JP2010176447A - Nc data correcting method and apparatus - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an NC data correcting method and apparatus for restoring a curved surface of a work shape only from NC data without referring to CAD data of the work shape and for correcting the NC data from the curved surface. <P>SOLUTION: In the NC data correcting method and apparatus for correcting the NC data of the work shape prepared for a machining path of a machine tool without using the CAD data of the work shape, all the NC data are read and decomposed for each machining path (steps S1, S2), an adjacent path table comprising the machining paths adjacent to each other is prepared (steps S3, S4), one curved surface is restored using the NC data of all the machining paths belonging to one adjacent path table to restore the curved surfaces for all the adjacent path tables (step S15), and the position of the NC data is corrected on the restored curved surface (step S16). <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

  The present invention relates to an NC data correction method and apparatus.

Normally, NC (Numerical Control) data for machine tools is processed by CAM (Computer-Aided Manufacturing) based on workpiece shape data (hereinafter referred to as CAD data) created by CAD (Computer-Aided Design). Created by giving information such as the path. For example, referring to FIG. 8A, a plurality of NC data point sequences D (i) are created by CAM based on a line L _CAD indicating CAD data. At this time, the CAM creates the point sequence D (i) with accuracy within a given tolerance (allowable range) T. The smaller the tolerance T is, the longer the calculation time is. Therefore, when the workpiece shape is large, it cannot be set too small, and an appropriate value is set.

When machining left dot sequence D of NC data output from the CAM (i), as shown in dotted line L _NC, processed surface becomes rough surface uneven. Therefore, during processing, smoothing correction (smoothing, curve interpolation, etc.) performed, performing the processing as a smooth curve as indicated by the line L _F in FIG. 8 (b). By performing such smoothing correction for each of all machining passes, a smooth workpiece shape surface is realized. FIGS. 8A and 8B show, as an example, displacement in a one-dimensional direction (X direction) with respect to the time axis t of one machining pass. Further, “i” is assigned a number indicating the processing order.

Japanese Unexamined Patent Publication No. 7-072913

  The smoothing correction has been performed so as to detect an edge indicating a boundary of a surface of a continuous point sequence (processing path) and to divide the detected edge into a smooth curve. . However, in this method, there is a problem that a step is generated at the boundary of the surface between other adjacent processing passes.

  This will be described with reference to FIG. For example, as NC data of a work shape having two curved surfaces B1 and B2 and having a boundary E between the curved surfaces B1 and B2, a plurality of point sequences D (i) as shown in FIG. Consider a case where a plurality of machining passes P1 to P5 are given. In this case, the machining is performed through machining paths P1 → P2 → P3 → P4 → P5 that reciprocate at a constant pitch.

  When conventional smoothing correction is performed on these machining passes, for example, as shown in FIG. 9B, when an edge is detected in the A1 portion of the machining pass P2, the edge is detected. The correction is performed by turning off the smoothing correction of the point sequence of the part and turning on the smoothing correction of the other point sequences. On the other hand, if no existing edge is detected in the A2 portion of the machining path P3, the correction is performed by turning on the smoothing correction of the point sequence of the entire machining path P3. This can occur when edge detection is performed based only on NC data without referring to CAD data of the workpiece shape.

For the machining path shown in FIG. 9A, edge detection based only on NC data is performed by, for example, P1: edge detection ○, P2: edge detection ○, P3: edge detection ×, P4: edge detection ○, P5: assuming became edge detection ×, with respect to the actual boundary E, after smoothing correction, the boundary E _F becomes as shown in FIG. 9 (c), the presence or absence of edge detection, the adjacent other processing paths In between, there was a round-trip step in the machining path.

  In addition, the NC data point sequence includes not only the workpiece shape point sequence, but also many point sequences other than the workpiece shape, such as movement from the machining path to the machining path and movement from the machining surface to the machining surface. Further, in the case of curved surface processing with a large curvature, point sequences such as retract and approach are also included. Therefore, it is desirable to remove point sequences other than the workpiece shape for the smoothing correction. This removal is easy if the CAD data of the workpiece shape can be referred to. However, when CAD data or the like cannot be referred to, a discrimination operation for removing point sequences other than the workpiece shape has been separately performed. The problem here will be described with reference to 10 (a) and (b).

  For example, as shown in FIG. 10A, in order to process a curved surface Bs, there are processing procedures of processing PC1, retract PC2, approach PC3, processing PC4, and from point sequences D (1) to D (i + 4). Suppose that a machining path is given. In this case, the point sequences D (1) and D (2) in the processing PC1 and the point sequences D (i + 2), D (i + 3), and D (i + 4) in the processing PC4 are point sequences on the curved surface Bs that is a workpiece shape. is there. On the other hand, the point sequences D (3) and D (4) in the retract PC2 and the point sequences D (i) and D (i + 1) in the approach PC3 are point sequences other than the workpiece shape.

