JP2008044033A - Wire electric discharge machine and wire discharge machining method - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To efficiently perform an auxiliary operation associated with measurement of the work parallelism in accordance with the taper processing and vertical processing. <P>SOLUTION: The operations and associated processing S1-S4 are executed under the condition that the mode of vertical processing is set, while the operations/processing S11-S16 are conducted under the condition that the mode of taper processing is set. At S1 and S11, the XY positions of P1-P3 corresponding to three measuring points not lying on one straight line on the work oversurface and the Z positions corresponding to a small distance over the work oversurface are entered into the screen. At S12, the height of the reference surface (work thickness) is entered, and at S2 and S13, the measuring program is started. At S14, the components Δx, Δy, Δz of the offset are determined using a tool and stored. At S3 and S15, the three-dimensional positions of the contacting points Q1-Q3 on the work oversurface corresponding to the points P1-P3 specified using a touch probe are measured. The overhung setting direction of a wire electrode is adjusted by using the data entered or measured in each mode, and straight processing or taper processing is executed upon calculating (S4 and S16) the correction amount of a command based on the processing program. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  The present invention relates to a wire electric discharge machine and a wire electric discharge machining method, and more specifically, in the wire electric discharge machine and the wire electric discharge machining method, the influence of workpiece inclination depending on whether taper machining or vertical machining is performed. The present invention relates to a technique for rationalizing a removal procedure.

  In general, in machining using a wire electric discharge machine, a workpiece is placed on a table, and a wire electrode is moved relative to the table on an XY plane composed of an X axis and a Y axis perpendicular to the X axis. Thus, the workpiece is processed. In this case, ideally, it is assumed that the workpiece mounting posture is such that “the reference surface (upper surface or lower surface) is completely parallel to the XY plane”. The movement command of each axis according to the machining program for determining the relative movement of the wire electrode with respect to the table is basically output so as to realize a desired machining path under this assumption.

  However, in actual machining, there is a deviation from such a “perfectly parallel” posture, and the workpiece is in a certain direction (inclination size) in either direction (inclination direction) with respect to the XY plane. ) Is usually inclined. As is well known, if processing is performed while ignoring this inclination, the intended processing cannot be realized. That is, as shown in FIG. 1A, when the inclination angle E cannot be ignored, the machining distance on the workpiece reference surface (here, the upper surface) does not follow the command, and the machining shape is also distorted.

  In order to avoid this, as shown in FIG. 1B, the stretching direction of the wire electrode (hereinafter also simply referred to as “wire”) is changed corresponding to the inclination of the workpiece, and the command C is changed to C + α ( A method of correcting to α = necessary correction amount) has already been proposed (see, for example, Patent Documents 1 and 2 below).

  Thus, in the machining using the wire electric discharge machine, the parallelism of the workpiece to be machined is measured, the inclination of the wire is corrected to be perpendicular to the workpiece inclined in the three-dimensional direction, and the amount of movement of the wire ( Correct machining distance). And the technique (henceforth a workpiece | work horizontal correction | amendment) which processes the workpiece | work inclined by this according to a command has been already established.

By the way, when measuring the parallelism of a workpiece for the purpose of workpiece horizontal correction, an elevating touch probe (measuring element) is attached to the upper guide, as shown in an embodiment described later. This means is used because the upper guide serving as a control point cannot be brought into direct contact with the workpiece (covered by the nozzle). The touch probe is attached at a position offset by a certain amount from the upper guide.
When performing measurement, the tip of the touch probe descends below the top guide tip, and when not performing measurement (such as during processing), it rises above the top guide tip. At the time of measurement, with the touch probe lowered, the Z axis (the vertical movement axis of the upper guide) is lowered, and the XYZ axis coordinate values when the tip of the probe contacts the workpiece upper surface are read. This measurement is performed for three or more points that are not aligned. Then, the following data (1) and (2) are acquired.

(1) The tilt angle and tilt direction of the workpiece. This data is obtained from the correlation of the coordinates of each measurement point.
(2) Three-dimensional position of the workpiece upper surface (measurement surface). This data is obtained from the coordinates of each measurement point. However, since the direct coordinate value of each measurement point is a coordinate value when the probe tip contacts the workpiece upper surface, the coordinate value is deviated from the upper guide serving as the control point by a certain amount. Therefore, it is necessary to measure this deviation amount (probe mounting offset amount).

  In the workpiece horizontal correction, the tilt of the wire is made perpendicular to the upper surface of the workpiece by correcting the position of the UV axis (wire tilt movement axis) with respect to the workpiece tilted in the three-dimensional direction. The data necessary for this correction is the above-mentioned data (1) (tilt angle / direction).

