Machining program correction device

Abstract

This machining program correction device comprises: a program analysis unit that analyzes a machining program to calculate a command point cloud comprising a plurality of command points that identify the relative position of a tool with respect to a workpiece; a shape estimation unit that estimates a post-machining shape that is the shape after machining the workpiece by machining using the command point cloud; a surface division unit that sets division surfaces obtained by dividing the post-machining shape; a surface quality evaluation unit that evaluates surface quality for each of the division surfaces; a division surface extraction unit that extracts, on the basis of the surface quality, a division surface to be edited; a command point editing unit that edits the command point cloud within the range of the extracted division surface so as to improve the surface quality of the division surface extracted by the division surface extraction unit; and a program change unit that changes the machining program so as to correspond to the command point cloud edited by the command point editing unit.

Description

Machining program correction device

[0001] The present disclosure relates to a machining program correction device.

[0002] Numerical control (NC) is widely used to control the operation of machine tools that machine workpieces by moving the tool and workpiece relative to each other according to a machining program. NCs machine the surface of a workpiece by moving the tool along multiple linear paths that are adjacent to each other with a small gap between them. Each tool path is specified by multiple command points.

[0003] In order to improve the accuracy of the post-machining shape of a workpiece, a technique has been proposed in which CAD data or the like indicating the target shape of the workpiece after machining is acquired and the density of command points in the machining program is adjusted (see, for example, Patent Document 1), and a technique in which command points are added in consideration of tool paths adjacent to the tool path connecting the command points, and command statements corresponding to the added command points are added to the machining program (see, for example, Patent Document 2).

[0004] JP 2021-39533 A JP 2020-67863 A

[0005] When correcting a machining program using the methods described in Patent Documents 1 and 2, the time required for correcting the machining program may be long because the entire machining program must be checked. Furthermore, correcting a machining program using the methods described in Patent Documents 1 and 2 may result in excessive addition of command points, increasing the size of the machining program, or increasing the computational load required to execute the machining program. Therefore, it is preferable to be able to make the minimum necessary corrections to the machining program according to the required quality.

[0006] A machining program correction device according to one aspect of the present disclosure is a machining program correction device that corrects a machining program that specifies the operation of a machine tool that machines a workpiece by relative movement between a tool and a workpiece, and includes: a program analysis unit that analyzes the machining program and calculates a command point group consisting of a plurality of command points that specify the relative position of the tool with respect to the workpiece; a shape estimation unit that estimates an after-machining shape that is the shape of the workpiece after machining using the command point group; a surface division unit that sets division surfaces that divide the after-machining shape; a surface quality evaluation unit that evaluates the surface quality for each division surface; a division surface extraction unit that extracts the division surface to be edited based on the surface quality; a command point editing unit that edits the command point group within the range of the extracted division surface so as to improve the surface quality of the division surface extracted by the division surface extraction unit; and a program modification unit that modifies the machining program to correspond to the command point group edited by the command point editing unit.

[0007] 1 is a block diagram showing a configuration of a machining program correction device according to a first embodiment of the present disclosure;

[0008] DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, embodiments of the present disclosure will be described with reference to the accompanying drawings. Fig. 1 is a block diagram showing the configuration of a machining program correction device 1 according to a first embodiment of the present disclosure.

[0009] The machining program correction device 1 corrects a machining program that specifies the operation of a machine tool that machines a workpiece by relative movement of a tool and a workpiece. The machining program correction device 1 may be realized by one or more computer devices that have, for example, a memory, a processor, an input / output interface, etc. and execute appropriate processing programs. The machining program correction device 1 may also be realized as a function of other computer devices, such as a management computer that manages the machine tool that executes the machining program, a CAM that creates the machining program, or a numerical control device that executes the machining program.

[0010] The machining program correction device 1 includes a program analysis unit 11, a shape estimation unit 12, a surface division unit 13, a surface quality evaluation unit 14, a divided surface extraction unit 15, a command point editing unit 16, a program modification unit 17, and a user selection unit 18. These components categorize the functions of the machining program correction device 1, and do not necessarily have to be clearly distinguishable in terms of physical configuration and program configuration.

[0011] The program analysis unit 11 analyzes the machining program and calculates a group of command points consisting of a plurality of command points that specify the relative position of the tool with respect to the workpiece. The method of calculating the group of command points is well known, so a detailed description will be omitted.