When performing a discriminating operation for removing the retract and approach point sequences from such a point sequence D (1) to D (i + 4), a huge amount of work and complicated processing are required for the discrimination. It is very difficult to distinguish between retracts and approach point sequences near the shape. For example, when the point sequence D (3), D (4) in the retract PC2 and the point sequence D (i), D (i + 1) in the approach PC3 are in the vicinity of the curved surface Bs, they are points other than the workpiece shape. It is difficult to identify a column and remove it completely. In that case, as shown in FIG. 10B, the point sequence D (1) to D (i + 4) is erroneously smoothed (see the dotted arrow in the figure), and the erroneous curved surface _BE is restored. It was difficult to correctly restore the curved surface of the workpiece shape.

  As described above, when a point sequence other than the workpiece shape is included, it is difficult to correctly restore the workpiece shape surface unless CAD data or the like is referred to. Moreover, the point sequence illustrated in FIG. 10A may include not only the workpiece-shaped curved surface Bs but also other processed curved surfaces Bs ′ as illustrated in FIG. 10C, for example.

  Therefore, in order to correctly restore the workpiece shape from the NC data, it is desirable to refer to the CAD data of the workpiece shape. However, in reality, the CAD data cannot be referred to and machining is performed using only the NC data. In many cases, there was a problem in actual use.

  The present invention has been made in view of the above-described problems. An NC data correction method for restoring a curved surface of a workpiece shape from only NC data and correcting NC data from the curved surface without referring to CAD data of the workpiece shape, and An object is to provide an apparatus.

The NC data correction method according to the first invention for solving the above-mentioned problem is as follows:
A NC data correction method for correcting NC data of a workpiece shape created for a machining path of a machine tool without using CAD data of the workpiece shape,
Disassemble all NC data for each machining pass,
For the machining path, create an adjacent path table consisting of adjacent machining paths,
The range of all machining paths in one adjacent path table is set as one area, and the curved surface for all the adjacent path tables is restored by restoring as one curved surface using NC data in one area. And
The position of each NC data in all adjacent path tables is corrected to the position on the curved surface closest to the NC data.

The NC data correcting method according to the second invention for solving the above-mentioned problem is as follows:
In the NC data correction method according to the first invention,
For a machining path belonging to one adjacent path table, a group including any one machining path and a plurality of machining paths adjacent to the machining path is created for each machining path, and one group is created. Re-specify as one area, and restore the curved surface for all the areas of all the adjacent path tables by using NC data of one area to restore as one curved surface. .

The NC data correction method according to the third invention for solving the above-mentioned problem is as follows:
In the NC data correction method according to the first or second invention,
For all machining paths in the adjacent path table, detect edges indicating the boundary of the curved surface,
Based on the detected edge, the NC data of the area is divided into a plurality of divided areas,
Using the NC data of one of the divided regions, the curved surface for all the divided regions is restored by restoring as one curved surface.

The NC data correction method according to the fourth invention for solving the above-mentioned problem is as follows.
In the NC data correction method according to the first or second invention,
For all machining paths in the adjacent path table, detect edges indicating the boundary of the curved surface,
Based on the detected edge, the NC data of the area is divided into a plurality of divided areas,
Using the NC data of one of the divided regions, restoring the curved surface for all the divided regions by restoring as one curved surface,
Based on the curved surface, find the curvature of each NC data of all the adjacent path tables, detect the inflection point indicating the boundary of the curved surface based on the curvature,
Based on the detected inflection point, the NC data of the region or the divided region is divided into a plurality of re-divided regions,
By using NC data of one subdivision area and restoring as one curved face, curved faces for all the subdivision areas are restored.

The NC data correcting method according to the fifth invention for solving the above-mentioned problem is as follows:
In the NC data correction method according to the fourth aspect,
If there is a difference in inflection point detection between adjacent machining paths, the inflection point judgment threshold for inflection point detection is changed, and inflection point detection is performed for machining paths where no inflection point is detected. It is performed again, and the inflection point detected by the inflection point detection performed again is added, and the image is divided into subdivision areas.

The NC data correction method according to the sixth invention for solving the above-mentioned problem is as follows.
In the NC data correction method according to any one of the third to fifth inventions,
If there is a difference in edge detection between adjacent machining paths, the edge judgment threshold for edge detection is changed, edge detection is performed again for machining paths for which no edge is detected, and detection is performed by performing edge detection again. It is characterized in that the divided edges are added and divided into divided regions.