Next, the movement amount correction of the wire is corrected so that the movement amount of the same surface of both the workpieces installed horizontally and inclined is the same. For example, the amount of movement between a workpiece upper surface (hereinafter referred to as a reference surface) installed horizontally (hereinafter referred to as a reference surface) and a workpiece upper surface (surface measured by a probe; hereinafter referred to as a correction target surface) installed at an inclination is The XY axis and the UV axis are corrected so as to be the same.
First, there is a reference plane as data necessary for this correction, and this data is input beforehand as data measured outside the machine, such as the workpiece thickness. Next, on the correction target surface, this can be given by the data of (2) above.

Japanese Patent No. 2667475 JP-A-2-139129

  As described above, in the workpiece horizontal correction and the workpiece parallelism measurement, ancillary operations such as data input of the reference surface height and measurement of the probe tip deviation amount are necessary, and complicated operations are always necessary. The basic object of the present invention is to make it possible to efficiently perform these incidental operations without waste depending on whether the workpiece machining is tapered or non-tapered (vertical machining).

  According to the present invention, a workpiece is placed on a table, and a wire electrode stretched between an upper guide and a lower guide is placed on the table in an XY plane composed of an X axis and a Y axis perpendicular to the X axis. Select the mode of taper machining and non-taper machining (vertical machining) in the wire-cut electric discharge machine that moves relative to the workpiece, or the wire-cut electric discharge machine using the same wire-cut electric discharge machine When the latter is selected, the above-mentioned problem is solved by reducing the necessary amount of incidental operations such as input of reference plane height data, measurement of probe offset, and input.

  According to the present invention, the wire cut electric discharge machine includes a machining mode selection unit that selects one of a taper machining mode in which taper machining is performed and a vertical machining mode in which taper machining is not performed, and the position of the upper guide. An inclination measuring means for measuring the inclination of the workpiece placed on the table using the measuring element, and a machining mode selecting means. When the taper machining mode is selected, based on the magnitude and direction of the inclination of the workpiece with respect to the XY plane measured by the inclination measuring means, the reference surface height of the workpiece, and the offset amount, Tilt correction for inclining the wire electrode with respect to the ± Z direction perpendicular to the XY plane, and the wire electrode with respect to the machining path specified by the machining program When the vertical correction mode is selected by the first correction unit that performs XY position correction and the processing mode selection unit, the magnitude and direction of the inclination of the workpiece with respect to the XY plane measured by the inclination measurement unit The second correction means for correcting the inclination of the wire electrode and the XY position of the wire electrode with respect to the machining path specified by the machining program, and the first correction means or the second correction. Means for executing machining according to the machining program under the correction of the inclination of the wire electrode and the XY position correction by the means.

Here, the reference surface height is a height from the lower surface of the workpiece placed horizontally on the table to the upper surface of the workpiece. Further, the inclination measuring means includes means for obtaining a three-dimensional relative positional relationship of at least three points that are not aligned on a straight line on the upper surface of the work placed on the table, using the measuring element. A device capable of measuring the magnitude and the direction of the inclination of the workpiece with respect to the XY plane based on the obtained three-dimensional relative positional relationship may be adopted.
The offset amount can be obtained by measuring a reference position whose three-dimensional position is known with the measuring element.

  In the wire-cut electric discharge machining method according to the present invention, a workpiece is placed on a table, and a wire electrode stretched between an upper guide and a lower guide is composed of an X axis and a Y axis perpendicular to the X axis. A measuring element that moves relative to the table in the XY plane and a position that is movable between the upper guide and the position of the upper guide, and is mounted on the table using the measuring element. The present invention is applied to a wire cut electric discharge machining method using a wire cut electric discharge machine equipped with an inclination measuring means for measuring the inclination of the placed workpiece.

The feature is that a step of selecting one of a taper machining mode in which taper machining is performed on the workpiece and a vertical machining mode in which taper machining is not performed are selected, and a first step group according to a selection result in the first step. Or it consists of the step which performs either one of the 2nd step group.
Here, the first step group uses an input step for inputting the reference surface height of the workpiece to the wire cut electric discharge machine, an offset amount measuring step for measuring the offset amount, and the inclination measuring means. A tilt measuring step for measuring a tilt magnitude and a tilt direction of the workpiece with respect to the XY plane, and a tilt magnitude with respect to the XY plane of the workpiece placed on the table, measured in the tilt measuring step; The wire electrode is inclined with respect to the ± Z direction perpendicular to the XY plane based on the direction of inclination, the reference surface height input in the input step, and the offset amount measured in the offset amount measuring step. First, the machining is performed while correcting the XY position of the wire electrode with respect to the machining path specified by the machining program. Consisting of a processing step.

  On the other hand, the second step group includes an inclination measuring step for measuring the magnitude and direction of inclination of the workpiece with respect to the XY plane using the inclination measuring means, and the table measured in the inclination measuring step. The wire electrode is inclined with respect to the ± Z direction perpendicular to the XY plane based on the magnitude and direction of the inclination of the workpiece placed on the XY plane and specified by the machining program. It consists of a second processing step for correcting the processing path and executing processing. The reference surface height is a height from the lower surface of the workpiece placed horizontally on the table to the upper surface of the workpiece.