[0012] The shape estimation unit 12 estimates a post-machining shape, which is the surface shape of the workpiece obtained by machining using the command point cloud. The shape estimation unit 12 may be configured to estimate the post-machining shape, for example, by simulation, based on the command point cloud as well as the pre-machining shape, which is the surface shape of the workpiece before machining, and the tool shape, which is the surface shape of the tool (for a rotating tool, the surface shape of the tool's rotating body may be used). The shape estimation unit 12 may refer to CAD data of the workpiece before machining as the pre-machining shape. Note that the CAD data of the workpiece before machining may be data on the target shape of the workpiece before machining, for example, target shape data of the workpiece in a previous process, catalog data of the material to be used as the workpiece, etc.

[0013] The surface dividing unit 13 sets dividing surfaces by dividing the post-machining shape. The method of dividing the post-machining shape is not particularly limited, and each dividing surface may be set within a predetermined coordinate range, or dividing surfaces may be set sequentially so that the area of ​​the dividing surfaces is constant, or the process of dividing the post-machining shape equally and then dividing again into equal parts any dividing surfaces whose index indicating the complexity of the surface shape does not satisfy a predetermined standard may be repeated.

[0014] The surface quality evaluation unit 14 evaluates the surface quality of each divided surface. As an index indicating the surface quality, any surface roughness such as the developed area ratio Sdr can be used, and it can be determined that the smoother the surface, the higher the surface quality. Alternatively, the surface quality may be evaluated using other indexes.

[0015] The division surface extraction unit 15 extracts division surfaces to be edited by the command point editing unit 16 based on the surface quality. The division surface extraction unit 15 may extract all low-quality division surfaces whose surface quality does not meet a predetermined standard, or may extract a certain number or a certain percentage of division surfaces whose surface quality is low. The division surface extraction unit 15 may also be configured to identify extraction candidates based on a predetermined standard and extract division surfaces selected by a user from the extraction candidates using a user selection unit 18 (described later).

[0016] The command point editing unit 16 edits the command point group within the range of the extracted dividing surface so as to improve the surface quality of the dividing surface extracted by the dividing surface extraction unit 15. Well-known techniques can be used as a method for editing the command point group, and one example is a method of moving, adding, or deleting command points so that the distances of the command points from the target shape of the machined workpiece fall within a predetermined range. In this case, the command point editing unit 16 may use a shape according to CAD data as the target shape of the machined workpiece, may use a surface including multiple command points as the target shape of the machined workpiece, or may use a set of tool paths, which are lines connecting multiple consecutive command points, as the target shape of the machined workpiece.

[0017] The program modification unit 17 modifies the machining program to correspond to the group of command points edited by the command point editing unit. Specifically, the program modification unit 17 can be configured to add command statements corresponding to added command points, modify command statements corresponding to moved command points, and delete command statements corresponding to deleted command points.

[0018] The user selection unit 18 displays information on the surface quality of each division surface and accepts the selection of a division surface by the user, thereby assisting the division surface extraction unit 15 in extracting the division surfaces. The user selection unit 18 may enable the user to directly select each division surface, or may enable the user to indirectly select a division surface by specifying conditions, etc.

[0019] As described above, the machining program correction device 1 estimates the post-machining shape of the workpiece, divides the post-machining shape into multiple division surfaces, evaluates the surface quality of each division surface, extracts division surfaces with low surface quality, and edits the command point cloud within the range of the extracted division surfaces, thereby improving surface quality. Therefore, the machining program correction device 1 corrects the machining program within a range considered to be the minimum necessary to achieve the required surface quality, so that the machining program can be corrected to achieve high-quality machining without excessively increasing the size of the machining program. Furthermore, even when an algorithm with a high computational load for correcting the machining program is adopted, the machining program correction device 1 limits the range of correction to some of the division surfaces, allowing for rapid correction of the machining program.