The NC data correcting method according to the seventh invention for solving the above-mentioned problem is as follows:
In the NC data correction method according to any one of the first to sixth inventions,
A machining path for which there is no adjacent machining path is restored as one curve using NC data of the machining path,
The position of the NC data of the machining path is corrected to a position on the curve closest to the NC data.

An NC data correction apparatus according to an eighth invention for solving the above-mentioned problems is as follows.
An NC data correcting device for correcting NC data of a workpiece shape created for a machining path of a machine tool without using CAD data of the workpiece shape,
Disassembling means for disassembling all NC data for each machining path;
For the machining path, a creation means for creating an adjacent path table composed of adjacent machining paths;
The range of all machining paths in one adjacent path table is set as one area, and the curved surface for all the adjacent path tables is restored by restoring as one curved surface using NC data in one area. Curved surface restoring means,
Curved surface correction means for correcting the position of each NC data in all adjacent path tables to the position on the curved surface closest to the NC data.

An NC data correction apparatus according to a ninth invention for solving the above-mentioned problems is
In the NC data correction apparatus according to the eighth invention,
The curved surface restoring means creates, for each machining path, a group composed of an arbitrary one machining path and a plurality of machining paths adjacent to the machining path before and after the machining path belonging to one adjacent path table. By redefining one group as one area and restoring as one curved surface using NC data of one of the areas, the curved surface for all the areas in all the adjacent path tables is restored. It is characterized by doing.

An NC data correction apparatus according to a tenth invention for solving the above-described problem is
In the NC data correction device according to the eighth or ninth invention,
Edge detection means for detecting an edge indicating a boundary of a curved surface for all processing paths of the adjacent path table;
Division means for dividing the NC data of the area into a plurality of divided areas based on the detected edge;
The curved surface restoration means restores curved surfaces for all the divided regions by restoring NC data of one divided region as one curved surface.

An NC data correction apparatus according to an eleventh invention for solving the above-mentioned problems is
In the NC data correction device according to the eighth or ninth invention,
Edge detection means for detecting an edge indicating a boundary of a curved surface for all processing paths of the adjacent path table;
A dividing means for dividing the NC data of the area into a plurality of divided areas based on the detected edge;
Using the NC data of one of the divided areas, the curved surface is restored for all the divided areas by restoring as one curved surface, and each NC data of all the adjacent path tables is based on the curved surface. An inflection point detecting means for detecting an inflection point indicating a boundary of a curved surface based on the curvature,
Re-dividing means for dividing NC data of the area or the divided area into a plurality of re-divided areas based on the detected inflection points;
The curved surface restoration means restores curved surfaces of all the subdivision areas by using NC data of one subdivision area to restore as one curved surface.

An NC data correction apparatus according to a twelfth invention for solving the above-described problems is
In the NC data correction device according to the eleventh aspect,
An inflection point changing means for changing an inflection point determination threshold for inflection point detection;
The inflection point detection means changes the inflection point determination threshold when there is a difference in inflection point detection between adjacent machining paths, and checks the inflection point for a machining path in which no inflection point is detected. Go out again,
The subdivision means adds the inflection point detected by the inflection point detection performed again, and divides the subdivision area.

An NC data correction apparatus according to a thirteenth invention for solving the above-mentioned problems is
In the NC data correction device according to any one of the tenth to twelfth inventions,
An edge changing means for changing an edge determination threshold for edge detection;
If there is a difference in edge detection between adjacent machining paths, the edge detection means changes the edge determination threshold, performs edge detection again for a machining path in which no edge is detected,
The dividing means adds the edges detected by the edge detection performed again, and divides into divided areas.

An NC data correction apparatus according to a fourteenth aspect of the present invention for solving the above problems is as follows.
In the NC data correction apparatus according to any one of the eighth to thirteenth inventions,
Curve restoration means for restoring a machining path that does not have an adjacent machining path as a single curve using NC data of the machining path;
It further comprises curve correction means for correcting the position of the NC data of the machining path to a position on the curve closest to the NC data.

  According to the present invention, even without referring to the CAD data of the workpiece shape, the curved surface is restored by using adjacent machining paths only from the NC data, and the NC data is corrected so as to be positioned on the curved surface. The curved surface can be restored to a smooth one with no reciprocal step, and as a result, the NC data can be appropriately corrected to make it easier to use and practical.

