WO2020178978A1

WO2020178978A1 - Machining program conversion device, numerical control device, and machining program conversion method

Info

Publication number: WO2020178978A1
Application number: PCT/JP2019/008587
Authority: WO
Inventors: 弘樹金子; 入口　健二
Original assignee: 三菱電機株式会社
Priority date: 2019-03-05
Filing date: 2019-03-05
Publication date: 2020-09-10
Also published as: JP6808106B1; DE112020000656T5; JPWO2020179798A1; WO2020179798A1; CN113490894A

Abstract

A machining program conversion device (100) is provided with: a curved path generation unit (104) which generates a curved path (TP) between a plurality of command points (P) provided on a tool path; an allowable dimensional tolerance input unit (107) which receives a value for a tolerance range for distances L, which are the distances between a reference point (C) and evaluation points (Q), where the evaluation points (Q) are points provided on the curved path (TP), and the reference point (C) is a point at which a tool is in contact with a machining surface; a curved path evaluation unit (108) which determines whether or not each distance L is within the tolerance range; a tool path modification unit (109) which, if there are evaluation points for which the distance L is outside the tolerance range, moves only these evaluation points to positions where the distance L is within the tolerance range, then sets the moved evaluation points as new command points (R), and modifies the tool path; and a converted machining program output unit (110) which converts the modified tool path into a program to be output to an external device.

Description

Machining program converter, numerical controller and machining program converting method

The present invention relates to a machining program conversion device for converting a numerical control machining program, a numerical control device, and a machining program conversion method.

In order to machine a machining object by a numerical control device, a tool mounted on the machining target or a machine tool controlled by the numerical control device (hereinafter, simply referred to as "numerical control machine tool") is set in advance. A numerically controlled machining program (hereinafter simply referred to as “machining program”) in which a movement command for moving to a different path is described is used. The processing program is created by, for example, a commercially available CAD (Computer-Aided Design)/CAM (Computer-Aided Manufacturing) system, and described in a predetermined format of a character string such as a G code and a macro statement.

Conventionally, when machining a shape having a free curved surface, a CAD / CAM system is used to virtually move the tool so as to be in contact with the curved surface to be machined (hereinafter, simply referred to as "machined curved surface"). The ideal path is sequenced by a machining program to generate command points, a path approximated by a minute line segment connecting each command point is created, and then a numerically controlled machine tool is used to create a tool along the tool path. Is being moved to cut the object to be processed.

The tool path output from the CAD / CAM system is described in the machining program as a G-code movement command that can be interpreted by the numerical control device, and the machining program is input to the numerical control device of the numerical control machine tool. The numerical control device creates and interpolates the tool path for each interpolation cycle from the movement command by reading and interpreting the machining program. The numerical control device controls each axis of the numerically controlled machine tool by the created interpolation data, and moves the tool to a desired position to machine the object to be machined.

When performing machining using the tool path generated by the above procedure, the machining quality is degraded because the machining is performed by interpolating on the straight line represented by the minute line segment. In such a case, a curved path is approximately generated from the tool path, and the generated curved path is interpolated for machining. As a result, it can be expected that a smooth processing result can be obtained.

For example, Patent Document 1 is characterized in that a plurality of target points are set at equal intervals on a tool path, an approximate curve is calculated based on the plurality of target points, and a tool path along the approximate curve is generated. A method of generating a tool path is disclosed.

JP, 2011-96077, A

However, in the tool path generation method and the tool path generation device described in Patent Document 1, since the curved path is approximately generated from the tool path created by the minute line segment, the generated curved path matches the desired machined curved surface. However, there is a problem that the processing result is far from the desired shape of the processed curved surface. In addition, since the desired machining accuracy could not be obtained, additional machining was required, and the process of returning to the CAD/CAM system, recreating the tool path, and outputting the machining program again occurred. There was a problem of decrease.

The present invention has been made to solve the above problems, and an object of the present invention is to provide a machining program conversion device and a numerical control device capable of improving the machining accuracy of a machining result of a machining object. ..

In order to solve the above-mentioned problems and achieve the object, the machining program conversion device according to the present invention is provided on the tool path according to the movement command based on the tool path obtained from the machining program in which the movement command for the tool is described. To determine whether or not the curve path generator that generates a curve path between a plurality of command points and the tool that operates according to the curve path operates along the machined curved surface that is the finished shape of the object to be machined. When the point provided on the curved path is set as the evaluation point and the point where the tool and the machined curved surface contact is set as the reference point, the value of the allowable range for the distance L, which is the distance between the evaluation point and the reference point, is input. A permissible dimension tolerance input section, a curved path evaluation section for judging whether or not the distance L is within a permissible range value input to the permissible dimension tolerance input section, and a case where the distance L is out of the permissible range, Only the evaluation points that are out of the permissible range are moved to a position where the distance L is within the permissible range, the evaluation points after the movement are set as new command points, and a tool path correction unit that corrects the tool path is provided.

