JPS61249223A - Posture control for tool in working machine - Google Patents

Abstract

PURPOSE:To continuously carry out plural kinds of works with high precision by automatically replacing tools by carrying out posture correction by comparing the calculated posture of the tool and the predetermined correct posture, in an electric-discharge machine, etc. CONSTITUTION:The X- and Y-direction slide tables 102 and 104 and Z-direction slide means 54 are shifted in the X, Y, and Z-directions by a driving circuit 56, and the coordinate of a touch sensor 52 on the contact with the shaped surface of an electrode 124 is memorized into a CPU 60, and the obtained coordinates of a plurality of electrode surfaces are input into a posture calcula tion circuit 62. Then, in the calculation circuit 62, the posture quantity is calcu lated by the comparison with the correct posture data, and a posture controller 42 is driven by a posture correcting circuit 64 on the basis of the calculated posture quantity, and the correction control for posture is performed. Since the CPU 60 calculates the feed dimension of the tool 124 on working by using the measured tool coordinates, preparatory work can be carried out efficiently. Thus, plural kinds of unmanned working can be carried out with high precision in a short time.

Description

[Detailed description of the invention]

[Industrial Field of Application] The present invention relates to a method for controlling the mounting posture of a tool in a processing machine.

[Prior art and its problems] Electrical discharge machining is generally used as one of the precision machining methods. Electrical discharge machining uses a tool as an electrode to generate an arc discharge in a minute gap between the workpiece and the workpiece, thereby removing a small amount of the workpiece surface and machining the workpiece into a shape that corresponds to the shape of the tool. It is something to do. According to electrical discharge machining, 4! l It is possible to machine tough materials and highly hard materials that are difficult to machine into accurate shapes, and the surface can be made relatively fine, and even surfaces of any shape can be machined as long as electrodes are prepared. Therefore, electrical discharge machining is used, for example, to manufacture molds for press working. A conventional example of an electrical discharge machine used for such electrical discharge machining is shown in FIG. 1O. In the figure, 102 is an X-direction slide table,
104 is a Y-direction slide table provided on the X-direction slide table 102; on the Y-direction slide table 104, a machining liquid storage tank 10B is fixed. 108 is a workbench provided in the tank 10B, and a workpiece 110 is fixed on the workbench 108. Note that during machining, a machining fluid such as water or oil is stored in the tank 106. 112 is a column, 1
14 is a tile, 116 is an insulating plate, 118 is a chuck, 12G is a rotary head, 122 is an electrode holder, and 124 is an electrode, that is, a tool. The rotating head 120 can rotate around the Z direction with respect to the chuck 118. That is, the one-rotation head 120 has a horizontally oriented protrusion 120a fixed thereto.
On the other hand, the chuck 118 has a rotation adjustment screw 118a that abuts from both sides in the rotation direction of the protrusion 120a around the Z direction. ttab is attached. Therefore two adjustment screws 11
By operating 8a and 118b, the rad 120 can be rotated relative to the chuck 11B. Further, the electrode holder 122 has adjustment screws 122a and 1 that are brought into contact with the electrode 124 from the X direction and the Y direction.
22b is attached, and the adjustment screws 122a, 122
By manipulating b, the inclination of the electrode 124 in the Z direction can be corrected. That is, by operating the adjustment screw 122a, the electrode 124 is rotated by an appropriate angle around the Y direction, and by operating the adjustment screw 122b, the electrode 124 is rotated by an appropriate angle around the X direction. During electrical discharge machining, the electrode 124 is connected to the column 112.
is moved downward along the Z direction, and discharge is started at a position where the gap between the electrode 124 and the workpiece 110 becomes minute. Thereafter, discharge is performed while moving the electrode 124 downward little by little, and the discharge is stopped at a predetermined position.