It is a schematic block diagram which shows an example of embodiment of the correction apparatus of NC data which concerns on this invention. It is a flowchart which shows an example of embodiment of the correction method of NC data which concerns on this invention. It is a figure explaining the outline | summary of the correction method of NC data which concerns on this invention. It is a figure explaining discrimination | determination of the process path in the correction method of NC data which concerns on this invention. It is a figure explaining the edge detection in the correction method of NC data concerning the present invention. It is a figure explaining the case where there exists an adjacent path | pass. It is a figure explaining the case where there is no adjacent path. It is a figure explaining the conventional smoothing correction | amendment. It is a figure explaining the problem of the conventional smoothing correction | amendment. It is a figure explaining the problem in the case of including point sequences, such as a retract and an approach.

  Embodiments of the NC data correction method and apparatus according to the present invention will be described below with reference to FIGS.

Example 1
FIG. 1 is a schematic configuration diagram showing an example of an embodiment of an NC data correction apparatus according to the present invention. FIG. 2 is a flowchart showing an example of an embodiment of the NC data correction method according to the present invention.

  As shown in FIG. 1, the NC data correction device 10 according to the present embodiment is a computer, a CPU (Central Processing Unit) 11, a main storage device 12 such as a RAM (Random Access Memory), a ROM (Read Only Memory). ), An auxiliary storage device 13 such as an HDD (Hard Disk Drive), an input device 14 such as a keyboard and a mouse, and an output device 15 such as a display and a printer, etc., and input / output information to / from each other via a bus 16 ing. The correction device 10 may be configured as a device independent of the machine tool body, or may be configured as a device incorporated in the machine tool body.

  The NC data correction method according to the present invention is implemented in the correction device 10. This will be described with reference to FIGS. 2 and 3 to 5. Here, FIG. 3 is a diagram for explaining the outline of the NC data correction method according to the present invention, FIG. 4 is a diagram for explaining machining path discrimination, and FIG. 5 is a diagram for explaining edge detection. It is. 3, 4, and 5 indicate the traveling direction of the machining pass.

  First, all the NC data of the workpiece shape is read into the main storage device 12 and the auxiliary storage device 13 of the correction device 10 (step S1). This NC data is created in advance by CAM based on CAD data of a workpiece shape for a machining path of a machine tool, and has coordinates, vector information, etc. for each point sequence D (i). . In the present invention, CAD data is unnecessary, and the curved surface is restored and the NC data is corrected by using the information of only the NC data by the following procedure.

  Next, all the point sequences D (i) of the NC data are decomposed for each machining pass (step S2; decomposition means). Specifically, by analyzing the coordinates, vector information, etc. of each point sequence D (i), each point sequence D (i) is decomposed for each processing path. For example, as shown in FIG. 3A, each point sequence D (i) is disassembled for each of the processing passes P1 to P5 that reciprocate while shifting at a constant interval. At this time, conventionally, the point sequence D (i) corresponding to the retract, approach, etc. is excluded in advance by referring to the CAD data or the like, but it is not necessary to exclude them in the present invention. This will be described later with reference to FIGS.

  Next, it is confirmed whether or not there is an adjacent path for the processing path created in step S2, and if there is, the following steps S4 to S16 are performed. If not, the following step S17 is performed. Processing is performed (step S3). For example, referring to FIG. 4, since there are adjacent paths for the processing paths P1 to P5 and the processing paths P7 to P11, the processes of steps S4 to S16 are performed, and the processing path P6 is adjacent. Since there is no path, the process of step S17 is performed. Whether the machining passes are adjacent to each other is determined from the distance (pitch) between the machining passes, the vector angle, and the like.

  Next, an adjacent path table including adjacent processing paths is created by organizing adjacent processing paths for processing paths having adjacent paths (step S4; creation means). For example, with reference to FIG. 3A, it is determined that the processing paths P1 to P5 are adjacent to each other, and one adjacent path table T1 is created. Further, as shown in FIG. 4, the adjacent path table T2 is created separately from the adjacent path table T1 for the processing paths P7 to P11 which are not adjacent to the processing paths P1 to P5 but are determined to be adjacent to each other. In this way, an adjacent path table is created for each machining path group determined to be adjacent. The adjacent path table may be composed of at least two machining paths adjacent to each other, but is preferably composed of three or more machining paths adjacent to each other.

  Note that the following steps S6 to S15 are performed for each adjacent path table created in step S4, but in the following description, the process will be basically described as processing for one adjacent path table.

  Next, for all machining paths belonging to one adjacent path table, the edge indicating the boundary of the curved surface is detected (edge detection means) using the angle of the vector of each point sequence D (i) and the edge is detected. If YES in step S6, the process advances to step S6. If no edge is detected from the machining path belonging to one adjacent path table, the following steps S6 to S14 are skipped and the process advances to step S15 (step S5).