  According to the present invention, whether the workpiece machining is a taper machining or not in connection with the necessity of ancillary operations related to workpiece parallelism measurement and horizontal correction, such as input of reference plane height data and measurement of probe mounting offset. Depending on whether it is non-taper processing (vertical processing), these incidental operations can be performed efficiently without waste.

  FIG. 2 is a diagram schematically showing a schematic configuration of the wire electric discharge machine employed in the embodiment of the present invention, and the configuration of the part related to the processing of the wire electric discharge machine is the same as the conventional one. In other words, reference numeral 1 denotes a work table on which a work 30 to be processed is set and fixed, and has a flat mounting surface 2. At the time of processing, the work 30 is installed and fixed to the work table so that the lower surface 32 thereof is in contact with the placement surface 2. The work 30 has a surface whose entire upper surface 31 is parallel to the lower surface 32. The workpiece 30 is assumed to have a surface (flat region) parallel to the lower surface 32. Here, a rectangular shape is illustrated as the work 30, and the entire upper surface 31 is a surface parallel to the lower surface 32, but only a part of the upper surface may be a surface parallel to the lower surface. .

  Reference numeral 7 denotes a wire electrode that is supplied from the wire supply unit 12 through the guide roller 11 and the like in order to perform electric discharge machining on the workpiece 30, and is stretched between the upper and lower guides 5 and 6 by a connection operation at the time of machining. During this period, a voltage for causing discharge is applied. Reference numeral 14 denotes a wire take-up portion that has a function of pulling and winding the wire electrode 7 that has passed through the lower guide 6 and the guide roller 13 with a predetermined tension.

  The machining location is a linear portion where the wire electrode 7 penetrates the workpiece 30, and is represented by a machining point 33 on the upper surface 31. In order to move the machining point 33 along the intended trajectory on the workpiece 30 (also called a machining line, which is usually specified by a machining program), the work table 1 has an X-axis that uses a servo motor as a drive source. The drive mechanism 3 and the Y-axis drive mechanism 4 can move in the XY plane. Reference numeral 34 exemplifies the movement trajectory (machined machining line) of the machining point 33.

  Further, the XYZ position of the upper guide 5 can be adjusted by a Z-axis drive mechanism 8, a U-axis drive mechanism 9 and a V-axis drive mechanism 10. In general, adjustment of the Z position is used to set the distance between the upper guide 5 and the upper surface 31 of the workpiece 30 to a predetermined appropriate value during processing. It is also used when measuring the degree. On the other hand, the U-axis / V-axis drive mechanisms 9 and 10 are generally used for adjusting the angle of the taper processing described above, but in this embodiment, the workpiece 30 is adjusted based on the measurement result. It is also used for upper guide position adjustment to compensate for installation posture errors.

Reference numeral 100 denotes a touch probe unit attached to the upper guide 5 for measuring the level of the workpiece installation posture, and includes a probe (measuring element) that contacts the upper surface 31 of the workpiece 30. The structure and function of the touch probe unit, the procedure for measuring the levelness, the details of the adjustment based on the measurement result, etc. will be described later.
Reference numeral 20 denotes an electrical component, which supplies a required voltage / current to a control device including a CPU, CNC, memory, input / output device (for external device) as well as an electrical element including a wire electrode in a known manner. Power supply for the purpose is incorporated. The CNC controls servo motors that drive the XYZ axes and the UV axes, and the input / output device (I / O) controls the power supply for discharge (not shown), wire feeding control, display (operation panel) 21) is controlled.

  Further, in the electrical unit 20, the load current of each axis of XYZUV is monitored in a known manner, and the function of displaying on the display screen (not shown), the potential of the wire electrode 7 with respect to the workpiece 30, the discharge current, etc. are monitored. It has functions. Further, as will be described later, a contact detection signal (contact signal) generated when the probe provided in the touch probe unit 100 contacts the upper surface 31 of the workpiece 30 is received and detected in order to measure the installation posture of the workpiece. It has a function. Further, the display screen described above is related to the features of the present invention for matters relating to the selection of the machining mode (taper machining / vertical machining), data input required when selecting the taper machining, display of measurement results, etc. Is also used (details will be described later).

  Since the method of wire electric discharge machining is well known, it will be described in a very simple manner. According to the machining program stored in the memory of the control device, the position of each axis of XYZUV is servo-controlled by the CNC, while the wire electrode 7 has a predetermined electric discharge. A voltage / current is supplied, and the workpiece 30 is processed along a predetermined cut line or cut surface. As described above, the movement of the XY position of the machining point 33 is normally performed by the movement of the XY axis, but the U axis / V axis may be substituted. The X-axis / Y-axis / Z-axis is also used for movement of the measurement probe (touch probe unit 100), and the U-axis / V-axis is also used for adjusting the upper guide position based on the measurement result. What is used is as described above.

