JP2024065176A - Machining program correction method and information processing program - Google Patents

Abstract

[Problem] To suppress the deterioration of machining quality caused by the above in a machine tool. [Solution] A method for correcting a machining program includes the steps of acquiring target shape information indicating a target shape, acquiring machining information including a tool path for machining a workpiece, generating a machining program based on the target shape information and the machining information, measuring the shape of the machined workpiece by executing the machining program and acquiring measured shape information indicating the measured shape of the workpiece, and correcting the machining program based on a shape error that is the difference between the measured shape information and the target shape information. [Selected Figure] Figure 8

Description

The present invention relates to information processing that corrects machining programs used in machine tools.

A known example of a machine tool is a five-axis machining center with three orthogonal linear axes (X-axis, Y-axis, Z-axis) and two rotational axes (B-axis, C-axis). Rotation of the B-axis tilts the main spindle, and rotation of the C-axis rotates the workpiece. In such a machine tool, a numerical control device executes a machining program (NC program) to control the five axes, and the workpiece is machined into the desired shape while changing the tip point position and attitude of the tool. When the machining program is executed, this tip point position is output as a control command, so below this tip point is also referred to as the "command point".

Machining programs are generated based on cutter location data (hereafter referred to as "CL data") obtained through computer-aided design (CAD) and computer-aided manufacturing (CAM). That is, the CAD/CAM device generates CL data, including the tool path and tool attitude, based on the CAD data. The path connecting the command points becomes the "tool path." The post-processor generates the machining program based on that CL data.

JP 2019-70953 A

However, even if a machining program generated in this way is executed to perform machining, various factors such as tool wear can cause errors between the target shape created by CAD and the actually machined shape (also called the "actual shape"), which can result in reduced machining quality.

One aspect of the present invention is a method for correcting a machining program. This correction method includes the steps of acquiring target shape information indicating a target shape, acquiring machining information including a tool path for machining a workpiece, generating a machining program based on the target shape information and the machining information, executing the machining program to measure the shape of the machined workpiece and acquiring measured shape information indicating the measured shape of the workpiece, and correcting the machining program based on a shape error that is the difference between the measured shape information and the target shape information.

Another aspect of the present invention is an information processing program that corrects a machining program for machining a workpiece into a target shape. This information processing program has a function of acquiring target shape information indicating the target shape, a function of acquiring machining information including a tool path for machining the workpiece, a function of generating a machining program based on the target shape information and the machining information, a function of executing the machining program to measure the shape of the machined workpiece and acquiring measured shape information indicating the measured shape of the workpiece, and a function of correcting the machining program based on a shape error that is the difference between the measured shape information and the target shape information.

The present invention makes it possible to suppress the deterioration of machining quality caused by the above in machine tools.

1 is a schematic diagram showing a general configuration of a machine tool according to an embodiment; FIG. 2 is a hardware configuration diagram of a machine tool. FIG. 2 is a functional block diagram of an information processing device. FIG. 10 is a diagram illustrating a method for correcting a machining program. FIG. 10 is a diagram illustrating a method for correcting a machining program. FIG. 10 is a diagram illustrating a method for correcting a machining program. FIG. 10 is a diagram illustrating a method for correcting a machining program. 11 is a flowchart showing a machining program generation process. 9 is a flowchart showing a command point correction process in S20 of FIG. 8;

Hereinafter, an embodiment of the present invention will be described with reference to the drawings.
1 is a schematic diagram showing a general configuration of a machine tool according to an embodiment of the present invention, in which the left-right direction, the front-rear direction, and the up-down direction when looking at the machine tool 1 from the front are defined as the X-axis, the Y-axis, and the Z-axis directions, respectively.

The machine tool 1 is a five-axis controlled machining center, and is equipped with a processing device 2 having three orthogonal linear axes (X-axis, Y-axis, Z-axis) and two rotational axes (B-axis, C-axis). These five axes are simultaneously controlled by a numerical control device (described later) to move the tool along a command point and perform various types of processing while changing the tool posture.

The machining device 2 includes a spindle head 12 that supports the spindle 10, and a table 14 that supports the workpiece W. The spindle head 12 has a B-axis and supports the spindle 10 so that it can rotate (tilt) around the B-axis. The spindle 10 coaxially supports a tool T. The tool T is, for example, an end mill. The spindle head 12 is provided with a spindle motor for driving the spindle 10 to rotate around its axis, and a servo motor for rotating the spindle 10 around the B-axis. The tilt angle of the tool T with respect to the Z-axis direction changes as the spindle rotates.