Further, the numerical control device according to the present invention generates a curved path between a plurality of command points provided on the tool path according to the movement command based on the tool path obtained from the machining program in which the movement command for the tool is described. The evaluation point is a point provided on the curved path to determine whether the curved path generator and the tool that operates according to the curved path operate along the machined curved surface that is the finished shape of the object to be machined. When the point where the processed curved surface contacts is used as the reference point, the allowable dimensional tolerance input unit in which the value of the allowable range for the distance L, which is the distance between the evaluation point and the reference point, is input, and the distance L is the allowable dimensional tolerance. Only the curve path evaluation unit that determines whether or not it is within the allowable range value input to the input unit and the evaluation points that are out of the allowable range when the distance L is out of the allowable range are the distance L. Is moved to a position within the allowable range, the evaluation point after the movement is set as a new command point, and a tool path correction unit for correcting the tool path is provided.

According to the machining program conversion device of the present invention, the machining path is corrected by correcting the tool path so that the distance between the evaluation point on the curved path and the reference point provided on the machining curved surface is within the allowable range. It is possible to improve the processing accuracy of the processing result of.
Further, according to the numerical control device according to the present invention, numerical control can be performed according to the modified tool path, so that the work efficiency can be improved.

It is the figure which showed the structure of the machining program converter which concerns on Embodiment 1 and Embodiment 2 of this invention. It is a flowchart of the operation of the machining program conversion apparatus which concerns on Embodiment 1 of this invention. It is the figure which showed an example of the tool path|route which the machining program conversion apparatus which concerns on Embodiment 1 of this invention read from the machining program. It is the figure which showed an example of the curve path|route produced according to the tool path|route which the machining program converter which concerns on Embodiment 1 of this invention read from the machining program. It is the figure which showed an example of the tool which passes along the tool path|route in Embodiments 1 to 3 of this invention. FIG. 5 is a diagram showing an example of a finished shape machined by a tool path in the machining program conversion device according to the first embodiment of the present invention. It is a figure which showed the state which arranged the curved path and the finished shape correspond with each other from the cross-sectional direction in the machining program conversion apparatus which concerns on Embodiment 1 of this invention. FIG. 6 is a diagram showing a state where the tool and the machining curved surface are apart from each other, in the machining program conversion device according to the first embodiment of the present invention, taking a case of a ball end mill tool as an example. FIG. 3 is a diagram showing a state where the tool and a machining curved surface are in contact with each other, in the machining program conversion device according to the first embodiment of the present invention, by taking a case of a ball end mill tool as an example. FIG. 6 is a diagram showing a state in which the tool and the machining curved surface are in an interference state in the machining program conversion device according to the first embodiment of the present invention, taking a case of a ball end mill tool as an example. FIG. 4 is a diagram showing a state where the tool and the machining curved surface are apart from each other, in the machining program conversion device according to the first embodiment of the present invention, taking a case of a flat end mill tool as an example. FIG. 6 is a diagram showing a state where the tool and a machining curved surface are in contact with each other, in the machining program conversion device according to the first embodiment of the present invention, by taking a case of a flat end mill tool as an example. FIG. 6 is a diagram showing a state in which the tool and the machining curved surface interfere with each other in the machining program conversion device according to the first embodiment of the present invention, taking a case of a flat end mill tool as an example. FIG. 6 is a diagram showing a state where the tool and the machining curved surface are apart from each other in the machining program conversion device according to the first embodiment of the present invention, by taking a case of a radius end mill tool as an example. FIG. 6 is a diagram showing a state where the tool and a machining curved surface are in contact with each other, in the machining program conversion device according to the first embodiment of the present invention, by taking a case of a radius end mill tool as an example. FIG. 4 is a diagram showing a state in which the tool and the machining curved surface are interfering with each other in the machining program conversion device according to the first embodiment of the present invention, taking a case of a radius end mill tool as an example. FIG. 6 is a diagram showing an example of a state in which the evaluation point is moved and a new command point is added so that the tool and the machining curved surface are in contact with each other in the machining program conversion device according to the first embodiment of the present invention. It is the figure which showed the tool path|route corrected by adding a new command point in the machining program converter which concerns on Embodiment 1 of this invention. It is a flowchart of the operation of the machining program conversion apparatus which concerns on Embodiment 2 of this invention. It is the figure which showed an example of the tool path|route which the machining program conversion apparatus which concerns on Embodiment 2 of this invention read from the machining program. FIG. 5 is a diagram showing an example of a curved path passing through two points after excluding the middle point from three adjacent command points in the machining program conversion apparatus according to the second embodiment of the present invention. It is the figure which showed an example of the finished shape processed by a tool path in the processing program converter which concerns on Embodiment 2 of this invention. It is a figure which showed the state which arranged the curved path and the finished shape correspond with each other from the cross-sectional direction in the machining program conversion apparatus which concerns on Embodiment 2 of this invention. FIG. 5 is a diagram showing a state in which the tool and the machining curved surface are separated from each other, taking the case of a ball end mill tool as an example in the machining program conversion apparatus according to the second embodiment of the present invention. FIG. 11 is a diagram showing a state where the tool and the machining curved surface are in contact with each other, in the machining program conversion device according to the second embodiment of the present invention, taking a case of a ball end mill tool as an example. FIG. 11 is a diagram showing a state in which the tool and a machining curved surface are in an interference state in the machining program conversion device according to the second embodiment of the present invention, taking a case of a ball end mill tool as an example. It is the figure which showed an example which corrected the tool path|route by deleting the command point from the tool path|route in the machining program converter which concerns on Embodiment 2 of this invention. It is the figure which showed the structure of the numerical control apparatus which concerns on Embodiment 3 of this invention. It is a flowchart of the operation of the numerical control apparatus which concerns on Embodiment 3 of this invention.