24 upward. As a result, the work 110
A processed surface corresponding to the shape of the lower and side surfaces of the electrode 124 is formed on the electrode 124 . Therefore, in order to perform highly accurate machining on a workpiece by electric discharge machining, it is necessary not only that the shape of the electrode 124 is accurate, but also that the electrode 124 be attached to the electrode holder 122 in an accurate posture. be. However, in conventional electric discharge machines such as the one or more, the posture of the electrode 124 attached to the electrode holder 122 is not necessarily accurate, so after the electrode 124 is attached, the electrode is moved up and down to adjust the electrode surface. Alternatively, a dial gauge is brought into contact with the reference surfaces 124a, 124b formed on the side surfaces of the electrode to measure the inclination of the electrode, and based on the measurement results, the adjusting screws 122a, 122b are operated to adjust the electrode 12.
Rotate around the X direction and around the Y direction in step 4, and then move the work bench in the X or Y direction while bringing the dial gauge supported on the work bench into contact with the electrode surface or reference surface. The rotation of the electrode around the Z direction is measured, and the adjustment screws 118a and 118b are adjusted based on the measurement results.
is operated to rotate the electrode 124 around the Z direction, thereby adjusting the desired electrode posture. On the other hand, in electrical discharge machining, one electrode is used to
For this reason, only one shape can be processed. When performing complex machining, multiple electrodes are required.
Electrode replacement is performed in an electric discharge machine. In addition, in electric discharge machining, even when machining the same shape, in order to maintain good finishing accuracy, machining may be performed first with a rough machining electrode and then with a finish machining electrode, and in this case, electric discharge machining Electrode exchange is performed at the machine. Depending on the type of 9-ri, it may take up to 100
More than one electrode may be used. However, in conventional electrical discharge machining, the attitude of the electrode is manually measured as described above each time the electrode is attached to the electrical discharge machine, and the attitude of the electrode is adjusted to within the desired tolerance range based on this measurement. being done. For this reason, the setup process required for electrical discharge machining takes a long time.
There was a problem in that it was not possible to improve work efficiency. In addition, attempts have been made to automatically exchange electrodes using an automatic electrode exchange device to reduce the time and manual labor required for one setup process, but current automatic electrode exchange devices have exchange errors and cannot be used as is. There is a problem in that sufficient machining accuracy cannot be obtained if machining is performed in this posture. For this reason, it has conventionally been thought that high precision machining cannot be performed automatically in electrical discharge machining. The above-mentioned problems exist not only in electrical discharge machining, but also in general machining machines that perform tool changes. [Means for Solving the Problems] According to the present invention, in order to solve one or more problems of the prior art, a plurality of Find the coordinates of the measurement point, calculate the tool posture by calculation based on the coordinates of the measurement point,
A method for controlling the posture of a tool in a processing machine, the method comprising comparing the thus calculated posture with a predetermined correct posture, and correcting the posture to bring it closer to the correct posture if the measured posture is outside of an allowable value. , is provided. [Example] Hereinafter, specific examples of the present invention will be described with reference to the drawings. FIG. 1 is a schematic configuration diagram showing a specific example of an electric discharge machine used in a cannibalism system including the attitude control method of the present invention. In this figure, the same members as in FIG. Therefore, the explanation of these will be omitted. In the figure, 42 is an attitude control device. 44 is an insulating plate, 46 is an electrode mounting face plate, 48 is a Solstat chuck, and 50 is an electrode holder. Also,
52 is a touch sensor. The attitude control device 42 has the electrode 124 side (that is, the lower side)
It can be rotated independently around this direction, around the Y direction, and around the Z direction, and this rotation is performed by a command from an appropriate drive circuit (described later). Further, FIG. 2 is a block diagram showing the configuration of a control system of the electrical discharge machine shown in FIG. 1 above. In the figure, the X-direction slide, the toe pull 102, the Y-direction slide table 104, and the electrode Z of the electrical discharge machine main body
The directional slide means 54 is connected to a drive circuit 56, by which it is moved in the X direction, Y direction and two directions, respectively. Furthermore, the coordinates of the touch sensor 52 when it touches the shaped surface of the electrode 124 moved in the X, Y, and Z directions can be stored in the CPU 60. Then, a plurality of electrode surface coordinates obtained by bringing the touch sensor 52 into contact with a plurality of measurement points of the electrode 124 are inputted into the posture amount calculation circuit 62, and are further input into the CPU 60 as the coordinates of the electrode surface in the correct posture. The stored data is also input to the arithmetic circuit 62, and the arithmetic circuit 6
In step 2, the attitude amount is calculated by comparing these data, and the result is stored in the CPU. Then, the attitude control device 42 is driven by the attitude correction drive circuit 64 based on this attitude amount. As a result, the attitude control device is driven to bring the attitude amount closer to the correct attitude. Note that an electrode exchange device 66 is also connected to the CPU 60. FIG. 3 is a schematic flow sheet showing an embodiment of the cannibalism system including the attitude control method of the present invention. First, the electrode exchange device 66 performs electrode exchange on the electrode holder 50 of the electrical discharge machine (step 3-1).