The rotation of the spindle 10 changes the inclination angle of the tool T relative to the workpiece W. The spindle head 12 is also driven in three axial directions by multiple servo motors. The spindle 10 can be moved freely in the X-axis, Y-axis, and Z-axis directions by driving the spindle head 12.

The workpiece W is fixed to the table 14 via a jig (not shown). A C-axis is provided along the axis of the table 14. The table 14 is driven to rotate about the C-axis by a servo motor (not shown). In other words, with the above configuration, the relative positions of the workpiece W and the tool T can be adjusted three-dimensionally.

FIG. 2 is a diagram showing the hardware configuration of the machine tool 1.
The machine tool 1 includes an operation control device 50, a numerical control device 52, a machining device 2, a tool exchange unit 54, a tool storage unit 56, and a shape measurement unit 58. The numerical control device 52 transmits control signals to the machining device 2 in accordance with a machining program (NC program) that is manually or automatically generated. The machining device 2 drives the spindle 10 and the table 14 in accordance with instructions from the numerical control device 52 to machine a workpiece W.

The operation control device 50 includes an operation panel that provides a user interface function to the operator. The operator controls the numerical control device 52 via the operation control device 50. The tool storage unit 56 stores tools. The tool changer 54 corresponds to a so-called ATC (Automatic Tool Changer). The tool changer 54 takes out a tool from the tool storage unit 56 in accordance with a change instruction from the numerical control device 52, and exchanges the taken-out tool for the tool in the spindle 10.

An information processing device 100 is connected to the numerical control device 52. The information processing device 100 generates a machining program based on CL data acquired from a CAD/CAM device (not shown) and outputs it to the numerical control device 52. The numerical control device 52 executes the machining program to control the machining device 2. The information processing device 100 may be configured as a part of the operation control device 50. The information processing device 100 may be a general laptop PC (Personal Computer) or a tablet computer.

The shape measuring unit 58 measures the shape of the workpiece obtained by processing the workpiece W by the processing device 2. The shape measuring unit 58 is a device capable of detecting the external shape of the workpiece W using an imaging device such as a camera, a laser displacement meter, a touch probe, etc., but as the shape detection itself can employ known technology, a detailed description thereof will be omitted. The shape measuring unit 58 detects the shape of the workpiece based on commands from the information processing device 100 and outputs the detection information.

In this embodiment, the information processing device 100 functions as a post-processor. The information processing device 100 generates a machining program (first machining program) based on CL data acquired from a CAD/CAM device, and then instructs the numerical control device 52 to perform test machining using the first machining program. The information processing device 100 corrects the first machining program based on a shape error, which is the difference between the measured shape information of the workpiece obtained by the test machining and the target shape information indicated by the CAD data, and generates a regular machining program (second machining program). The details are described below.

FIG. 3 is a functional block diagram of the information processing device 100.
Each component of the information processing device 100 is realized by hardware including a computing unit such as a CPU (Central Processing Unit) and various computer processors, a storage device such as a memory or storage, and a wired or wireless communication line connecting them, and software stored in the storage device and supplying processing instructions to the computing unit. The computer program may be composed of a device driver, an operating system, various application programs located in higher layers, and a library that provides common functions to these programs. Each block described below shows a functional block rather than a hardware configuration.

The operation control device 50 and the numerical control device 52 may also be realized by hardware including a processor or other computing unit, a memory or storage device, and wired or wireless communication lines connecting them, and software stored in the memory device that supplies processing instructions to the computing unit.

The information processing device 100 includes an input/output interface unit 110, a data processing unit 112, and a data storage unit 114. The input/output interface unit 110 is responsible for processing related to the input/output interface, including the exchange of data with external devices. The data processing unit 112 executes various processes based on data acquired by the input/output interface unit 110 and data stored in the data storage unit 114. The data processing unit 112 also functions as an interface for the input/output interface unit 110 and the data storage unit 114. The data storage unit 114 stores various programs and setting data.

The input/output interface unit 110 includes an input unit 120 and an output unit 122. The input unit 120 acquires various information output from an external device. The output unit 122 outputs various information and commands to the external device.

The input unit 120 includes a target shape information acquisition unit 124, a machining information acquisition unit 126, and a measurement shape information acquisition unit 128. The input unit 120 acquires various information related to machining of the workpiece W from the CAD/CAM device 60. In this embodiment, the CAD/CAM device 60 has the functions of both a CAD device and a CAM device, but the CAD device and the CAM device may be provided separately. In that case, the CAM device acquires the CAD data generated by the CAD device and also acquires path generation information (coordinate system, tool shape, feed rate, spindle speed, etc.). The CAM device generates CL data based on the CAD data and path generation information.

