JP6342073B1 - Wire electric discharge machine and method for determining reference position - Google Patents

Abstract

The wire electric discharge machine (50) includes a wire electrode (1), a traveling unit for traveling the wire electrode (1), a distance adjusting unit for adjusting a distance between the workpiece (5) and the wire electrode (1), A contact detection unit that detects contact and non-contact between the workpiece (5) and the wire electrode (1), and a reference position determination unit that determines a reference position of the workpiece (5) and the wire electrode (1). . The reference position determination unit brings the workpiece (5) and the wire electrode (1) close to each other, and when the first contact state is detected, the workpiece (5) and the wire electrode (1) are moved. The initial position is set based on the position of the wire electrode (1) when the non-contact state is detected by the contact detector, and the wire electrode (1) and the workpiece (5) are moved from the initial position. The position of the wire electrode (1) when the second contact state between the workpiece (5) and the wire electrode (1) is detected is determined as a reference position. The travel unit travels the wire electrode (1) while the reference position is determined.

Description

  The present invention relates to a wire electric discharge machine for processing a workpiece with a wire electrode and a method for determining a reference position.

  Wire electric discharge machines that process workpieces using wire electrodes are used. In the wire electric discharge machine, as shown in Patent Document 1, a reference position that is a machining start position at which the wire electrode starts machining a workpiece is detected.

Japanese Patent No. 4027834

  In the process of detecting the reference position, the reference position may be detected while running the wire electrode. When detecting the reference position while running the wire electrode, the processing time can be reduced by reducing the time required to detect the reference position and reducing the amount of wire electrode used to detect the reference position. There is a desire to plan.

  The present invention has been made in view of the above, and an object of the present invention is to reduce the amount of wire electrodes used for detecting a reference position.

  In order to solve the above-described problems and achieve the object, the present invention is a wire electric discharge machine that processes a workpiece with a wire electrode, and the wire electrode and the wire electrode are extended along the direction in which the wire electrode extends. A travel unit that travels, a distance adjustment unit that adjusts a distance between the workpiece and the wire electrode, a contact detection unit that detects contact and non-contact between the workpiece and the wire electrode, A reference position determination unit that determines a reference position. The reference position determination unit controls the distance adjustment unit to bring the workpiece and the wire electrode closer to each other, and when the first contact state between the workpiece and the wire electrode is detected by the contact detection unit, the distance is determined. The adjustment unit is controlled so that the workpiece and the wire electrode are separated from each other, and the initial state of the wire electrode is determined based on the position of the wire electrode when the non-contact state between the workpiece and the wire electrode is detected by the contact detection unit. The position is set, the distance adjusting unit is controlled to bring the wire electrode and the workpiece closer from the initial position, and the contact detection unit detects the second contact state between the workpiece and the wire electrode. The position of the wire electrode is determined as the reference position. The travel unit travels the wire electrode while the reference position is determined by the reference position determination unit.

  The wire electric discharge machine according to the present invention has an effect that the amount of wire electrode used for detecting the reference position can be suppressed.

The figure which shows schematic structure of the wire electric discharge machine concerning Embodiment 1 of this invention. Block diagram showing functional configuration of contact detection circuit and NC unit The flowchart which shows the procedure which determines a reference position in the wire electric discharge machine concerning Embodiment 1. FIG. The flowchart which shows the procedure which determines a reference position in the wire electric discharge machine concerning Embodiment 1. FIG. The figure which shows the hardware constitutions of NC apparatus with which the wire electric discharge machine concerning Embodiment 1 is provided. A diagram showing the vibration of the wire electrode traveling at the first speed and the vibration of the wire electrode traveling at the second speed The figure for demonstrating the general procedure which detects the center position of a hole with the wire electrode penetrated to the hole The figure which shows the state which inserted the wire electrode in the hole with little clearance in Embodiment 1

  Hereinafter, a wire electric discharge machine and a reference position determination 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 illustrating a schematic configuration of a wire electric discharge machine according to a first embodiment of the present invention. The wire electric discharge machine 50 includes a wire electrode 1 fed out from the wire bobbin 15, an upper machining head 4 that is a first guide part that supports the wire electrode 1, and a wire disposed below the upper machining head 4. And a lower processing head 7 which is a second guide portion for supporting the electrode 1. The wire electrode 1 delivered from the wire bobbin 15 passes through the upper machining head 4 and then passes through the lower machining head 7.

