Control device for machine tool

Abstract

The invention provides a technology capable of obtaining a desired surface roughness with high precision, improving readability of a machining program, and reducing the workload of manufacturing the machining program even if a cutting tool is replaced or the shape of a cutting edge of the cutting tool changes after start of machining. A control device (1) for a machine tool that performs machining while moving a cutting tool (T) relative to a workpiece (W), the control device (1) comprising: a surface roughness acquisition unit (11) that acquires, from a machining program, a target surface roughness set for the workpiece (W) to be machined; a tool surface roughness information acquisition unit (12) that acquires tool surface roughness information associated with the surface roughness of the cutting tool (T); and a feed amount control unit (14) that determines feed amount information relating to the feed amount per rotation of the cutting tool (T) and the workpiece (W) on the basis of the tool surface roughness information such that the surface roughness of the workpiece (W) becomes a target surface roughness.

Description

Technical Field

[0001] The present disclosure relates to a control device for a machine tool. Background Art

[0002] Conventionally, there is known a technique in which a spindle feed amount for moving a workpiece to be machined is specified in advance in a machining program or the like, and the cutting machining is performed (for example, refer to Patent Documents 1 and 2).

[0003] Prior art literature

[0004] Patent Literature

[0005] Patent Document 1: Japanese Patent Application Publication No. 2003-323204

[0006] Patent Document 2: Japanese Patent Application Publication No. 2018-094690 Summary of the invention

[0007] Problems to be solved by the invention

[0008] One of the indicators of the workpiece after processing is the surface roughness. The surface roughness is determined by the cutting tool's tip shape and feed rate. Therefore, the spindle feed rate per unit time is determined so that the workpiece after processing can obtain the desired surface roughness.

[0009] However, if the cutting tool is changed during cutting, or the cutting tool tip shape changes due to wear, cutting will continue at the original feed rate regardless of whether the feed rate needs to be changed. If the feed rate is not appropriate for the conditions, the desired surface roughness may not be obtained.

[0010] In addition, in the method of setting the feed rate reflecting the surface roughness in the machining program, it is difficult to grasp the surface roughness as one of the indicators from the machining program, and there is room for improvement in the conventional technology in terms of improving readability.

[0011] In addition, in the method of setting the feed rate reflecting the surface roughness in the machining program, it is necessary to calculate the feed rate so that the workpiece after machining can obtain the desired surface roughness and reflect it in the machining program, so these operations require a lot of labor.

[0012] The present disclosure is completed in view of the above-mentioned problems, and its purpose is to provide a technology that can obtain the desired surface roughness with high precision even if the cutting tool is changed or the cutting tool tip shape changes after the start of processing, and can improve the readability of the processing program and reduce the workload of making the processing program.

[0013] Means for solving problems

[0014] The present invention discloses a control device for a machine tool, which performs machining while moving a cutting tool and a workpiece relative to each other, wherein the control device comprises: a surface roughness acquisition unit, which acquires a target surface roughness set for the workpiece as a machining object from a machining program; a tool surface roughness information acquisition unit, which acquires tool surface roughness information associated with the surface roughness of the cutting tool; and a feed rate control unit, which determines feed rate information associated with the feed rate per relative rotation of the cutting tool and the workpiece based on the tool surface roughness information, so that the surface roughness of the workpiece becomes the target surface roughness.

[0015] Effects of the Invention

[0016] According to the present disclosure, a technology can be provided that can obtain the desired surface roughness with high accuracy even if the cutting tool is changed or the cutting edge shape of the cutting tool is changed after the start of processing, improve the readability of the processing program, and reduce the workload of creating the processing program. BRIEF DESCRIPTION OF THE DRAWINGS

[0017] Figure 1 This is a functional block diagram of the control device for the machine tool according to the first embodiment.

[0018] Figure 2 It is a schematic diagram showing an example of cutting processing in which a target surface roughness is set.

[0019] Figure 3 This is a diagram showing an example of a machining program.

[0020] Figure 4 It is a diagram showing an example of a tool surface roughness information table.

[0021] Figure 5 This is a functional block diagram of a control device for a machine tool according to a second embodiment.

[0022] Figure 6 This is a diagram for explaining swing cutting.