  Although not shown, as is well known, the work table 1 is installed in a machining tank filled with machining fluid, and electric discharge machining for the workpiece 30 is performed in the machining fluid. In addition, equipment for controlling the temperature and cleanliness of the processing liquid by circulating the processing liquid through a constant temperature device, a cleaning device (ion exchange resin), etc. is attached and controlled by the electrical component 20. Is not particularly relevant to the present invention, and therefore will not be described in detail.

  As already described in the section of the background art, the installation posture of the work 30 on the work table 1 is not horizontal (the upper surface 31 and the lower surface 32 are in the XY plane) in order to perform electric discharge machining. May occur. FIG. 3 exemplifies such a situation, in which a sludge 40 is present on the mounting surface 2 of the work table 1 and the right end of the work 30 is on the sludge 40. In such a case, the lower surface 32 of the workpiece 30 floats slightly from the placement surface 2 around the right end portion, and cannot be brought into close contact. Therefore, the upper surface 31 and the lower surface 32 are inclined at a small angle with respect to the XY plane.

  A similar situation may occur due to a processing error or the like of the mounting surface 2 of the work table 1. In any case, if the machining is performed without ignoring or ignoring the inclination of the upper surface 31 / lower surface 32, which should be essentially parallel to the XY plane, the machining accuracy deteriorates as described above. For example, in the case where the XY positions of the upper and lower guides 5 and 6 are exactly matched with the intention of vertical machining, the wire electrode 7 is stretched parallel to the Z axis (perpendicular to the XY plane), but the workpiece 30 Processing that is not perpendicular to the upper surface 31 and the lower surface 32 is performed. In the case of taper machining, the intended taper angle machining cannot be realized. Further, in either case of vertical machining or taper machining, the movement distance based on the command based on the machining program is not realized on the reference surface of the workpiece 30.

  Therefore, in either case of vertical machining or taper machining, it is necessary to incline the stretching direction of the wire electrode 7 so as to compensate for the inclination of the workpiece 30 in order not to reduce the machining accuracy. A touch probe unit 100 attached to the guide 5 is used. 4A to 4D are diagrams for explaining the touch probe unit 100, and FIG. 4A is an overview diagram showing an attachment manner to the upper guide 5. FIG. FIGS. 4B to 4D are a front view and two side views 1 and 2 for explaining the offset in the mounting of the touch probe unit 100 to the upper guide 5. This represents the component, the Y component, and the Z component.

  As shown in FIG. 4A, the touch probe unit 100 includes a touch probe 102 having a tip point 101 and is attached to a side portion (or front portion) of the upper guide 5. The touch probe 102 can be moved back and forth between a lowered position and a retracted position (indicated by a broken line) by an advance / retreat function (not shown), and is lifted to the retracted position except during measurement so as not to interfere with processing. . For example, an air cylinder mechanism can be used as the advance / retreat mechanism, and the advance / retreat control thereof is performed by a signal from the electrical unit 20.

  The three-dimensional position (XYZ position) of the upper guide 5 (control point) to which the touch probe unit 100 is attached can be recognized by the CPU of the electrical component unit 20 as the position of the X axis / Y axis / Z axis. By the way, the XYZ coordinate value when the tip point 101 contacts the workpiece upper surface 31 cannot be used as it is as the coordinate value of the control point. That is, there is a certain shift determined by the state at the time of attachment between the position of the upper guide 5 and the position (contact position) of the tip point 101. This is “offset”. The front view of FIG. 4B, the side view 1 of FIG. 4C, and the side view 2 of FIG. 4D sequentially represent the X component, the Y component, and the Z component of the offset. Yes.

  Now, in this embodiment, the work 30 installed and fixed on the mounting surface 2 of the work table 1 is processed using the wire-cut electric discharge machine with the touch probe unit 100 attached. When the preparation (so-called “setup”) and the machining based thereon are to be executed, a mode setting screen as shown in FIG. 5 is first displayed on the display. The operator designates (for example, clicks with a mouse) one (□ column) depending on whether the machining to be executed is “vertical machining” or “taper machining”.

  When “vertical machining” is designated on the setting screen of FIG. 5, “screen 1” shown in FIG. 6 is displayed. When “taper processing” is designated, “screen 2” shown in FIG. 7 is displayed. 6 and 7 show a state in which various numerical values are input to the screen 1 or the screen 2.

  Next, according to the mode setting result, the flow on the left side of FIG. 8 (steps S1 to S4) under the display of screen 1 or the flow on the right side of FIG. In accordance with S16), the operation and related processes are advanced. As is clear from FIG. 8, the difference between the left and right flows includes “input of reference surface height” (step S12) and “offset amount measurement” (step S14) when taper machining is selected. (The reason will be described later).

