Machining program correction device

Abstract

The present invention provides a machining program correction device with which it is possible to correct a machining program that defines a tool path without requiring high knowledge or many work hours from an operator even when there is no shape data for a target machining workpiece. This machining program correction device 10 comprises: a machining program analysis unit 12 that analyzes a machining program 22 and extracts a command point cloud; an estimated machining surface generation unit 14 that generates an estimated machining surface from the command point cloud; a tool path correction unit 16 that corrects a tool path by moving, adding, or deleting command points on the basis of the distance to the estimated machining surface; and a machining program output unit 18 that converts the tool path corrected by the tool path correction unit 16 to a machining program and outputs the machining program.

Description

Machining program correction device

[0001] The present disclosure relates to an apparatus for correcting a machining program.

[0002] Machining programs that define tool paths are sometimes corrected for the purposes of shortening cycle time, improving machining accuracy, or improving surface quality. Machining programs are usually recreated or modified using CAM, an interactive programming device, or a text editor, with reference to shape data of the target workpiece. Regarding the modification of a machining program in conjunction with the modification of a tool path, Patent Document 1 discloses a technique for generating a curved path between command points and modifying the tool path while taking into account a tolerance range relative to the curved path. Patent Document 2 also discloses a polygon generation system that can be used to estimate the shape of a workpiece from a machining program.

[0003] International Publication WO2020 / 179798 Japanese Patent Application Laid-Open No. 11-339071

[0004] However, if the machining site does not have CAD data for the target workpiece or documentation for the target shape, it is usually difficult to change the target tolerance, pick feed, or path pattern. Furthermore, making these changes requires a high level of knowledge from the operator and takes a lot of work time. A path pattern refers to a tool movement pattern, such as a parallel pattern or a spiral pattern. Hereinafter, the target workpiece will be referred to as the target machining workpiece.

[0005] Regarding the shape of the target workpiece, it is possible to estimate the shape of the workpiece by machining simulation. However, to make this estimation, information on the tool shape and information on the material shape of the workpiece are required.

[0006] Therefore, the present invention aims to provide a machining program correction device that enables correction of a machining program that defines a tool path, even when shape data for the target workpiece is not available, without requiring the operator to have a high level of knowledge or spend a lot of time working on it.

[0007] The machining program correction device disclosed herein is a machining program correction device that corrects a machining program used in a numerical control device and that specifies the relative movement paths of a tool and a machined workpiece, and includes a machining program analysis unit that analyzes the machining program and extracts a command point group, an estimated machining surface generation unit that generates an estimated machining surface from the command point group, a tool path correction unit that corrects the tool path by moving, adding or deleting command points based on the distance from the estimated machining surface, and a machining program output unit that converts the tool path corrected by the tool path correction unit into a machining program and outputs it.

[0008] According to the machining program correction device disclosed herein, even when there is no shape data for the target workpiece, it is possible to correct the machining program that defines the tool path without requiring the operator to have a high level of knowledge or spend a lot of time on the job.

[0009] FIG. 1 is a block diagram showing a schematic configuration of a machining program correction device disclosed herein. FIG. 2 is a block diagram showing a modified example of the machining program correction device disclosed herein. FIG. 3 is a diagram showing an outline of a procedure for generating an estimated machining surface in Example 1. FIG. 4 is a diagram showing an outline of adding a command point in Example 1. FIG. 5A is a diagram showing a machining program after correction in Example 1. FIG. 5B is a diagram showing a corrected tool path after adding a command point in Example 1. FIG. 6 is a diagram showing an outline of adding and deleting a command point in Example 2. FIG. 7 is a diagram showing an outline of moving a command point in Example 3. FIG. 8 is a flowchart showing an outline of a machining program correction method.

[0010] (Machining program correction device) An embodiment of the present disclosure will be described with reference to the drawings. Fig. 1 is a block diagram showing a schematic configuration of a machining program correction device 10 according to an embodiment of the present disclosure. The machining program correction device 10 according to the present disclosure is a device that corrects a command point based on the distance from the command point to a generated estimated machining surface, and thereby corrects a tool path. The machining program correction device 10 is used in a numerical control device 1.

[0011] 1, the machining program correction device 10 includes a machining program analysis unit 12, an estimated machining surface generation unit 14, a tool path correction unit 16, and a machining program output unit 18. In the machining program correction device 10, the machining program analysis unit 12, the estimated machining surface generation unit 14, the tool path correction unit 16, and the machining program output unit 18 are connected in this order.