[0023] Figure 7 This is a functional block diagram of a control device for a machine tool according to a third embodiment.

[0024] Figure 8 This is a functional block diagram of a control device for a machine tool according to a fourth embodiment.

[0025] Fig. 9 This is a functional block diagram of a control device for a machine tool according to a fifth embodiment.

[0026] Fig.10 This is a functional block diagram of a control device for a machine tool according to a sixth embodiment. DETAILED DESCRIPTION

[0027] Hereinafter, embodiments of the present disclosure will be described in detail with reference to the drawings. In the description of the second embodiment and thereafter, the same reference numerals are given to the same configurations as those of the first embodiment, and the description thereof is omitted as appropriate.

[0028] [First embodiment]

[0029] Figure 1 1 is a functional block diagram of a control device 1 of a machine tool according to a first embodiment. The control device 1 of the first embodiment controls a machine tool that performs machining while moving a cutting tool T relative to a workpiece. The control device 1 performs cutting machining on a workpiece using a tool by operating at least one spindle and at least one feed axis, wherein the at least one spindle is used to rotate the cutting tool T relative to the workpiece, and the at least one feed axis is used to move the cutting tool T relative to the workpiece.

[0030] In addition, Figure 1 For convenience, only the motor 3 driving one feed axis and the cutting tool T are shown. In addition, in the cutting process of this embodiment, the shape of the workpiece is not limited. That is, even if the workpiece has a tapered portion or an arc-shaped portion on the processing surface and requires multiple feed axes (Z axis and X axis), even if the workpiece is cylindrical or cylindrical and the feed axis is a specific axis (Z axis), the present invention can be applied.

[0031] like Figure 1 As shown, the control device 1 of the machine tool of the first embodiment includes: a first storage unit 10, a surface roughness acquisition unit 11, a second storage unit 20, a tool surface roughness information acquisition unit 12, and a feed amount control unit 14. The control device 1 of the machine tool is composed of, for example, a computer having a memory such as a ROM (read only memory) and a RAM (random access memory) connected to each other via a bus, a CPU (control processing unit), and a communication control unit. The functions and actions of the above-mentioned functional units are achieved by the cooperation of the CPU, the memory, and the control program stored in the memory mounted on the above-mentioned computer.

[0032] The machine tool control device 1 may be composed of a CNC (Computer Numerical Controller), or may be connected to a host computer (not shown) such as a CNC or a PLC (Programmable Logic Controller). In addition to the machining program, machining conditions such as rotation speed are input from the host computer to the machine tool control device 1.

[0033] The first storage unit 10 stores a machining program for the machine tool to execute. The machining program includes workpiece machining conditions, etc. The workpiece machining conditions include: the relative rotation speed of the workpiece and the cutting tool T around the central axis of the workpiece, the relative feed speed of the cutting tool T and the workpiece, the position instruction of the feed axis, the target surface roughness, etc.

[0034] The target surface roughness is the value of the desired surface roughness set for the workpiece to be processed. As surface roughness, for example, at least one of the following is included: arithmetic mean roughness, maximum height of the maximum distance between peaks and valleys, maximum peak height of the maximum height of the surface from the average line, maximum valley depth of the absolute value of the minimum height of the surface from the average line, average height of the height of adjacent peaks and valleys as a group of contour curve elements, maximum cross-sectional height of the sum of the maximum height of the peaks and the maximum depth of the valleys of the above contour curve elements, and load length ratio of the ratio of the load length of the above contour curve elements at a specified cutting level (height % or μm) to the evaluation reference length. As surface roughness indicators, representative indicators are listed, but they are not limited to these, and other surface roughness indicators can also be used.

[0035] The surface roughness acquisition unit 11 acquires a target surface roughness from the machining program. In the first embodiment, the surface roughness acquisition unit 11 acquires the target surface roughness set in the machining program via the first storage unit 10 and outputs the acquired target surface roughness to the feed rate control unit 14 .

[0036] The second storage unit 20 stores tool surface roughness information related to the surface roughness of the cutting tool T. As the tool surface roughness information related to the surface roughness of the cutting tool T, information (tool shape information) that determines the shape of the cutting tool T can be cited. The tool shape information is, for example, information indicating the diameter length of the tool tip of the cutting tool T, the tool tip (nose) R (mm), and the like. The second storage unit 20 acquires and stores information for determining the shape of the cutting tool T from the machining program.

