Machining command correction device and machining command correction method

Abstract

The tool path after the change of the tool posture is not deteriorated compared with the tool path before the change of the tool posture, and the tool posture is optimized in a range in which no interference is generated. This machining command correction device is provided with: a machining command analysis unit that generates first machine coordinate information on the basis of a first machining command and machine configuration information; a tool orientation correction unit that corrects the orientation of the tool on the basis of the first machine coordinate information and generates second machine coordinate information; an interference calculation unit that calculates interference between the tool and the workpiece on the basis of the second machine coordinate information, the machine configuration information, the tool shape information, and the workpiece shape information; and a machining command generation unit that generates a second machining command on the basis of the second machine coordinate information without interference, and the tool orientation correction unit determines the orientation of the corrected tool using an evaluation value that evaluates the quality of the tool path.

Description

Technical Field

[0001] The present disclosure relates to a processing instruction correction device and a processing instruction correction method for correcting processing instructions for controlling a machine tool, and in particular to a processing instruction correction device and a processing instruction correction method for correcting processing instructions that change the posture of a tool relative to a workpiece. Background Art

[0002] Patent Document 1 describes a method and apparatus for generating a tool path when surface machining of a workpiece is performed using a machine tool having at least one rotary feed axis while changing the tool posture of an end mill relative to the workpiece.

[0003] Specifically, Patent Document 1 describes the following: a processing point on a multi-column tool path is set as an object processing point, processing points within a predetermined range with the object processing point as the center are selected as focus processing points, the tool postures at the selected focus processing points are averaged, thereby calculating the tool posture of the object processing point, correcting data related to the tool posture of the object processing point based on the calculated average tool posture, obtaining shape data of a workpiece to be processed and shape data of a ball end mill to be used, performing an interference check between the workpiece and the ball end mill based on the corrected tool posture data, and generating a new tool path based on data related to the corrected tool posture when there is no interference between the workpiece and the ball end mill.

[0004] Prior art literature

[0005] Patent Literature

[0006] Patent Document 1: Japanese Patent Re-Publication No. WO2018 / 179401 Summary of the invention

[0007] Problems to be solved by the invention

[0008] Patent Document 1 describes that interference check between a workpiece and a ball end mill is performed based on corrected tool posture data, and when there is no interference between the workpiece and the ball end mill, a new tool path is generated based on data related to the corrected tool posture.

[0009] When changing the tool posture, it is desired that the tool path after the tool posture change does not deteriorate compared to the tool path before the tool posture change.

[0010] Therefore, a machining command correction device and a machining command correction method are desired that do not deteriorate the tool path after the tool posture is changed compared to the tool path before the tool posture is changed and optimize the tool posture within a range where no interference occurs.

[0011] Means for solving problems

[0012] A first representative aspect of the present disclosure is a machining instruction correction device, comprising: a machining instruction analysis unit, which generates first machine coordinate information, which is a time-series change of coordinates of each axis of a machine tool, based on a first machining instruction that describes a time-series change of a position and a posture of a tool and machine structure information for performing coordinate transformation between a coordinate system based on a workpiece and a coordinate system based on a machine tool;

[0013] a tool posture correction unit, which corrects the posture of the tool according to the first mechanical coordinate information to generate second mechanical coordinate information;

[0014] an interference calculation unit that calculates interference between the tool and the workpiece when the machine tool operates according to the second machine coordinate information, based on the second machine coordinate information, the machine structure information, tool shape information related to the shape of the tool used in the processing of the first processing instruction, and workpiece shape information related to the shape of the workpiece obtained when the first processing instruction is executed; and

[0015] a processing instruction generating unit, which generates a second processing instruction based on the second machine coordinate information in the absence of the interference,

[0016] The tool posture correction unit determines a corrected posture of the tool using an evaluation value for evaluating the quality of a tool path.

[0017] A second representative aspect of the present disclosure is a processing instruction correction device having:

[0018] a machining instruction analysis unit for generating first mechanical coordinate information, which is a time-series change of coordinates of each axis of the machine tool, based on a first machining instruction describing a time-series change of a position and a posture of a tool and mechanical structure information for performing coordinate transformation between a coordinate system based on a workpiece and a coordinate system based on a machine tool;

[0019] an interference calculation unit that calculates interference between the tool and the workpiece when the machine tool operates according to the first machine coordinate information, based on the first machine coordinate information, the machine structure information, tool shape information related to the shape of the tool used in the processing of the first processing instruction, and workpiece shape information related to the shape of the workpiece obtained when the first processing instruction is executed;

[0020] a tool posture correction unit, which corrects the posture of the tool according to the first machine coordinate information to generate second machine coordinate information; and

[0021] a processing instruction generating unit, which generates a second processing instruction based on the second machine coordinate information in the absence of the interference,

[0022] The interference calculation unit calculates a range of tool postures where no interference occurs.

[0023] The tool posture correction unit corrects the tool posture within the calculated range of the tool posture, and determines the posture of the tool after correction using an evaluation value for evaluating the quality of a tool path.

[0024] A third representative embodiment of the present disclosure is a processing instruction correction method.

[0025] The computer as the processing instruction correction device performs the following processing:

[0026] Generate first mechanical coordinate information, which is a time-series change of coordinates of each axis of the machine tool, based on a first machining instruction describing a time-series change of a position and a posture of a tool and mechanical structure information for performing coordinate transformation between a coordinate system based on a workpiece and a coordinate system based on a machine tool;

[0027] Correcting the posture of the tool according to the first mechanical coordinate information to generate second mechanical coordinate information;

[0028] Calculate interference between the tool and the workpiece when the machine tool operates according to the second mechanical coordinate information based on the second mechanical coordinate information, the mechanical structure information, tool shape information related to the shape of the tool used in the processing of the first processing instruction, and workpiece shape information related to the shape of the workpiece obtained when the first processing instruction is executed; and

[0029] In the absence of the interference, a second machining instruction is generated based on the second machine coordinate information. BRIEF DESCRIPTION OF THE DRAWINGS

[0030] Figure 1 It is a block diagram showing the structure of the data generation system.

[0031] Figure 2 This is a diagram showing the flow of data generation by the data generation system.

[0032] Figure 3 It is a block diagram showing the structure of the processing instruction correction device according to the first embodiment of the present disclosure.