  The wire electric discharge machine 50 includes a main tension roller 2, a main tension motor 3, a wire collection roller 11, and a wire collection motor 12. The main tension roller 2, the main tension motor 3, the wire recovery roller 11, and the wire recovery motor 12 cause the wire electrode 1 to travel from the upper processing head 4 toward the lower processing head 7. That is, the wire electrode 1 travels along the direction in which the wire electrode 1 extends. In the following description, upstream and downstream terms are used with reference to the traveling direction of the wire electrode 1.

  The wire recovery roller 11 and the wire recovery motor 12 are provided on the downstream side of the lower processing head 7. The wire recovery roller 11 is connected to the output shaft of the wire recovery motor 12 and rotates in conjunction with the output shaft of the wire recovery motor 12. The wire recovery motor 12 has an encoder (not shown), and rotates the wire recovery roller 11 to cause the wire electrode 1 to travel at a constant speed. The wire electrode 1 that has passed through the wire collection roller 11 and the wire collection motor 12 is collected in a collection box 16.

  The main tension roller 2 and the main tension motor 3 are provided on the upstream side of the upper processing head 4. The main tension roller 2 is connected to the output shaft of the main tension motor 3 and rotates in conjunction with the output shaft of the main tension motor 3. The main tension motor 3 has an encoder (not shown) and applies a specified tension to the traveling wire electrode 1.

  In other words, the wire electrode 1 travels from the upper processing head 4 toward the lower processing head 7 while applying a specified tension by the main tension motor 3 and the wire recovery motor 12. A portion of the wire electrode 1 between the upper machining head 4 and the lower machining head 7 becomes a machining area, and the workpiece 5 is cut and processed when the machining area approaches the workpiece 5.

  The wire electric discharge machine 50 includes a surface plate 6 on which a workpiece 5 to be cut by the wire electrode 1 is placed. The surface plate 6 and the workpiece 5 are formed of a conductive material. Further, the wire electric discharge machine 50 includes a surface plate motor 9. The surface plate motor 9 is a distance adjusting unit that adjusts the distance between the workpiece 5 and the wire electrode 1 by moving the surface plate 6. In the first embodiment, an example is given in which the distance between the workpiece 5 and the wire electrode 1 is adjusted by moving the surface plate 6, but the wire electrode 1 is moved together with the upper machining head 4 and the lower machining head 7. Thus, the distance between the workpiece 5 and the wire electrode 1 may be adjusted. Moreover, you may comprise so that both the surface plate 6 and the wire electrode 1 may be moved and the distance of the to-be-processed object 5 and the wire electrode 1 may be adjusted.

  The wire electric discharge machine 50 includes a machining liquid supply device 13 that supplies a machining liquid to the wire electrode 1 between the upper machining head 4 and the lower machining head 7. The processing liquid is, for example, water. The wire electric discharge machine 50 includes a linear scale 17 that detects a relative position between the surface plate 6 and the wire electrode 1.

  The wire electric discharge machine 50 includes a contact detection circuit 8 and an NC (Numerical Control) device 10. FIG. 2 is a block diagram showing functional configurations of the contact detection circuit 8 and the NC device 10.