The following is a brief description of each step.
● About steps S1 and S11;
The XY positions of the three points P1, P2, and P3 that are measured using the touch probe unit 100 are measured on the screen 1 (step S1) or on the screen 2 (step S11). In addition, the Z position is also input corresponding to P1, P2, and P3. The reason for inputting the Z position is that the probe is lowered in two stages of high speed and low speed during measurement.

  Therefore, the Z position is a Z-axis position where the probe is positioned above the upper surface 31 of the work 30 by an appropriate small distance (for example, about 1 cm). As will be described later, at the time of measurement, the probe descends at a high speed to the input Z position, switches from there to a low speed, and descends toward the upper surface 31 of the workpiece 30 until contact is detected.

  The numerical values shown in FIGS. 6 and 7 are merely examples, and the numerical values in the screens 1 and 2 are the same, but it goes without saying that they may be different. In general, three points that do not line up on the XY plane within a range that does not deviate from the movable range of the touch probe unit 100 may be selected.

  After entering the numerical value, click the “Input Complete” key. It should be noted that the software can confirm that the three specified points are not aligned on a straight line, and if three points aligned on a straight line are specified, an alarm message prompting re-input is displayed. Also good. Also, the number of measurement points to be specified may be four or more. In that case, a numerical value such as P4, P5.

● About step S12;
This step is executed only when the taper machining mode is selected. The “reference surface height” is the height of the “reference surface” measured from the placement surface 2 of the table 1. Here, the reference surface is the upper surface 31 of the workpiece 30. Therefore, the “reference surface height” is the thickness of the workpiece 30. For this data, a separately measured thickness value can be adopted, which is performed on the screen 2 shown in FIG. Note that h = 24.5 mm is merely an example.

● About steps S2 and S13;
When the required data is performed on screen 1 or screen 2 and the input completion key is clicked, the measurement program can be activated. Then, when the safety key is checked and the activation key is clicked, the measurement program is activated.
The measurement executed by the measurement program is “position measurement of three points on the workpiece upper surface” (step S3) when “vertical machining mode” is selected, and “measurement of offset amount” (step S14) when “taper machining mode” is selected. And “Measurement of three positions on the upper surface of the workpiece” (step S15).

● About step S14;
This step is executed only when the taper machining mode is selected. The procedure for measuring the offset amount will be described as follows with reference to FIGS. 9 (a) to 9 (c). On the mounting surface 2 of the work table 1, a jig 50 is installed in a portion (a preliminarily prepared empty area) that is not occupied by the work 30 (not shown in FIGS. 9A to 9C). The jig 50 has a hole 51 having a diameter larger than the tip point 101 of the touch probe.
Here, it is assumed that the wire electrode 7 is adjusted in advance so as to be stretched parallel to the Z axis (perpendicular to the XY plane).

First, the upper and lower guides 5 and 6 move to the position of the hole 51 of the jig 50, and the wire electrode 7 is passed through the hole 51 (see FIG. 9A). The position of the hole 51 that moves here is stored in advance in the memory as an approximate position that does not hinder the wire electrode 7 from passing through the hole 51. Next, the guides 5 and 6 are moved in the + X (or -X) direction, and the position where the jig 50 and the wire electrode 7 are in contact is stored. Next, it moves in the opposite direction, that is, in the −X (or + X) direction, and similarly stores the position where the jig 50 and the wire electrode 7 are in contact with each other. The center of the two stored position data, that is, the center position of the hole 51 in the X direction is obtained. The center in the Y direction of the hole 51 is obtained in the same procedure. The central coordinate position (x1, y1) of the hole 51 obtained here is stored in the memory of the electrical equipment unit 20.
In order to increase the measurement accuracy, these procedures may be performed a plurality of times, and the average value of the obtained center coordinate positions may be taken.

  Next, the wire electrode 7 is once removed from the vertical guide, a control signal is sent to the touch probe unit 100, and the tip point 101 of the probe 102 is lowered (see FIG. 4A). Then, as shown in FIG. 9B, the upper and lower guides 5 and 6 are moved to a position where the tip point 101 enters the hole 51. In addition, the approximate position that does not hinder the tip point 101 from entering the hole 51 is stored in the memory in advance.

  Next, the guides 5 and 6 are moved in the + X (or -X) direction, that is, the touch probe is moved, and the position where the jig 50 and the tip point 101 are in contact is stored. Next, it moves in the opposite direction, that is, in the −X (or + X) direction, and similarly stores the position where the jig 50 and the tip point 101 are in contact with each other. The center of the two stored position data, that is, the center position of the hole 51 in the X direction is obtained. The center in the Y direction of the hole 51 is obtained in the same procedure. The center coordinate position (x2, y2) of the hole 51 obtained here is stored in the memory of the electrical equipment unit 20.