  If there is no edge detection at all, the range of all machining paths belonging to one adjacent path table is determined as one area, and one simple curved surface can be restored from this one area. S14 is skipped and the process proceeds to step S15. On the other hand, as shown in FIG. 5A, for all the machining paths P1 to P5 belonging to one adjacent path table, the edges E1 and E2 are detected in the machining paths P1 and P2, and the machining paths P3 to P5 are detected. If no edge is detected, the process proceeds to step S6.

  Next, it is checked whether there is a difference in the presence or absence of edge detection between adjacent machining passes. If yes, step S7 is executed. If not, step S7 is skipped and the process proceeds to step S8. (Step S6).

  If there is a difference in the presence or absence of edge detection between adjacent processing passes, the edge determination threshold for edge detection is locally changed, and edge detection is performed again (step S7; edge changing means, edge detecting means). This is because there is a possibility that an actual edge cannot be detected, and the edge detection threshold value is changed to a gentle condition so that edge detection is reliably performed. When the vector angle is used as the edge determination threshold, for example, the edge determined at 25 ° in step S5 is changed to an edge at 20 ° in step S7. . Here, the term “local” does not mean that it is applied to all machining paths, but is provisionally applied to a machining path in which no edge is detected.

  The process in step S7 will be described with reference to FIGS. As shown in FIG. 5B, when edges E1, E2, and E4 are detected in the processing paths P1, P2, and P4 in step S5 and no edge is detected in the processing paths P3 and P5, between adjacent processing paths. There is a difference in the presence or absence of edge detection. In such a case, in step S7, the edge determination threshold is changed, and edge detection is performed again on the processing paths P3 and P5 in which no edge is detected, as shown in FIG. Edges E1 to E5 are detected in all the processing paths P1 to P5 in one adjacent path table. By detecting the edge in this manner, it is possible to reduce the occurrence of a reciprocal step that has conventionally occurred in the periphery of the edge.

  Then, based on the adjacent path and edge information acquired by the above processing, the point sequence D (i) of the machining path belonging to one adjacent path table is divided into a plurality of divided areas, and detected again by edge detection. If there is an edge that has been set, the edge is also added and divided into divided areas (dividing means). After that, by using the point sequence D (i) of one divided region, it is restored as one curved surface, and this is performed for all the divided regions, thereby restoring all the curved surfaces of the workpiece shape (step S8; curved surface restoration). means).

  For example, in the case of FIG. 5A, from the information of the processing paths P1 to P5 belonging to one adjacent path table and the edges E1 and E2 determined to be edges, the curved surface B1, It is determined that B2 and B3 exist, and each curved surface is restored to be a smooth surface using the point sequence D (i) of the region corresponding to each curved surface B1 to B3. In the case of FIG. 5C, from the information of the processing paths P1 to P5 belonging to one adjacent path table and the edges E1 to E5 determined to be edges, the curved surface B1, It is determined that B2 exists, and each curved surface is restored to be a smooth surface using the point sequence D (i) of the area corresponding to each of the curved surfaces B1 and B2. As a method for restoring a curved surface, a known method such as NURBS (Non-Uniform Rational B-Spline) may be used.

  Next, based on each curved surface restored in step S8, the position of each point sequence D (i) of the corresponding divided region is corrected to be a position on the curved surface closest to each point sequence D (i). (Step S9; curved surface correction means). For example, a point on the curved surface that is closest to the point sequence D (i) may be searched by a bisection search, and the point may be corrected to be this point.

  Next, based on each curved surface restored in step S8, the curvature (Gaussian curvature etc.) in each point sequence D (i) of the corresponding divided region is calculated (step S10), and the curved surface is calculated based on the calculated curvature information. An inflection point (singular point) indicating the boundary of the image is detected (inflection point detection means), and if an inflection point is detected, the process proceeds to step S12 to detect the inflection point from one region or one divided region. If there is no at all, the following steps S12 to S16 are skipped, and the process proceeds to step S18 (step S11). As an inflection point, for example, in the case of a Gaussian curvature, when the Gaussian curvature becomes 0, it is determined as an inflection point.

  Next, it is confirmed whether or not the inflection points detected in step S11 are continuous between adjacent machining passes. If they are not continuous, step S13 is executed, and if they are continuous, step S13 is skipped. Then, the process proceeds to step S14.

  If inflection points are not continuous between adjacent machining paths, that is, if there is a difference in inflection point detection, the inflection point determination threshold for inflection point detection is locally changed, and the inflection point is again (Step S13; inflection point changing means, inflection point detecting means). This is because, as in step S7 described above, there is a possibility that an existing edge may not be detected. By changing the inflection point determination threshold value to a gentle condition, it becomes easier to extract inflection points. Thus, edge detection is performed more reliably. The meaning of “local” here is not to apply to all machining paths, but to provisionally apply to machining paths in which an inflection point has not been detected.