  The contact detection circuit 8 includes a potential difference applying unit 21, a potential difference detection unit 22, and a contact determination unit 23. The potential difference applying unit 21 applies a potential difference between the wire electrode 1 and the surface plate 6. Thereby, a potential difference is generated between the workpiece 5 placed on the surface plate 6 and the wire electrode 1. The potential difference detection unit 22 detects a potential difference generated between the workpiece 5 and the wire electrode 1. The contact determination unit 23 determines contact or non-contact between the workpiece 5 and the wire electrode 1 based on the change in potential difference detected by the potential difference detection unit 22. The contact determination unit 23 determines contact and non-contact every sampling cycle. Contact information indicating contact and non-contact determined for each sampling period is transmitted to the NC device 10. In the following description, contact detection means detection of contact in one sampling cycle, and non-contact detection means non-contact detection in one sampling cycle. means.

  The NC device 10 includes a drive control unit 31, a storage unit 32, a machining control unit 33, and a contact state determination unit 34. The drive control unit 31 drives the main tension motor 3 and the wire recovery motor 12 to run the wire electrode 1. The drive control unit 31 is a traveling unit that causes the wire electrode 1 to travel. Further, the drive control unit 31 drives the surface plate motor 9 to adjust the distance between the workpiece 5 and the wire electrode 1. The storage unit 32 stores a machining program. The machining control unit 33 controls the drive control unit 31, the potential difference applying unit 21, and the machining liquid supply device 13 according to the machining program stored in the storage unit 32 to process the workpiece 5. Specifically, the wire electrode 1 to which a potential difference is applied is moved closer to the workpiece 5 while traveling at the first speed, and the workpiece 5 is cut by electric discharge generated when the wire electrode 1 is moved closer. The processing control unit 33 continues to supply the processing liquid from the processing liquid supply device 13 to the wire electrode 1 during the processing process in which the workpiece 5 is processed by the wire electrode 1.

  The contact state determination unit 34 performs a position detection process for determining a reference position based on the contact information transmitted from the contact determination unit 23. The contact state determination unit 34 is a reference position determination unit that determines a reference position that is a processing start position when the workpiece 5 is processed by the wire electrode 1. In the position detection process, the contact state determination unit 34 controls the drive control unit 31, the potential difference applying unit 21, and the machining liquid supply device 13 to determine a reference position. During the position detection process, the contact state determination unit 34 drives the main tension motor 3 and the wire recovery motor 12 by the drive control unit 31 to cause the wire electrode 1 to travel at a second speed lower than the first speed. . Further, the contact state determination unit 34 continues to supply the processing liquid from the processing liquid supply device 13 to the wire electrode 1 during the position detection process. Further, in the position detection process, the contact state determination unit 34 controls the surface plate motor 9 by the drive control unit 31 to determine the reference position while changing the distance between the workpiece 5 and the wire electrode 1. The procedure for determining the reference position while changing the distance between the workpiece 5 and the wire electrode 1 in the position detection step will be described in detail.

  FIG. 3 and FIG. 4 are flowcharts showing a procedure for determining the reference position in the wire electric discharge machine 50 according to the first embodiment. First, as shown in FIG. 3, the machining fluid is taken out from the machining fluid supply device 13 and supplied to the wire electrode 1 (step S1). Next, the wire electrode 1 is caused to travel at a second speed that is the same tension as that in the processing step and is lower than the first speed (step S2). Next, when there is an input from the user in the direction in which the workpiece 5 and the wire electrode 1 are brought closer to each other when performing the position detection process (step S3, Yes), the surface plate 6 is moved in the inputted approaching direction. Then, the workpiece 5 and the wire electrode 1 are brought closer to each other (step S4). If there is no input from the user in the direction in which the workpiece 5 and the wire electrode 1 are brought closer to each other when performing the position detection step (No in step S3), the determination in step S3 is repeated to wait for the input in the approaching direction .

  Here, the vibration of the wire electrode 1 while the wire electrode 1 is traveling will be described. The wire electrode 1 vibrates with an amplitude in a direction perpendicular to the extending direction of the wire electrode 1 by friction with a wire guide (not shown) in the upper processing head 4 and the lower processing head 7.