In order to improve measurement accuracy, these procedures may be performed a plurality of times, and an average value of the obtained center coordinate positions may be taken. Here, the hole 51 of the jig 50 is used as the reference position, but the corner portion of the jig 50 may be used as the reference position, and a measurement sequence for that purpose may be used.
From the difference between these two measurement results, the X component Δx and the Y component Δy of the offset amount Δ can be obtained. Δx = x2−x1 and Δy = y2−y1. These are stored in the memory of the electrical unit 20.

  In order to obtain the Z component Δz of the offset amount Δ, as shown in FIG. 9C, the wire electrode 7 is detached from the upper guide 5 and the touch probe unit 100 is retracted. A Z coordinate value is obtained and stored in advance when the upper guide 5 is manually operated and brought into contact with the placement surface 2 or the upper surface of the jig 50. Let this be z0. Then, the Z coordinate value when the touch probe unit 100 is brought into contact with the same surface (the placement surface 2 of the work table 1 or the upper surface of the jig 50) while being lowered to the measurement position is obtained. If this is z3, the Z component Δz of the offset amount Δ is Δz = z0−z3. This is stored in the memory of the electrical unit 20. This completes the measurement of the offset amount.

● About steps S3 and S15;
The upper guide 5 is moved to the position P1 input on the screen 1 or 2 (positioning to the position P1 once). As described above, the Z position of P1 is designated (input) so that the probe does not come into contact (collision) with the upper surface 31 of the workpiece 30 by this movement, so this movement can be performed at high speed.

  After this movement, the touch probe unit 100 is gradually lowered along the Z axis (low speed descent), and the tip point 101 is brought into contact with the workpiece upper surface 31. As described above, the contact signal is sent to the electrical component 20 by this contact, and the contact is detected. Note that the Z-axis (probe) automatically stops moving simultaneously with contact detection. And the XYZ position at the time of this contact detection is memorize | stored. The XYZ position at the time of contact with the workpiece upper surface 31 is stored in the same procedure for the positions P2 and P3.

Since the stored XYZ position at the time of contact detection is the position when the tip point 101 of the touch probe contacts the workpiece, the upper guide position (control point) is obtained using the above-described offset amount ΔxΔyΔz.
Coordinates (Xn, Yn, Zn) of upper guide position (control point) of measurement point n
= Coordinates (xn, yn, zn) + offset amount (Δx, Δy, Δz) (n = 1, 2, 3)

● About steps S4 and S16;
In these correction steps, first, the workpiece inclination and the three-dimensional position of the workpiece upper surface are obtained from the coordinates (Xn, Yn, Zn) of the upper guide position (control point) obtained in steps S3 and S15. FIG. 10 is a diagram for explaining an example of how to obtain it. Here, in order to simplify the explanation, it is assumed that the workpiece is inclined only with respect to the XZ plane. Therefore, in the following description, the inclination can be obtained only from the measured data of two points, but this is an example.

The workpiece inclination θ can be obtained by θ = tan ⁻¹ [(z2−z1) / (x2−x1)]. Also, the Z position of the tilted workpiece upper surface is Z = tan θ * X + b.
The value of b can be obtained by solving the following simultaneous equations.
z1 = tanθ * x1 + b
z2 = tanθ * x2 + b

The guide position of the intersection point P between the reference surface and the tilted workpiece upper surface is Px = (tb) / tan θ. Here, t is the Z coordinate at the input reference plane height. (It can be obtained from the Z coordinate of the table surface registered as the existing value and the value of the reference surface height.)
11 to 13 show the flow of correction. First, FIG. 11 shows the moment when correction is performed. The wire position A (broken line) is the wire position before correction. When the correction is started, first, an intersection coordinate Pa between the wire position A and the reference plane is obtained. Thereby, the distance Da from Px can be obtained. Next, when the difference Δ1 between the wire positions Q and Pa that are separated by a distance Da from the upper surface of the workpiece tilted starting from Px, Δ1 = Da−Da * cos θ.

  Next, an upper guide movement amount Δ2U and a lower guide movement amount Δ2L for inclining the wire about the intersection point of the wire position Q and the inclined workpiece upper surface (so that the wire is perpendicular to the inclined workpiece) When calculated, Δ2U = (L−Da * sin θ−L1−L2) * tan θ, Δ2L = (Da * sin θ + L1 + L2) * tan−θ. Here, L1 is the input reference surface height, and L2 is the distance between the table and the lower guide (the existing value registered in advance). Accordingly, the upper guide movement amount ΔU and the lower guide movement amount ΔL at the moment of correction are ΔU = Δ1 + Δ2U and ΔL = Δ1 + Δ2L, and the wire moves to the position A ′.

