WO2016174748A1 - Wire electrical discharge machining apparatus and wire position detection method - Google Patents

Abstract

A wire electrical discharge machining apparatus (100) determines the position of a wire electrode (1) with respect to a workpiece (2) on the basis of the relationship of the inter-electrode distance, between the wire electrode (1) and the workpiece (2), with electrical data that changes according to the inter-electrode distance, and electrical data measured at a given inter-electrode distance.

Description

Wire electric discharge machine and wire position detection method

The present invention relates to a wire electric discharge machine and a wire position detection method for detecting the position of a wire electrode from a work end surface.

In wire electric discharge machining, prior to machining, it is necessary to accurately grasp the positional relationship between the electrodes between the wire electrode and the workpiece and execute positioning between the electrodes. As a conventional positioning method between poles, as shown in Patent Document 1, a method of detecting electrical contact between a wire electrode and a work is generally used. Since the wire electrode vibrates when the wire electrode travels, when the positions of the electrodes are positioned using electrical contact, the contact state is detected when the workpiece approaches the range of vibration of the wire electrode. At this time, the amplitude and frequency of the vibration are not constant due to a difference in wire tension between the machines, and it is difficult to detect the relative position between the poles based only on the contact information. Therefore, even when the wire electrode is positioned with respect to the same workpiece end surface, the positioning repeatability varies by the vibration width of the wire.

Even when the wire electrode is stopped and positioned, the end face position is difficult to detect accurately because variations occur in the clearance range, which is the gap between the wire penetrating portions of the die holding the wire.

Japanese Patent Laid-Open No. 4-171120

Therefore, in order to accurately position the wire electrode with respect to the workpiece end surface, a position detection method that does not depend on vibration is required even when the wire electrode is running and vibration is generated.

The present invention has been made in view of the above, and an object of the present invention is to provide a wire electric discharge machine capable of accurately detecting the position of the wire electrode from the workpiece end surface regardless of whether or not the wire electrode is traveling. .

In order to solve the above-described problems and achieve the object, the present invention provides a relationship between the distance between the electrode between the wire electrode and the workpiece and the electrical data that varies depending on the distance between the electrode and the given distance between the electrodes. The position of the wire electrode with respect to the workpiece is determined based on the electrical data measured in step (1).

The wire electric discharge machine according to the present invention has an effect that it is possible to accurately detect the position of the wire electrode from the workpiece end surface regardless of whether or not the wire electrode is traveling.

The figure which shows the structure of the wire electric discharge machine concerning Embodiment 1 of this invention. The figure which shows an example of a structure of the data measurement part of the wire electric discharge machine concerning Embodiment 1. FIG. The figure which shows an example of a structure of the control part of the wire electric discharge machine concerning Embodiment 1. FIG. The perspective view explaining the vibration of the wire electrode in the wire electric discharge machine concerning Embodiment 1. FIG. The figure which shows the mode of the time change of the distance between electrodes in the wire electric discharge machine concerning Embodiment 1. FIG. The figure which shows the relationship between the wire electrode and workpiece | work concerning Embodiment 1. FIG. The figure which shows the point charge model by the mirror image method which produces the same electric field as the electric field which the wire electrode concerning Embodiment 1 and a workpiece | work generate | occur | produce 1 is a flowchart showing a procedure of a wire position detection method by a wire electric discharge machine according to a first embodiment;

Hereinafter, a wire electric discharge machine and a wire position detection method according to an embodiment of the present invention will be described in detail with reference to the drawings. Note that the present invention is not limited to the embodiments.

Embodiment 1 FIG.
FIG. 1 is a diagram showing a configuration of a wire electric discharge machine 100 according to a first embodiment of the present invention. The wire electric discharge machine 100 includes a wire electrode 1 serving as a discharge electrode, a wire bobbin 7 that winds the wire electrode 1 and supplies the wire electrode 1, a wire feed roller 5 disposed on a path along which the wire electrode 1 travels, A machining head 3 provided with an upper nozzle 21 for feeding the wire electrode 1; a lower nozzle 22 for accommodating the wire electrode 1; a data measuring unit 4 for determining the capacitance between the wire electrode 1 and the workpiece 2; A drive unit 8 that drives and moves the machining head 3 and the workpiece 2 by driving a drive shaft (not shown), and a control unit 6 that controls the drive unit 8 based on the measurement result of the data measurement unit 4 are provided. One end of the data measuring unit 4 is electrically connected to the wire electrode 1 via the power supply 9, and the other end is connected to the work 2. The drive unit 8 can move the wire electrode 1 relative to the workpiece 2 by driving the drive shaft. The control unit 6 positions the wire electrode 1 with respect to the work 2 by causing the drive unit 8 to control the horizontal positions of the machining head 3 and the work 2 based on the measurement result of the data measurement unit 4. Thereafter, the control unit 6 processes the workpiece 2 by generating a discharge between the wire electrode 1 and the workpiece 2.