  In a state where the workpiece 5 and the wire electrode 1 are sufficiently separated, the non-contact between the workpiece 5 and the wire electrode 1 is continuously detected. When the workpiece 5 and the wire electrode 1 are brought close to some extent from there, contact and non-contact between the workpiece 5 and the wire electrode 1 are repeated by vibration of the wire electrode 1. As the workpiece 5 and the wire electrode 1 are further brought closer from there, the number of times the contact between the workpiece 5 and the wire electrode 1 is detected per unit time increases and eventually continues. Touch is detected.

  As described above, on the assumption that the wire electrode 1 is vibrating, the description returns to the procedure of the position detection step. When the workpiece 5 and the wire electrode 1 are brought closer to each other and the first contact state between the workpiece 5 and the wire electrode 1 is detected (step S5, Yes), the workpiece 5 is fixed in a direction opposite to the approaching direction. The board 6 is moved to separate the workpiece 5 and the wire electrode 1 (step S6). If the first contact state between the workpiece 5 and the wire electrode 1 is not detected (step S5, No), the determination in step S5 is repeated until the first contact state is detected. 5 and the wire electrode 1 are brought close to each other. The first contact state in the first embodiment is a state in which the contact between the workpiece 5 and the wire electrode 1 continues for a set time.

  When the non-contact between the workpiece 5 and the wire electrode 1 is detected in the process of separating the workpiece 5 and the wire electrode 1 in step S6 (step S7, Yes), the surface plate 6 is stopped. (Step S8).

  Here, when the non-contact state between the workpiece 5 and the wire electrode 1 is detected (step S9, Yes), the number of positionings n = 0 is stored in the storage unit 32 (step S11). The coordinates of the board 6 are stored in the storage unit 32 (step S12). Note that the coordinates of the surface plate 6 stored in step S12 are set as initial positions. When setting the initial position, the surface plate 6 is moved by a specified distance from the position where the non-contact state between the workpiece 5 and the wire electrode 1 is detected, and the workpiece 5 and the wire electrode 1 are moved. The released position may be set as the initial position. The non-contact state is a state in which non-contact has continued for a set time, that is, a state in which non-contact between the workpiece 5 and the wire electrode 1 has been detected for the designated number of sampling times.

  In step S9, when the non-contact between the workpiece 5 and the wire electrode 1 is not detected for a set time (step S9, No), the workpiece 5 and the wire electrode 1 are further separated (step S10). Then, the surface plate 6 is stopped (step S8), and it is confirmed whether the non-contact between the workpiece 5 and the wire electrode 1 continues for a set time (step S9). That is, separating the workpiece 5 and the wire electrode 1 is repeated until the non-contact between the workpiece 5 and the wire electrode 1 continues for a set time. For example, the set time is 1 second. Further, it is desirable that the moving distance of the surface plate 6 when separating the workpiece 5 and the wire electrode 1 in step S10 is a very small distance, for example, the minimum unit moving distance that can be realized in the wire electric discharge machine 50. Also good. Alternatively, the distance may be the same as the diameter of the wire electrode 1.

When the initial position is stored in step S12, contact counter information i = 0 and non-contact counter information j = 0 are stored in the storage unit 32 as shown in FIG. 4 (step S13). Next, when contact between the workpiece 5 and the wire electrode 1 is detected (step S14, Yes), the contact counter information i is updated with i = i + 1 (step S18). Next, when i ≧ 500 is satisfied (step S19, Yes), the coordinates of the surface plate 6 at that time are stored in the storage unit 32 as the temporary reference position _Pn (step S20). If i ≧ 500 is not satisfied in step S19 (No in step S19), the process returns to step S14. The state where the contact counter information i is i ≧ 500 is the second contact state.

  When contact between the workpiece 5 and the wire electrode 1 is not detected in step S14 (No at step S14), that is, when contact between the workpiece 5 and the wire electrode 1 is detected, non-contact counter information. j is updated with j = j + 1 (step S15). Next, when j ≧ 500 is satisfied (step S16, Yes), the workpiece 5 and the wire electrode 1 are brought close to each other (step S17), and the process returns to step S13, where i = 0 and j = 0. Is memorized. In step S16, when j ≧ 500 is not satisfied (step S16, No), the process returns to step S14.