[0037] The tool surface roughness information related to the surface roughness of the cutting tool T may be, for example, information (such as table data or a relational expression) indicating the relationship between the feed speed and the surface roughness obtained when machining is performed at the feed speed.

[0038] The tool surface roughness information related to the surface roughness of the cutting tool T may be the information itself related to the surface roughness of the cutting tool T, or may be indirect information such as a tool number for determining the tool shape information. In this case, the following method may be used: the numerical value of the cutter head R (mm) corresponding to each tool number as indirect information is stored in the second storage unit 20 in a table form, and the tool number in the machining program or the tool number of the connected cutting tool T is determined, thereby determining the cutting tool T in use.

[0039] In addition, the second storage unit 20 stores information indicating tool surface roughness information, which is obtained from the cutting tool T connected to the control device 1 and is related to the surface roughness of the current cutting tool T. By obtaining information indicating tool surface roughness information related to surface roughness from the cutting tool T, changes in tool surface roughness information related to the surface roughness of the cutting tool T after processing caused by replacement or wear of the cutting tool T are also reflected in the second storage unit 20. The information indicating tool surface roughness information related to the surface roughness of the current cutting tool T obtained from the cutting tool T may be information related to the surface roughness of the tool itself, or indirect information such as a tool number. To detect changes in tool surface roughness information related to the surface roughness of the cutting tool T, for example, information for determining tool surface roughness information related to the surface roughness of the cutting tool T may be included in an external signal indicating that a new cutting tool T has been replaced. In addition, to detect changes in tool surface roughness information related to the surface roughness of the cutting tool T, for example, detection may be performed by image processing of a camera, or detection may be performed by measuring the tool tip shape by a contact or non-contact sensor.

[0040] The tool surface roughness information acquisition unit 12 acquires the tool surface roughness information of the cutting tool T from the second storage unit 20. The tool surface roughness information acquisition unit 12 may acquire the tool surface roughness information stored in the second storage unit 20, or may determine the tool surface roughness information based on the information for determining the cutting tool T stored in the second storage unit 20. The tool surface roughness information acquisition unit 12 outputs the acquired tool surface roughness information to the feed rate control unit 14.

[0041] The feed rate control unit 14 determines feed rate information related to the feed rate per relative rotation of the cutting tool T and the workpiece, and controls the driving of the motor 3. The feed rate control unit 14 calculates the feed rate information based on the target surface roughness input from the surface roughness acquisition unit 11 and the tool surface roughness information input from the tool surface roughness information acquisition unit 12.

[0042] The feed amount information is information related to the feed amount per rotation of the cutting tool T and the workpiece. The information related to the feed amount is, for example, the feed amount F (mm / rev) per rotation of the spindle. In addition, the information related to the feed amount may also be the spindle speed (rev / min) and the feed amount (mm / min). Therefore, the feed amount control unit 14 can control both the feed shaft motor and the spindle motor.

[0043] The input unit 15 inputs processing-related information according to the operator's input operation on an input unit (not shown) such as a keyboard or a touch panel. The processing-related information input through the input unit 15 is stored in the first storage unit 10 or the like, or input to each unit of the control device 1.

[0044] The display unit 16 displays various information related to the machine tool, the control device 1 , and processing.

[0045] Next, an example of the control process of the control device 1 according to the first embodiment will be described. Figure 2 is a schematic diagram showing an example of a cutting process in which a target surface roughness is set. Figure 2 In the example shown in FIG. 1 , "Rz: 3.0" is preset in the machining program as the target roughness.

[0046] Figure 3 This is a diagram showing an example of a machining program. Figure 3 The "S2000 M03" program block in the machining program is a statement indicating that the spindle is rotated forward. The "T05" program block is a statement indicating the tool number, which is information used to determine the surface roughness information of the tool. The program blocks starting from "G00" or "G01", such as "G00 Z40.0 X20.0", are statements indicating actions or coordinates such as positioning or linear interpolation. Among them, the "Rz3.0" in the "G01 Z20.0Rz3.0" program block is a statement indicating the target surface roughness. When the operation based on the machining program starts, the surface roughness acquisition unit 11 of the control device 1 starts to analyze the "G01 Z20.0Rz3.0" program block and obtains the target surface roughness Rz as 3.0.