A machining program conversion device, a machining program conversion method, and a numerical control device according to an embodiment of the present invention will be described below with reference to the drawings. The invention is not limited to the embodiments.

Embodiment 1.
1 is a diagram showing a configuration example of a machining program conversion device according to a first embodiment of the present invention. The machining program conversion device 100 is obtained by a machining program input unit 101 that receives a machining program input from the outside, a machining program analysis unit 102 that analyzes the input machining program and obtains a tool path, and a machining program analysis unit 102. A tool path storage unit 103 for storing a tool path stored therein, a curve path generation unit 104 for generating a curve path according to the tool path stored in the tool path storage unit 103, and a tool data input unit 105 for inputting tool data. A shape data input unit 106 for inputting the shape data of the processed object after processing, and points formed on the curved path for determining whether the tool operates along the processed curved surface of the processed object and the processed curved surface. Allowable dimension tolerance input unit 107 for inputting the allowable range of distance, curved path evaluation unit 108 for determining whether the distance between a point provided on the curved path and the machined curved surface is within the allowable range, and modifying the tool path. The tool path correction unit 109 and the post-conversion machining program output unit 110 are provided. The post-conversion machining program output unit 110 converts the machining program after the tool path is corrected according to a predetermined conversion method, and outputs the converted machining program to the numerical controller 111, which is an external device. In addition, although the case where the external device is a numerical control device will be described in the present embodiment, the external device is not limited to the numerical control device and may be, for example, a program confirmation device or a tool path display device.

FIG. 2 is a flowchart showing an operation example of the machining program conversion device 100 according to the first embodiment. The procedure of the operation of the machining program conversion device 100 for generating or correcting the tool path will be described with reference to FIG.

In the operation of the machining program conversion device 100 to generate a tool path, first, a machining program is input to the machining program conversion device 100 (step S101). That is, in the machining program conversion device 100, the machining program input unit 101 reads a machining program for controlling the machine tool from the outside. The machining program describes a movement command for moving a workpiece or a tool, which is a machining object, to a preset route.

The input of the machining program executed in step S101 is realized by reading the file in which the format of the G code is described, which is output by the CAD / CAM system. Alternatively, it is realized by the operator operating the input device such as the keyboard to input necessary information and creating the machining program.

Next, the machining program conversion apparatus 100 analyzes the machining program acquired by executing step S101 by the machining program analysis unit 102 and obtains the tool path described in the machining program (step S102). Specifically, the processing program described in G code or the like, that is, the tool path information is read. The read tool path is stored in the tool path storage unit 103 (step S103). FIG. 3 is an example of a tool path converted from the machining program. In FIG. 3, the tool path has command points P1 to P6, and the command points are connected by a straight line. Here, the command point means a point commanded by the machining program. The intervals between the command points are predetermined by the machining program.

Next, the curved path generation unit 104 generates a curved path between the adjacent command points according to the tool path stored in the tool path storage unit 103 (step S104). FIG. 4 shows an example of a curved path generated according to the tool path having the command points P1 to P6. The curved path shown in FIG. 4 is generated such that the tool passes between the command points along the curved paths TP1 to TP6.

Further, the curve path generated by the machining program conversion device 100 needs to be the same curve as the curve on which the numerical control device 111 moves, that is, the curve that can form the shape of the machining object to be machined by the numerical control device 111. Therefore, it is desirable that the method of generating the curve path is the same as the method of generating the curve path in the numerical control device 111 in which the machining program input to the machining program conversion device 100 is finally input. As another example of the method of generating the curved path, for example, there is a method of interpolating the spline curve so as to pass each command point.

Tool data is externally input to the tool data input unit 105 (step S105). The tool data is information that defines the shape of the tool for processing the object to be processed, and includes information that expresses the type of the tool and information that expresses the shape of the tool such as the tool diameter, the tool cutting edge radius, and the tool length. Further, in the case of a tool shape having a taper or the like, the tool data input unit 105 may be given information on the inclination of the tool outer diameter bus with respect to the central axis of the tool, or has an asymmetric shape such as a turning tool. Tool information may be provided. The external input is performed by a method such as an input operation of a keyboard by an operator or a data conversion from CAD data. The machining program conversion device 100 can generate a tool model based on the tool data. FIG. 5 shows an example of a tool passing on the tool path. The tool T10 is the shape of the ball end mill generated based on the tool data.

Shape data is externally input to the shape data input unit 106 (step S105). The shape data is information that defines the shape of the processed object after processing, and is information that can generate a finished shape that is the target shape of the processed object. The finished shape has a processed curved surface S1 that is a curved surface to be processed. In addition, the finished shape is an ideal shape of a workpiece that is machined as a result by the machine tool processing the object according to the machining program. The machine tool processes the object to be processed so that the difference between the finished shape and the object is reduced. The external input is performed by a method such as an input operation of a keyboard by an operator or a data conversion from CAD data.

FIG. 6 is an example of the finished shape processed by the tool path. The finished shape M1 shown in FIG. 6 is generated based on the shape data input to the shape data input unit 106, and has a processed curved surface S1.