[0033] Figure 4 This is a diagram showing information on the type of mechanical structure.

[0034] Figure 5 This is a diagram for explaining information on the positions of the rotation axis center and the workpiece coordinate system.

[0035] Figure 6This is a diagram showing a state in which the center position of the ball head of a ball end mill is fixed and the tool posture is changed within a certain range.

[0036] Figure 7 It is a characteristic diagram showing an example of the first machine coordinate information.

[0037] Figure 8 It is a diagram showing the machine coordinates before and after the coordinate values ​​of the rotation axes of each command point in the correction section are changed.

[0038] Fig. 9 It is a characteristic diagram showing the amount of change (ΔLaxis(pi)) of the axis axis.

[0039] Fig.10 This is a diagram showing an example of information on parameters of each height of a tool and a radius at that height.

[0040] Fig.11 This is a diagram showing CAD data serving as an example of workpiece shape information.

[0041] Fig.12 This is a flowchart showing the operation of the processing instruction correction device.

[0042] Fig.13 This is a block diagram showing the structure of a processing instruction correction device according to a first modified example of the first embodiment of the present disclosure.

[0043] Fig.14 It is a block diagram showing the structure of a processing instruction correction device according to a second modified example of the first embodiment of the present disclosure.

[0044] Fig.15 This is a diagram showing an area where interference occurs between the tool shape calculated by the interference calculation unit and the workpiece.

[0045] Fig.16 (A) is a diagram showing an example of generating new tool shape information by increasing the protrusion amount of the tool. Fig.16 (B) is a diagram showing an example in which the diameter of the jig portion of the tool shape information is reduced to generate new tool shape information.

[0046] Fig.17 This is a diagram showing a state where the interference area disappears and the interference disappears.

[0047] Fig.18 It is a block diagram showing the structure of a processing instruction correction device according to a third modified example of the first embodiment of the present disclosure.

[0048] Fig.19 It is a block diagram showing the structure of a processing instruction correction device according to a second embodiment of the present disclosure.

[0049] Fig. 20This is a diagram showing the changeable range of the tool posture without causing interference. DETAILED DESCRIPTION

[0050] Before describing the embodiment of the present disclosure, a data generation flow of a data generation system that generates data for controlling a machine tool will be described. The processing instruction correction device of the present disclosure can be applied to the data generation system.

[0051] Figure 1 It is a block diagram showing the structure of the data generation system. Figure 2 This is a diagram showing the flow of data generation by the data generation system.

[0052] like Figure 1 As shown, the data generation system 10 includes a CAM device 11 and a CNC device 12. The CAM device 11 includes a main processor 111 and a post-processor 112.

[0053] Based on the shape data (CAD data) of the workpiece generated by a CAD device (not shown), a tool trajectory is generated by the main processor 111 of the CAM device 11. The tool trajectory is time series data of the position and posture (tool axis vector) of the tool, and sometimes also includes the feed speed or the movement method (linear movement, circular movement) from the immediately previous position.

[0054] The tool path generated by the main processor 111 is a general command that does not depend on the type of machine tool. Therefore, the tool path generated by the CAM device 11 is not necessarily optimal for controlling the machine without considering the axis structure of the machine actually performing processing.

[0055] The tool path generated by the main processor 111 is converted into a machining program corresponding to each machine by the postprocessor 112. The postprocessor 112 inserts commands (spindle rotation, cutting fluid ON / OFF, etc.) that can be used in the machine, but does not perform operations such as changing the tool path.

[0056] The CNC device 12 calculates the time series data (referred to as mechanical coordinate information) of the coordinates of the mechanical control points observed from the mechanical coordinate system according to the machining program (referred to as motion transformation). The motors of the machine tool are controlled based on the mechanical coordinate information. The mechanical control points are points used to calculate the coordinates of the linear axis. They are fixed to the machine and do not change their positions even when the rotary axis is moved. For example, the mechanical control points are Figure 2 shown.

[0057] The position and acceleration / deceleration of the motor are calculated based on the coordinates of the mechanical control point. Therefore, if the trajectory of the mechanical control point is not smooth, the acceleration / deceleration of the axis will increase, which will become the main cause of reduced processing speed or increased power consumption. In addition, the vibration caused by the acceleration / deceleration of the axis may also deteriorate the processing surface.

[0058] If the tool posture is corrected in the CNC device 12 to make the mechanical control point smooth, the tool and the workpiece may interfere with each other. The greater the change in the tool posture, the higher the risk of interference. In order to avoid interference, the tool posture can only be changed by a very small amount with a small risk of interference. Therefore, the effect of smoothing the mechanical movement obtained by correcting the tool posture is also limited. Therefore, it is desirable to optimize the tool posture within a range where no interference occurs while checking the interference between the tool and the workpiece.

[0059] Furthermore, when changing the tool posture, it is desirable that the tool path after the tool posture change does not deteriorate compared to the tool path before the tool posture change, for example, problems such as an increase in the amount of movement of the axis do not occur.

[0060] The embodiments and modifications of the present disclosure described below relate to a machining instruction correction device and a machining instruction correction method that optimize the tool posture without causing interference, while ensuring that the tool path after the tool posture is changed does not deteriorate compared to the tool path before the tool posture is changed.

[0061] Hereinafter, embodiments of the present disclosure will be described in detail using the drawings.

[0062] (First Embodiment)

[0063] Figure 3 It is a block diagram showing the structure of the processing instruction correction device according to the first embodiment of the present disclosure.

[0064] like Figure 3 As shown in FIG. 1 , the processing instruction correction device 20 includes a processing instruction analysis unit 21, a tool posture correction unit 22, an interference calculation unit 23, and a processing instruction generation unit 24. The processing instruction correction device 20 can be mounted on Figure 1 The CAM device 11 or the CNC device 12 shown may also be provided with a device different from the CAM device 11 and the CNC device 12 .

[0065] Hereinafter, each component of the machining instruction correction device will be described.

[0066] (Processing instruction analysis unit)

[0067] The processing instruction analyzing unit 21 generates a processing instruction according to the first processing instruction P which is the processing instruction before correction. A and mechanical structure information, generating first mechanical coordinate information M related to the mechanical coordinates of each control axis of the machine tool A The first processing instruction P A Contains data describing the time-series changes in the position and posture of a tool described in the workpiece coordinate system.