[0047] Figure 4 FIG. 2 is a diagram showing an example of a table of tool surface roughness information. Figure 4 In the example of FIG. 1 , the second storage unit 20 stores at least the tool numbers T01 to T06 and the information of the tool heads R corresponding to the tool numbers T01 to T06 in a table format. The tool surface roughness information acquisition unit 12 obtains the tool surface roughness information based on the tool numbers and the tool heads R respectively described in the machining program. Figure 4 In this example, the tool head R0.4 (mm) corresponding to the tool number "T05" included in the machining program is acquired as the tool surface roughness information.

[0048] The tool surface roughness information acquisition unit 12 may acquire the tool surface roughness information by referring to the tool number and table stored in the second storage unit 20 , or may acquire the tool surface roughness information predetermined based on the tool number and table from the second storage unit 20 .

[0049] The feed rate control unit 14 determines the feed rate based on the target surface roughness obtained by the surface roughness acquisition unit 11 and the tool surface roughness information obtained by the tool surface roughness information acquisition unit 12. The feed rate control unit 14 calculates the feed rate using the following formula when the maximum depth Rz is used as the target surface roughness index. In this example, if the target surface roughness h=3.0 and the tool head R=0.4 are substituted into the following formula, the feed rate F≈0.098 (mm / rev).

[0050] [Mathematical formula 1]

[0051]

[0052] In the mathematical formula (1), h represents the target surface roughness Rz (μm), f represents the feed rate per spindle rotation (mm / rev), and RE represents the 7-point R (mm) used to represent the cutting edge shape of the cutting tool T.

[0053] The feed amount control unit 14 controls the motor 3 by the feed amount based on the target surface roughness until the target surface roughness of the machining program is updated. When the target surface roughness of the machining program is updated, the feed amount is calculated according to the updated new target surface roughness, and the motor 3 is controlled based on the feed amount.

[0054] In addition, the tool surface roughness information acquisition unit 12 monitors the surface roughness state of the cutting tool T. For this purpose, for example, it monitors whether the cutting tool T has been replaced. When the replacement of the cutting tool T is detected, the tool surface roughness information acquisition unit 12 recalculates the feed amount information based on the surface roughness information of the replaced cutting tool T and the target surface roughness.

[0055] In addition, as another means for monitoring the surface roughness state of the cutting tool T, the blade shape of the cutting tool T is monitored. When a change in the blade shape of the cutting tool T is detected, the tool surface roughness information acquisition unit 12 recalculates the feed amount information based on the tool shape information indicating the blade shape of the cutting tool T after the change and the target surface roughness.

[0056] According to the control device 1 of the machine tool for performing machining while relatively moving the cutting tool T and the workpiece W according to the first embodiment, the following effects are achieved.

[0057] In the control device 1 of the machine tool of the present embodiment, there is a surface roughness acquisition unit 11, which acquires the target surface roughness set for the workpiece W as the processing object from the processing program; a tool surface roughness information acquisition unit 12, which acquires the tool surface roughness information associated with the surface roughness of the cutting tool T; and a feed rate control unit 14, which determines the feed rate information associated with the feed rate per relative rotation of the cutting tool T and the workpiece W according to the tool surface roughness information, so that the surface roughness of the workpiece W becomes the target surface roughness. Thus, the target surface roughness is set in the processing program, so the feed rate can be controlled according to the target surface roughness, the readability of the processing program can be improved, and the workload of making the processing program can be reduced. In addition, even if the cutting tool T changes after the start of processing, or the tool tip shape (for example, the tool head R) of the cutting tool T changes, the feed rate information can be recalculated according to the target surface roughness and the surface roughness information of the cutting tool T, so that the desired surface roughness can be obtained with high accuracy.

[0058] In addition, in the present embodiment, when the tool surface roughness information acquisition unit 12 detects a change in the tool surface roughness information of the cutting tool T, it acquires the changed tool surface roughness information, and the feed rate control unit 14 reflects the changed tool surface roughness information and determines the feed rate information again. Thus, the change in the cutting edge of the cutting tool T caused by the replacement or wear of the cutting tool T can be quickly reflected in the feed rate information.