FIG. 2 is a diagram illustrating an example of the configuration of the data measurement unit 4 of the wire electric discharge machine 100 according to the first embodiment. The data measurement unit 4 includes a measurement AC power supply 40 that supplies a sinusoidal AC voltage V _in having an angular frequency ω, a DC component blocking capacitor 41 connected to one end of the AC power supply 40, and the AC power supply 40 grounded. A current detection resistor 42 connected to the other end of the current detection resistor 42, and a rectifier circuit 43 that converts the AC voltage _Vout at the terminal of the current detection resistor 42 that is not grounded into a voltage amplitude value | _Vout | . The capacitance of the DC component blocking capacitor 41 is C _f , and the resistance value of the current detection resistor 42 is R _s . The DC component blocking capacitor 41 is connected to the wire electrode 1, and the current detection resistor 42 is connected to the work 2. With the above configuration, the data measuring unit 4 has the combined capacitance C _{t of} C _g that is the interelectrode capacitance 101 between the wire electrode 1 and the workpiece 2 and C _s that is the stray capacitance 102 of the wire electric discharge machine 100. It is possible to measure | V _out | which is electrical data corresponding to. Stray capacitance 102 is a capacitance generated due to factors such as the wiring of a wire electric discharge machine 100, the combined capacitance C _t is the sum of the C _g and C _s.

FIG. 3 is a diagram illustrating an example of the configuration of the control unit 6 of the wire electric discharge machine 100 according to the first embodiment. The control unit 6 is a numerical control device, and includes a calculation unit 61 that executes calculation processing, a memory 62 that the calculation unit 61 uses for a work area, and a storage unit 63 that stores various types of information including machining programs. Prepare. The calculation unit 61 is a central processing unit (CPU) or a system LSI (Large Scale Integration). The memory 62 is a volatile storage device such as a random access memory (RAM: Random Access Memory). The storage unit 63 is a nonvolatile storage device such as a hard disk drive or a solid state drive. The control unit 6 controls the positions of the machining head 3 and the workpiece 2 when the calculation unit 61 executes the machining program held in the storage unit 63.

FIG. 4 is a perspective view for explaining the vibration of the wire electrode 1 in the wire electric discharge machine 100 according to the first embodiment. In FIG. 4, for simplicity, a part of the configuration of the wire electric discharge machine 100 such as the data measurement unit 4, the control unit 6, the upper nozzle 21, and the lower nozzle 22 is omitted. When the wire electrode 1 travels in the wire travel direction from top to bottom, the wire electrode 1 vibrates in the order of μm in the horizontal direction perpendicular to the wire travel direction in order to receive friction from the travel route. Therefore, the distance between the electrodes, which is the distance between the wire electrode 1 and the workpiece 2, changes over time when the wire travels.

FIG. 5 is a diagram showing a state of the change in the distance between the electrodes in the wire electric discharge machine 100 according to the first embodiment. In FIG. 5, the change with time of the distance between the electrodes when the wire is stationary is indicated by a broken line, and the change with time of the distance between the electrodes when the wire is running is indicated by a solid line. While the distance between the poles when the wire is stationary does not change with time, the distance between the poles when the wire travels is shown to change with time as it becomes larger or smaller than the distance between the poles when the wire is stationary.

Hereinafter, a method of obtaining C _g which is the interelectrode capacitance 101 between the wire electrode 1 and the workpiece 2 by the data measuring unit 4 and the control unit 6 will be described.

The relationship between the AC voltage V _in , the angular frequency ω, the capacitance C _f of the DC component blocking capacitor 41, the combined capacitance C _t , the resistance value R _{s of} the current detection resistor 42, the current i flowing through the current detection resistor 42, and the voltage V _out is as follows: (1) and (2).

From the equations (1) and (2), the relationship of the following equation (3) is derived.

