provided by the second data D ₂ and change amount data [Delta] D, the third data
It is possible to determine the content of D _3.

However, the configuration of the change unit 5 shown in FIG. 1 is merely an example, and the processing efficiency is selected stepwise or continuously, and the second data expressed in an appropriate format according to the selected processing efficiency. modified in an appropriate way the contents of the D _2, by modifying, processing parameters OFF commensurate with selected processing efficiency, the third data D ₃ other suitable configuration obtaining indicating the value of SV, for example by a microcomputer It may be a data processing device, an arithmetic circuit using a memory as a conversion table, or the like. Further, the data for the change shown in the table is an example, and is not limited to this example, and can be appropriately determined.

The control unit 3 is responsive to the first data D ₁ and the third data D _3, each processing parameter is set to a value according to these data D _1, D _3, desired processing on the workpiece 21 is performed .

According to such a configuration, when performing an electric discharge machining operation, first, a required set of machining condition data corresponding to the machining is selected from a machining condition table prepared in advance, as in the related art. A required set of processing condition data is determined based on the experience of the above, and the required processing condition parameters are set by the processing parameter setting device 4. If machining under the set conditions is desired, the selector 6
If the machining efficiency 1 is selected, the machining conditions set by the machining parameter setting device 4 are not changed,
The workpiece 21 is subjected to electrical discharge machining according to the set machining parameters.

If a more stable machining is desired, the selector 6 selects a desired value having a machining efficiency smaller than 1, and the changing unit 5 sets the machining parameters OFF and SV to the machining efficiency selected at that time. Corrections and changes are made accordingly, and electric discharge machining is executed in a more stable state. On the other hand, if a higher processing speed is desired even if the processing becomes somewhat unstable, by selecting a processing efficiency larger than 1,
Electric discharge machining is performed at high speed. That is to say, based on the above table, for example, when the processing efficiency 0.6 is selected, the value of ΔOFF becomes 2, the pause period of the processing pulse voltage becomes longer by two steps, and more stable processing is performed. However, the required processing time becomes longer by that amount.
On the other hand, for example, when the processing efficiency 1.1 is selected, the value of ΔSV becomes −2, and the processing gap is narrowed accordingly, and the processing is slightly impaired, but faster processing is performed, and the desired processing is shortened. It can be completed in time.

As already explained, the change based on the above table is an example.
It can be appropriately determined based on experience or the like, and the present invention is not limited to the mode of change based on the above table.

By selecting the processing efficiency as described above,
In any case, there is an advantage that the processing speed can be adjusted without substantially affecting the finished state of the workpiece 21.

In the embodiment shown in FIG. 1, the processing parameter setting device 4 and the selector 6 may be mechanical switches, but may be appropriately provided directly on a display tube, for example, a CRT, or on a CRT via a console keyboard. Of course, may be configured as an electronic selection device for selecting the value of. In this case, in the computer system in the control unit 3, setting of processing parameters, selection of processing efficiency values, correction of necessary parameters, A configuration for making a change may be adopted.

Although the present invention has been described with reference to the embodiment shown in FIG. 1, the present invention is not only applicable to a wire cut electric discharge machine, but also applicable to a die sinking electric discharge machine. Of course you can.

(Effects of the Invention) According to the present invention, as described above, the value of a required set of machining parameters is set by the machining condition setting means by the machining condition table or other appropriate means, and the discharge with respect to the machining speed is performed. By setting an index value indicating the stability of machining, a set of basic machining parameters that have been set is corrected, and only the setting of the index value is used to adjust the degree of stability of electric discharge machining with respect to machining speed. Anyone can easily do this without need. In addition, this does not substantially change the finish of the processing,
For example, only the processing speed can be changed.

[Brief description of the drawings]

FIG. 1 is a system block diagram showing one embodiment of the present invention. 1 ...... wire-cut electric discharge machine, 2 ...... wire-cut electric discharge machine main body, 3 ...... control unit, 4 ...... processing parameters installation unit, 5 ...... change unit, 6 ...... selector, D ₁
... First data, D ₂ ... Second data, D ₃ ... Third data, SS... Selection signal, ΔD... Change amount data.

Claims (1)

(57) [Claims] 1. A machining condition setting means for setting values of a plurality of machining parameters required for performing an electric discharge machining, a means for setting an index value indicating stability of the electric discharge machining at least with respect to an electric discharge machining speed, At least one of the processing parameter values set by the processing condition setting means based on the index value set by the index value setting means and at least one of the processing parameter change amounts that substantially contributes to the realization of the index value Change amount determining means for determining: a value of the at least one processing parameter based on the change amount determined by the change amount determining means; and a value of the processing parameter corrected by the correcting means; Based on processing parameter values other than the corrected processing parameter among the processing parameters set by the processing condition setting means, Means for performing electrical discharge machining based on the electrical discharge machining.