  Although it becomes the description substantially the same as the process in step S7, the process in step S13 is demonstrated using FIG.5 (b), (c). As shown in FIG. 5B, the machining paths P1, P2, and P4 have inflection points, edges E1, E2, and E4 based on the inflection points are detected, and the machining paths P3 and P5 have inflection points. If no edge is detected, it is determined in step S11 that the inflection points are not continuous between adjacent machining passes. In such a case, in step S13, the inflection point determination threshold is changed, and the inflection points are obtained again for the machining paths P3 and P5 having no inflection points, as shown in FIG. As described above, inflection points are extracted in all the processing paths P1 to P5 in one adjacent path table, and the edges E1 to E5 are detected. By detecting the edge in this way, it is possible to further reduce the occurrence of a reciprocal step that has conventionally occurred in the periphery of the edge.

  In addition, for a certain machining path, when inflection points (edges) are not detected in both adjacent machining paths, and when there is an inflection point determination threshold that is slightly less than the machining path, Conversely, it may be determined that there is no inflection point (edge), and the region may not be divided in step S14 described later.

  Then, based on the adjacent path and inflection point information acquired by the above processing, the one area determined in step S5 or the divided area divided in step S8 is divided into smaller subdivision areas, and If there is an inflection point detected by the inflection point detection again, the inflection point is added and the image is divided into re-divided areas (step S14; re-division means).

Next, the point sequence D (i) of one subdivision area divided in step 14 is used to restore a single curved surface, and this is performed for all the subdivision areas so that all the curved surfaces of the workpiece shape are obtained. Restoration (step S15; curved surface restoration means). For example, with reference to FIGS. 3A and 3B, based on the edges E _F detected by the adjacent paths P1 to P5 and the inflection points, the areas correspond to the curved surfaces B1 _F and B2 _F. The curved surfaces B1 _F and B2 _F are restored from the point sequence D (i) of the divided area. As a result, a curved surface that is smooth and has no reciprocal step can be restored.

  On the other hand, in step S5, when no edge is detected at all for all machining paths belonging to one adjacent path table, the range of all machining paths belonging to one adjacent path table is determined as one area, By using the point sequence D (i) of this area, it is restored as one curved surface, and this is performed for all adjacent path tables, thereby restoring all the curved surfaces of the workpiece shape (curved surface restoring means). Even in this case, since one simple curved surface can be restored from one region, a smooth curved surface having no reciprocal step can be restored.

Next, based on the curved surface restored in step S8 or step S15, the position of each point sequence D (i) of all adjacent path tables is the position on the curved surface closest to each point sequence D (i). (Step S16; curved surface correcting means). For example, referring to FIG. 3 (a) ~ (c) , as the initial point sequence D (i) becomes a position on the restored curved B1 _F, B2 _F, the position D (i) _F Will be corrected to the position. As a method for correcting the point sequence D (i), for example, a point on the curved surface that is closest to the point sequence D (i) may be searched by a bisection search and corrected to be this point. .

  In steps S8 to S9 and S15 to S16, one area (one adjacent path table) that can be determined as the same plane, one divided area, or one subdivision area is restored as one curved surface. On the other hand, about processing paths belonging to one area (one adjacent path table), one divided area, or one subdivision area that can be determined as the same surface, about 2 to 4 before and after adjacent to the target processing path Machining paths, that is, a group consisting of about 5 to 9 machining paths in total is created for each machining path, and one group is redefined as one area for the created groups. You may make it restore | restore as one curved surface using the point sequence D (i) of one area | region (curved surface restoration means). In that case, the processing path to be processed is shifted in the order of NC data, and each time, one area is redefined, and a single curved surface is restored using the point sequence D (i) of the one area. All of the curved surfaces of the workpiece shape may be restored by performing it for all the regions of all adjacent path tables.

  On the other hand, if there is no adjacent path in step S3, for example, for a processing path that does not have an adjacent processing path, such as the processing path P6 shown in FIG. 4, the point sequence D (i) of the processing path is used. Then, it is restored as one curve so that it becomes a smooth curve, and the position of each point sequence D (i) of the machining path is corrected to the position on the curve closest to the point sequence D (i). (Step S17: curve restoration means, curve correction means). Normally, a path that does not have an adjacent path, such as the processing path P6, is considered to be a path for movement. Conventionally, it has been excluded in advance by preprocessing with reference to CAD data or the like. In the invention, there is no need to exclude (no pre-processing is required), and correction is performed using all the point sequences D (i). In addition, when the point sequence D (i) in the machining path in which there is no adjacent machining path is two points, the curve may be corrected as a straight line connecting the two points without performing the correction as a curve.