When formula (3) is transformed, the following formula (4) is obtained.

If the expression using the amplitude value of the voltage actually measured from Expression (4) is expressed as Expression (5) below.

When formula (5) is arranged, the following formula (6) is obtained.

Here, _if the value of C _f is set to a value sufficiently larger than the value of C _t , the DC component blocking capacitor 41 has a function only for blocking the DC component, and it is approximated that C _t / C _f is zero. it can. Therefore, equation (6) can be transformed into the following equation (7).

As shown in Expression (7), | V _out | and C _t have a unique relationship. As a result, _in a situation where | V _in | and R _s are given to the control unit 6, if | V _out | is obtained by measurement of the data measurement unit 4, the control unit 6 uses the equation (7) to It is possible to obtain a combined capacitance C _t of C _g which is the inter-electrode capacitance 101 and C _s which is the stray capacitance 102. The situation _{in which} | V _in | and R _s are given to the control unit 6 is a situation _in which the storage unit 63 stores | V _in | and R _s .

In order to obtain C _g which is the interelectrode capacitance 101 from the combined capacitance C _t, it is necessary to obtain C _s which is the stray capacitance 102 in advance. In order to obtain C _s , the combined capacitance C _t may be obtained in a state where the distance between the wire electrode 1 and the workpiece 2 is sufficiently separated and C _g can be regarded as 0 [F]. Since the value of the combined capacity C _t at that time can be regarded as C _s , it is stored in the storage unit 63 of the control unit 6. Then, by taking the difference between the obtained composite capacitance C _t and C _s by measurement of the data measurement portion 4 in a state in which close the distance between the wire electrode 1 and the workpiece 2, the stray capacitance component from the composite capacitance C _t can be obtained C _g is the machining gap capacitance 101 excluding. Therefore, the relationship between | V _out | and C _g is also a unique relationship via the equation (7). That is, | V _out | is a voltage value corresponding to C _g .

A method for obtaining the inter-electrode distance h between the center of the wire electrode 1 and the end face of the workpiece 2 from the value C _{g of} the inter-electrode capacitance 101 obtained as described above will be described below.

The value C _g of the interelectrode capacitance 101 between the wire electrode 1 and the workpiece 2 can theoretically be obtained as follows.

FIG. 6 is a diagram illustrating a relationship between the wire electrode 1 and the workpiece 2 according to the first embodiment. Since the workpiece 2 is sufficiently large with respect to the diameter of the wire electrode 1, it can be regarded as a conductor having an infinite width as shown in FIG.

When the workpiece 2 can be regarded as a conductor having an infinite width, the electric field generated in the space when a potential difference is applied between the wire electrode 1 and the workpiece 2 can be obtained using a mirror image method. . FIG. 7 is a diagram showing a point charge model by a mirror image method that generates the same electric field as that generated by the wire electrode 1 and the workpiece 2 according to the first embodiment. The workpiece end surface is the y axis, and the direction perpendicular to the y axis is the x axis. The side where the wire electrode 1 actually exists is taken as the positive direction of the x axis. In FIG. 7, a point charge + q is arranged at a coordinate (s, 0) that is separated from the workpiece end surface by a distance s, and a point charge -q is placed at the opposite coordinate (−s, 0) with the workpiece end surface as the target axis. Is placed.

As shown in FIG. 7, when it is considered that the electric field is generated by the point charge + q arranged at the coordinate (s, 0), the electric field E at the position separated from the coordinate (s, 0) by the distance r is Gaussian. Is expressed by the following equation (8). In the equation (8), ε is the dielectric constant of the space where the wire electrode 1 and the workpiece 2 exist.

Since the electric potential up to the surface of the wire electrode 1 is equipotential, the potential φ generated at a position r away from the center of the wire electrode 1 by r is given by the following formula (9 ).

ここで、φ（ｓ，０）＋φ（－ｓ，０）＝０の関係を用いた。 Therefore, the potential φ generated at the position (x, y) where the point charge + q and the point charge −q are present is expressed by the following equation (10).

Here, the relationship of φ (s, 0) + φ (−s, 0) = 0 was used.

The equipotential surface in the equation (10) is a position of (x, y) that satisfies the following equation (11).

When formula (11) is arranged, the following formula (12) is obtained.