[0068] According to the position and posture of the tool described in the workpiece coordinate system (included in the first machining instruction P A ), the first mechanical coordinate information M is obtained using the mechanical structure information A The calculation of the coordinates of each control axis of a machine (motion transformation) is a well-known technique.

[0069] The first processing instruction P A For example, it is information recording the time series data of the position and posture (tool axis direction vector) of the tool observed in the workpiece coordinate system, and the movement method (linear movement, circular movement, etc.) from the immediately previous position. A It may also include information on tool movement speed and spindle speed.

[0070] The first processing instruction P A For example, it is a file of a character string described in G code included in a machining program, or an independent format file of a CAM device called CL data. A Any format is acceptable as long as it includes time series data of the position and posture of the tool observed in the workpiece coordinate system, and information describing the method of movement from the immediately previous position. A It can also be binary data, etc.

[0071] For example, when the main processor 111 and the post-processor 112 of the CAM device 11 generate the machine coordinate information, the first machining instruction P A When the post-processor 112 and the CNC device 12 generate the machine coordinate information, the first machining instruction P A After the G code file is input to the CNC device 12, when the machine coordinate information is generated during the motion transformation in the CNC device 12, the first machining instruction P A The data is in a binary format and is stored in the CNC device 12.

[0072] Mechanical structure information is information used to perform coordinate transformation between a coordinate system based on a workpiece and a coordinate system based on a machine tool. When used to generate machine coordinate information, mechanical structure information is information required to transform (kinematic transformation) the tool position and posture described in the workpiece coordinate system into the coordinates of each axis of the machine. Mechanical structure information is also used when performing the inverse kinematic transformation described later.

[0073] The mechanical structure information includes, for example, the following information.

[0074] (1) Information on the type of mechanical structure

[0075] Information on the type of mechanical structure includes, for example, information indicating whether the machine tool is a four-axis machining center or a five-axis machining center, information indicating whether the axis structure is a worktable rotation type, a spindle rotation type, or a combination of the worktable rotation type and the spindle rotation type, and information indicating whether the direction of the rotation axis of the worktable rotation type is an AC axis structure or a BC axis structure.

[0076] Figure 4 The diagram shows the structures of a table rotary type, a spindle rotary type, and a hybrid type, as well as the AC axis structure and the BC axis structure of the table rotary type.

[0077] (2) Information on the position of the rotation axis center and the workpiece coordinate system

[0078] Figure 5 This is a diagram for explaining information on the positions of the rotation axis center and the workpiece coordinate system.

[0079] Figure 5 Represents the A-axis rotation center and the workpiece coordinate system origin, indicating that the difference between the A-axis rotation center and the workpiece coordinate system origin is dx in the X direction and dZ in the Z direction.

[0080] (Tool Posture Correction Department)

[0081] The tool posture correction unit 22 generates the first machine coordinate information M generated by the machining command analysis unit 21. A To correct the tool posture, generate the second machine coordinate information M B An example of a method of correcting the tool posture is shown below.

[0082] (A) Processing with a ball end mill

[0083] In the ball end mill, since the front end is spherical, Figure 6 As shown in the figure, even if the center position of the ball head of the ball end mill is fixed and the tool posture is changed within a certain range, the shape obtained after processing will not change. Therefore, in the correction of the tool posture, the position of the ball head center observed in the workpiece coordinate system is not changed, but only the tool posture is changed. Figure 6 In the tool, when the posture is changed by 90 degrees or more, the cylindrical portion of the tool contacts the workpiece and the shape after processing changes. However, this can be avoided by setting an upper limit on the change amount of the tool posture.

[0084] (B) In the first machine coordinate information M A The case where the tool posture should not be corrected and the period in which it can be corrected are included

[0085] The first machine coordinate information M ASometimes, the tool posture should not be corrected for movement including positioning movement of rapid feed. Therefore, the tool posture correction unit 22 uses the first machine coordinate information M A A correction interval that can correct the tool posture is extracted. As an example of a correction interval, there is a cutting feed interval composed of continuous broken line segments. There may be multiple correction intervals.

[0086] Figure 7 It is a characteristic diagram showing an example of the first machine coordinate information.

[0087] like Figure 7 As shown, the first machine coordinate information M A There are four rapid feed positioning periods and three correction periods for the X-axis, Y-axis, Z-axis, A-axis, and C-axis. The four rapid feed positioning periods are periods during which the tool posture should not be corrected, and the three correction periods are periods during which correction can be made.

[0088] The tool posture correction unit 22 is for Figure 7 In each correction section shown, the tool posture is corrected by the following method.

[0089] First, the tool posture correction unit 22 calculates the evaluation value E1 of the tool path before correction for the extracted correction section by a calculation method described later.

[0090] Next, the coordinate values ​​of the rotation axis of each command point in the correction interval are changed. Here, if a limit is set on the amount of change in posture, the coordinates of the changed rotation angle are determined in such a way that the posture change does not exceed the limit. For example, Figure 8 In the case where the mechanical coordinate of the A-axis at time t1 is set to not exceed A1, the coordinate of the changed rotation axis is determined so that the coordinate of the A-axis at time t1 does not exceed A1. When the coordinate of the rotation axis is determined, the coordinate value of the direct-acting axis is determined based on the condition that the center coordinate of the ball head in the workpiece coordinate system does not change.

[0091] It is preferred that the tool posture is not changed at the first and last command points of the correction interval, so that the tool posture does not change sharply at the boundary of the previous and next intervals. In addition, the speed of each axis can be set not to change at the first and last points of the correction interval to prevent sharp speed changes at the boundary of the interval.

[0092] The tool posture correction unit 22 calculates the evaluation value E2 for the tool path after the tool posture is changed, and adopts the evaluation value E2 as the corrected machine coordinate information if the evaluation value is better than the evaluation value E1.

[0093] It is not necessary to calculate the corrected machine coordinate information by a single change. For example, a correction amount is added to the rotation axis coordinates to change the tool path. If the evaluation of the changed tool path is better than that before the change, it is adopted. If the evaluation after the change is poor, the change is abandoned and a correction amount different from the last time is added to change the tool path. It is also possible to repeatedly add a correction amount to the tool path to be adopted next to change the tool path, and find the tool path with the best index value through repeated searches.