  In step S13 to step S16 described above, contact and non-contact are detected at that position until the contact counter information i or the non-contact counter information j reaches a specified number. When the non-contact counter information j reaches the specified number, 500 in the first embodiment, before the contact counter information i, the workpiece 5 and the wire electrode 1 are brought close to each other, and the contact counter information i After the non-contact counter information j is reset to 0, contact and non-contact are detected again at that position until the contact counter information i or the non-contact counter information j reaches a specified number.

  When the contact counter information i reaches the designated number 500 in the first embodiment before the non-contact counter information j, the coordinates of the position are stored as a temporary reference position. That is, in steps S13 to S20, the position at which the contact counter information i reaches the specified number is detected while gradually moving the workpiece 5 and the wire electrode 1 from the initial position. Here, as shown in step S9 to step S12, the position where the non-contact between the workpiece 5 and the wire electrode 1 continues for the set time is the initial position, and the contact counter information i indicates the designated number first in the initial position. It is hard to think of exceeding. In the process of gradually approaching the workpiece 5 and the wire electrode 1 from there, the non-contact counter information j is also a value close to the specified number when the contact counter information i first exceeds the specified number. It is thought that it has become. That is, in the first embodiment, a position where contact and non-contact are detected at substantially the same rate per unit time is set as a temporary reference position. In addition, when i> = 500 in step S19 (step S19, Yes), it is more reliable by adding a step of confirming whether the non-contact counter information j is a constant value, for example, j> 490. Positions where contact and non-contact are detected at substantially the same rate per unit time may be set as the temporary reference position. If j ≧ 490 is not satisfied, it is determined that the workpiece 5 and the wire electrode 1 are too close to each other, and the temporary reference position is detected again after returning to the initial position.

When the temporary reference position P _n is stored in step S20, the positioning number n is updated with n = n + 1 (step S21). If became n ≧ N (step S22, Yes), as the temporary reference position of the specified is detected, it calculates the coordinates obtained by averaging the P _n from P ₁ (step S24), and calculated coordinate reference The table 6 is stored as a position, and the surface plate 6 is moved to the reference position (step S25). If n ≧ N is not satisfied in step S22 (No in step S22), the surface plate 6 is moved to the initial position (step S23), and then the process returns to step S13 until n ≧ N. The detection of the reference position is repeated. In the description of the procedure of the position detection step, an example in which the surface plate 6 is moved is described. However, when a mechanism for moving the wire electrode 1 is also provided, the surface plate 6 and the wire electrode 1 are moved. At least one of them may be moved. Moreover, what is necessary is just to move the wire electrode 1, when the mechanism which moves the surface plate 6 is not provided but the mechanism which moves the wire electrode 1 is provided. In the above procedure, Step S1 to Step S5 is the first period in which the workpiece 5 and the wire electrode 1 are brought close to each other, and Step S6 to Step S12 separate the workpiece 5 and the wire electrode 1 from each other. This is a second period, and Steps S13 to S25 are a third period in which the workpiece 5 and the wire electrode 1 are brought closer to each other.

  Since the reference position determined by the above procedure is a position where contact and non-contact are detected at substantially the same rate per unit time, the center of amplitude of the vibrating wire electrode 1 and the workpiece 5 In other words, the position where the end face of the reference line is the reference position. Therefore, by setting the reference position as the processing start position, the position at which the wire electrode 1 starts processing the workpiece 5 can be optimized, and the quality of the product obtained by the processing can be improved.