Expression (12) is an expression representing a circular locus. Accordingly, since the surface of the wire electrode 1 is an equipotential surface, when the inter-electrode distance h and the radius a of the wire electrode 1 are used, the following expression (13) is obtained as the relationship between s and K.

When Equation (13) is solved, s and K can be expressed as Equation (14) and Equation (15) below.

Here, when Expression (11) and Expression (14) are substituted into Expression (10), the potential V generated in the space by the conductor having + q point charge and infinite width is expressed by the following Expression (16). Can be requested.

The value C _g of the interelectrode capacitance 101 can be calculated from C _g = q / V, and the capacitance C _g between the wire electrode 1 and the workpiece 2 per unit length in the wire traveling direction of the workpiece end surface is The following equation (17) is expressed.

The capacitance actually obtained by measurement is a value obtained by multiplying Equation (17) by the workpiece thickness t. Here, since 2πεt of the numerator is a proportional term, if it is set as A, the equation (18) is obtained.

The storage unit 63 of the control unit 6 holds the radius a of the wire electrode 1 input by the user. Since the amount to be obtained from the equation (18) is the inter-pole distance h, if the value of A is known, the inter-pole distance h can be derived from C _g obtained by measurement.

Therefore, C ₁ which is the capacitance C _g at the first inter-electrode distance h ₁ is obtained in a state where the wire electrode 1 is stationary and there is no wire vibration. Then, the wire electrode 1 feed drive unit 8 as further away from the workpiece 2 by a distance d of the drive shaft, obtaining the C ₂ is the capacitance C _g in the second inter-electrode distance h _2. Thereby, the following formulas (19), (20), and (21) are established.

The simultaneous equations consisting of equations (19), (20) and (21) can be solved for h ₁ , h ₂ and A if C ₁ , C ₂ and d are obtained. The resulting A by substituting into Equation (18) can obtain the relationship between the value C _g of interelectrode distance h and the machining gap capacitance 101. As described above, the relationship between | V _out | and C _g is a unique relationship via the equation (7). Therefore, the relationship between the interpole distance h and | V _out | It is obtained.

Then, with the wire electrode 1 running, the value C _g of the interelectrode capacitance 101 at that time is obtained by measurement. Based on the value of C _g, the inter-electrode distance h can be obtained from Expression (18). That is, since the inter-electrode distance h can be accurately measured including the case where the wire electrode 1 is in a vibrating state, positioning can be performed with high accuracy.

Based on the above discussion, the wire electric discharge machine 100 can determine the exact position of the wire electrode 1 from the workpiece end surface regardless of whether or not the wire electrode 1 is traveling. FIG. 8 is a flowchart illustrating a procedure of a wire position detection method performed by the wire electric discharge machine 100 according to the first embodiment.

First, the control unit 6 determines whether or not C _s that is the stray capacitance 102 is stored in the storage unit 63 (step S1). When C _s is not stored (step S1: No), C _s of the stray capacitance 102 is obtained at a position where the distance between the poles is sufficiently separated (step S2). Specifically, in a state where the values of | V _in | and R _s are stored in the storage unit 63 _in advance, the control unit 6 sets the rectifier circuit 43 in a state where the distance between the wire electrode 1 and the workpiece 2 is sufficiently separated. The value of | V _out |, which is the measurement result, is obtained. If the control unit 6 calculates the value of C _t using Equation (7) based on the value of | V _out | obtained here and the values of known | V _in | and R _s , It can be regarded as the value of C _s . The value of C _s thus obtained is stored in the storage unit 63 (step S3). Then, it returns to step S1. Note that the values of | V _in | and R _s may be set in advance in the storage unit 63 by the user of the wire electric discharge machine 100, or the data measurement unit 4 notifies the control unit 6 and the control unit 6 stores the values. You may make it preserve | save in the part 63. FIG. The control unit 6 is set | V _in | the AC power supply 40 in value may be supplied with AC voltage V _in.

When C _s is stored (step S1: Yes), the user sets a positioning direction in which the wire electrode 1 approaches the workpiece 2 in the control unit 6 based on the relative position between the wire electrode 1 and the workpiece 2 (step S1). S4). Thereafter, when the wire electrode 1 is traveling, the traveling is stopped and the wire electrode 1 is stopped (step S5). Next, the control unit 6 causes the drive unit 8 to send a drive shaft (not shown) in the positioning direction so that the wire electrode 1 approaches the workpiece 2 (step S6). Then, it is determined by the control part 6 whether the electrical contact of the wire electrode 1 and the workpiece | work 2 was detected (step S7). If no electrical contact is detected (step S7: No), the process returns to step S6.