The target shape information acquisition unit 124 acquires target shape information indicating the target shape when machining the workpiece from the CAD/CAM device 60. The target shape information includes CAD data. The machining information acquisition unit 126 acquires machining information for machining the workpiece from the CAD/CAM device 60. The tool path of the machining information can be acquired from the CL data. The tool information of the machining information can be acquired from the CL data or data in a specified data format. The machining information includes a machining reference point, a tool path, and tool information. The tool path is made up of multiple command points through which the tool passes when machining the workpiece. The tool information includes shape-related information of the tool used in machining (hereinafter also referred to as "tool shape-related information"). The tool shape-related information is, for example, the tool type, the tool shape such as a CAD drawing, and information from which the tool shape can be calculated (such as the total length and diameter of the cutting tool).

The measurement shape information acquisition unit 128 acquires shape information (measurement shape information) of the workpiece measured by the shape measurement unit 58. The shape measurement unit 58 measures, for example, the profile of the outer shape along the horizontal cross section (XY plane) of the workpiece. The three-dimensional shape of the workpiece can be measured by scanning the measurement surface in the vertical direction (Z direction).

The data storage unit 114 includes a program storage unit 130, a target shape storage unit 132, a processing information storage unit 134, a command point data storage unit 136, and a measured shape storage unit 138. The data storage unit 114 includes a memory that functions as a working area when the data processing unit 112 performs calculation processing.

The program storage unit 130 stores an information processing program for generating a machining program. The target shape memory unit 132 stores the target shape information acquired by the target shape information acquisition unit 124. The machining information memory unit 134 stores the machining information acquired by the machining information acquisition unit 126. The tool path and the tool shape related information in the machining information are linked by a tool number. The command point data memory unit 136 temporarily stores command point data calculated or corrected by the data processing unit 112 (described in detail later). The measured shape memory unit 138 stores the measured shape information acquired by the measured shape information acquisition unit 128.

The data processing unit 112 includes a machining program generation unit 140, a test machining instruction unit 142, a measurement instruction unit 144, and a machining program correction unit 146. The machining program generation unit 140 generates a machining program (first machining program) based on information (CL data) acquired from the CAD/CAM device 60.

The test machining instruction unit 142 outputs the generated first machining program and an instruction to execute the first machining program to the numerical control device 52. In other words, it instructs test machining by executing the first machining program. The numerical control device 52 receives the instruction and executes test machining by the machining device 2. The measurement instruction unit 144 instructs the shape measurement unit 58 to measure the shape of the workpiece obtained by the test machining. The shape measurement unit 58 receives the instruction and executes the shape measurement, and outputs the measured shape information to the information processing device 100.

The machining program correction unit 146 corrects the first machining program based on the shape error, which is the difference between the measurement shape information acquired by the measurement shape information acquisition unit 128 and the target shape information, to obtain the second machining program. Details of this correction method will be described later.

The output unit 122 includes a program output unit 129. The program output unit 129 outputs the generated machining program to the numerical control device 52.

Next, a method for correcting the machining program will be described.
4 to 7 are diagrams that typically show a method of correcting a machining program.
In the CAD/CAM device 60, a tool path (command point data) is calculated based on a target shape indicated by the CAD data, on the assumption that the tool is free from defects such as wear. The post-processor generates a machining program based on the CL data including the command point data.

For this reason, if the length or shape of the tool changes due to wear or the like, an error may occur between the target shape and the machined shape (actual shape). In this embodiment, test machining is performed using a machining program (first machining program) generated based on CAD data, and the actual shape obtained by the test machining is measured. The shape measured at this time is also called the "measured shape." The command points (command point data that is the basis for calculating the first machining program) are corrected so that the error between this measured shape and the target shape is small, and a machining program (second machining program) is generated based on CL data including the corrected command point data.

As a prerequisite for this correction process, the target shape information acquisition unit 124 acquires shape data, and the machining information acquisition unit 126 acquires machining data and tool data as the above-mentioned machining information. The shape data is based on CAD data and includes target shape information after machining of the workpiece. The shape data is stored in the target shape memory unit 132. The command point data memory unit 136 stores command point data calculated based on the target shape data and used to generate the first machining program. Meanwhile, the measured shape information acquisition unit 128 acquires measured shape data of the workpiece obtained by test machining. This measured shape data is stored in the measured shape memory unit 138.