[0059] In addition, in this embodiment, the surface roughness acquisition unit 11 continues to output the target surface roughness acquired from the machining program to the feed rate control unit 14 until the next target surface roughness is acquired from the machining program. Thus, the target surface roughness instruction becomes modal information, and machining programming becomes easy.

[0060] [Second embodiment]

[0061] Figure 5 1A is a functional block diagram of a control device 1A for a machine tool according to a second embodiment. The control device 1A for the second embodiment controls the machine tool to perform swing cutting while swinging the cutting tool T and the workpiece relative to each other. Figure 5 As shown, the control device 1A of the machine tool of the second embodiment is different from the control device 1 of the machine tool of the first embodiment in that it also has a third storage unit 30 and a swing condition acquisition unit 13, and the control of the feed amount control unit 14A is different. The other structures are common to the first embodiment.

[0062] Figure 6 This is a diagram for explaining swing cutting. Figure 6 In the example of swing cutting shown, at least one spindle S and at least one feed axis are operated so that the cutting tool T and the workpiece W rotate relative to each other, and the cutting tool T and the workpiece W are swung relative to each other in the feed direction while cutting. At least one spindle S is used to rotate the cutting tool T and the workpiece W relative to each other, and at least one feed axis is used to move the cutting tool T relative to the workpiece W. At this time, the trajectory of the cutting tool T, that is, the tool path, is set so that the current path partially overlaps with the previous path. That is, the part processed by the previous path is partially included in the current path, thereby generating an air-cutting swing in which the cutting tip of the cutting tool T leaves the surface of the workpiece W, thereby breaking the chips.

[0063] The third storage unit 30 stores the swing conditions for swing cutting processing. The swing conditions are obtained, for example, from the processing program. As the swing conditions, it includes: information related to the number of swings per rotation of the cutting tool and the workpiece W, and information related to the swing amplitude relative to the feed amount per rotation of the cutting tool and the workpiece W. As information related to the number of swings per rotation of the cutting tool and the workpiece W, the swing frequency multiplier I (times) representing the swing frequency per rotation of the spindle can be listed. In addition, as information related to the swing amplitude relative to the feed amount per rotation of the cutting tool and the workpiece W, the swing amplitude multiplier K (times) representing the swing amplitude size relative to the feed amount per rotation of the spindle can be cited. The swing frequency multiplier I (times) can be directly specified, or it can be calculated based on the swing frequency (Hz) and the spindle speed S (1 / min) after the swing frequency (Hz) is specified. In addition, the swing amplitude magnification K (times) can also be directly specified, or it can be calculated based on the swing amplitude (mm), feed speed (mm / min) and spindle speed S (1 / min) after the swing amplitude (mm) is specified.

[0064] The swing condition acquisition unit 13 acquires the swing condition and outputs it to the feed amount control unit 14A. The swing condition acquisition unit 13 acquires the swing condition from the third storage unit 30. In addition, the swing condition acquisition unit 13 may acquire the swing condition specified by an external signal, etc. The swing condition acquisition unit 13 outputs the acquired swing condition to the feed amount control unit 14A.

[0065] The feed rate control unit 14A of the second embodiment calculates feed rate information based on the target surface roughness input from the surface roughness acquisition unit 11, the tool surface roughness information input from the tool surface roughness information acquisition unit 12, and the swing condition input from the swing condition acquisition unit 13. The motor 3 is controlled based on the feed rate information calculated by the feed rate control unit 14A to perform swing cutting.

[0066] In addition, when the swing condition in the machining program is updated, the updated swing condition is stored in the third storage unit 30. The swing condition acquisition unit 13 monitors whether the swing condition has changed. The change in the swing condition is, for example, a case where the swing condition of the machining program is changed, a case where the swing condition is changed due to an external signal, etc. When a change in the swing condition is detected, the swing condition acquisition unit 13 recalculates the feed amount information based on the changed swing condition, the tool surface roughness information, and the target surface roughness.

[0067] According to the control device 1A for a machine tool according to the second embodiment, the following effects are achieved.