  FIG. 5 is a diagram illustrating a hardware configuration of the NC apparatus 10 included in the wire electric discharge machine 50 according to the first embodiment. The NC device 10 includes an arithmetic device 41 and a storage device 42. The computing device 41 is exemplified by a CPU (Central Processing Unit). The functions of the drive control unit 31, the processing control unit 33, and the contact state determination unit 34 described above are realized by the arithmetic device 41. Examples of the storage device 42 include a semiconductor memory, a magnetic disk, and an optical disk. The functions of the storage unit 32 described above are realized by the storage device 42. The storage device 42 stores a program that causes the arithmetic device 41 to perform the above functions. The storage device 42 is also used as a primary storage area when the arithmetic device 41 executes a program. Examples of the program include software, firmware, or a combination of software and firmware.

  According to the wire electric discharge machine 50 described above, in the position detection process for detecting the reference position, the wire electrode is operated at the second speed that is lower than the first speed that is the traveling speed of the wire electrode 1 in the machining process. 1 is running. Therefore, consumption of the wire electrode in the position detection process can be suppressed, and processing costs can be suppressed. Further, the position detection is performed in a state close to the state of the wire electrode 1 during the processing step, that is, the wire electrode 1 is run and the processing liquid is also supplied to the wire electrode 1 for position detection. The detection accuracy can be improved.

  Further, until the initial position is determined in the position detecting step, the workpiece 5 and the wire electrode 1 are not brought close in steps in the process of bringing the workpiece 5 and the wire electrode 1 closer, so that the workpiece 5 and the wire electrode can be obtained in a short time. The surface plate 6 can be moved to a position where the plate 1 comes into contact. Therefore, it is possible to reduce the time until the initial position is determined, that is, the time required for the position detection process. Thereby, consumption of the wire electrode 1 used in a position detection process can be suppressed, and processing cost can be suppressed.

  In addition, since the initial position is determined in step S12 and returned to the initial position every time the temporary reference position is determined, it is not necessary to repeat the process of determining the initial position, and the time required for the position detection process can be shortened. Can be planned. Thereby, consumption of the wire electrode 1 used in a position detection process can be suppressed, and processing cost can be suppressed.

  Further, the workpiece 5 and the wire electrode 1 as shown in FIG. 3 and FIG. 4 are brought closer in the first period, separated in the second period, and approached in the third period. Even if it is not a procedure for determining the position, if the reference position is determined while the wire electrode 1 is traveling at the second speed that is lower than the first speed, the consumption of the wire electrode can be suppressed. Processing costs can be reduced. That is, the term of the reference position used in the present embodiment does not indicate only the position determined by the procedure shown in FIGS.

  Moreover, since the position detection is performed by running the wire electrode 1 at the second speed lower than the first speed, the amplitude of the wire electrode 1 can be suppressed. FIG. 6 is a diagram showing the vibration of the wire electrode 1 traveling at the first speed and the vibration of the wire electrode 1 traveling at the second speed. In FIG. 6, the vertical axis represents the position of the wire electrode 1, and the horizontal axis represents time. As shown in FIG. 6, since the amplitude of the wire electrode 1 can be suppressed by running the wire electrode 1 at a low second speed, the accuracy of position detection can be improved.

  Further, in the wire electric discharge machine 50, the reference position is determined while moving the workpiece 5 and the wire electrode 1 from the initial position in a direction in which they are brought closer. Here, the machining liquid is supplied to the wire electrode 1 in the position detection step. The machining fluid supplied to the wire electrode 1 flows down around the wire electrode 1.

  In the case where the reference position is determined while moving the workpiece 5 and the wire electrode 1 closer to each other as in the first embodiment, until the wire electrode 1 contacts the workpiece 5, the wire electrode Since the machining liquid is flowing down around the entire circumference of the wire 1, excessive deformation of the wire electrode 1 hardly occurs due to the force of the wire electrode 1 flowing down the machining liquid.