[0012] The machining program analysis unit 12 is a unit that analyzes the machining program 22 and extracts a group of command points. The machining program analysis unit 12 receives the machining program 22 from outside the machining program correction device 10. The estimated machining surface generation unit 14 generates an estimated machining surface from the group of command points extracted by the machining program analysis unit 12. The tool path correction unit 16 corrects the tool path by moving, adding, or deleting command points based on the distance from the estimated machining surface generated by the machining program analysis unit 12. The machining program output unit 18 converts the tool path corrected by the tool path correction unit 16 into a machining program and outputs it. The machining program generated by converting the corrected tool path is called a corrected machining program 24. These will be described in order below.

[0013] (First embodiment) A first embodiment of the present disclosure will be described with reference to Fig. 3 to Fig. 5B. Fig. 3 is a diagram showing an outline of a procedure for generating an estimated machining surface in the first embodiment. In Fig. 3, the generation procedure progresses in the order from arrow 311 to arrow 313. In the first embodiment, the correction method of the tool path correction unit 16 is to move, add, or delete command points so as to fit within a predetermined tolerance.

[0014] First, the machining program analysis unit 12 reads the machining program 22. Alternatively, the machining program 22 is input to the machining program analysis unit 12. A machining program 301 in Fig. 3 shows an example of the machining program 22 before correction. Hereinafter, the program before correction may be referred to as the original program.

[0015] Next, the machining program analysis unit 12 analyzes the machining program 22 and extracts a group of command points. In the example shown in Fig. 3, the machining program analysis unit 12 extracts command points for a block of the machining program 22 whose modal is G01.

[0016] 3 shows the extracted command point group. The extracted command point group includes six command points, from command point n-2 to command point n+3. The position of each command point is indicated by its coordinates in the XYZ coordinate system.

[0017] The tool path diagram 303 in Fig. 3 shows the command points 32 of the extracted command point group 30 plotted on an XYZ coordinate system. In the tool path diagram 303 and the following figures, the directions of the axes in the XYZ coordinate system are illustrated as necessary. A path obtained by sequentially connecting the command points 32 is called a tool path 60. The tool path 60 before correction shown in the tool path diagram 303 is called a pre-correction tool path 61.

[0018] 3 shows an estimated machining surface 90 generated from the extracted command point group 30. The estimated machining surface 90 is generated by the estimated machining surface generating unit 14 based on the extracted command point group 30. The method for generating the estimated machining surface 90 from the command point group 30 is not particularly limited. For example, the estimated surface machining can be generated from the point group using the technology disclosed in Patent Document 2.

[0019] The addition of the command point 32 will be described with reference to FIG. 4. The command point 32 is added by the tool path correction unit 16 based on the distance between the command point 32 and the estimated machining surface 90. FIG. 4 is a diagram showing an outline of the addition of the command point 32 in the first embodiment. A tool path diagram 401 in FIG. 4 shows the pre-correction tool path 61. Furthermore, command point diagrams 402 to 404 in FIG. 4 show the addition of the command point 32 in a frame 410 of the tool path diagram 401, as indicated by an arrow 411. The procedure for adding the command point 32 proceeds in the order of arrows 412 and 413. Note that the matters described using the command point 32 included in the frame 410 as an example also apply to other command points.

[0020] The addition of the command point 32 will be described below using an example in which the target tolerance is 1 μm. Note that various parameters related to the tool path correction used for correcting the machining program, such as the target tolerance, may be set in advance in the machining program correction device 10. Alternatively, the parameters related to the tool path correction may be set separately by an operator. This will be described with reference to FIG. 2.

[0021] FIG. 2 is a block diagram showing a modified example of the machining program correction device 10 of the present disclosure. The machining program correction device 10 shown in FIG. 2 differs from the machining program correction device 10 shown in FIG. 1 in that a tool path correction parameter 26 can be input to the tool path correction unit 16 by an operator or the like. The tool path correction parameter 26 refers to information specifying at least one of the distance between the estimated machining surface 90 and the command point 32, the target tolerance, the pick feed, and the path pattern. The tool path correction unit 16 can switch the tool path correction method based on the input tool path correction parameter 26. This allows for more flexible correction of the machining program according to the operator's needs.