FIG. 7 shows a state in which the curved path and the finished shape M1 are arranged so as to correspond to each other from the cross-sectional direction. Further, as an example, the evaluation points Q1 to Q5 are set on the curved path TP3. Here, the evaluation point refers to a point provided on the curved path for determining whether or not the tool that operates according to the curved path moves along the machining curved surface of the machining target. The evaluation points can be obtained, for example, as points sampled on the curve path so that the curve parameters are evenly spaced, or the maximum error between the line segment connecting adjacent evaluation points and the curve path is a predetermined value. There is a method of iteratively determining until the following.

8, 9, and 10 are diagrams showing the relationship between the tool T10 and the machining curved surface S1 when the tool is a ball end mill tool (hereinafter, referred to as tool T10). FIG. 8 shows a state where the processing curved surface S1 and the tool T10 are apart from each other. In FIG. 8, the point on the machining curved surface S1 where the distance between the tool T10 and the machining curved surface S1 is the shortest is defined as a reference point C1. The reference point C1 is also a point on the machining curved surface S1 in which the distance between the evaluation point Q arranged on the tool and the machining curved surface S1 in step S106 described later is the shortest. Here, the distance between the evaluation point Q and the reference point C1 is defined as the distance L1.

FIG. 9 shows a state where the machining curved surface S1 and the tool T10 are in contact with each other. In FIG. 9, the point where the tool T10 and the machining curved surface S1 come into contact is defined as the reference point C2. The reference point C2 is also a cutting point when the tool T10 cuts the machining curved surface S1. Assuming that the distance between the evaluation point Q and the reference point C2 is the distance L2, the distance L2 is the most ideal value for machining an object to be machined with a machine tool.

FIG. 10 shows a state in which the tool T10 interferes with the machining curved surface S1. In FIG. 10, a point on the machining curved surface S1 where the distance between the evaluation point Q of the tool T10 and the machining curved surface S1 is the shortest is defined as a reference point C3. Further, in the case where the tool and the machined curved surface interfere with each other, the tool may be offset until the tool and the machined surface come into contact with each other, and the point where the offset tool and the machined surface contact with each other may be obtained as the reference point C3. it can. It can be said that the reference point C3 is a point where the tool T10 offset indicated by a dotted line in FIG. 10 and the machining curved surface S1 are in contact with each other. Here, the distance between the evaluation point Q and the reference point C3 is defined as the distance L3.

Here, the allowable range with respect to the distance L will be described assuming that the distance L2 is 2.00 mm. If the dimensional tolerance of the machining curved surface of a certain object is ±0.05 mm with respect to the standard tolerance, the distance L1 is 2.00 mm<distance L1≦2.05 mm, and the distance L3 is 1.95 mm≦. The distance L3 becomes <2.00 mm. Therefore, the allowable range of the distance L is 1.95 mm≦distance L≦2.05 mm.

In FIGS. 8, 9, and 10, the evaluation point Q of the tool T10 is provided on the central axis and near the tip of the tool T10, but the evaluation point Q may be provided, for example, at the tip of the tool. It may be provided at a portion or a point on the tool T10 where the object to be processed is cut, or may be provided at a point on the tool T10 where the distance between the tool T10 and the processing curved surface S1 is the shortest. However, after setting a specific position on the tool as the evaluation point Q, the distance L is evaluated at the set evaluation point Q.

The allowable dimension tolerance input unit 107 inputs an allowable range with respect to the distance L (step S105). The value of the allowable range is determined by the machining accuracy targeted by each of the objects to be machined. Further, when the shape data input by the shape data input unit 106 has information on the machining tolerance with respect to the machining curved surface of the machining object, the allowable range value may be obtained according to the machining tolerance. In this case, the allowable range can be automatically set according to the machined portion, and the work efficiency is improved.

Further, the value of the allowable range input to the allowable dimension tolerance input unit 107 may be the allowable range of the shortest distance between the tool and the finished shape. For example, if the dimensional tolerance of the machining curved surface of a certain object is ±0.05 mm with respect to the standard tolerance, the difference in the shortest distance between the tool and the machining curved surface of the finished shape may be within 0.05 mm. Therefore, the value in the allowable range is given as 0.05 mm.

In the present embodiment, the allowable range for the distance L is input to the allowable dimensional tolerance input unit 107, but the value of the allowable range for the distance L is input to the allowable dimensional tolerance storage unit of the machining program conversion device 100 (not shown in advance). It may be stored.

11, 12, and 13 are diagrams showing the relationship between the tool T11 and the machining curved surface S2 when the tool is a flat end mill tool (hereinafter, referred to as tool T11). FIG. 11 shows a state in which the machining curved surface S2 and the tool T11 are separated from each other. In FIG. 11, a point on the machining curved surface S2 where the distance between the tool T11 and the machining curved surface S2 is the shortest is defined as a reference point C2. The distance between the evaluation point Q and the reference point C11 is defined as the distance L11.

FIG. 12 shows a state in which the machining curved surface S2 and the tool T11 are in contact with each other. In FIG. 12, the point where the tool T11 and the machining curved surface S2 meet is defined as the reference point C12. Assuming that the distance between the evaluation point Q and the reference point C12 is the distance L12, the distance L12 is the most ideal value for machining an object to be machined with a machine tool.