[0068] The control device 1A of the machine tool of the present embodiment also has: a surface roughness acquisition unit 11; a tool surface roughness information acquisition unit 12; a swing condition acquisition unit 13, which acquires the swing condition of swing cutting, wherein the swing cutting refers to making the cutting tool T and the workpiece W swing relative to each other, and a feed rate control unit 14A determines the feed rate information based on the tool surface roughness information and the swing condition so that the surface roughness of the workpiece W becomes the target surface roughness. Thus, in addition to the effect of the control device 1 of the first embodiment, even if the swing condition changes after the start of processing, the feed rate information can be recalculated based on the target surface roughness and the tool surface roughness information of the cutting edge of the cutting tool T and the changed swing condition, so that the desired surface roughness can be obtained with high precision in the swing cutting process. In addition, the workload for determining the feed speed taking into account the swing condition can be reduced.

[0069] In addition, when the swing condition acquisition unit 13 of the present embodiment detects a change in the swing condition, it acquires the changed swing condition, and the feed amount control unit 14A reflects the changed swing condition and determines the feed amount information again. Thus, the change in the swing condition after the start of machining can be quickly reflected in the feed amount information.

[0070] [Third Embodiment]

[0071] Figure 7 1B is a functional block diagram of a control device 1B for a machine tool according to a third embodiment. The control device 1B according to the third embodiment controls a machine tool that performs cutting while moving a cutting tool T and a workpiece relative to each other. Figure 7 As shown, the machine tool control device 1B of the third embodiment is different from the machine tool control device 1 of the first embodiment in that it further includes a designated feed amount acquisition unit 17 and controls a feed amount control unit 14B differently, and the other structures are the same as those of the first embodiment.

[0072] The designated feed amount acquisition unit 17 acquires designated feed amount information that specifies information related to the feed amount per one relative rotation of the cutting tool T and the workpiece W. The designated feed amount information is a pre-set numerical value, which is a numerical value in the same unit as the feed amount information. The designated feed amount information is set by recording it in the machining program or inputting it from the input unit 15.

[0073] The designated feed amount acquisition unit 17 acquires the designated feed amount when the designated feed amount information is recorded in the machining program in the first storage unit 10. When acquiring the designated feed amount information, the designated feed amount acquisition unit 17 outputs the designated feed amount information to the feed amount control unit 14B.

[0074] The feed amount control unit 14B of the third embodiment gives priority to the designated feed amount information rather than the feed amount information calculated based on the target surface roughness and the tool surface roughness information when acquiring the designated feed amount information from the designated feed amount acquisition unit 17. Therefore, the motor 3 is controlled based on the designated feed amount information.

[0075] According to the control device 1B for a machine tool according to the third embodiment, the following effects are achieved.

[0076] The control device 1B of the machine tool of the present embodiment, when acquiring designated feed rate information designating information related to the feed rate per one relative rotation of the cutting tool T and the workpiece W, controls the feed rate per one relative rotation of the cutting tool T and the workpiece W according to the designated feed rate information. Thus, even when there is a non-machining program block, or when the designated feed rate is more appropriate, it is possible to flexibly cope with the situation.

[0077] The designated feed amount acquisition unit 17 of the third embodiment may be added to the structure of the second embodiment for performing swing cutting. In this case, when the feed amount control unit 14B acquires designated feed amount information, it controls the motor 3 with priority given to the designated feed amount information.

[0078] [Fourth Embodiment]

[0079] Figure 8 1C is a functional block diagram of a machine tool control device according to a fourth embodiment. Figure 8 As shown, the machine tool control device 1C of the fourth embodiment is different from the machine tool control device 1 of the first embodiment in that it further includes a deviation correction value acquisition unit 18 and controls a feed amount control unit 14C differently, and the other structures are the same as the first embodiment.

[0080] The deviation correction value acquisition unit 18 acquires a deviation correction value for correcting the deviation between the theoretical value and the measured value of the surface roughness. The deviation correction value is calculated, for example, based on the processing conditions obtained from the first storage unit 10. The processing conditions are calculated based on processing conditions including at least one of the cutting edge material of the cutting tool, the cutting edge shape of the cutting tool, the material of the workpiece W, the cutting speed, the cutting thickness, and the cutting angle. In addition, the deviation correction value can be calculated based on mechanical parameters as needed. The deviation correction value acquisition unit 18 outputs the obtained deviation correction value to the feed amount control unit 14C.