[0022] Returning to FIG. 4 , the addition of a command point 32 when the target tolerance is 1 μm will be described. First, as shown in a command point diagram 402 in FIG. 4 , it is determined whether three consecutive command points 32 satisfy the target tolerance. In the command point diagram 402, the three consecutive command points 32 are command point 32n-1, command point 32n, and command point 32n+1. A line connecting command point 32n-1 and command point 32n+1 is defined as line 421. The distance from command point 32n to line 421 is defined as distance 422. If distance 422 exceeds the target tolerance, a command point 32 is added.

[0023] A specific example of adding a command point 32 will be described with reference to command point diagram 403 in Fig. 4. A command point 32 is added by adding a command point 32 midway between command point 32n and command point 32n-1 and midway between command point 32n and command point 32n+1. The line segment connecting command point 32n and command point 32n-1 is defined as line segment 431. A command point 32n-1' is added to the midpoint of line segment 431. The line segment connecting command point 32n and command point 32n+1 is defined as line segment 432. A command point 32n+1' is added to the midpoint of line segment 432.

[0024] Movement of the command points 32 in the Z-axis direction, etc., will be described with reference to the command point diagram 404 in FIG. 4. The added command points 32n-1' and 32n+1' shown in the command point diagram 403 are positioned without taking into consideration the distance from the estimated machining surface 90. In other words, the command points 32n-1' and 32n+1' are temporarily positioned, i.e., temporary command points 32. Therefore, the command points 32n-1' and 32n+1' are moved in the Z-axis direction, etc., as necessary. This movement makes the command points 32n-1' and 32n+1' tangent to the estimated machining surface 90, or moves the command points 32n-1' and 32n+1' to positions a predetermined distance away from the estimated machining surface 90. In other words, the command points 32n-1' and 32n+1' are moved to positions a certain distance away, such as +0.1 μm, from the estimated machining surface.

[0025] This movement can be a uniform movement in the Z-axis direction regardless of the command point 32, as shown by lines 411 and 422 in the command point diagram 404, for example.

[0026] Alternatively, the movement may be a movement in the tool axis direction, which can be known from the machining program 22 or the settings of the numerical control device 1. The tool axis direction refers to, for example, a direction perpendicular to the tool path at each command point 32. For example, the angle 471 is 90 degrees. The tool axis direction differs for each command point 32. Lines 461, 463, and 465 indicate the tool axis directions for the corresponding command points 32n-1, 32n, and 32n+1, respectively.

[0027] The tool axis directions of the added command points 32n-1' and 32n+1' can be determined, for example, by the following method. The tool axis direction of command point 32n-1' is indicated by line 462, and the tool axis direction of command point 32n+1' is indicated by line 462. The tool axis directions of the added command points 32n-1' and 32n+1' may be the tool axis directions of the pre-correction command points 32 (original command points) located either before or after the added command points. In other words, for example, the direction of line 462 may be the same as the direction of line 461 or the direction of line 463.

[0028] Alternatively, the tool axis directions of the added command points 32n-1' and 32n+1' may be calculated as the average of the tool axis directions of the pre-correction command points 32 before and after the added command points. That is, for example, the direction of line 464 may be calculated by averaging the directions of lines 463 and 465.

[0029] By moving the added command points 32n-1' and 32n+1' in the tool axis direction, the new command points 32 can be positioned closer to the midpoint of the adjacent pre-correction command points 32 compared to moving them in the Z axis direction.

[0030] As described above, the tool path correction unit 16 generates the corrected command point cloud 30 by adding the command points 32, etc. The corrected command point cloud 30 generates the corrected tool path.

[0031] The machining program after the command point 32 has been added is called the corrected machining program 24. The corrected machining program 24 will be described with reference to Fig. 5A. Fig. 5A is a diagram showing the corrected machining program 24 and the like.

[0032] 5A shows the command point cloud after correction by adding and moving the command points. The command points n-1' and n+1' shown in bold are the command points 32 added by the tool path correction unit 16.

[0033] A machining program 502 in Fig. 5A shows the corrected machining program 24. As shown by arrow 511, the machining program output unit 18 converts the tool path indicated by the command point group corrected by the tool path correction unit 16 into the corrected machining program 24. The portions shown in bold in the corrected machining program 24 are the portions corresponding to the added command point n-1' and command point n+1'. The machining program output unit 18 outputs the converted corrected machining program 24, and the series of processes ends.