FIG. 13 shows how the tool T11 is in a state of interfering with the machining curved surface S2. In FIG. 13, the point on the machining curved surface S2 where the distance between the evaluation point Q of the tool T11 and the machining curved surface S2 is the shortest is set as a reference point C13. Further, when such a tool and the machining curved surface interfere with each other, the tool may be offset inward until the tool comes into contact with the machining curved surface. It can be said that the reference point C13 is a point where the tool T11 offset indicated by the dotted line in FIG. 13 and the machining curved surface S2 are in contact with each other. The distance between the evaluation point Q and the reference point C13 is defined as the distance L13.

In FIGS. 11, 12, and 13, the evaluation point Q of the tool T11 is provided at the center of the tip of the tool T11. The evaluation point Q is, for example, a portion of the tool T11 for cutting an object to be machined. It may be provided at a point, or may be provided at a point on the tool T11 where the distance between the tool T11 and the processing curved surface S2 is the shortest. However, after setting a specific position on the tool as the evaluation point Q, the distance L is evaluated at the set evaluation point Q.

14, 15, and 16 are diagrams showing the relationship between the tool T12 and the machining curved surface S3 when the tool is a radius end mill tool (hereinafter referred to as a tool T12). FIG. 14 shows a state where the machining curved surface S3 and the tool T12 are apart from each other. In FIG. 14, a point on the machining curved surface S3 where the distance between the tool T12 and the machining curved surface S3 is the shortest is defined as a reference point C21. The distance between the evaluation point Q and the reference point C21 is defined as a distance L21.

FIG. 15 shows a state in which the machining curved surface S3 and the tool T12 are in contact with each other. In FIG. 15, the point where the tool T12 and the machining curved surface S3 meet is defined as the reference point C22. Assuming that the distance between the evaluation point Q and the reference point C22 is the distance L22, the distance L22 is the most ideal value for machining an object to be machined with a machine tool.

FIG. 16 shows a state in which the tool T12 interferes with the processing curved surface S3. In FIG. 16, a point on the machining curved surface S3 where the distance between the evaluation point Q of the tool T12 and the machining curved surface S3 is the shortest is set as a reference point C23. Further, when such a tool and the machining curved surface interfere with each other, the tool may be offset inward until the tool comes into contact with the machining curved surface. It can be said that the reference point C23 is a point where the tool T12 offset indicated by the dotted line in FIG. 16 and the machining curved surface S3 are in contact with each other. The distance between the evaluation point Q and the reference point C23 is defined as the distance L23.

In FIGS. 14, 15, and 16, the evaluation point Q of the tool T12 is provided near the central axis and the tip of the tool T12. The evaluation point Q is, for example, cutting an object to be machined on the tool T12. It may be provided at a portion or a point to be formed, or may be provided at a point on the tool T10 where the distance between the tool T12 and the processing curved surface S3 is the shortest. However, after setting a specific position on the tool as the evaluation point Q, the distance L is evaluated at the set evaluation point Q.

Next, the curve path evaluation unit 108 evaluates the curve path TP generated by the curve path generation unit 104 according to the values of the allowable range input to the tool data, the shape data, and the allowable dimensional tolerance input unit (step S106). .. First, a plurality of evaluation points are obtained on the curved paths TP1 to TP6. Subsequently, as shown in FIGS. 8 to 16, the tools generated based on the tool data input in step 5 are arranged so as to correspond to the obtained evaluation points Q. At this time, when the tool is arranged at the evaluation point Q, ideally the tool and the finished curved surface of the shape come into contact with each other.

The curved path evaluation unit 108 evaluates whether or not the value of the distance L is within the allowable range for the curved path TP. When the distance L obtained in a certain curved path TP is larger than the allowable range with respect to the distance L, the process proceeds to step S107 described later with the curved path TP as the curved path to be corrected. When the distance L obtained on all the curved paths TP is within the allowable range for the distance L, the process proceeds to step S108 described later.

In the curved path evaluation unit 108, if the value of the distance L exceeds the allowable range for the distance L, that is, if “NO” in step S106, the tool path is corrected (step S107). Here, the operation for correcting the tool path will be described with reference to FIG. 17, taking as an example the case where the tool T10, which is a ball end mill, is in a state where the tool T10 and the machining curved surface S1 as shown in FIG. 10 interfere with each other. To do.

FIG. 17 is a diagram showing an example of how the evaluation point is moved so that the tool T10 and the machining curved surface S1 are in contact with each other and a new command point is added. First, the tool path correction unit 109 extracts the evaluation point Q that is the largest out of the allowable range for the distance L from the evaluation points Q on the correction target curved path TP obtained in step S106. In FIG. 17, it is assumed that the curved path TP3 is the curved path to be corrected, and the evaluation point Q3 on the curved path TP3 is the evaluation point that deviates most from the allowable range for the distance L3.

Next, the evaluation point Q3 is moved so that the tool T10 and the machining curved surface S1 are in contact with each other. At this time, the evaluation point after movement is set as a new command point R1. At this time, the evaluation point Q3 is moved in the tool axis direction, the normal direction of the machining curved surface at the reference point on the machining curved surface when the tool is arranged at the evaluation point Q3, or the arbitrary direction. May be.

A method of moving the evaluation point Q3 so that the tool T10 and the machining curved surface S1 are in contact with each other is to calculate a distance L3 at the movement evaluation point Q after the movement by moving a small distance in the given movement direction. , Can be obtained by repeating until the distance becomes equal to or less than the allowable range for the distance L3.