When electrical contact is detected (step S7: Yes), the control unit 6 causes the drive unit 8 to temporarily stop the drive shaft feed. Then, this time, the drive shaft is retracted from 10 μm to 20 μm so that the wire electrode 1 moves away from the work 2, and the distance between the electrodes between the wire electrode 1 and the work 2 becomes the first distance between the electrodes h ₁ (step S 8 ). In this state, the control unit 6 obtains | V _out | as a measurement result from the data measurement unit 4. The obtained first is the electrical data | and values, the known | | V _out V _in | based on the value of and R _s, the control unit 6 by using the equation (7) is C _t The value is calculated and the value of C _s is subtracted therefrom to obtain the value C _g of the interelectrode capacitance 101. The C _g obtained at this time is set as C ₁ in the equation (19), and the value of C ₁ is stored in the storage unit 63 (step S9).

Next, the control unit 6 causes the drive unit 8 to further retract the drive shaft by d in Formula (21) so that the wire electrode 1 is further away from the work 2, and the gap between the wire electrode 1 and the work 2 is increased. The distance is set to the second inter-electrode distance h ₂ (step S10). The value of d is a value of 5 μm to 10 μm. The value of d, it is necessary change in the value C _g of the machining gap capacitance 101 is a value of a degree that can be measured. In this state, the control unit 6 obtains | V _out | as a measurement result from the data measurement unit 4. The obtained is the second electrical data | and values, the known | | V _out V _in | based on the value of and R _s, the control unit 6 by using the equation (7) is C _t The value is calculated and the value of C _s is subtracted therefrom to obtain the value C _g of the interelectrode capacitance 101. The C _g obtained at this time is set as C ₂ in the equation (20), and the value of C ₂ is stored in the storage unit 63 (step S11).

From steps S9 to S11, C ₁ , C ₂ and d of equation (21) are obtained from equation (19). Therefore, the control unit 6 solves the simultaneous equations of equation (19) to equation (21). Thus, h ₁ , h ₂ and A are obtained. By substituting the A obtained here formula (18), the relationship between the value C _g of interelectrode distance h and the machining gap capacitance 101 from the center of the wire electrode 1 to the end surface of the work 2 is obtained ( Step S12).

After step S12, the control unit 6 controls the drive unit 8 so that the distance h between the electrodes becomes an appropriate value to be used when the wire travels, and the position of the drive shaft of the drive unit 8 is determined. Is stored in the storage unit 63. In this state, the wire electrode 1 is caused to travel (step S13). Next, in a state where the wire electrode 1 travels and vibration is generated, based on the value of | V _out | that is the measurement result of the data measuring unit 4 and the values of | V _in | and R _s , Using the equation (7), the control unit 6 calculates the value of C _t and subtracts the value of C _s therefrom to obtain the value C _g of the interelectrode capacitance 101. Furthermore, the control unit 6 calculates the inter-electrode distance h from the center of the wire electrode 1 to the end face of the workpiece 2 using Expression (18). That is, in a state where the wire electrode 1 is traveling and vibrating, the control unit 6 calculates the inter-electrode distance h in real time (step S14).

Thereby, the control part 6 can acquire the time series data of the distance h between poles. In the time-series data of the interelectrode distance h obtained in this way, the interelectrode distance h is distributed due to the vibration of the wire electrode 1. Therefore, the control unit 6 calculates an average value h ₀ such as a time average or a sample average of the inter-electrode distance h (step S15). That is, h ₀ which is the distance between the center position of the position distribution of the wire electrode 1 and the workpiece end surface during traveling, which is the same state as during machining, is obtained. Since the average value h ₀ of the position of the drive shaft of the drive unit 8 already recorded in the storage unit 63 and the distance h between the electrodes when the wire travels in that state is obtained, the distance between the electrodes with respect to the position of the drive shaft The average value h ₀ of h is obtained accurately. As a result, the control unit 6 can cause the drive unit 8 to accurately control the average value h ₀ of the inter-electrode distance h when the wire electrode 1 is traveling. The position detection operation for the wire electrode 1 is thus completed.