  Then, all the point sequences D (i) corrected as described above are arranged in the original point sequence (step S18). As a result, the NC data is corrected (step S19). Therefore, by performing the above processing procedure, the curved surface is restored within a range in which the adjacent path can be specified without referring to the CAD data, and the point sequence D (i) of the NC data is corrected on the curved surface. Data can be made practical and easier for machine tool users to use.

  In the present invention, the above-described processing is performed without excluding point sequences corresponding to retracts and approaches that have been excluded in advance by preprocessing with reference to CAD data or the like. This will be described with reference to FIG. 6 when there is an adjacent path and FIG. 7 when there is no adjacent path.

  Through the processing in steps S1 to S4, all point sequences including the point sequences corresponding to the retract and approach are disassembled for each processing path, and are created as an adjacent path table including adjacent processing paths. For example, as shown in FIG. 6 (a), not only the processing PC1 and PC4 for the curved surface Bs but also processing paths P1 to P5 including point sequences corresponding to the retract PC2 and the approach PC3 are adjacent to each other. The processing paths P1 to P5 are created as one adjacent path table.

  Then, the edge (curved surface boundary) is detected by the processing of steps S5 to S15, the region is divided, and the curved surface is restored for each divided region, and then the processing path is processed by the processing of step S16. The position of the point sequence is corrected on the restored curved surface. For example, FIG. 6A to FIG. 6C show not only a curved surface B1 corresponding to the machining PC1 and a curved surface B4 corresponding to the machining PC4, but also a curved surface B2 corresponding to the retract PC2 and a curved surface B3 corresponding to the approach PC3. Etc. are also restored, and the position of the point sequence of the machining path Pn is corrected on the restored curved surfaces B1 to B4.

  In this way, in the present invention, since the point sequence corresponding to the retract and approach is restored as a curved surface, the point sequence of the approach and retract is removed by preprocessing in advance by referring to the CAD data or the like. Failures that occur when not done, that is, an incorrect curved surface is restored (see FIG. 10B, etc.), or even point sequences used for actual machining are removed (FIG. 10C). Etc.).

On the other hand, if it is determined in step S3 that there is no adjacent path for the processing path including the point sequence corresponding to the retract and approach, the process proceeds to step S17, and this is performed using the point sequence of the processing path. It restores as one curve so that it becomes a smooth curve, and corrects the position of each point sequence of the processing path to the position on the curve closest to the point sequence. For example, as shown in FIG. 7A, not only the processing PC1 and PC4 for the curved surface Bs but also the processing path Pn including the point sequence corresponding to the retract PC2 and the approach PC3, when there is no adjacent path, If the point sequence of the machining path Pn is used to restore as one curve L _F and correction is made so that the position is on this curve L _F , as shown in FIG. 7B and FIG. processing PC1, retract PC2, approach PC3, thereby correcting the position of the point sequence of the machining path Pn on the curve L _F that corresponds to the processing PC 4.

  The present invention corrects NC data used for a numerically controlled machine tool, and is suitable for realizing a smooth machined surface even when CAD data cannot be referred to.

10 Correction device 11 CPU
12 Main storage device 13 Auxiliary storage device 14 Input device 15 Output device 16 Bus

Claims (14)