As shown in FIG. 4, the machining program correction unit 146 compares the target shape with the measured shape and corrects the command points so that the shape error is reduced. In this embodiment, the target shape and the measured shape are compared for each same cross section. To achieve this, the measured shape data is acquired as point cloud data for each cross section of the workpiece. The measured shape information from the shape measurement unit 58 may be acquired as the point cloud data, or the measured shape information acquired from the shape measurement unit 58 may be converted into point cloud data by the machining program correction unit 146.

On the other hand, the machining program correction unit 146 identifies point cloud data (also referred to as "target point cloud data") for the target shape data that corresponds to the point cloud data of the measured shape data (also referred to as "measurement point cloud data"). The target point cloud data is data that represents a collection of cutting points that follow the outer shape of the target shape. The cutting points correspond to the points at which the tool contacts the workpiece when the tool is positioned based on the command points. In other words, since the cutting points and the command points are associated with each other, it is possible to identify the cutting point data (corresponding to the target point cloud data) from the command point data.

Figure 5(A) shows an example of comparing the target shape and the measured shape for a certain cross section. The two-dot chain line in the figure indicates the target shape, and the points (corner points) on the target shape indicate the cutting points. The solid line indicates the measured shape, and the points (circle points) on the measured shape indicate the measurement points. Figure 5(B) is an enlarged view of part A in Figure 5(A). In this example, the target shape and the measured shape match at the position of cutting point Pn. On the other hand, at the position of cutting point Pn+1, there is a positive error Δh1 between the target shape and the measured shape, resulting in insufficient machining (uncut portion). At the position of cutting point Pn-1, there is a negative error Δh2 between the target shape and the measured shape, resulting in over-machining (over-cutting).

When comparing the target shape and the measured shape in this way, it is necessary to align the cutting points and measurement points to be compared so that they correspond to each other, that is, so that they are the same points in an ideal state where the target shape and the measured shape perfectly match. Therefore, in this embodiment, these are aligned based on the machining reference point included in the machining data.

As shown in FIG. 6, the machining data includes information on the tool path and machining reference point. The position of each command point that constitutes the tool path is set based on a predetermined machining reference point (machining origin). The machining reference point is data required to match the target shape and the tool path. The machining reference point is a reference point for the tool path, and is set in advance in relation to the target shape. The CL data output from the CAD/CAM device 60 includes multiple tool paths, and a machining reference point is provided for each tool path.

When generating the first machining program, the machining program generation unit 140 acquires the above-mentioned shape data, machining data, and tool data from the data storage unit 114. Then, based on this information, it first places a target shape in a three-dimensional virtual space, and places a machining reference point on the target shape. Next, it places a tool path based on the machining reference point, and places a tool (tool shape) on the tool path.

The machining program correction unit 146 identifies a reference point (also called an "alignment reference point") that corresponds to the machining reference point for the measurement shape data. Then, the measurement shape and the target shape are compared with the alignment reference point aligned with the machining reference point.

Figure 7 shows a specific example of command point data (tool path) correction processing. Here, an end mill is used as the tool. Figure 7(A) shows a case where the tool T is not worn, and Figure 7(B) shows a case where the tool T is worn. Figure 7(C) shows an example of a command point correction method.

When ideal machining is performed without wear on the tool T, the workpiece is machined so that the cutting point Pc of the tool T comes into contact with the machining surface Fc set in the target shape, and the target shape and the measured shape match (Figure 7 (A)). Therefore, a high-quality cutting surface that conforms to the target shape is obtained.

In this embodiment, the command point Pp to be the subject of position control is set at the cutting edge of the tool T, and the tip center is set as the reference point Po (virtual reference point). The tip surface of the tool T is located at a position of tool radius r from the reference point Po, and the command point Pp is located on the axis L of the tool T on the tip surface. The tool radius r is the radius of the cross section of the tool T. The "cutting point Pc" is the point where the tool T and the machining surface Fc meet when the tool T is positioned based on the command point Pp on the tool path. In the illustrated example, the "cutting point Pc" is the point where the normal line drawn from the reference point Po to the machining surface Fc intersects with the machining surface Fc.