In step S <b> 15, the control unit 6 has grasped the relationship between the accurate distance between the center position of the position distribution of the wire electrode 1 and the workpiece end surface during traveling and the position of the drive shaft of the drive unit 8. That is, according to the wire electric discharge machine 100 according to the first embodiment, it is possible to accurately detect the position of the wire electrode 1 from the workpiece end surface regardless of whether or not the wire electrode 1 is traveling. Since the center position of the position distribution of the wire electrode 1 at the time of traveling does not necessarily coincide with the position of the wire electrode 1 at rest, the average value h ₀ of the inter-electrode distance h can be obtained with respect to the workpiece end surface. This is essential information for accurately positioning the wire electrode 1. As a result, the wire electrode 1 can be positioned with high accuracy with respect to the workpiece 2 in consideration of the vibration state of the wire electrode 1. Specifically, in positioning when the wire electrode 1 is brought into contact with the workpiece end surface, the control unit 6 controls the drive unit 8 to move the drive shaft h ₀ -a in the direction in which the wire electrode 1 approaches the workpiece 2. You can do it.

Further, in the case of the conventional positioning method for detecting the electrical contact between the wire electrode 1 and the work 2, it takes 30 to 40 seconds to acquire one position data for detecting the electrical contact, thereby reducing variations. Therefore, it took a very long time to perform multiple measurements. On the other hand, according to the wire position detection method by the wire electric discharge machine 100 according to the first embodiment, the inter-electrode distance h of the traveling wire electrode 1 can be acquired in a large amount in real time in a short time. It is possible to realize a highly accurate positioning operation of the wire electrode 1 with respect to 2 in a short time.

In the above description, the electrical data is described as the voltage value | V _out | which is the amplitude value of the voltage. However, the function and the data measurement unit for obtaining C _g based on the voltage value | V _out | The four functions may be collectively regarded as a data measurement unit. In that case, the value of C ₁ obtained in step S9 becomes the first electrical data, and the value of C ₂ obtained in step S11 becomes the second electrical data.

It is also required to control the average value h ₀ of the inter-electrode distance h in a state where the wire electrode 1 and the workpiece 2 are immersed in the machining fluid. When the working fluid is oil, the resistance value of the oil is high. Therefore, if the dielectric constant ε in the equation (8) is changed to a value corresponding to the oil, the above argument is established as it is. That is, it is possible to cope with a processing liquid having a high insulating property by a difference in dielectric constant ε.

On the other hand, when the working fluid is water, electricity flows when the distance h between the electrodes is reduced because water is an electrolyte. Therefore, the resistance value between the wire electrode 1 and the workpiece 2 through the machining fluid changes according to the inter-electrode distance h. In this case, the resistance value between the wire electrode 1 and the workpiece 2 via the machining fluid or the current value flowing between the wire electrode 1 and the workpiece 2 via the machining fluid is electrical data. Also in this case, if the relationship between the inter-electrode distance h and the resistance value or current value between the wire electrode 1 and the workpiece 2 is obtained through measurement, the above argument is established. That is, if the resistance value or the current value is measured and the inter-electrode distance h is calculated in real time in a state where the wire electrode 1 travels and vibration is generated, the control unit 6 can control the wire electrode 1 during travel. Since the relationship between the accurate distance between the center position of the position distribution and the workpiece end surface and the position of the drive shaft of the drive unit 8 can be grasped, the wire electrode 1 from the workpiece end surface can be detected regardless of whether the wire electrode 1 is traveling. Accurate position detection is possible.

The configuration described in the above embodiment shows an example of the contents of the present invention, and can be combined with another known technique, and can be combined with other configurations without departing from the gist of the present invention. It is also possible to omit or change the part.

1 wire electrode, 2 workpieces, 3 machining heads, 4 data measurement unit, 5 wire feed roller, 6 control unit, 7 wire bobbin, 8 drive unit, 9 electronic supply, 21 upper nozzle, 22 lower nozzle, 40 AC power supply, 41 DC Component blocking capacitor, 42 current detection resistor, 43 rectifier circuit, 61 arithmetic unit, 62 memory, 63 storage unit, 100 wire electric discharge machine, 101 interelectrode capacitance, 102 stray capacitance.