[0094] The tool path correction process is a multivariable optimization problem in which the coordinates of the rotation axis of each command point are used as variables to find the value of the variable with the best evaluation value. Therefore, a method commonly used in multivariable optimization problems can be used to find the tool posture with the best evaluation value. Examples of this method include the steepest descent method and the Nelder-Mead method.

[0095] (Calculation example of evaluation value)

[0096] The evaluation value can use at least one of the movement amount of the drive shaft, the acceleration of the drive shaft, the consumed energy, and the machining time. Hereinafter, an example of calculating the evaluation value will be described.

[0097] (1) When the evaluation value is the total movement amount of the axis

[0098] The tool posture correction unit 22 can use the sum of the axis movement amounts as the evaluation value of the tool path. If the total movement amount is small, it can be expected that the time and energy required for movement will be reduced, so the tool posture correction unit 22 determines that the smaller the evaluation value, the better the tool path.

[0099] The calculation formula of the total movement amount is expressed as Mathematical Formula 1 (hereinafter referred to as Formula 1).

[0100] [Formula 1]

[0101]

[0102] In mathematical formula 1, axis represents the driving axis of the machine tool (for example, the linear axes X, Y, Z and the rotation axes A, C), ΔLaxis(pi) represents the change in axis from the first instruction point to the (i+1)th instruction point, and Waxis represents the weighted coefficient.

[0103] For an axis with a large inertia or an axis with a low maximum acceleration setting, set the coefficient Waxis to a large value.

[0104] Fig. 9 It is a characteristic diagram showing ΔLaxis(pi). Fig. 9 ΔL A (pi) represents ΔLaxis(pi).

[0105] (2) When the evaluation value is total acceleration

[0106] The tool posture correction unit 22 can use the sum of the accelerations of the axes as an evaluation value of the tool path. If the acceleration is small, it can be expected that the time or energy required for acceleration and deceleration will be small, so the tool posture correction unit 22 determines that the smaller the evaluation value is, the better the tool path is. The calculation formula of the total acceleration is shown in Mathematical Formula 2 (hereinafter Formula 2).

[0107] [Formula 2]

[0108]

[0109] In Mathematical Formula 2, Accaxis(pi) represents the acceleration of the i-th axis, and Waxis represents a weighting coefficient. The weighting coefficient Waxis is set large for an axis with large inertia or an axis with a low maximum acceleration setting.

[0110] (3) When the evaluation value is the total energy consumption

[0111] The tool posture correction unit 22 predicts the energy consumption of the machine by simulation and uses it as an evaluation value, and determines that the smaller the predicted energy consumption is, the better the tool path is. The existing technology can be used to predict the energy consumption of the machine. For example, the technology described in Japanese Patent No. 4571225, Japanese Patent No. 4805329, etc. can be used.

[0112] (4) When the evaluation value is processing time

[0113] The tool posture correction unit 22 can use the machining time as an evaluation value. Regarding the evaluation value of the machining time, a method of predicting the machining time from an NC program is a conventional technique (for example, Japanese Patent No. 06871207). B By performing inverse kinematic transformation, a machining command such as an NC command describing the position and posture of the tool in the workpiece coordinate system is obtained, so that machining time prediction can be performed. The tool posture correction unit 22 determines that the shorter the predicted machining time, the better the tool path.

[0114] Using the first machine coordinate information M A Although the example in which the period in which the tool posture should not be corrected and the period in which the tool posture can be corrected are included has been described, the invention can also be applied to a case in which the period in which the tool posture should not be corrected is not included.

[0115] (Interference Calculation Department)

[0116] The interference calculation unit 23 calculates the second machine coordinate information M B, mechanical structure information, tool shape information and workpiece shape information, and calculate the interference between the tool and the workpiece.

[0117] First, the interference calculation unit 23 calculates the mechanical coordinate information M according to the mechanical structure information. B The inverse kinematic transformation is performed on each point, thereby calculating the position and posture of the tool described in the workpiece coordinate system.

[0118] Then, the interference calculation unit 23 performs coordinate transformation on the tool shape information to obtain the calculated tool position and tool posture, and calculates the interference between the tool shape after coordinate transformation and the workpiece shape. Calculation of interference between shape data is a well-known technique widely used in CAM devices and the like.

[0119] The interference calculation unit 23 calculates the interference between the tool and the workpiece, and terminates the process when interference occurs, and outputs the corrected tool posture to the machining command generation unit 24 when no interference occurs.

[0120] The mechanical structure information is used for inverse kinematic transformation.

[0121] As an example of tool shape information, any of the following information is given. However, when interference detection is required, the tool shape includes not only the tip tool but also the shape up to the jig or the spindle.

[0122] The tool shape information includes, for example, CAD data of the tool shape, information on parameters such as each height of the tool and the radius at the height, and information capable of expressing the tool shape such as ISO standards (ISO13399, etc.).

[0123] Fig.10 : is a diagram showing an example of information on parameters of each height of a tool and the radius at that height. Fig.10 , h1 to h4 represent heights, and r1 to r4 represent radii at respective heights h1 to h4.

[0124] As workpiece shape information, CAD data of the shape of the workpiece after machining is considered. Fig.11 The CAD data serving as an example of workpiece shape information is shown.

[0125] (Processing instruction generation unit)

[0126] When the interference calculation unit 23 determines that there is no interference, the machining command generation unit 24 generates a machining command P with the tool posture corrected. B .

[0127] Generated processing instruction P B The form of may be different from the form of the input processing instruction, but it is reasonable to follow the form of the input processing instruction.

[0128] Below, refer to Fig.12 The operation (machining correction method) of the machining command correction device 20 will be described. Fig.12 This is a flowchart showing the operation of the processing instruction correction device.

[0129] In step S11, the processing command analyzing unit 21 generates a processing command based on the first processing command P which is the processing command before correction. A and mechanical structure information, generating first mechanical coordinate information M related to the mechanical coordinates of each control axis of the machine tool A .

[0130] In step S12, the tool posture correction unit 22 generates the first machine coordinate information M generated by the machining command analysis unit 21. A To correct the tool posture, generate the second machine coordinate information M B .

[0131] In step S13, the interference calculation unit 23 calculates the second machine coordinate information M B , mechanical structure information, tool shape information, workpiece shape information, and calculate the interference between the tool and the workpiece.