In this electrode exchange, if the electrode used in the previous machining is attached to the electrode holder 50 of the electric discharge machine, it will be replaced with a new electrode, and if the electrode is attached to the pull-stat chuck, it will be replaced with a new electrode. If not, only a new electrode needs to be installed. At this time, in order to correct the tilted position due to attitude control, an attitude control orientation command signal is sent from cpus, o to the attitude correction drive circuit before the primary electrode exchange. After the orientation, the end signal is received from the attitude control device and the electrode exchange operation is started. After a new electrode is installed in the electric discharge machine, control is performed to correct the orientation of the electrode (step 3-2).This electrode orientation control involves measuring the orientation of the installed electrode. After that, it is determined whether the posture is within the desired tolerance range, and if it is not within the desired range, the electrode posture is corrected and the posture is further measured, and this is repeated until the desired accuracy is achieved. This is done by taking an inner posture. After the newly attached electrode is in the desired posture, the electric discharge machine is operated to move the electrode close to the workpiece and perform electric discharge machining (step 3-3). Through the above steps, accurate electrical discharge machining regarding the electrode is completed. Subsequently, in order to perform accurate electrical discharge machining using another electrode, steps 3-1 to 3-3 described above may be repeated. Next, details of the electrode attitude control step 3-2, which corresponds to the method of the present invention, will be explained. The electrode moves in parallel relative to the workpiece during machining, so when measuring the posture of the electrode. What is necessary is to find the rotation angle around the X direction, ie, the Y rotation, the rotation angle, ie the X rotation, around the Y direction, and the rotation angle, ie, the Z rotation, around the Z direction from the reference posture. Therefore, a square electrode 124 as shown in FIG. 4(L)
In this case, the coordinates of the electrode surface on a plane parallel to the Z-X plane are measured in order to obtain the %X ratio. As measurement points, for example, two locations (Xl, X2) from the side surface of the electrode or two locations (X31X4) from the bottom surface of the electrode are selected. Similarly, the coordinates of the electrode plane on a plane parallel to the Y-Z plane are measured in order to obtain the Y direction. As measurement points, for example, two points (yx, y2) from the side surface of the electrode or two points (Y3, Y4) from the bottom surface of the electrode are selected. Furthermore, in order to obtain the Z rotation, the coordinates of the electrode surface on a plane parallel to the X-Y plane are measured. As measurement points, for example, two locations (zl. zz) or (23, 24) on the side surface of the electrode are selected. In the case of a round electrode as shown in Figure 4(b), Z
Since there is no need to take rotation into consideration, it is sufficient to measure the X direction and the Y direction in the same manner as in the case of the square electrode. Furthermore, in the case of a round electrode, two sets of measurements with different coordinates on a plane parallel to the x-Z plane and a plane parallel to the Y-Z plane are performed as shown in FIG. 4(C). Points W1 to W4
and W5 to W8 can also be selected. Then, the coordinates of the center point W1 are calculated from the coordinates of the measurement points W1 to W4, and further. The coordinates of the center point W2 are calculated from the coordinates of the measurement points W5 to W8, and the direction of the line connecting w, . The electrode coordinate measurement as described above can be performed, for example, as follows. First, the coordinate system is set so that the origin is located inside the tool shape section. In FIG. 4(a), when measuring the X direction, the measurement point x1. For x2, a suitable distance away from the measurement point in the X direction! txt',X2
”, and use these as the starting points for coordinate measurement of the measurement points.