Further, the tool path correction unit 109 issues a new command to the evaluation point Q3 after movement, in which the distance L3 is equal to or less than the allowable range for the distance L3 with respect to the tool path stored in the tool path storage unit 103 in step S103. The point R1 is added to the tool path to correct the tool path. This improves the accuracy of the processing result of the processing target object.

The corrected tool path is stored in the tool path storage unit 103. FIG. 18 is a diagram showing the tool paths corrected for the command points P1 to P6 by adding a new command point R1 in step S107. After the execution of step S107, the process returns to step S104 and the process is repeated. In this case, the process of step S105 may be omitted.

In the process of step S106, when the distance L3 at all the evaluation points Q falls within the allowable range for the distance L3 and the tool path correction is completed, the corrected tool path is stored in the tool path storage unit 103. Next, the post-conversion machining program output unit 110 generates a modified machining program from the tool path according to a predetermined conversion method according to the tool path stored in the tool path storage unit 103, and after converting the modified machining program. The data is output to the outside of the machining program conversion device 100 (step S108).

After the execution of step S108, the processing is terminated, and the output converted machining program is input to the numerical controller 111, and the machining target is machined. Although the case where the tool T10 that is a ball end mill and the machining curved surface S1 interfere with each other has been described in steps S106 to S108, the same applies to other cases.

From the above, according to the machining program conversion device according to the first embodiment of the present invention, the tool path is modified so that the distance L between the evaluation point and the reference point is equal to or less than the allowable range with respect to the distance L. The processing accuracy of the processing result can be improved.

Furthermore, since the distance L moves only the evaluation points that exceed the allowable range for the distance L and a new command point is added, the number of command points to be added can be suppressed to the required number, and the data amount of the program is required. It is possible to prevent the processing from increasing due to the increase above.

Embodiment 2.
Since the configuration of the machining program conversion device 100 according to the second embodiment of the present invention is the same as the configuration of the machining program conversion device 100 according to the first embodiment, the description thereof will be omitted. The machining program conversion device 100 according to the second embodiment of the present invention operates according to the flowchart shown in FIG.

The operation from step S201 to step S203 is similar to the operation from step S101 to step S103 in the first embodiment of the present invention. In the second embodiment, the method of generating the curved path is different from that of the first embodiment.

FIG. 20 is a diagram showing an example of a tool path read from the machining program by the machining program conversion device. The tool path shown in FIG. 20 has command points P11 to P17, and the command points are connected by a straight line. In step S204 of the second embodiment, a curved path passing between the first, second, and third command points, which are adjacent three command points, between the first and third command points at both ends. To generate. In FIG. 21, as an example, a curved path TP11 is generated between P13 and P15 among the command point P13 that is the first command point, the second command point P14, and the third command point P15. It shows the situation. Next, the tool data is externally input to the tool data input unit 105, and the shape data is externally input to the shape data input unit 106 (step S205).

In the curved path evaluation unit 108, the respective distances L at the evaluation points set to a plurality of points on the curved path TP11 are evaluated according to the tool data, the shape data, and the value of the allowable range input to the allowable dimension tolerance input unit (step S206). ). That is, it is evaluated whether the distance L is less than or equal to the allowable range or greater than the allowable range for the distance L. If all the distances L are within the allowable range for the distance L, the command point P14 is deleted from the tool path stored in the tool path storage unit 103 (step S207). Further, in this case, since there is no correction target curve path, the curve path TP11 is a tool path that is finally converted and output (step S208).

FIG. 22 is an example of a finished shape machined in the tool path. The finished shape M2 shown in FIG. 22 is generated based on the shape data input to the shape data input unit 106, and has a processed curved surface S4.

Step S206 will be specifically described with reference to FIGS. 23, 24, and 25. FIG. 23 shows a state in which the curved path and the finished shape M2 are arranged so as to correspond to each other from the cross-sectional direction. Further, as an example, the evaluation points Q11 to Q14 are set on the curved path TP11. FIG. 24 shows a state where the machining curved surface S4 and the tool T10 are in contact with each other when the tool is a ball end mill tool. In FIG. 24, the point where the tool T10 and the machining curved surface S4 meet is set as the reference point C31. In FIG. 24, the tool is placed at the evaluation point Q12 on the curved path TP11, and the distance L32 is defined between the evaluation point Q12 and the reference point C31.

24, 25, and 26 are diagrams showing the relationship between the tool T10 and the machining curved surface S4 when the tool is a ball end mill tool (hereinafter, referred to as tool T10). The tool TP10 is arranged at the evaluation point Q12 on the curved path TP11. FIG. 24 shows a state where the machining curved surface S4 and the tool T10 are apart from each other. In FIG. 24, a point on the machining curved surface S4 where the distance between the tool T10 and the machining curved surface S4 is the shortest is a reference point C31. Here, the distance between the evaluation point Q12 and the reference point C31 is defined as the distance L31.

FIG. 25 shows a state in which the machining curved surface S4 and the tool T10 are in contact with each other. In FIG. 25, the point where the tool T10 and the machining curved surface S4 meet is defined as the reference point C32. Assuming that the distance between the evaluation point Q12 and the reference point C32 is the distance L32, the distance L32 is the most ideal value for machining an object to be machined with a machine tool.