Claims (21)

Based on the relationship between the distance between the electrode between the wire electrode and the workpiece and the electrical data that varies depending on the distance between the workpiece, and the electrical data measured at the given distance between the workpiece, A wire electric discharge machine that determines a position of the wire electrode. A data measuring unit for measuring the electrical data;
A drive unit that moves the wire electrode relative to the workpiece;
A control unit that determines the position of the wire electrode with respect to the workpiece by controlling the driving unit;
The wire electric discharge machine according to claim 1, comprising: The data measuring unit has a first electrical data when the distance between the wire electrode and the workpiece is a first inter-pole distance, and a second inter-electrode distance between the wire electrode and the work. Measuring the second electrical data of
The control unit obtains the relationship based on the first electrical data, the second electrical data, and a difference between the first inter-pole distance and the second inter-pole distance. The wire electric discharge machine according to claim 2. The data measurement unit measures the electrical data when the wire electrode travels in a state where the position of the drive shaft of the drive unit is fixed,
4. The wire electric discharge machining according to claim 3, wherein the control unit obtains an average value of the distance between the electrodes during traveling of the wire electrode based on the electrical data during the traveling and the relationship. Machine. The wire electrical discharge machine according to any one of claims 1 to 4, wherein the electrical data is a voltage value corresponding to a capacitance between electrodes. The wire electrical discharge machine according to any one of claims 1 to 4, wherein the electrical data is an inter-electrode capacitance. The wire electrical discharge machine according to any one of claims 1 to 4, wherein the electrical data is a resistance value between the wire electrode and the workpiece. The wire electrical discharge machine according to any one of claims 1 to 4, wherein the electrical data is a current value between the wire electrode and the workpiece. Based on the relationship between the distance between the electrode between the wire electrode and the workpiece and the electrical data that varies depending on the distance between the workpiece, and the electrical data measured at the given distance between the workpiece, A wire electric discharge machine that determines the position of the wire electrode,
The wire electrical discharge machine is characterized by measuring the electrical data at two different distances between the poles. A data measuring unit for measuring the electrical data;
A drive unit that moves the wire electrode relative to the workpiece;
A control unit that determines the position of the wire electrode with respect to the workpiece by controlling the driving unit;
The wire electric discharge machine according to claim 9, comprising: The data measuring unit has a first electrical data when the distance between the wire electrode and the workpiece is a first inter-pole distance, and a second inter-electrode distance between the wire electrode and the work. Measuring the second electrical data of
The control unit obtains the relationship based on the first electrical data, the second electrical data, and a difference between the first inter-pole distance and the second inter-pole distance. The wire electric discharge machine according to claim 10. The data measurement unit measures the electrical data when the wire electrode travels in a state where the position of the drive shaft of the drive unit is fixed,
The wire electric discharge machining according to claim 11, wherein the control unit obtains an average value of the distance between the electrodes when the wire electrode is traveling based on the electrical data during the traveling and the relationship. Machine. The wire electrical discharge machine according to any one of claims 9 to 12, wherein the electrical data is a voltage value corresponding to a capacitance between electrodes. The wire electrical discharge machine according to any one of claims 9 to 12, wherein the electrical data is an inter-electrode capacitance. The wire electrical discharge machine according to any one of claims 9 to 12, wherein the electrical data is a resistance value between the wire electrode and the workpiece. The wire electrical discharge machine according to any one of claims 9 to 12, wherein the electrical data is a current value between the wire electrode and the workpiece. Obtaining first electrical data when the distance between the wire electrode and the workpiece is the first inter-electrode distance;
Obtaining second electrical data when the distance between the wire electrode and the workpiece is a second inter-pole distance;
Based on the first electrical data, the second electrical data, and the difference between the distance between the first pole and the distance between the second poles, an electric power that varies depending on the distance between the poles and the distance between the poles. Obtaining a relationship with the target data;
Measuring electrical data during travel of the wire electrode in a state where the position of the drive shaft of the drive unit that moves the wire electrode relative to the workpiece is determined;
Based on the electrical data during the travel and the relationship, obtaining an average value of the distance between the electrodes during travel of the wire electrode;
A wire position detection method comprising: The wire position detection method according to claim 17, wherein the electrical data is a voltage value corresponding to a capacitance between electrodes. The wire position detection method according to claim 17, wherein the electrical data is an inter-electrode capacitance. The wire position detection method according to claim 17, wherein the electrical data is a resistance value between the wire electrode and the workpiece. The wire position detection method according to claim 17, wherein the electrical data is a current value between the wire electrode and the workpiece.

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