, a touch sensor 52 is placed at a position x3' * x4' separated by an appropriate distance in the Z direction from the measurement point.
, and use these as the starting point for coordinate measurement of the measurement point. These starting points are set by prior teaching according to the type of electrode. That is, before starting the electrode posture measurement for actual machining, the measurement starting point for the electrode is stored as data in the CPU 60. For example, the X-direction slide table 102, the Y-direction slide table 104, and The two-way slide means 54 is operated to position the touch sensors 52 at the respective starting points, and the touch sensors 52 at that time are
There is a way to store the coordinates of in cpuso. Furthermore, the fourth
In the case of a round electrode as shown in figure (b), the measurement point x
Instead of manually setting measurement start points for all of 1 to x4 and 71'''74, for example, manually teach only the measurement start points for measurement points Xi. It is also possible to automatically set the measurement start points for 1 to y4 from the three measurement start point coordinates set above based on the axial symmetry of the electrodes.Such automatic setting can be done by incorporating a program into the CPU 60 in advance. This can be easily done by setting the coordinates of the starting point to the CPU 60.Furthermore, instead of performing such manual teaching, the data of the starting point coordinates may be directly input to the CPU 60 and stored. However, the same applies to the measurement of Y rotation and Z rotation. In the case of measurement as shown in FIG. Teaching at another measurement point W31W
4. The measurement starting points for W11 to W8 are shown in Figure 4 (b) above.
) can also be set automatically. When the measurement start point is set as described above, the touch sensor 52 can be moved in a predetermined direction in the direction in which the absolute value of the coordinates becomes smaller when measuring electrode coordinates, and movement control is performed. becomes easier. Further, the touch sensor is moved between each measurement point, for example, along the x, Y, or Z direction so as not to collide with the electrode 124. A flow sheet of the attitude control process as described above is shown in FIG. That is, first, after moving the touch sensor 52 to the first measurement starting point, the coordinates of the first measurement point are measured, and the coordinates of the second and subsequent measurement points are similarly measured, and the X direction towel is measured. The coordinate measurements regarding the rotation are completed, and the coordinate measurements regarding the Y direction orientation and Z rotation are completed in the same manner as the first step (step 5-1). Posture amount calculation is performed based on the coordinates thus measured (step 5-2). Next, the attitude state quantity obtained by the calculation is compared with the correct attitude state quantity which is stored in advance in the CPU 60 as a reference (step 5-3), and if the difference is within the tolerance value, Next, the process moves on to the processing process. On the other hand, if it is outside the allowable value, the posture control device 142 is driven to rotate the electrode 124 by an appropriate angle around the X direction, Y direction, and/or Z direction (step 5-4), and then Then return to step 5-1. Next, details of the processing step 3-3 will be explained. Before proceeding to actual machining, the positional relationship between the electrode and the workpiece is determined, and the electrode feed dimension is calculated. Figure 6(a), (
b) is a diagram for explaining a method of calculating an electrode feed dimension. The results of the electrode coordinate measurement performed after the posture correction is completed in the posture control step 3-2 are used to calculate the electrode feed dimension. That is, after measuring the electrode coordinates, the posture amount is calculated based on the measured values, and if it is found to be within the allowable range in comparison with a reference value, the measured values represent the coordinates of the electrodes. Therefore, the feed dimension can be calculated from these coordinates and the position coordinates of the workpiece 110 fixed on the workbench 108. In FIG. 6 (JL), a specific example of calculating the feed dimension regarding the tapered electrode 124 will be described. First, measurement point x1. The angle θ is calculated from the difference in the X coordinate of x2. The X coordinate of point P is calculated from the angle θ, the X coordinate of measurement point x2, and the Z coordinate of measurement point x3.The Y coordinate of point 0 P is measurement point Kl. x2. It is the same as the Y coordinate of x3, and the Z coordinate of one point P is the same as the Z coordinate of measurement point x3. As a result, the coordinates of point P can be determined. On the other hand, the coordinates of the point Q on the workpiece 110 with respect to the touch sensor 52 are measured in advance (that is, when the workpiece 110 is fixed to the workbench 108). Then, attach the measuring ball so that the measuring ball contacts point Q of the workpiece 11G.