FIG. 26 shows a state in which the tool T10 interferes with the machining curved surface S4. In FIG. 26, the point on the machining curved surface S4 where the distance between the evaluation point Q12 of the tool T10 and the machining curved surface S4 is the shortest is set as the reference point C31. Further, when such a tool and the machining curved surface interfere with each other, the tool may be offset until the tool comes into contact with the machining curved surface. It can be said that the reference point C31 is a point where the tool T10 offset indicated by the dotted line in FIG. 26 and the machining curved surface S4 are in contact with each other. Here, the distance between the evaluation point Q12 and the reference point C33 is defined as the distance L33.

In the curve path evaluation unit 108, when all the distances L (distance L31 to distance L33) are equal to or less than the allowable range with respect to the distance L, the second command point is obtained from the tool path stored in the tool path storage unit 103. The command point P14 which is is deleted (step S207). Further, in this case, since there is no correction target curve path, the curve path TP11 is a tool path that is finally converted and output (step S208). FIG. 27 is an example of the final form in which the tool path is corrected in the second embodiment.

In the curved path evaluation unit 108, if at least one of the evaluation points Q set in the curved path TP11 is a distance larger than the allowable range for the distance L, the command point P14 becomes Without deleting, a curved path between the command points P13 and P14 and a curved path between P14 and P15 are generated (step S209).

Next, similar to the flow from step S106 to step 108 of the first embodiment, in the curved path evaluation unit 108, each curved path generated by the curved path generation unit 104 is input with tool data, shape data, and allowable dimension tolerance. It is evaluated whether or not the value of the distance L is within the allowable range according to the value of the allowable range input to the unit (step S210). In the curved path evaluation unit 108, when the value of the distance L exceeds the allowable range for the distance L, that is, when “NO” in step S210, the tool path is corrected (step S211). Here, the operation for correcting the tool path is the same as that in the first embodiment.

In the process of step S210, when the distance L at all the evaluation points Q becomes equal to or less than the allowable range with respect to the distance L and the correction of the tool path is completed, the corrected tool path is stored in the tool path storage unit 103. Next, the post-conversion machining program output unit 110 generates a modified machining program from the tool path according to a predetermined conversion method according to the tool path stored in the tool path storage unit 103, and after converting the modified machining program. The data is output to the outside of the machining program conversion device 100 (step S208).

As described above, according to the machining program conversion apparatus according to the second embodiment of the present invention, the distance between the evaluation point and the reference point provided on the curved path that passes through the two points at both ends of the three adjacent command points. When L satisfies the condition that the distance L is equal to or less than the allowable range with respect to the distance L, the existing middle command point is deleted from the tool path, so that the data amount of the machining program can be reduced and the work efficiency is improved. Further, the processing accuracy of the processing result of the processing object can satisfy the desired accuracy. ‥

Embodiment 3.
A numerical controller according to Embodiment 3 of the present invention will be described below with reference to the drawings. The invention is not limited by this embodiment.

The numerical control device 200 uses a machining program input unit 201 that receives a machining program input from the outside, a machining program analysis unit 202 that analyzes the input machining program and finds a tool path, and a machining program analysis unit 202. A tool route storage unit 203 for storing a tool route, a curved route generation unit 204 for generating a curved route according to the tool route stored in the tool route storage unit 203, a tool data input unit 205 for inputting tool data, A shape data input unit 206 for inputting the shape data of the processed object after processing, and a distance between a point provided on a curved path and the processed curved surface for determining whether the tool operates along the processed curved surface of the processed object. Allowable dimension tolerance input section 207 for inputting the allowable range of the above, a curved path evaluation section 208 for judging whether or not the distance between a point provided on the curved path and the machining curved surface is within the allowable range, and a tool for correcting the tool path. A route correction unit 209 and a curved route interpolation unit 210 are provided. When the enclosing program is input from outside, the numerical control device 200 according to the present embodiment analyzes the machining program, generates a tool path, and outputs the tool path to the motor drive unit 211.

A procedure for generating the tool path by the numerical control device 200 according to the third embodiment shown in FIG. 28 will be described. FIG. 29 is a flowchart showing an operation example of the numerical control device 200 according to the third embodiment. The flowchart of FIG. 29 shows a procedure of an operation in which the numerical control device 200 generates a tool path. In FIG. 29, the procedure from step S301 to step S307 is the same as the procedure of the operation from step S101 to step S107 in the first embodiment.

In step S306, the curved route generation unit 204 passes the generated curved route to the curved route interpolation unit 210 when the distance L at the evaluation point Q is less than or equal to the allowable range for the distance L.

The numerical controller 200 then interpolates the curved path in the curved path interpolation unit 210 (step S308). Specifically, the curved path interpolation unit 210 generates an interpolated point on the curved path received from the curved path generation unit 204 by calculating the amount of movement of the tool per interpolation cycle that is a unit time. The curved path after the interpolation processing in step S308 becomes the final tool path. When the generation of the interpolation points is completed, the curved path interpolation unit 210 passes the interpolation points to the external motor drive unit 211.

By operating according to the above procedure, the numerical control device 200 according to the third embodiment generates a tool path.