Next, FIG. 12 shows a case where vertical machining is performed from the wire position A to the wire position B. First, the distance Db from Px is obtained from Pa and the movement command D.
The guide position G of the wire position Q that is separated from the upper surface of the workpiece inclined by Px by the distance Db is G = Px + Db * cos θ. The upper guide movement amount Δ2U and the lower guide movement amount Δ2L for inclining the wire are Δ2U = (L−Db * sin θ−L1−L2) * tan θ and Δ2L = (Db * sin θ + L1 + L2) * tan−θ. . Accordingly, the upper guide position BU and the lower guide position BL at the wire position B ′ are BU = G + Δ2U and BL = G + Δ2L.

Next, FIG. 13 shows a case where taper processing is performed from the wire position A to the wire position B.
In general, the movement command D is a command on the program surface, not a command on the reference surface (work upper surface). When the movement amount Du on the reference plane is obtained, Du = D + (L1−L3) * tanΦ, and the distance Db from Px is obtained from Pa and the movement instruction Du of the reference plane.

  Since the wire is inclined by the angle of Φ commanded compared to the above-described vertical machining, the upper guide movement amount Δ2U and the lower guide movement amount Δ2L for inclining the wire are Δ2U = (L−Db * sin θ−L1−). L2) * tan (θ + Φ), Δ2L = (Db * sin θ + L1 + L2) * tan− (θ + Φ). Accordingly, the upper guide position BU and the lower guide position BL at the wire position B ′ are BU = G + Δ2U and BL = G + Δ2L.

FIG. 14 shows an example in the case where an incorrect reference plane value is set (for example, an operator input error or an workpiece thickness measurement error in an external device) in the case of vertical machining. In the case of vertical machining, the movement amount at any height on the workpiece with respect to the movement command is the same, so there is no influence on obtaining the distance Db. Therefore, in the present correction method, in the case of vertical machining, correct correction can be performed regardless of the value of the reference surface.
FIG. 15 shows an example of a case where the position of the upper surface of the workpiece has not been correctly measured in the case of vertical machining (such as an error in measuring the probe mounting offset in step 14).

In the case of vertical machining, since the amount of movement at any height on the workpiece with respect to the movement command is the same, correct machining can be performed even if the position of the correction target surface (inclined workpiece upper surface) is different.
FIG. 16 is an example in which an incorrect reference surface value is set in the case of taper machining. In taper machining, the amount of movement relative to the movement command varies depending on the workpiece height position. If an incorrect reference plane is specified, the distance Db value differs from the amount of movement on the correct reference plane, and correct correction is performed. I can't.
FIG. 17 shows an example in which the position of the workpiece upper surface is not correctly measured in the case of taper machining.

In this case, since correct correction is performed on the wrong workpiece upper surface, correct correction is not performed on the actual workpiece upper surface.
As described above, in the vertical machining, the input reference plane data and the measured position of the workpiece upper surface (the influence of the measured probe mounting offset amount) do not affect the correction, and therefore can be omitted. .

In the wire electric discharge machining, when the workpiece is inclined, the drawing is performed to incline the wire and (a) shows the case where the workpiece is processed without inclining the wire when the workpiece is inclined. ) Represents a case where machining is performed by properly tilting the wire when the workpiece is tilted. It is the figure which showed schematically the schematic structure of the wire electric discharge machine employ | adopted by embodiment of this invention. It is the figure which illustrated a mode that the installation posture of a work inclines. It is a figure explaining a touch probe and its offset, (a) is a general-view figure which shows the attachment aspect to the upper guide 5, (b)-(d) is the offset in the attachment to the upper guide 5 of the touch probe unit 100, respectively. It is the front view and two side views 1 and 2 for demonstrating X component of this, Y component, and Z component. It illustrates a mode setting screen. FIG. 6 illustrates a data input screen for selecting a vertical machining mode. FIG. FIG. 6 illustrates a data input screen for selecting a taper machining mode. FIG. It is the figure which showed the flow at the time of vertical process mode selection and taper process mode selection. It is a figure explaining the measurement procedure of the offset amount of a touch probe, (a) * (b) represents the measurement procedure of XY component of offset amount, (c) represents the measurement procedure of Z component of offset amount, respectively. It is a figure explaining the example of how to obtain | require the inclination of a workpiece | work, and the three-dimensional position of a workpiece | work upper surface. It is a figure showing the moment when correction | amendment was performed based on the input reference plane height. It is a figure explaining the correction | amendment in the case of performing a vertical process from the wire position A to the wire position B. FIG. It is a figure explaining correction in the case of performing taper processing from wire position A to wire position B. It is a figure explaining the example when the value of an incorrect reference plane is set (for example, the operator's input mistake, the workpiece thickness measurement mistake in an external device, etc.) in the case of perpendicular processing. It is a figure explaining the example when the position of the workpiece | work upper surface is not measured correctly in the case of vertical processing (a mistake of the probe attachment offset amount measurement of step 14, etc.). It is a figure explaining the example when the value of an incorrect reference plane is set in the case of taper processing. It is a figure explaining the example when the position of the workpiece | work upper surface is not correctly measured in the case of a taper process.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Worktable 2 Mounting surface 3 X-axis drive mechanism 4 Y-axis drive mechanism 5 Upper guide 6 Lower guide 7 Wire electrode 8 Z-axis drive mechanism 9 U-axis drive mechanism 10 V-axis drive mechanism 11, 13 Guide roller 12 Wire supply part 14 Wire winding part 20 Electrical part 21 Operation panel 30 Work piece 31 Upper surface (surface work surface parallel to the lower surface)
32 Lower surface 33 Processing point 34 Processing line (machined)
40 Sludge 50 Jig 51 Hole 100 Touch probe unit 101 Touch probe tip point 102 Touch probe