[0034] FIG. 5B is a diagram showing an example of a corrected tool path 62, which is a tool path corrected after a command point is added. In a frame 511 shown in FIG. 5B, command points 3201, 3202, and 3203 are command points before correction. Command points 3211, 3212, and 3213 are command points added after correction. For example, by adding command point 3211 between command point 3201 and command point 3202, a tool path corresponding to a change in the target tolerance is obtained. Note that, as shown by command point 3212 and command point 3213, the number of command points 32 added between command points 32 is not limited to one. Two or more command points may be added between command points 32. Furthermore, if the target tolerance is satisfied, it is not necessary to add a new command point 32 between command points 32.

[0035] Furthermore, if the target tolerance is satisfied even when the command points 32 are deleted, the command points 32 may be deleted. By deleting the command points 32, the burden on information processing can be reduced. Deleting the command points 32 is an effective measure when there are a large number of command points 32 before correction.

[0036] (Second embodiment) A second embodiment of the present disclosure will be described with reference to Fig. 6. Fig. 6 is a diagram showing an overview of adding and deleting command points 32 in the second embodiment. In the description of the second embodiment, differences from the first embodiment will be mainly described. Items not specifically described in the second embodiment can be the same as those in the first embodiment. In the second embodiment, the correction method of the tool path correction unit 16 is to move, add, or delete command points 32 so as to fit within a predetermined pick feed.

[0037] The process of analyzing the machining program 22 and generating the estimated machining surface 90 is the same as in the first embodiment.

[0038] In the second embodiment, after the estimated machining surface 90 is generated, the tool path correction unit 16 calculates the pick feed from the command point cloud 30. The pick feed will be explained with reference to the tool path diagram 601 in Fig. 6. The tool path diagram 601 shows the pre-correction tool path 61. The pick feed is the distance between paths.

[0039] As shown in the tool path diagram 601, the tool path 60 includes a main path and a connecting path. The main path is a path corresponding to the main movement in the tool path 60, such as the path from command point 201 to command point 204. The connecting path is a path connecting two adjacent main paths, such as the path from command point 204 to command point 205. The distance of the connecting path is the pick feed.

[0040] The pre-correction tool path 61 includes four main paths, namely, main path 101 to main path 104. The pre-correction tool path 61 also includes three connection paths, namely, connection path 141 to connection path 143. The connection paths 141, 142, and 143 have the same distance (length).

[0041] The pick feed of the pre-correction tool path 61 is indicated by a double-headed arrow 631 in the tool path diagram 601. The pick feed 631 of the pre-correction tool path 61 is 10 μm.

[0042] Here, we will explain how to calculate the pick feed. First, we will explain how to determine whether two lines are on the same path. For line segments connecting command points, if the angle between two consecutive line segments is less than 30 degrees, the two line segments are determined to be on the same path. If the angle between the consecutive line segments is 30 degrees or more, the two line segments are determined to not be on the same path.

[0043] Furthermore, if the angle between the two adjacent line segments at both ends of a line segment is 30 degrees or greater, it is determined that there is movement between paths on this line segment. Furthermore, it is determined that the two command points located at both ends of the line segment are not on the same path. If the angle is less than 30 degrees, the opposite determination is made.

[0044] 6 are both greater than 30 degrees, it is determined that there is movement between paths on the line segment 142. In this case, it is also determined that the command points 207 and 208 are not on the same path.

[0045] Also, the length of the line segment 142 is the pick feed. That is, the distance 631 between the command point 207 and the command point 208 is the pick feed 631. In the example shown in Fig. 6, the length of the pick feed 631 before the change, i.e., the original length, is 10 µm.

[0046] In the second embodiment, the cases of lengthening and shortening the length of the pick feed will be described. Arrow 611 in Fig. 6 shows an example of a path change when the pick feed is lengthened. Arrow 612 in Fig. 6 shows an example of a path change when the pick feed is shortened.

[0047] First, a path change when the pick feed is lengthened will be described with reference to the tool path diagram 602 in Fig. 6. The tool path diagram 602 in Fig. 6 shows a corrected tool path 63 in which the pick feed has been lengthened. The corrected tool path 63 is a tool path in which the pick feed of the pre-correction tool path 61, 10 µm, has been changed to 15 µm. A double-headed arrow 632 in the tool path diagram 602 indicates the pick feed of the corrected tool path 63. The length of the pick feed 632 is 15 µm.