On the other hand, even if the tool T is worn, the CL data generated by the CAD/CAM device 60 does not take wear into account. As a result, the machined product obtained by executing the first machining program will not match the target shape. For example, wear shortens the tool T, resulting in an error ΔP between the cutting point Pc in the program and the actual cutting point (measurement point Pc') (Figure 7 (B)). In the example shown, there is residual cutting on the surface of the workpiece.

This means that there is a similar error between the command point Pp on the program and the apparent command point Pp' (the command point when the measurement point Pc' is assumed to be the cutting point), and between the reference point Po on the program and the apparent reference point Po' (the reference point when the measurement point Pc' is assumed to be the cutting point). Therefore, the cutting point Pc on the program is corrected based on the error ΔP between the cutting point Pc and the measurement point Pc' (Figure 7 (C)).

That is, if the command point Pp=(Ppx, Ppy, Ppz) ^T , the cutting point Pc=(Pcx, Pcy, Pcz) ^T , and the measurement point Pc'=(Pcx', Pcy', Pcz') ^T , the corrected command point Pp' is obtained by the following equation (1).
Pp' = Pp - (Pc' - Pc) ... (1)

The machining program correction unit 146 corrects the command point Pp using the above formula (1). Note that, although an example is shown here in which uncut portions occur due to wear of the tool T, if overcutting occurs, the sign of the vector (Pc'-Pc) is reversed, so the above formula (1) can be applied as is. If there is no error, Pp'=Pp will remain the same.

After each command point Pp has been corrected as described above, the machining program correction unit 146 modifies the CL data to include a tool path having each corrected command point Pp', and generates a machining program (second machining program) based on the CL data.

Next, the machining program generation process will be specifically described.
Fig. 8 is a flowchart showing the machining program generation process. Fig. 9 is a flowchart showing the command point correction process in S20 in Fig. 8. The following "S" indicates a processing step.

As shown in FIG. 8, the machining program generation unit 140 first reads target shape information from the target shape storage unit 132 (S10), and then reads machining information from the machining information storage unit 134 (S12). As described above, the machining information includes tool path information (the tool path before correction) and tool information.

Then, the machining program generation unit 140 places a machining reference point on the acquired target shape (S14), and places the tool path (each command point before correction) based on the machining reference point (S16). It also places the measurement shape (shape of the workpiece) so that the alignment reference point is aligned with the machining reference point (S18). Then, it executes a command point correction process to correct each command point (S20).

As shown in FIG. 9, the machining program correction unit 146 sequentially corrects each command point that constitutes the tool path in the command point correction process. Note that "n" below corresponds to the ordinal number of the correction process. The machining program correction unit 146 clears n to zero and starts the process (S30).

The machining program correction unit 146 updates the ordinal number n (S32) and obtains the nth command point Ppn (S34). When it is the first command point, it reads out the position information of command point Pp1. It then identifies the cutting point Pcn associated with command point Ppn (S36) and identifies the measurement point Pcn' that corresponds to cutting point Pcn (S38).

Then, the machining program correction unit 146 calculates a correction value for the command point Ppn based on the measurement point Pcn' and the cutting point Pcn. That is, the error between the measurement point Pcn' and the cutting point Pcn is calculated (S40). This correction value is an error vector (movement vector) for correction. Then, the cutting point Pcn is corrected using this error vector (S42). That is, the command point Ppn' is set based on the above formula (1).

The command point data storage unit 136 stores the corrected command point Ppn'. The above process is repeated until the correction of the last command point is completed (N in S46). When the correction of the last command point is completed (Y in S46), the machining program generation unit 140 updates each command point Ppn' stored up to that point with corrected command point data (S48).

Returning to FIG. 8, if the correction of the command point data for all tool paths has been completed (Y in S22), the machining program correction unit 146 modifies the CL data based on the corrected command point data (S24). It generates a machining program (second machining program) based on the CL data (S26). If the correction has not been completed (N in S22), the process returns to S12.

The information processing device 100 has been described above based on the embodiment.
According to this embodiment, the machining program is corrected to match the shape of the workpiece after the test machining, so that the quality of the machined surface of the workpiece in the subsequent actual machining can be maintained high. In other words, the error between the target shape and the actual shape caused by various factors such as tool wear can be suppressed, and the deterioration of the machining quality can be suppressed.

[Modification]
In the above embodiment, an end mill is used as an example of a tool, but it goes without saying that the above correction method can be applied to various other tools such as milling cutters, taps, and cutting tools.