Claims (4)

Place the workpiece on the table, move the wire electrode stretched between the upper guide and the lower guide relative to the table in the XY plane consisting of the X axis and the Y axis perpendicular to the X axis, In a wire cut electric discharge machine that processes the workpiece,
Machining mode selection means for selecting one of a taper machining mode for performing taper machining and a vertical machining mode for not performing taper machining;
Inclination measuring means for measuring the inclination of the workpiece placed on the table using the measuring element, including a measuring element that is movable while maintaining a certain offset amount with respect to the position of the upper guide; ,
When the taper machining mode is selected by the machining mode selection means, the magnitude and direction of the inclination of the workpiece with respect to the XY plane measured by the inclination measurement means, the reference surface height of the workpiece, and the offset Based on the amount, a first correction for tilting the wire electrode with respect to the ± Z direction perpendicular to the XY plane and correcting the XY position of the wire electrode with respect to the machining path specified by the machining program Means,
When the vertical machining mode is selected by the machining mode selection unit, the inclination correction of the wire electrode is performed based on the magnitude and direction of the inclination of the workpiece with respect to the XY plane measured by the inclination measurement unit, and Second correction means for correcting the XY position of the wire electrode with respect to the processing path specified by the processing program;
Execution means for executing processing according to a processing program under the correction of the inclination of the wire electrode and the correction of the XY position by the first correction means or the second correction means,
The wire-cut electric discharge machine, wherein the reference surface height is a height from the lower surface of the workpiece placed horizontally on the table to the upper surface of the workpiece.   The inclination measuring means includes means for obtaining a three-dimensional relative positional relationship of at least three points that are not aligned on a straight line on the upper surface of the workpiece placed on the table using the measuring element, and is obtained by the means. The wire-cut electric discharge machine according to claim 1, wherein a magnitude and a direction of inclination of the workpiece with respect to the XY plane are measured based on the three-dimensional relative positional relationship.   The wire-cut electric discharge machine according to claim 1 or 2, wherein the offset amount is obtained by measuring a reference position whose three-dimensional position is known with the measuring element. Means for placing a workpiece on a table and moving a wire electrode stretched between an upper guide and a lower guide relative to the table on an XY plane composed of an X axis and a Y axis perpendicular to the X axis Inclination measurement that measures the inclination of the workpiece placed on the table using a measuring element that is movable while maintaining a certain offset amount between the upper guide position and the position of the upper guide In a wire cut electric discharge machining method using a wire cut electric discharge machine equipped with means,
Selecting one of a taper machining mode for performing taper machining on the workpiece and a vertical machining mode for not performing taper machining;
The method includes a step of executing either the first step group or the second step group according to the selection result in the first step,
The first step group includes:
An input step of inputting the reference surface height of the workpiece into the wire cut electric discharge machine;
An offset amount measuring step for measuring the offset amount;
An inclination measuring step for measuring the magnitude and direction of the inclination of the workpiece with respect to the XY plane using the inclination measuring means;
The magnitude and direction of the inclination of the workpiece placed on the table with respect to the XY plane measured in the inclination measurement step, the reference surface height input in the input step, and the offset amount measurement step Based on the measured offset amount, the wire electrode is tilted with respect to the ± Z direction perpendicular to the XY plane, and processing is performed while correcting the XY position of the wire electrode with respect to the processing path specified by the processing program. And a first machining step that executes
The second step group includes:
An inclination measuring step for measuring the magnitude and direction of the inclination of the workpiece with respect to the XY plane using the inclination measuring means;
The wire electrode with respect to the ± Z direction perpendicular to the XY plane based on the magnitude and the direction of the inclination of the workpiece placed on the table with respect to the XY plane measured in the inclination measuring step. And a second machining step for performing machining by correcting the machining path specified by the machining program,
The wire electric discharge machining method, wherein the reference surface height is a height from the lower surface of the workpiece placed horizontally on the table to the upper surface of the workpiece.

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