[0132] In step S14, the interference calculation unit 23 calculates the interference between the tool and the workpiece, and terminates the processing if there is interference, and sends a second machining instruction P for generating a corrected tool posture if there is no interference. B The processing instruction generating unit 24 outputs it and transfers to step S15.

[0133] In step S15, the machining command generating unit 24 generates a second machining command P having a corrected tool posture. B .

[0134] In the present embodiment described above, there is an effect that the tool path after the tool posture is changed does not deteriorate compared to the tool path before the tool posture is changed, and the tool posture can be optimized within a range where no interference occurs.

[0135] (First Modification)

[0136] In the above embodiment, when interference is detected in the corrected tool posture, the tool posture is not corrected. In this modification, when interference is detected in the corrected tool posture, the tool posture is corrected to the optimal one within a range where no interference occurs.

[0137] Fig.13 This is a block diagram showing the structure of a processing instruction correction device according to a first modified example of the first embodiment of the present disclosure.

[0138] Fig.13 The processing instruction correction device 20A shown in FIG. Figure 3The processing instruction correction device 20 shown in the figure has a constraint setting unit 25 and a correction completion determination unit 26 added thereto. The processing instruction correction device 20A is the same as the processing instruction correction device 20 except for the operations of the constraint setting unit 25 and the correction completion determination unit 26, and thus description thereof is omitted.

[0139] The interference calculation unit 23 calculates the interference between the tool and the workpiece, and when interference occurs, outputs the corrected tool posture to the constraint condition setting unit 25. When no interference occurs, the interference calculation unit 23 outputs the corrected tool posture to the correction completion determination unit 26, and the correction completion determination unit 26 outputs the corrected tool posture to the machining instruction generation unit 24.

[0140] There are three methods (1) to (3) below for correcting the tool posture to the optimum posture within a range where no interference occurs, using the constraint condition setting unit 25 and the correction completion determination unit 26.

[0141] (1) A method of gradually correcting the tool posture so that the evaluation value becomes better.

[0142] When interference occurs at a tool position on the tool path, the following processing (a) and (b) are performed.

[0143] (a) The constraint setting unit 25 sets restrictions (constraints) so that the tool posture at the tool position returns to the posture before the interference occurs and the tool posture at the tool position does not change further. Changes to the posture before correction do not cause interference and are therefore permitted.

[0144] The correction completion determination unit 26 notifies the tool posture correction unit 22 of the incompleteness including the constraint condition. The tool posture correction unit 22 attempts to correct the tool posture under the constraint condition, and continues the correction when the evaluation value becomes better.

[0145] (b) When it is determined that the correction has been repeated a predetermined number of times or the evaluation value does not become better than the evaluation value at the current time point even if the tool posture is changed, the correction completion determination unit 26 determines that the correction of the tool path is completed and outputs the corrected tool posture to the machining instruction generation unit 24. The determination that the evaluation value does not become better than the evaluation value at the current time point can be made by obtaining the evaluation value from the tool posture correction unit 22.

[0146] This method (1) is suitable when interference is frequent and the tool posture does not change too much.

[0147] (2) A method of calculating the optimal tool path without considering interference and returning to the part where the interference occurred.

[0148] First, a tool posture with the best evaluation value is calculated without considering interference. If interference is detected at the tool position on the optimal tool path, the following processes (a) and (b) are performed.

[0149] (a) The constraint setting unit 25 calculates a tool posture that is between the tool posture before correction and the optimal tool posture and does not interfere with the tool, and returns the tool posture to the posture. A restriction (constraint) is set so that the tool posture at the tool position does not change further. Changes close to the posture before correction may also be allowed.

[0150] The correction completion determination unit 26 notifies the tool posture correction unit 22 of the incompleteness including the constraint condition. The tool posture correction unit 22 attempts to correct the tool posture under the constraint condition, and continues the correction when the evaluation value becomes better.

[0151] (b) When a predetermined number of corrections have been repeated or no interference is detected in the tool path with the best evaluation value at the current time point, the correction completion determination unit 26 determines that the correction of the tool posture is completed and outputs the corrected tool posture to the processing instruction generation unit 24.

[0152] This method (2) is suitable when almost no interference occurs even when the posture of the tool is greatly changed.

[0153] (3) A combined method of the above method (1) and method (2).

[0154] As an example, first, the best tool posture is calculated in the same manner as in method (2), and when interference is detected, the tool posture at the tool position where the interference occurs is returned to a posture that does not cause interference. In addition, a restriction (constraint condition) is set so that the tool posture at that position does not change further. After that, in the same manner as in the above (1), there is a method of correcting the tool posture little by little so that the evaluation value becomes better.

[0155] In this case, the correction completion determination unit 26 determines that the correction of the tool path is completed when it is determined that the correction is repeated a predetermined number of times or the evaluation value does not become better than the evaluation value at the current time point even if the tool posture is changed.

[0156] In addition to the effects of the above-described embodiment, this modification has an effect of making it possible to improve the efficiency of optimization calculation by such a method when there are a mixture of sites with much interference and sites with little interference in the tool path.

[0157] (Second Modification)

[0158] In the first modification, when interference is detected in the tool posture obtained by the tool posture correction unit 22, the tool posture is changed so as not to cause interference. However, the evaluation value of the tool path may be worse in the changed tool posture than in the tool posture obtained by the tool posture correction unit.

[0159] In this modification, instead of changing the tool posture so as not to cause interference, the tool shape is changed so as not to cause interference in the tool posture obtained by the tool posture correction unit 22, thereby making it possible to use a tool posture that is evaluated to be good.

[0160] Fig.14 It is a block diagram showing the structure of a processing instruction correction device according to a second modified example of the first embodiment of the present disclosure.

[0161] Fig.14 The processing instruction correction device 20B shown in FIG. Fig.13 The machining instruction correction device 20A shown in the figure is provided with a tool shape generation unit 27 and an avoidance method selection unit 28. In the machining instruction correction device 20B, the same components as those of the machining instruction correction device 20A are denoted by the same reference numerals and their description is omitted.

[0162] In the second modification, the interference calculation unit 23 has a function of not only calculating the presence or absence of interference but also calculating the area interfering with the workpiece in terms of the tool shape.

[0163] Fig.15 This shows the area where the tool shape calculated by the interference calculation unit interferes with the workpiece.

[0164] The tool shape generating unit 27 generates new tool shape information in which at least the interference region is removed from the tool shape, and outputs the new tool shape information to the avoiding method selecting unit 28 .