[0020] The following supplementary note is further disclosed regarding the above embodiment and modified examples. (Supplementary Note 1) A machining program correction device (1) corrects a machining program that specifies the operation of a machine tool that machines a workpiece by relative movement of a tool and a workpiece, and includes: a program analysis unit (11) that analyzes the machining program and calculates a command point group consisting of a plurality of command points that specify the relative position of the tool with respect to the workpiece, a shape estimation unit (12) that estimates an after-machining shape that is the shape of the workpiece after machining using the command point group, a surface division unit (13) that sets division surfaces that divide the after-machining shape, a surface quality evaluation unit (14) that evaluates the surface quality for each division surface, a division surface extraction unit (15) that extracts division surfaces to be edited based on the surface quality, a command point editing unit (16) that edits the command point group within the range of the extracted division surface so as to improve the surface quality of the division surface extracted by the division surface extraction unit (15), and a program modification unit (17) that modifies the machining program to correspond to the command point group edited by the command point editing unit (16).

[0021] (Supplementary Note 2) The machining program correction device (1) of Supplementary Note 1 may further include a user selection unit (18) that displays information on surface quality for each divided surface and accepts a selection of a divided surface by a user, and the divided surface extraction unit (15) may be capable of extracting the divided surface selected by the user in the user selection unit (18).

[0022] (Supplementary Note 3) In the machining program correction device (1) of Supplementary Notes 1 and 2, the command point editing unit (16) may perform at least one of moving, adding, and deleting command points so that the distances of the command points from the target shape of the workpiece after machining are within a predetermined range.

[0023] (Supplementary Note 4) In the machining program correction device (1) of Supplementary Notes 1 to 3, the command point editing unit (16) may set a shape according to CAD data of the machined workpiece as the target shape of the machined workpiece.

[0024] (Supplementary Note 5) In the machining program correction device (1) of Supplementary Notes 1 to 3, the command point editing unit (16) may set a surface including a plurality of command points as the target shape of the workpiece after machining.

[0025] (Supplementary Note 6) In the machining program correction device (1) of Supplementary Notes 1 to 3, the command point editing unit (16) may set a set of tool paths, which are lines connecting a plurality of consecutive command points, as the target shape of the workpiece after machining.

[0026] Although the present disclosure has been described in detail above, the present disclosure is not limited to the individual embodiments described above. Various additions, substitutions, modifications, partial deletions, etc. are possible to these embodiments without departing from the gist of the present disclosure or the spirit of the present disclosure derived from the content of the claims and their equivalents. These embodiments can also be implemented in combination. For example, in the above-described embodiments, the order of each operation and the order of each process are shown as examples and are not limited to these. The same applies when numerical values ​​or mathematical expressions are used in the description of the above-described embodiments. For example, the user selection unit in the above-described embodiments is an optional configuration and can be omitted.

[0027] REFERENCE SIGNS LIST 1 Machining program correction device 11 Program analysis unit 12 Shape estimation unit 13 Surface division unit 14 Surface quality evaluation unit 15 Division surface extraction unit 16 Command point editing unit 17 Program modification unit 18 User selection unit

Claims

1. A machining program correction device that corrects a machining program that specifies the operation of a machine tool that machines a workpiece by relative movement of a tool and a workpiece, comprising: a program analysis unit that analyzes the machining program and calculates a command point group consisting of a plurality of command points that specify the relative position of the tool with respect to the workpiece; a shape estimation unit that estimates an after-machined shape that is the shape of the workpiece after machining using the command point group; a surface division unit that sets division surfaces that divide the after-machined shape; a surface quality evaluation unit that evaluates surface quality for each division surface; a division surface extraction unit that extracts the division surface to be edited based on the surface quality; a command point editing unit that edits the command point group within the range of the extracted division surface so as to improve the surface quality of the division surface extracted by the division surface extraction unit; and a program modification unit that modifies the machining program to correspond to the command point group edited by the command point editing unit.

2. The machining program correction device according to claim 1, further comprising a user selection unit that displays information on the surface quality for each divided surface and accepts the user's selection of the divided surface, and the divided surface extraction unit is capable of extracting the divided surface selected by the user in the user selection unit.

3. A machining program correction device as described in claim 1 or 2, wherein the command point editing unit moves, adds, or deletes the command points so that the distance of the command points from the target shape of the workpiece after machining falls within a predetermined range.

4. The machining program correction device according to claim 3, wherein the command point editing unit sets a shape according to CAD data as a target shape of the workpiece after machining.

5. The machining program correction device according to claim 3, wherein the command point editing unit sets a surface including the plurality of command points as the target shape of the workpiece after machining.

6. A machining program correction device according to claim 3, wherein the command point editing unit sets a set of tool paths, which are lines connecting a plurality of consecutive command points, as the target shape of the workpiece after machining.

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