According to the numerical control device according to the third embodiment of the present invention, numerical control can be performed according to the modified tool path. Therefore, it is necessary to convert the machining program once and then output the converted machining program. In addition, since it is possible to satisfy the desired processing accuracy of the object to be processed, reworking does not occur and the work efficiency is improved.

100 Machining program converter, 101, 201 Machining program input unit, 102, 202 Machining program analysis unit, 103, 203 Tool path storage unit, 104, 204 Curved path generator, 105, 205 Tool data input unit, 106, 206 Shape Data input unit, 107, 207 Allowable dimension tolerance input unit, 108, 208 Curve path evaluation unit, 109, 209 Tool path correction unit, 110 Post-conversion machining program output unit, 111, 200 Numerical controller, 210 Curve path interpolation unit, P1 to P6, P11 to P17, R1 Command point Q1 to Q Evaluation point, C1 to C3, C11 to C13, C21 to C23 Reference point, L1 to L3, L11 to L13, L21 to L23 Distance L, S1 to S3 Machining curved surface , T10-T12 tools, TP1-TP curved path

Claims

A curve route generation unit that generates a curved route between a plurality of command points provided on the tool route according to the movement command, based on the tool route obtained from a machining program in which a movement command for the tool is described,
A tool that operates according to the curved path is a point provided on the curved path for determining whether or not the tool moves along a machining curved surface that is a finished shape of a machining target, and the tool and the machining are used as evaluation points. An allowable dimension tolerance storage unit that stores a value of an allowable range for a distance L, which is a distance between the evaluation point and the reference point, when a point where the curved surface contacts is used as the reference point;
A curve path evaluation unit that determines whether or not the distance L is within the value of the allowable range stored in the allowable dimension tolerance storage unit.
When the distance L is out of the allowable range, an evaluation point outside the allowable range is moved to a position where the distance L is within the allowable range, and the evaluation point after the movement is a new command point. And a tool path correction unit that corrects the tool path,
A machining program converter equipped with.
The curved path generation unit generates a curved path connecting the first command point and the third command point among the continuous first, second, and third command points,
The tool path correction unit deletes the second command point when the distance L when the tool passes through the curved path connecting the first and third command points is equal to or less than the allowable range. The machining program conversion device according to claim 1, wherein:
A tool data input unit for inputting tool data that defines the tool,
A shape data input unit for inputting shape data defining the processing curved surface of the processing object;
The machining program conversion device according to claim 1 or 2, further comprising:
The shape data includes a machining tolerance on the machining surface, and the permissible range is determined according to the machining tolerance on the machining surface.
The machining program conversion apparatus according to claim 3.
A curve route generation unit that generates a curved route between a plurality of command points provided on the tool route according to the movement command, based on the tool route obtained from a machining program in which a movement command for the tool is described,
A point provided on the curved path is set as an evaluation point in order to determine whether the tool operating according to the curved path operates along the machining curved surface which is the finished shape of the object to be machined, and the tool and the machining curved surface are When the point of contact is used as the reference point, the permissible dimension tolerance storage unit in which the value of the permissible range for the distance L, which is the distance between the evaluation point and the reference point, is input.
A curve path evaluation unit for determining whether or not the distance L is within the value of the allowable range input to the allowable dimension tolerance input unit, and
When the distance L is out of the permissible range, only the evaluation points out of the permissible range are moved to a position where the distance L is within the permissible range, and the evaluation points after the movement are given a new command. A point, and a tool path correction unit that corrects the tool path,
Numerical control device equipped with.
A curve path interpolation unit is provided on the curve path generated by the curve path generation unit to generate an interpolation point obtained by obtaining the amount of movement of the tool per interpolation cycle having a fixed time period.
The numerical control device according to claim 5.
The tool path correction unit moves the evaluation point outside the allowable range for the distance L to a position where the distance L is equal to or less than the allowable range, and adds the evaluation point as a new command point after the movement.
The numerical controller according to claim 5 or 6, characterized in that.
The curved path generation unit generates a curved path connecting the first command point and the third command point among the continuous first, second, and third command points,
The tool path correction unit deletes the second command point when the distance L when the tool passes through the curved path connecting the first and third command points is equal to or less than the allowable range. The numerical control device according to claim 5, wherein
A tool data input unit for inputting tool data that defines the tool,
A shape data input unit for inputting shape data defining a finished shape of the processing object;
The numerical controller according to claim 5, further comprising:
The shape data includes a machining tolerance on the machining surface, and the permissible range is determined according to the machining tolerance on the machining surface.
9. The numerical control device according to claim 9.
A step of generating a curved path between a plurality of command points provided on the tool path according to the move command, based on the tool path obtained from a machining program in which a move command for the tool and the object to be machined is described;
A tool operating according to the curved path, the point provided on the curved path in order to determine whether to operate along the processing curved surface that is the finished shape of the workpiece is an evaluation point, the tool and the processing curved surface When the point of contact is used as the reference point, the step of inputting the value of the allowable range for the distance L, which is the distance between the evaluation point and the reference point, and
Determining whether the distance L is within a value of the input allowable range,
When the distance L is outside the allowable range, only the evaluation points that are outside the allowable range are moved to a position where the distance L is within the allowable range, and the evaluation point after the movement is given a new command. As a point, the step of correcting the tool path and
Converting the tool path corrected by the tool path correction unit into a program for outputting to the outside,
Machining program conversion method including.