[0165] The avoidance method selection unit 28 selects whether to avoid interference by changing the tool path or by changing the tool to a new tool shape.

[0166] When the avoidance method selection unit 28 selects to avoid interference by changing the tool shape, the tool shape information output by the interference calculation unit 23 is changed to the new tool shape information generated by the tool shape generation unit 27, and the optimization process is continued. When the avoidance method selection unit 28 selects to avoid interference by changing the tool path, the operation using the constraint condition setting unit 25 and the correction completion determination unit 26 is performed in the same manner as in the first modified example.

[0167] Furthermore, the tool shape generation unit 27 may be provided after the avoidance method selection unit 28 , and when the avoidance method selection unit 28 selects to avoid interference by changing the tool shape, the tool shape generation unit 27 may generate new tool shape information.

[0168] As a method for generating a new tool shape, there is a method of generating a tool shape with a larger protrusion amount of the tool based on the input tool shape information, or a method of generating a new tool shape by replacing a jig portion of the tool shape information with a jig shape having a smaller diameter.

[0169] Fig.16 (A) shows an example in which the protrusion amount of the tool is increased to generate new tool shape information. Fig.16 (B) shows an example in which the jig portion of the tool shape information is replaced with a jig shape having a smaller diameter to generate new tool shape information.

[0170] The selection in the avoidance method selection unit 28 may be made by an operator to instruct the avoidance method selection unit 28, or may be made automatically by the avoidance method selection unit 28. In the case of automatic selection, the avoidance method selection unit 28 automatically determines whether the new tool shape is appropriate as the tool shape, and selects interference avoidance by changing the tool shape if it is appropriate.

[0171] Fig.17 The figure shows a state where the interference area disappears and the interference disappears by replacing the jig portion of the tool shape information with a jig shape having a smaller diameter.

[0172] It is also possible to determine whether the new tool shape information is appropriate as a tool shape. There are methods of determining based on the tool diameter and protrusion length, or determining by calculating the rigidity using FEM or the like.

[0173] In this modification, in addition to the effects of the first modification described above, by changing the tool shape, it is possible to use a tool posture that is evaluated well.

[0174] (Third Modification)

[0175] In the above-described embodiment, first modification, and second modification, CAD data of the shape of the workpiece after machining is input as workpiece shape information. However, the CAD data may not be available.

[0176] For example, even if CAD data of the final shape of the product exists, CAD data of the intermediate shape of rough machining is usually not generated. Therefore, in order to correct the machining program other than the final finishing by the proposed method, it is required to generate CAD data of the intermediate shape of machining for interference detection.

[0177] As a method of generating such CAD data, machining simulation can be used. In this modification, machining simulation is performed and the obtained shape is used as CAD data.

[0178] Fig.18It is a block diagram showing the structure of a processing instruction correction device according to a third modified example of the first embodiment of the present disclosure.

[0179] Fig.18 The processing instruction correction device 20C shown in FIG. Fig.13 The processing instruction correction device 20A shown in the figure is provided with a processing simulation unit 29. In the processing instruction correction device 20C, the same components as those of the processing instruction correction device 20A are denoted by the same reference numerals, and the description thereof will be omitted.

[0180] In the third modification, the machining simulation unit 29 performs machining simulation using the machining command PA before correction and the tool shape information, and outputs CAD data of the obtained shape to the interference calculation unit 23 as workpiece shape information.

[0181] In addition, this modification is not limited to the processing instruction correction device 20A of the first modification, and can be applied to the processing instruction correction device 20 of this embodiment and the processing instruction correction device 20B of the second modification.

[0182] In addition to the effects of the first modification described above, this modification has an effect of being able to correct the tool posture even when the CAD data after processing cannot be obtained.

[0183] (Second Embodiment)

[0184] In the first embodiment and the first to third modified examples, the interference calculation unit 23 calculates the interference in a certain specific tool posture corrected by the tool posture correction unit 22 .

[0185] In the present embodiment, the interference calculation unit calculates a range of the tool posture in which no interference occurs, and the tool posture correction unit corrects the tool posture within the calculated range.

[0186] Fig.19 It is a block diagram showing the structure of a processing instruction correction device according to a second embodiment of the present disclosure.

[0187] Fig.19 The processing instruction correction device 30 shown in FIG. Figure 3 The tool posture correction unit 22 and the interference calculation unit 23 of the machining command correction device 20 are replaced by a tool posture correction unit 31 and an interference calculation unit 32. In the machining command correction device 30, the same components as those of the machining command correction device 20 are denoted by the same reference numerals and their description is omitted.

[0188] The interference calculation unit 32 calculates the mechanical coordinate information M A , mechanical structure information, tool shape and workpiece shape, perform interference check, and calculate at each tool position the range where interference will not occur even if the tool posture is changed from the tool posture before correction. Fig. 20 Indicates the range within which tool posture can be changed without causing interference.

[0189] The tool posture correction unit 31 corrects the tool posture by changing the tool posture only within the calculated range where no interference occurs, and outputs the corrected tool posture to the machining command generation unit 24 .

[0190] Furthermore, in the present embodiment, the machining simulation unit 29 of the machining instruction correction device 20C of the third modified example may be added to perform machining simulation and output CAD data of the obtained shape to the interference calculation unit 32 as workpiece shape information.

[0191] In this embodiment, in addition to the effects of the first embodiment described above, the tool posture correction unit only needs to correct the tool posture within a range where no interference occurs, which has an effect of being able to reduce the amount of calculation.

[0192] To realize the components included in the processing instruction correction device in each embodiment and each modified example, the processing instruction correction device can be realized by hardware, software or a combination thereof. Here, realization by software means realization by reading and executing a program by a computer.

[0193] In order to realize the structural parts included in the processing instruction correction device in each embodiment and each modified example by software or a combination thereof, the processing instruction correction device specifically includes a CPU (Central Processing Unit) and other computing devices. The computing device functions as an execution unit. In addition, the processing instruction correction device also includes an auxiliary storage device such as a HDD (Hard Disk Drive) storing various control programs such as application software or OS (Operating System), and a main storage device such as a RAM (Random Access Memory) for storing data temporarily required when the computing device executes the program. The main storage device includes at least one of a storage area and a synchronous storage area.