  On the other hand, when determining the reference position while moving the workpiece 5 and the wire electrode 1 away from the state in which the workpiece 5 and the wire electrode 1 are in contact, the workpiece 5 and the wire electrode are determined. In the state where 1 is in contact, the machining fluid cannot enter the contact portion. Then, in the process of separating the workpiece 5 and the wire electrode 1, when the force for the wire electrode 1 to contact the workpiece 5 is weakened, the workpiece 5 and the wire electrode are in contact with each other. The machining fluid flows in. For this reason, the wire electrode 1 is pushed away by the processing liquid that has flowed in, and excessive deformation easily occurs. Therefore, when the reference position is determined while moving the workpiece 5 and the wire electrode 1 closer to each other as in the first embodiment, the occurrence of the reference position error due to the deformation of the wire electrode 1 can be suppressed. it can.

  Further, the wire electric discharge machine 50 can detect the center position of the minute hole formed in the workpiece 5. FIG. 7 is a diagram for explaining a general procedure for detecting the center position of the hole with the wire electrode 1 penetrating the hole. When the center position of the hole 25 formed in the workpiece 5 is detected, steps (1) to (6) shown in FIG. 7 are performed. In step (1), the end surface in the + Y direction is measured, and in step (2), the end surface in the -Y direction is measured. In the step (3), the wire electrode 1 is moved to the center position of the end face measured in the step (1) and the end face measured in the step (2). In step (4), the end surface in the + X direction is measured, and in step (5), the end surface in the -X direction is measured. In step (6), the wire electrode 1 is moved to the center position between the end face measured in (4) and the end face measured in (5). The position where the wire electrode 1 is located after the step (6) is the center position of the hole 25. Here, in steps (1), (2), (4), (5), the reference position shown in FIGS. 3 and 4 is detected, and the detected reference position is the position of the end face of the hole 25. Become.

  FIG. 8 is a diagram showing a state in which the wire electrode 1 is inserted into a hole having a small clearance in the first embodiment. The diameter of the hole 25 formed in the workpiece 5 is 70 μm, and the diameter of the wire electrode 1 inserted into the hole 25 is 50 μm. Therefore, the gap between the wire electrode 1 and the hole 25 is 10 μm at the maximum. Even in such a case, in the wire electric discharge machine 50 according to the first embodiment, the distance between the workpiece 5 and the wire electrode 1 is realized in the wire electric discharge machine 50 in step S10 shown in FIG. If the distance is set to a minute distance such as the smallest possible moving distance, the center position of the hole 25 can be detected without causing the wire electrode 1 to collide with the workpiece 5 in step S10.

  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 Main tension roller, 3 Main tension motor, 4 Upper processing head, 5 Work piece, 6 Surface plate, 7 Lower processing head, 8 Contact detection circuit, 9 Surface plate motor, 10 NC device, 11 Wire recovery Roller, 12 wire recovery motor, 13 machining fluid supply device, 15 wire bobbin, 16 recovery box, 17 linear scale, 21 potential difference application unit, 22 potential difference detection unit, 23 contact determination unit, 25 holes, 31 drive control unit, 32 storage unit , 33 Processing control unit, 34 Contact state determination unit, 50 Wire electric discharge machine.

Claims (9)