[0048] First, we will explain the matters common to both lengthening and shortening the pick feed. When changing the pick feed, the path is increased or decreased, that is, command points are added or deleted, so that the pick feed reaches the target value. In this case, the paths at both ends of the tool path are not changed. When changing the path from the pre-correction tool path 61 shown in tool path diagram 601 to the corrected tool path 63 shown in tool path diagram 602, the main path 101 from command point 201 to command point 204 and the main path 104 from command point 209 to command point 210 are not changed. The main path 101 and the main path 104 are shown in bold lines. When changing the pick feed, the path between the main path 101 and the main path 104 is changed.

[0049] A case where the pick feed is lengthened will be described. When the pick feed is lengthened, the path is reduced, that is, command points are deleted, so that the target pick feed is achieved. In the example shown in the tool path diagram 602, the number of main paths arranged between the main path 101 and the main path 104 is reduced from two to one. The pre-correction tool path 61 included two main paths, the main path 102 and the main path 103. In contrast, the post-correction tool path 63 includes only the main path 111.

[0050] When lengthening the pick feed, if the changed pick feed can be realized by deleting the main path included in the pre-correction tool path 61, the unnecessary main path is deleted and the corrected tool path 63 is generated. On the other hand, if the changed pick feed cannot be realized by deleting the main path included in the pre-correction tool path 61, the unnecessary main path is deleted and a new main path is added. In the corrected tool path 63, the main paths 102 and 103 included in the pre-correction tool path 61 are deleted and a new main path 111 is added. Then, the main paths 101 and 111 are connected by a connection path 161, and the main paths 111 and 104 are connected by a connection path 162, thereby generating the corrected tool path 63.

[0051] The position of the main path to be added can be determined by, for example, equally dividing the space between the main path 101 and the main path 104 in accordance with the pick feed. The addition of a main path will be described in detail later.

[0052] As with the command points added in the first embodiment, the main path and the like arranged according to the changed pick feed, and in turn the command points and the like, are in a so-called temporary placement state, with the distance from the estimated machining surface 90 not optimized. Therefore, the position relative to the estimated machining surface 90 is optimized using the same method as described in the first embodiment. That is, the command points are moved in the Z-axis direction or the like so that the path (command points) contact the estimated machining surface 90. This results in a corrected tool path 63. Thereafter, a machining program is generated from the corrected tool path 63, and the series of processes is completed.

[0053] Next, a path change when shortening the pick feed will be described with reference to the tool path diagram 603 in Figure 6. The following will focus on the differences from when the pick feed is lengthened. Items that are not specifically described can be performed in the same way as when the pick feed is lengthened.

[0054] The tool path diagram 603 in Fig. 6 shows a corrected tool path 64 in which the pick feed has been shortened. The corrected tool path 64 is a tool path in which the pick feed of the pre-correction tool path 61, 10 µm, has been changed to 5 µm. A double-headed arrow 633 in the tool path diagram 603 indicates the pick feed 633 of the corrected tool path 64. The length of the pick feed 633 is 5 µm.

[0055] When the pick feed is shortened, a path is added, that is, a command point is added, so as to achieve the target pick feed. In the example shown in the tool path diagram 603, the number of main paths arranged between the main path 101 and the main path 104 is increased from two to five. Of the main paths arranged between the main path 101 and the main path 104, the main paths 102 and 103 are main paths that were included in the pre-correction tool path 61.

[0056] In the corrected tool path 64, a new main path portion 121 is added between the main path 101 and the main path 102, a new main path portion 122 is added between the main path 102 and the main path 103, and a new main path portion 123 is added between the main path 103 and the main path 104. Then, the corrected tool path 64 is generated by connecting adjacent main paths in order using a connection path 151, a connection path 152, etc.

[0057] The following describes how to add a main path, that is, how to add a command point. When adding a path, that is, a command point, the position of the command point to be added can be determined using the difference between the command points that make up the original path. The difference between command points is also called an incremental amount. In the tool path diagram 601, the difference between command points is indicated by an arrow 661. The difference 661 is the difference from command point 201 to command point 202. When adding a command point, a new command point can be added by referring to the difference between the corresponding position in the pre-correction tool path 61. This will be described in detail below.

[0058] When determining the position of the command point 223 shown in the tool path diagram 603, the position of the command point 223 is determined using a difference 661, which is the difference from the command point 201 to the command point 202. Specifically, the position of the command point 223 is determined to be the position obtained by moving the difference 661 from the command point 224.

[0059] The command point 224 can be determined based on the command point 201 of the pre-correction tool path 61 as a reference, and on the distance of the changed pick feed 633 .