A NC data correction method for correcting NC data of a workpiece shape created for a machining path of a machine tool without using CAD data of the workpiece shape,
Disassemble all NC data for each machining pass,
For the machining path, create an adjacent path table consisting of adjacent machining paths,
The range of all machining paths in one adjacent path table is set as one area, and the curved surface for all the adjacent path tables is restored by restoring as one curved surface using NC data in one area. And
A method of correcting NC data, wherein the position of each NC data in all adjacent path tables is corrected to a position on the curved surface closest to the NC data. The NC data correction method according to claim 1,
For a machining path belonging to one adjacent path table, a group including any one machining path and a plurality of machining paths adjacent to the machining path is created for each machining path, and one group is created. Re-specify as one area, and restore the curved surface for all the areas of all the adjacent path tables by using NC data of one area to restore as one curved surface. NC data correction method. In the NC data correction method according to claim 1 or 2,
For all machining paths in the adjacent path table, detect edges indicating the boundary of the curved surface,
Based on the detected edge, the NC data of the area is divided into a plurality of divided areas,
A method of correcting NC data, wherein the curved surfaces of all the divided regions are restored by restoring NC data of one of the divided regions as one curved surface. In the NC data correction method according to claim 1 or 2,
For all machining paths in the adjacent path table, detect edges indicating the boundary of the curved surface,
Based on the detected edge, the NC data of the area is divided into a plurality of divided areas,
Using the NC data of one of the divided regions, restoring the curved surface for all the divided regions by restoring as one curved surface,
Based on the curved surface, find the curvature of each NC data of all the adjacent path tables, detect the inflection point indicating the boundary of the curved surface based on the curvature,
Based on the detected inflection point, the NC data of the region or the divided region is divided into a plurality of re-divided regions,
A method of correcting NC data, wherein the NC data of one of the subdivision areas is restored as one curved face by using the NC data of one subdivision area to restore the curved surfaces of all the subdivision areas. The NC data correction method according to claim 4,
If there is a difference in inflection point detection between adjacent machining paths, the inflection point judgment threshold for inflection point detection is changed, and inflection point detection is performed for machining paths where no inflection point is detected. A method of correcting NC data, characterized in that it is performed again, and the inflection points detected by the inflection point detection performed again are added to perform division into subdivision areas. In the NC data correction method according to any one of claims 3 to 5,
If there is a difference in edge detection between adjacent machining paths, the edge judgment threshold for edge detection is changed, edge detection is performed again for machining paths for which no edge is detected, and detection is performed by performing edge detection again. A method of correcting NC data, characterized in that the divided edges are added and divided into divided regions. In the NC data correction method according to any one of claims 1 to 6,
A machining path for which there is no adjacent machining path is restored as one curve using NC data of the machining path,
A method of correcting NC data, wherein the NC data position of the machining path is corrected to a position on the curve closest to the NC data. An NC data correcting device for correcting NC data of a workpiece shape created for a machining path of a machine tool without using CAD data of the workpiece shape,
Disassembling means for disassembling all NC data for each machining path;
For the machining path, a creation means for creating an adjacent path table composed of adjacent machining paths;
The range of all machining paths in one adjacent path table is set as one area, and the curved surface for all the adjacent path tables is restored by restoring as one curved surface using NC data in one area. Curved surface restoring means,
A NC data correction apparatus comprising: a curved surface correction unit that corrects the position of each NC data in all adjacent path tables to a position on the curved surface closest to the NC data. The NC data correction device according to claim 8,
The curved surface restoring means creates, for each machining path, a group composed of an arbitrary one machining path and a plurality of machining paths adjacent to the machining path before and after the machining path belonging to one adjacent path table. By redefining one group as one area and restoring as one curved surface using NC data of one of the areas, the curved surface for all the areas in all the adjacent path tables is restored. An NC data correction device characterized by: In the NC data correction device according to claim 8 or 9,
Edge detection means for detecting an edge indicating a boundary of a curved surface for all processing paths of the adjacent path table;
Division means for dividing the NC data of the area into a plurality of divided areas based on the detected edge;
The curved surface restoration means restores curved surfaces of all the divided areas by restoring NC data of one of the divided areas as a single curved face. In the NC data correction device according to claim 8 or 9,
Edge detection means for detecting an edge indicating a boundary of a curved surface for all processing paths of the adjacent path table;
A dividing means for dividing the NC data of the area into a plurality of divided areas based on the detected edge;
Using the NC data of one of the divided areas, the curved surface is restored for all the divided areas by restoring as one curved surface, and each NC data of all the adjacent path tables is based on the curved surface. An inflection point detecting means for detecting an inflection point indicating a boundary of a curved surface based on the curvature,
Re-dividing means for dividing NC data of the area or the divided area into a plurality of re-divided areas based on the detected inflection points;
The curved surface restoration unit restores curved surfaces of all the subdivision areas by using the NC data of one subdivision area to restore as one curved surface. . The NC data correction device according to claim 11,
An inflection point changing means for changing an inflection point determination threshold for inflection point detection;
The inflection point detection means changes the inflection point determination threshold when there is a difference in inflection point detection between adjacent machining paths, and checks the inflection point for a machining path in which no inflection point is detected. Go out again,
The NC data correction device, wherein the subdivision means adds the inflection point detected by the inflection point detection performed again, and divides the subdivision area. In the NC data correction device according to any one of claims 10 to 12,
An edge changing means for changing an edge determination threshold for edge detection;
If there is a difference in edge detection between adjacent machining paths, the edge detection means changes the edge determination threshold, performs edge detection again for a machining path in which no edge is detected,
The NC data correction apparatus, wherein the dividing means adds an edge detected by edge detection performed again and divides the data into divided areas. The NC data correction device according to any one of claims 8 to 13,
Curve restoration means for restoring a machining path that does not have an adjacent machining path as a single curve using NC data of the machining path;
An NC data correction apparatus, further comprising curve correction means for correcting the position of NC data of the machining path to a position on the curve closest to the NC data.

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