A wire electric discharge machine for processing a workpiece with a wire electrode,
The wire electrode;
A traveling unit that travels the wire electrode along a direction in which the wire electrode extends;
A distance adjusting unit for adjusting a distance between the workpiece and the wire electrode;
A contact detection unit for detecting contact and non-contact between the workpiece and the wire electrode;
A reference position determining unit for determining a reference position of the workpiece and the wire electrode,
The reference position determination unit
In the first period, the distance adjusting unit is controlled to bring the workpiece and the wire electrode closer, and when a first contact state between the workpiece and the wire electrode is detected, And controlling the distance adjusting unit to separate the workpiece and the wire electrode during a period of 2, and based on a non-contact time between the workpiece and the wire electrode, the workpiece and the wire electrode The initial position of the wire electrode is set based on the position of the wire electrode when a non-contact state is detected, and the distance adjustment unit is controlled in the third period from the initial position to the wire electrode. Approaching the workpiece, determining the position of the wire electrode when the second contact state between the workpiece and the wire electrode is detected as the reference position,
The traveling unit causes the wire electrode to travel in the first period, the second period, and the third period,
The non-contact state is a state in which non-contact between the workpiece and the wire electrode is detected continuously for a set time by the contact detection unit,
The reference position determination unit performs a plurality of times to detect the second contact state by bringing the wire electrode closer to the workpiece from the initial position in the third period, and the second contact state is A wire electric discharge machine, wherein a position of the wire electrode when detected is set as a temporary reference position, and a position obtained by averaging a plurality of the temporary reference positions is determined as the reference position.   The wire electric discharge machine according to claim 1, wherein the first contact state is a state detected based on a contact time between the workpiece and the wire electrode.   The wire electric discharge machine according to claim 1 or 2, wherein the second contact state is a state detected based on the number of contact between the workpiece and the wire electrode.   The second contact state is a state in which the contact detection unit determines that the ratio of contact between the workpiece and the wire electrode per unit time is a certain level or more. The wire electric discharge machine described in 1. A machining fluid supply unit for supplying a machining fluid to the wire electrode;
5. The processing liquid supply unit supplies the processing liquid to the wire electrode in the first period, the second period, and the third period. 6. Wire electrical discharge machine as described in 1.   2. The traveling part makes the traveling speed of the wire electrode lower than the traveling speed of the wire electrode when the workpiece is processed while the reference position is determined. To 5. The wire electric discharge machine according to any one of 5 to 5. A method for determining a reference position of the workpiece and the wire electrode in a wire electric discharge machine that processes the workpiece with a wire electrode,
Bringing the workpiece and the wire electrode closer in a first period, and detecting a first contact state between the workpiece and the wire electrode;
When the first contact state is detected in the second period, the workpiece and the wire electrode are separated from each other, and a non-contact state between the workpiece and the wire electrode is detected Setting the initial position of the wire electrode based on the position of the wire electrode;
In the third period, the wire electrode and the workpiece are brought closer from the initial position, and the position of the wire electrode when the second contact state between the workpiece and the wire electrode is detected is determined. Determining the reference position; and
Running the wire electrode along the extending direction of the wire electrode in the first period, the second period, and the third period;
The non-contact state is a state where non-contact between the workpiece and the wire electrode is continuously detected for a set time,
In the step of determining the reference position, the second contact state is detected a plurality of times by bringing the wire electrode closer to the workpiece from the initial position in the third period, and detecting the second contact state. A method for determining a reference position, wherein the position of the wire electrode when a state is detected is set as a temporary reference position, and a position obtained by averaging a plurality of the temporary reference positions is determined as the reference position. A wire electric discharge machine for processing a workpiece with a wire electrode,
The wire electrode;
A traveling unit that travels the wire electrode along a direction in which the wire electrode extends;
A distance adjusting unit for adjusting a distance between the workpiece and the wire electrode;
A potential difference applying unit that generates a potential difference between the workpiece and the wire electrode;
A contact detection unit that detects contact and non-contact between the workpiece and the wire electrode based on the change in the potential difference ;
A reference position determination unit that determines a reference position of the workpiece and the wire electrode based on a detection result by the contact detection unit;
The travel unit causes the wire electrode to travel at a lower speed than the travel speed of the wire electrode when the workpiece is processed while the reference position is determined by the reference position determination unit. Wire electric discharge machine. A method for determining a reference position of the workpiece and the wire electrode in a wire electric discharge machine that processes the workpiece with a wire electrode,
A potential difference is generated between the workpiece and the wire electrode, a contact state between the workpiece and the wire electrode is detected based on a change in the potential difference, and the reference is based on the detected contact state Determining the position,
While the reference position is determined, the wire electrode travels along the direction in which the wire electrode extends, and the wire electrode travels at a lower speed than the traveling speed of the wire electrode when the workpiece is processed. And determining a reference position.

Images