[0060] In a similar manner, the positions of other command points of the main path 121 and the command points of the additional main paths 122 and 123 can be determined.

[0061] The method for determining the position of the command point 202 to be added is not limited to the above method. For example, the position of the command point 202 to be added can be determined based on two command points on either side of the command point to be added, rather than based on the difference between two adjacent command points. An example will be described below using command points 203 and 206 on the pre-correction tool path 61. A line segment connecting command point 203 and command point 206 is defined as line segment 651. A midpoint of line segment 651 is defined as midpoint 652.

[0062] When a new main route is added between the main route 101 including the command point 203 and the main route 102 including the command point 206, midpoints are similarly found for the other command points between the main route 101 and the main route 102. Then, a new main route can be generated by connecting the found midpoints.

[0063] The command point 222 of the main path 121 in the tool path diagram 603 is at the same position as the midpoint 652 shown in the tool path diagram 601 obtained as described above. In a similar manner, the positions of other command points of the main path 121 and the command points of the main paths 122 and 123 to be added can be determined.

[0064] Even when the pick feed is shortened, similar to when the pick feed is lengthened, the position of the command point in the temporarily placed state is optimized relative to the estimated machining surface 90. After that, a machining program is generated from the corrected tool path 63, and the series of processes is completed.

[0065] (Third embodiment) A third embodiment of the present disclosure will be described with reference to Fig. 7. Fig. 7 is a diagram showing an overview of the movement of the command point 32 in the third embodiment. In the description of the third embodiment, differences from the first embodiment will be mainly described. Matters not specifically described in the third embodiment can be the same as those in the first embodiment. In the third embodiment, the correction method of the tool path correction unit 16 is to move, add, or delete the command point 32 so as to match a predetermined path pattern.

[0066] The process of analyzing the machining program 22 and generating the estimated machining surface 90 is the same as in the first embodiment.

[0067] In the third embodiment, after the estimated machining surface 90 is generated, the tool path correction unit 16 moves 32 the command point so that it matches the target path pattern, and then further moves the command point in the Z-axis direction so that the moved command point 32 comes into contact with the estimated machining surface 90. The following will explain each step in order.

[0068] The tool path diagram 701 in Fig. 7 is a diagram showing a path pattern of a scanning line with the Y-axis fixed. In the path pattern of a scanning line with the Y-axis fixed, the Y-axis coordinate values ​​of all command points determined to be on the same path are changed to the same Y-axis coordinate value as the starting point of the path, and then the command points are moved in the Z-axis direction so as to be tangent to the estimated machining surface 90. Note that whether or not the command point 32 is on the same path can be determined in the same manner as in the second embodiment. In other words, if the angle between the line segments at both ends of the line segment connecting the two command points is less than 30 degrees, the two command points are determined to be on the same path.

[0069] A specific description will be given with reference to the drawings. The corrected tool path 65, which is a path pattern in which the Y-axis is fixed, will be described with reference to the tool path diagram 701. A command point 250 is the start point of the path. In a main path 261 (path shown in bold) from command point 250 to command point 253, the coordinate values ​​of each command point are converted so that the Y-axis coordinate value becomes the same as the Y-axis coordinate value of command point 250, i.e., the Y-axis coordinate value is not changed, and only the X-axis and Z-axis coordinate values ​​are moved. As a result, the main path 261 becomes a path having a scanning line in which the Y-axis is fixed.

[0070] After the above-described transformation of coordinate values ​​is performed for one main path, the coordinate values ​​of the next main path that continues via a connecting path such as the connecting path 262 are transformed in the same manner.

[0071] After completing the conversion of coordinate values ​​for all command points, the distance between the command points and the estimated machining surface is adjusted by, for example, moving the command points in the Z-axis direction so that they are in contact with the estimated machining surface, as in Example 1.

[0072] In the corrected tool path 65 in the path pattern in which the Y axis is fixed, the main paths move mainly in the X direction as shown by main paths 261 and 263. Then, these main paths are connected by connection paths 262 and 264, etc., to form a tool path.

[0073] Next, the corrected tool path 66, which is a path pattern with the X-axis fixed, will be described with reference to the tool path diagram 702. The command point 250 is the starting point of the path, just like the corrected tool path 65. In the main path 271 (path shown in bold) from the command point 250 to the command point 259, the coordinate values ​​of each command point are converted so that the X-axis coordinate value becomes the same as the X-axis coordinate value of the command point 250, i.e., the X-axis coordinate value is not changed, but only the Y-axis and Z-axis coordinate values ​​are moved. As a result, the main path 271 becomes a path having a scanning line with the X-axis fixed.