Drive the X-direction slide table 102, Y-direction slide table 104, and Z-direction slide means 54, and then drive the measurement ball so as to contact the touch sensor 52,
The coordinates of the point Q on the workpiece 110 with respect to the touch sensor 52 are determined from the amount of movement at this time. Note that the coordinates of point Q may be measured by directly bringing the measuring ball into contact with point Q as described above, but as shown in FIG.
11, (12. It is also possible to measure the coordinates of these points by contacting q3 and calculate them from the coordinates. In addition, R is the point on the machined surface formed on the workpiece corresponding to the point P of the electrode 124. The relationship between point 0 Q and point R is determined by the design dimensions. Therefore, from the coordinates of point P, the coordinates of touch sensor 52, and the relative positional relationship between the touch sensor and point Q, The coordinates of point Q are found. Based on this, the coordinates of point R are found from the relative positional relationship between point Q and point R. From the above, the X direction for machining feed from point P to point R. , the feed dimensions in the Y direction and the Z direction are calculated.The calculation of the feed dimension for this machining is performed in the CPU 60.Thus, after the calculation of the machining feed dimension is completed, the electrode is moved and electrical discharge machining is executed. A detailed flow sheet of the overall configuration of the embodiment as explained above is shown in Fig. 7. Fig. 8 shows a flow sheet of another embodiment of the Canadian system including the attitude control method of the present invention. In the example, if there are n or more cases in which the attitude amount obtained in the attitude amount calculation step for the same electrode is outside the allowable value, the electrode is replaced without further attitude correction for the electrode. As a result, it is possible to move on to processing using the next electrode without attempting long-term posture control for an electrode whose posture cannot be properly controlled for some reason.Furthermore, in this embodiment When moving to the electrode replacement process due to poor posture correction, a related electrode path command is issued. The related electrode paths will be explained below. FIG.
It is a figure showing 0,111. Workpiece 11O is processed part A,
The workpiece 111 has processing parts E and F. These processed parts A to F are provided with electrodes 124a to 124a, respectively.