[0194] Then, in the processing instruction correction device, the operation processing device reads the application software or OS from the auxiliary storage device, expands the read application software or OS in the main storage device, and performs operation processing based on the application software or OS. In addition, various hardwares equipped in the processing instruction correction device are controlled based on the operation results. In this way, the structural parts of each embodiment and each modified example are realized.

[0195] Each component included in the processing instruction correction device can be realized by hardware including an electronic circuit, etc. In the case where the processing instruction correction device is composed of hardware, for example, a part or all of the functions of each component included in the processing instruction correction device can be composed of an integrated circuit (IC) such as an ASIC (Application Specific Integrated Circuit), a gate array, an FPGA (Field Programmable Gate Array), or a CPLD (Complex Programmable Logic Device).

[0196] The program can be stored using various types of non-transitory computer readable media (non-transitorycomputer readable medium) and provided to the computer. Non-transitory computer readable media include various types of tangible recording media (tangible storage medium). Examples of non-transitory computer readable media include magnetic recording media (e.g., hard disk drives), optical magnetic recording media (e.g., optical magnetic disks), CD-ROMs (read only memory), CD-Rs, CD-R / Ws, and semiconductor memories (e.g., mask ROMs, PROMs (programmable ROMs), EPROMs (erasable PROMs), flash ROMs, and RAMs (random access memory)). In addition, the program can also be provided to the computer via various types of transitory computer readable media (transitory computerreadable medium).

[0197] Regarding at least one effect of at least one embodiment and modification described above, the tool path after the tool posture change does not deteriorate compared to the tool path before the tool posture change, and the tool posture can be optimized within a range where no interference occurs.

[0198] The present disclosure is described above, but the present disclosure is not limited to the above-mentioned embodiments and modifications. These embodiments and modifications can be variously added, replaced, changed, partially deleted, etc. without departing from the scope of the main purpose of the present disclosure, or without departing from the scope of the main purpose of the present disclosure derived from the contents recorded in the patent protection scope and its equivalents.

[0199] In addition, these embodiments and modified examples can also be implemented in combination. For example, in the above-mentioned embodiments and modified examples, the order of each operation and the order of each process are shown as an example, and are not limited to this.

[0200] The following supplementary notes are also disclosed with respect to each of the above-mentioned embodiments and modifications.

[0201] (Note 1)

[0202] The processing instruction correction device (20, 20A, 20B, 20C) comprises:

[0203] A machining instruction analysis unit (21) generates first mechanical coordinate information, which is a time series change of coordinates of each axis of the machine tool, based on a first machining instruction that describes a time series change of a position and a posture of a tool and mechanical structure information for performing coordinate transformation between a coordinate system based on a workpiece and a coordinate system based on a machine tool;

[0204] a tool posture correction unit (22) which corrects the posture of the tool according to the first mechanical coordinate information to generate second mechanical coordinate information;

[0205] an interference calculation unit (23) for calculating the interference between the tool and the workpiece when the machine tool moves according to the second machine coordinate information, based on the second machine coordinate information, the machine structure information, the tool shape information related to the shape of the tool used in the processing of the first processing instruction, and the workpiece shape information related to the shape of the workpiece obtained when the first processing instruction is executed; and

[0206] A processing instruction generating unit (24) generates a second processing instruction based on the second machine coordinate information when there is no interference.

[0207] The tool posture correction unit determines a corrected posture of the tool using an evaluation value for evaluating the quality of a tool path.

[0208] (Note 2)

[0209] According to the machining instruction correction device of Supplementary Note 1, at least one of the movement amount of the drive axis, the acceleration of the drive axis, the consumed energy and the machining time when machining is performed using the tool according to the tool path is used as the evaluation value.

[0210] (Note 3)

[0211] The processing instruction correction device according to Supplementary Note 1 comprises:

[0212] a constraint setting unit (25) for setting a constraint related to a range of an allowable amount of change in the tool posture when interference is detected in the interference calculation unit; and

[0213] a correction completion determination unit (26) for determining whether the correction of the tool path under the constraint condition has been completed,

[0214] The tool posture correction unit corrects the first machine coordinate information within the range constrained by the constraint condition to generate the second machine coordinate information.

[0215] (Note 4)

[0216] According to the processing instruction correction device described in Supplement 3,

[0217] The interference calculation unit calculates an interference area where the tool having the shape of the tool shape information interferes with the workpiece.

[0218] The processing instruction correction device has:

[0219] an avoidance method selection unit (28) for selecting a method for avoiding the interference when interference is detected in the interference calculation unit; and

[0220] a tool shape generating unit (27) which generates new tool shape information from which the interference area is removed when interference is detected in the interference calculating unit;

[0221] The avoidance method selection unit has at least two methods for avoiding interference between the tool having the shape of the tool shape information and the workpiece, namely, changing a tool path and generating new tool shape information as options.

[0222] When the avoidance method selection unit selects generation of the new tool shape information, the tool posture correction unit generates the second machine coordinate information by correcting the posture of the tool using the tool having the new tool shape information based on the first machine coordinate information.

[0223] (Note 5)

[0224] The processing instruction correction device according to Supplementary Note 1 comprises:

[0225] A machining simulation unit (29) generates the workpiece shape information based on the first machining instruction and the tool shape information.

[0226] (Note 6)

[0227] A processing instruction correction device, comprising:

[0228] A machining instruction analysis unit (21) generates first mechanical coordinate information, which is a time series change of coordinates of each axis of the machine tool, based on a first machining instruction that describes a time series change of a position and a posture of a tool and mechanical structure information for performing coordinate transformation between a coordinate system based on a workpiece and a coordinate system based on a machine tool;

[0229] an interference calculation unit (32) for calculating interference between the tool and the workpiece when the machine tool moves according to the first machine coordinate information, based on the first machine coordinate information, the machine structure information, tool shape information related to the shape of the tool used in the processing of the first processing instruction, and workpiece shape information related to the shape of the workpiece obtained when the first processing instruction is executed;

[0230] a tool posture correction unit (31) which corrects the posture of the tool according to the first mechanical coordinate information to generate second mechanical coordinate information; and

[0231] A processing instruction generating unit (24) generates a second processing instruction based on the second machine coordinate information when there is no interference.

[0232] The interference calculation unit calculates a range of tool postures where no interference occurs.