In the above embodiment, an example has been shown in which the information processing device 100 functions as a post-processor independent of the CAD/CAM device 60. In a modified example, the functions of the machining program generation unit 140, the test machining instruction unit 142, the measurement instruction unit 144, and the machining program correction unit 146 may be incorporated as functions of the CAD/CAM device (or the CAM device alone). Alternatively, they may be incorporated as functions of a numerical control device.

In the above embodiment, a configuration in which the information processing device 100 instructs the numerical control device 52 to perform test machining has been exemplified. In a modified example, the information processing device 100 may not instruct test machining, and the numerical control device 52 may perform test machining based on an operation by an operator, and the shape measurement unit 58 may perform shape measurement of the machined product. The information processing device 100 may perform a correction process for the machining program when it receives measured shape data from the shape measurement unit 58.

Although not mentioned in the above embodiment, the information processing device 100 may execute the above-mentioned machining program correction process multiple times. For example, the correction process may be repeated until the error between the measured shape and the target shape becomes equal to or less than a predetermined reference value. The second machining program may be generated using the command point data when the error becomes equal to or less than the reference value.

In the above embodiment, a five-axis machining center is used as an example of a machine tool. That is, an example is shown in which the linear axes are three axes, the X-axis, the Y-axis, and the Z-axis, and the rotational axes are two axes, the B-axis and the C-axis. In a modified example, the rotational axes may be the A-axis and the C-axis. Alternatively, they may be the A-axis and the B-axis. Also, a four-axis machining center may be used, with one rotational axis (for example, only the B-axis).

In the above embodiment, the machining device 2 is configured to rotate a tool around one of two rotation axes (B-axis) and rotate a table around the other rotation axis (C-axis). In a modified example, the two rotation axes may be provided on the spindle side. Alternatively, the two rotation axes may be provided on the table side. For example, a configuration may be adopted in which the table is supported by a first member so as to be rotatable around the C-axis, and the first member is supported by a second member so as to be rotatable around the A-axis or B-axis. If the second member has the A-axis, the second member may be supported so as to be movable in the Y-axis direction. If the second member has the B-axis, the second member may be supported so as to be movably in the X-axis direction.

Although not mentioned in the above embodiment, the above-mentioned information processing program may be recorded on a computer-readable recording medium and provided.

The present invention is not limited to the above-described embodiment and modifications, and can be embodied by modifying the components without departing from the spirit of the invention. Various inventions may be formed by appropriately combining multiple components disclosed in the above-described embodiment and modifications. In addition, some components may be deleted from all the components shown in the above-described embodiment and modifications.

1 Machine tool, 2 Machining device, 10 Spindle, 52 Numerical control device, 58 Shape measurement unit, 100 Information processing device, 110 Input/output interface unit, 112 Data processing unit, 114 Data storage unit, 120 Input unit, 122 Output unit, 124 Target shape information acquisition unit, 126 Machining information acquisition unit, 128 Measurement shape information acquisition unit, 130 Program storage unit, 132 Target shape memory unit, 134 Machining information memory unit, 136 Command point data memory unit, 138 Measurement shape memory unit, 140 Machining program generation unit, 142 Test machining instruction unit, 144 Measurement instruction unit, 146 Machining program correction unit, Fc Machining surface, T Tool, W Workpiece.

Claims (3)

acquiring target shape information indicating a target shape;
A step of acquiring machining information including a tool path when machining a workpiece;
generating a machining program based on the target shape information and the machining information;
a step of executing the machining program to measure a shape of a machined workpiece and acquiring measured shape information indicating the measured shape of the workpiece;
correcting the machining program based on a shape error that is a difference between the measured shape information and the target shape information;
A method for correcting a machining program comprising: the tool path is made up of a plurality of command points through which the tool passes;
the step of generating the machining program includes generating the machining program based on the command point whose position is set so that the tool is in contact with the target shape at a cutting point;
2. The method for correcting a machining program according to claim 1, wherein the step of correcting the machining program includes calculating an error between a cutting point in the target shape and a measurement point in the measurement shape while a reference point of the target shape and a reference point of the measurement shape are aligned with a machining reference point of the tool path, and correcting the position of the command point based on the error. An information processing program for correcting a machining program for machining a workpiece into a target shape,
A function of acquiring target shape information indicating a target shape;
A function to acquire machining information including the tool path when machining the workpiece,
A function of generating a machining program based on the target shape information and the machining information;
a function of executing the machining program to measure a shape of a machined workpiece and acquiring measured shape information indicating the measured shape of the workpiece;
a function of correcting the machining program based on a shape error that is a difference between the measured shape information and the target shape information;
An information processing program comprising:

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