[0074] After the above-described transformation of coordinate values ​​is performed for one main path, the coordinate values ​​of the next main path that continues via a connecting path such as the connecting path 272 are transformed in the same manner.

[0075] After completing the conversion of coordinate values ​​for all command points, the distance between the command points and the estimated machining surface is adjusted by, for example, moving the command points in the Z-axis direction so that they are in contact with the estimated machining surface, as in Example 1.

[0076] In the corrected tool path 66 in the path pattern in which the X axis is fixed, the main paths move mainly in the Y direction as shown by main paths 271 and 273. Then, these main paths are connected by connection paths 272 and 274, etc., to form a tool path.

[0077] In the example shown in FIG. 7, the corrected tool path 65 and the corrected tool path 66 both target the same estimated machining surface 90, but have different end points.

[0078] By changing the path pattern in this way, it is possible to obtain a tool path that is suited to the characteristics of the device, such as one that has good movement accuracy in a predetermined direction or one that has poor movement accuracy.

[0079] 7 is an example. Other path patterns include, for example, a spiral path pattern, a contour path pattern with a constant height, i.e., a constant Z-axis coordinate value, etc. For these path patterns, a corrected tool path can also be generated using the same method as described above.

[0080] Furthermore, after the above-described change in the path pattern has been made, the previously described changes in the target tolerance and pick feed may also be made.

[0081] The machining program correction device 10 may be configured using a computer including a memory such as a ROM (read only memory) or a RAM (random access memory), a CPU (control processing unit), and a communication control unit, all connected to one another via a bus. The functions and operations of the above-mentioned functional units are achieved by the cooperation of the CPU and memory mounted on the computer and the control program stored in the memory. The machining program correction device 10 may be configured using a CNC (computer numerical controller), a PLC (programmable logic controller), or the like, and may be connected to a higher-level computer that outputs machining conditions and the like in addition to the machining program.

[0082] (Method of correcting machining program) A method of correcting a machining program performed by the machining program correction device 10 of the present disclosure will be described with reference to Fig. 8. Fig. 8 is a flowchart showing an outline of the method of correcting a machining program. In Fig. 8 and the following description, S1 indicates step 1. The same applies to the other steps.

[0083] 8 shows the correction methods performed by the tool path correction unit, including changes in the target tolerance, the pick feed, and the path pattern. In the machining program correction method, steps S1 to S3 and steps S4 to S5 are common to the three correction methods described above.

[0084] In the machining program correction method, first, in step S1, the machining program is read in a machining program analysis unit, etc. Next, in step S2, the machining program is analyzed and a command point group is extracted.

[0085] Next, in S3, an estimated machining surface is generated from the command point group in an estimated machining surface generating unit or the like.

[0086] After S3, if the target tolerance is to be changed, in S11, the tolerance is calculated from the command point group in a tool path correction unit or the like. Next, in S12, temporary command points are added between command points that exceed the target tolerance. Note that in S12, command points may be deleted as necessary.

[0087] After S3, if the pick feed is to be changed, in S21, the pick feed is calculated from the command point group in a tool path correction unit, etc. Next, in S22, command points are added or deleted based on the changed pick feed, thereby increasing or decreasing the tool path.

[0088] After S3, if the path pattern is to be changed, in S31, the coordinate values ​​of the command points that match the specified path pattern are converted in a tool path correction unit, etc., by fixing the coordinate values ​​of a specified coordinate axis among the X, Y, and Z axes.

[0089] After completing the steps corresponding to each correction method, the process proceeds to S4. In S4, a tool path correction unit or the like moves a tentative command point based on the distance from the estimated machining surface. This optimizes the distance between the command point and the estimated machining surface. Next, in S5, a machining program output unit or the like generates a machining program from the corrected tool path. This completes the flow of the machining program correction method.

[0090] As described above, the machining program correction device 10 disclosed herein extracts the command point group 30 from the machining program 22 and generates the estimated machining surface 90. Then, the tool path 60 is corrected by moving, adding, or deleting the command points 32 so that the distance from the estimated machining surface 90 falls within a predetermined range.

[0091] Specifically, command points can be moved or added to fit within a predetermined tolerance (change target tolerance), within a predetermined pick feed (change pick feed), and to match a predetermined path pattern (change path pattern).