[0233] The tool posture correction unit corrects the tool posture within the calculated range of the tool posture, and determines the posture of the tool after correction using an evaluation value for evaluating the quality of a tool path.

[0234] (Note 7)

[0235] A processing instruction correction method, a computer as a processing instruction correction device (20, 20A, 20B, 20C) performs the following processing:

[0236] Generate first mechanical coordinate information, which is a time-series change of coordinates of each axis of the machine tool, based on a first machining instruction describing a time-series change of a position and a posture of a tool and mechanical structure information for performing coordinate transformation between a coordinate system based on a workpiece and a coordinate system based on a machine tool;

[0237] Correcting the posture of the tool according to the first mechanical coordinate information to generate second mechanical coordinate information;

[0238] Calculate interference between the tool and the workpiece when the machine tool operates according to the second mechanical coordinate information based on the second mechanical coordinate information, the mechanical structure information, tool shape information related to the shape of the tool used in the processing of the first processing instruction, and workpiece shape information related to the shape of the workpiece obtained when the first processing instruction is executed; and

[0239] In the absence of the interference, a second machining instruction is generated based on the second machine coordinate information.

[0240] Description of Reference Numerals

[0241] 10 Data Generation System

[0242] 11CAM device

[0243] 12CNC device 12

[0244] 20, 20A, 20B, 20C, 30 processing instruction correction device

[0245] 21 Processing instruction analysis unit

[0246] 22, 31 tool posture correction department

[0247] 23, 32 Interference calculation unit

[0248] 24 Processing instruction generation unit

[0249] 25Constraint setting unit

[0250] 26 Correction completion judgment unit

[0251] 27 Tool shape generation unit

[0252] 28 Avoid method selection

[0253] 29Processing simulation department.

Claims

1. A processing instruction correction device, characterized in that: have: a machining instruction analysis unit for generating first mechanical coordinate information, which is a time-series change of coordinates of each axis of the machine tool, based on a first machining instruction describing a time-series change of a position and a posture of a tool and mechanical structure information for performing coordinate transformation between a coordinate system based on a workpiece and a coordinate system based on a machine tool; a tool posture correction unit, which corrects the posture of the tool according to the first mechanical coordinate information to generate second mechanical coordinate information; an interference calculation unit that calculates interference between the tool and the workpiece when the machine tool operates according to the second machine coordinate information, based on the second machine coordinate information, the machine structure information, tool shape information related to the shape of the tool used in the processing of the first processing instruction, and workpiece shape information related to the shape of the workpiece obtained when the first processing instruction is executed; as well as a processing instruction generating unit, which generates a second processing instruction based on the second machine coordinate information in the absence of the interference, The tool posture correction unit determines a corrected posture of the tool using an evaluation value for evaluating the quality of a tool path.

2. The processing instruction correction device according to claim 1, characterized in that: As the evaluation value, at least one of the movement amount of the drive axis, the acceleration of the drive axis, the consumed energy, and the machining time when machining is performed using the tool according to the tool path is selected.

3. The processing instruction correction device according to claim 1, characterized in that: The processing instruction correction device comprises: a constraint setting unit that sets a constraint related to a range of an allowable amount of change in a tool posture when interference is detected in the interference calculation unit; as well as a correction completion determination unit for determining whether correction of the tool path under the constraint condition has been completed, The tool posture correction unit corrects the first machine coordinate information within the range constrained by the constraint condition to generate the second machine coordinate information.

4. The processing instruction correction device according to claim 3, characterized in that: The interference calculation unit calculates an interference area where the tool having the shape of the tool shape information interferes with the workpiece. The processing instruction correction device comprises: an avoidance method selection unit that selects a method for avoiding the interference when interference is detected in the interference calculation unit; and a tool shape generating unit that generates new tool shape information from which the interference area is removed when interference is detected in the interference calculating unit; The avoidance method selection unit has at least two methods for avoiding interference between the tool having the shape of the tool shape information and the workpiece, namely, changing a tool path and generating new tool shape information as options. When the avoidance method selection unit selects generation of the new tool shape information, the tool posture correction unit generates the second machine coordinate information by correcting the posture of the tool using the tool having the new tool shape information based on the first machine coordinate information.

5. The processing instruction correction device according to claim 1, characterized in that: The machining instruction correction device includes a machining simulation unit that generates the workpiece shape information based on the first machining instruction and the tool shape information.

6. A processing instruction correction device, characterized in that: have: a machining instruction analysis unit for generating first mechanical coordinate information, which is a time-series change of coordinates of each axis of the machine tool, based on a first machining instruction describing a time-series change of a position and a posture of a tool and mechanical structure information for performing coordinate transformation between a coordinate system based on a workpiece and a coordinate system based on a machine tool; an interference calculation unit that calculates interference between the tool and the workpiece when the machine tool operates according to the first machine coordinate information, based on the first machine coordinate information, the machine structure information, tool shape information related to the shape of the tool used in the processing of the first processing instruction, and workpiece shape information related to the shape of the workpiece obtained when the first processing instruction is executed; a tool posture correction unit, which corrects the posture of the tool according to the first mechanical coordinate information to generate second mechanical coordinate information; as well as a processing instruction generating unit, which generates a second processing instruction based on the second machine coordinate information in the absence of the interference, The interference calculation unit calculates a range of tool postures where no interference occurs. The tool posture correction unit corrects the tool posture within the calculated range of the tool posture, and determines the posture of the tool after correction using an evaluation value for evaluating the quality of a tool path.

7. A processing instruction correction method, characterized in that: The computer as the processing instruction correction device performs the following processing: Generate first mechanical coordinate information, which is a time-series change of coordinates of each axis of the machine tool, based on a first machining instruction describing a time-series change of a position and a posture of a tool and mechanical structure information for performing coordinate transformation between a coordinate system based on a workpiece and a coordinate system based on a machine tool; Correcting the posture of the tool according to the first mechanical coordinate information to generate second mechanical coordinate information; Calculate interference between the tool and the workpiece when the machine tool moves according to the second mechanical coordinate information, based on the second mechanical coordinate information, the mechanical structure information, tool shape information related to the shape of the tool used in the processing of the first processing instruction, and workpiece shape information related to the shape of the workpiece obtained when the first processing instruction is executed; as well as In the absence of the interference, a second machining instruction is generated based on the second machine coordinate information.

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