Processed by 124f. Processing of the processing portion B by the electrode 124b is performed after processing of the processing portion A by the electrode 124a, and processing of the processing portion C by the electrode 124C is performed after processing of the processing portion B by the electrode 124b. Therefore, if machining of machining part A is not performed due to a defective posture correction of the electrode 124a, machining of machining parts B and C cannot be performed subsequently. It is desirable that the electrodes 124b and 124c are also not attached to the electrical discharge machine. Therefore, when the electrodes related to the related machining parts belonging to the same block are passed, the electrodes related to the machining parts belonging to the same block are also passed thereafter. Such a path of related electrodes can be performed by the software of the CPU 60 by attaching a code to each electrode. When machining the workpieces 110 and 111 as shown in FIG. 9, the following code is attached to each electrode, and the machining system is controlled by this code. Code 124a 110-A-1 124b 110-A-2 124c 110-A-3 124d 110-D-1 124e 110-E-1 124e 111-E-1 124f l1l-F-1 Here, the code The first number indicates the type of workpiece to be processed by the electrode, the next code indicates the type of processing section block, and the last number indicates the processing order of the processing section within the processing section block. As shown in 124e with two codes, the electrode may have two or more codes when processing two or more locations with the same electrode. Therefore, when, for example, the electrode 124a is passed due to a defective posture correction, a command is issued and stored so that the electrodes 124b and 124c having the code A of the same processing section block type will pass from now on. Then, in the electrode replacement step 3-1, before performing electrode replacement, it is confirmed whether the newly installed electrode is one that has been given a pass command, and if it is one that has been given a pass command, it is immediately replaced. Move on to the next electrode in the processing order. In the above embodiments, a touch sensor is used as the electrode coordinate measuring means, but a means using electrical continuity or a non-contact means may be used instead. Although the above embodiments have been described with respect to electric discharge machining, the posture control method of the present invention can be similarly applied to general machining in which tools or workpieces are replaced other than electric discharge machining. [Effect of the Invention 1] According to the posture control method of the present invention, it is possible to configure a machining system that automatically exchanges tools and performs a plurality of types of machining continuously and with high precision unmanned. Further, since the feed dimension of the tool during machining can be calculated using the tool coordinates measured in the posture control method of the present invention, setup can be performed efficiently and machining can be completed in a short time. Furthermore, according to the present invention, since the attitude of the tool is corrected by directly measuring the contact surface of the tool with the workpiece, the mounting accuracy of the tool on the processing machine can be rough, and therefore the tool holder of the processing machine and the tool on the processing machine are Since the mounting part does not require much precision, costs can be reduced.

[Brief explanation of drawings]

FIG. 1 is a configuration diagram of an electric discharge machine. FIG. 2 is a block diagram of the control system of the electrical discharge machine. FIG. 3 is a flow sheet of the cannibalism system including the attitude control method of the present invention. FIGS. 4(L), (b), and (c) are partial perspective views of the electrodes. FIG. 5 is a flow sheet of the attitude control process. FIGS. 6(a) and 6(b) are diagrams for explaining calculation of machining feed size. FIGS. 7 and 8 are flow sheets of the cannibalism system including the attitude control method of the present invention. FIG. 9 is a diagram showing a processing section of a workpiece. FIG. 10 is a schematic diagram of a conventional electric discharge machine. 42: Posture control device 50: Electrode holder 52: Touch sensor 102: X-direction slide table 104: Y-direction slide table 108: Workbench 110.111: Work 124: Electrode agent Patent attorney Sekihira Yamashita Figure 2, Figure 4 Figure (0) Figure 4 (b) Figure 5 Figure 7 Figure 8 Figure 9 Figure 10

Claims (4)

[Claims] (1) The coordinates of a plurality of measurement points on the shape surface of the tool attached to the processing machine to be transferred to the workpiece are determined, and the posture of the tool is calculated by calculation based on the coordinates of the measurement points. A method for controlling the posture of a tool in a processing machine, the method comprising comparing the posture with a predetermined correct posture, and correcting the posture to bring it closer to the correct posture if the measured posture is outside an allowable value. (2) A method for controlling the posture of a tool in a processing machine according to claim 1, wherein after the posture is corrected, the same process is repeated to confirm that the measured posture is within an allowable value. (3) For the coordinates of the measurement point, set the coordinate system so that the origin is inside the tool shape part, and use a measuring stylus that is fixed to a means that can move relative to the tool holder and that can detect the coordinates with respect to the origin. Determined by contacting the tool,
A method for controlling the posture of a tool in a processing machine according to claim 1. (4) A patent claim in which the measuring stylus is controlled so as to be brought into contact with the tool by moving in a predetermined direction from a preset measurement start point for each workpiece in a direction in which the absolute value of the coordinates becomes smaller. A tool attitude control method in a processing machine according to the scope of Item 3.