[0092] When moving or adding the command point 32, it is preferable to set the distance from the estimated machining surface 90 to 0 mm, and to move or add the command point 32 so that the command point 32 is in contact with the estimated machining surface 90. The distance of the command point 32 from the estimated machining surface 90 is not limited to 0 mm, but can also be a predetermined distance. The direction in which the command point 32 is moved or the direction in which the distance from the estimated machining surface is calculated includes the Z-axis direction, the tool axis direction, etc.

[0093] Then, the corrected tool path 60 is converted and output into a machining program, that is, the corrected machining program 24. This makes it possible to correct the tool path without using a post-processor or the like.

[0094] The machining program correction device 10 disclosed herein can correct the machining program, i.e., the tool path, even when shape data for the target workpiece is unavailable, without requiring the operator to have advanced knowledge or spend a lot of time on the job. This can result in the effects of shortening the cycle time, improving machining accuracy, and improving surface quality. Typically, these three effects are in a trade-off relationship. In this regard, the machining program correction device 10 disclosed herein can achieve these effects to a high level. Furthermore, the machining program correction device 10 disclosed herein does not require information on the tool shape and the material shape of the workpiece, as compared to when the shape of the workpiece is estimated using a machining simulation. Therefore, path correction can be easily performed.

[0095] The present disclosure is not limited to the above-described embodiments, examples, and modifications, and includes modifications and improvements within the scope of achieving the object of the present disclosure.

[0096] The following supplementary note is further disclosed regarding the above embodiment: (Supplementary note 1) A machining program correction device (10) for correcting a relative movement path between a tool and a machined workpiece, the machining program correction device (10) comprising: a machining program analysis unit (12) for analyzing a machining program and extracting a command point group, an estimated machining surface generation unit (14) for generating an estimated machining surface from the command point group, a tool path correction unit (16) for correcting a tool path by moving, adding or deleting command points based on a distance from the estimated machining surface, and a machining program output unit (18) for converting the tool path corrected by the tool path correction unit into a machining program and outputting it.

[0097] (Note 2) In the above machining program correcting device (1), the correction method of the tool path correcting unit (16) moves, adds or deletes command points so as to fit within a predetermined tolerance.

[0098] (Supplementary Note 3) In the above machining program correcting device (1), the correction method of the tool path correcting unit moves, adds or deletes command points so as to fit within a predetermined pick feed.

[0099] (Supplementary Note 4) In the above machining program correcting device (1), the correction method of the tool path correcting unit moves, adds or deletes command points so as to match a predetermined path pattern.

[0100] (Supplementary Note 5) In the above-mentioned machining program correction device (1), the tool path correction unit switches the tool path correction method based on a tool path correction parameter, which is information specifying at least one of the distance to the estimated machining surface, the target tolerance, the pick feed, and the path pattern.

[0101] REFERENCE SIGNS LIST 1 Numerical control device 10 Machining program correction device 12 Machining program analysis unit 14 Estimated machining surface generation unit 16 Tool path correction unit 18 Machining program output unit 22 Machining program 24 Corrected machining program 30 Command point cloud 32 Command point 60 Tool path 61 Tool path before correction 62 to 65 Corrected tool path 90 Estimated machining surface 100 Main path 140 Connecting path

Claims

1. A machining program correction device for use in a numerical control device that corrects a machining program that specifies the relative movement path between a tool and a machined workpiece, the machining program correction device comprising: a machining program analysis unit that analyzes the machining program and extracts a group of command points; an estimated machining surface generation unit that generates an estimated machining surface from the group of command points; a tool path correction unit that corrects the tool path by moving, adding or deleting command points based on the distance from the estimated machining surface; and a machining program output unit that converts the tool path corrected by the tool path correction unit into a machining program and outputs it.

2. A machining program correction device according to claim 1, wherein the correction method of the tool path correction unit is to move, add or delete command points so as to fit within a predetermined tolerance.

3. The machining program correction device according to claim 1, wherein the correction method of the tool path correction unit is to move, add or delete command points so as to fit within a predetermined pick feed.

4. A machining program correction device according to claim 1, wherein the correction method of the tool path correction unit is to move, add or delete command points so as to match a predetermined path pattern.

5. A machining program correction device according to any one of claims 2 to 4, wherein the tool path correction unit switches the tool path correction method based on a tool path correction parameter, which is information specifying at least one of the distance from the estimated machining surface, the target tolerance, the pick feed, and the path pattern.

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