[0081] The feed rate control unit 14C of the fourth embodiment calculates feed rate information based on the target surface roughness input from the surface roughness acquisition unit 11, the tool surface roughness information input from the tool surface roughness information acquisition unit 12, and the deviation correction value obtained from the deviation correction value acquisition unit 18. The motor 3 is controlled based on the feed rate information calculated by the feed rate control unit 14C to perform cutting processing.

[0082] In addition, the deviation correction value acquisition unit 18 may also utilize machine learning such as supervised learning. For example, it may be configured such that feed rate information associated with machining conditions and feed rate is used as input, a learning model is constructed by outputting a large number of data sets of actual surface roughness, and the deviation correction value is determined based on the output result of the learning model, i.e., the surface roughness.

[0083] According to the control device 1C for a machine tool according to the fourth embodiment, the following effects are achieved.

[0084] The control device 1C of the machine tool of the present embodiment further includes: a deviation correction value acquisition unit 18, which acquires a deviation correction value for correcting the deviation between the theoretical value of the surface roughness and the actual measured value of the surface roughness of the workpiece W, and the feed amount control unit 14C determines the feed amount information with reference to the deviation correction value. Thus, the feed amount information is determined with reference to the deviation between the theoretical value of the surface roughness and the actual value of the surface roughness, so that a higher precision machining can be performed to achieve a desired surface roughness.

[0085] In addition, the deviation correction value acquisition unit 18 of the fourth embodiment can also be added to the structure of the second embodiment for performing swing cutting. In this case, it is preferred that the deviation correction value acquisition unit 18 determines the feed amount information by referring to the swing condition in addition to the machining condition. In the case of combining machine learning, it is preferred to add the swing condition to the input of the data set.

[0086] [Fifth Embodiment]

[0087] Fig. 9 1D is a functional block diagram of a machine tool control device according to a fifth embodiment. Fig. 9As shown, the control device 1D of the machine tool of the fifth embodiment is different from the control device 1 of the machine tool of the first embodiment in that it also has a surface roughness correction value acquisition unit 21 and a surface roughness determination unit 22, and the control of the feed amount control unit 14D is different. The other structures are common to the first embodiment.

[0088] The surface roughness correction value acquisition unit 21 acquires a surface roughness correction value for correcting the target surface roughness. The surface roughness correction value acquisition unit 21 is, for example, a magnification (correction coefficient) specified by an operator operating an input unit such as a dial of the input unit 15 or operating an external computer. The operator can adjust the surface roughness by setting the target surface roughness as a reference of 100% and changing it to 90% or 110%.

[0089] The surface roughness determination unit 22 corrects the target surface roughness input from the surface roughness acquisition unit 11 using the surface roughness correction value input from the surface roughness correction value acquisition unit 21 , and outputs the corrected target surface roughness to the feed amount control unit 14 .

[0090] The feed rate control unit 14D of the fifth embodiment calculates feed rate information based on the corrected target surface roughness input from the surface roughness determination unit 22 and the tool surface roughness information input from the tool surface roughness information acquisition unit 12. The motor 3 is controlled based on the feed rate information calculated by the feed rate control unit 14D to perform cutting.

[0091] According to the control device 1D for a machine tool according to the fifth embodiment, the following effects are achieved.

[0092] The control device 1D of the machine tool of the present embodiment further comprises: a surface roughness correction value acquisition unit 21, which acquires a surface roughness correction value for correcting a target surface roughness; a surface roughness determination unit 22, which determines the surface roughness based on the target surface roughness acquired by the surface roughness acquisition unit 11 and the surface roughness correction value acquired by the surface roughness correction value acquisition unit 21, and a feed amount control unit 14D determines the feed amount information so as to achieve the surface roughness determined by the surface roughness determination unit 22. Thus, the operator can adjust the accuracy of the surface roughness after processing without changing the processing program.

[0093] The surface roughness correction value acquisition unit 21 and the surface roughness determination unit 22 of the fifth embodiment may be added to the configuration of other embodiments such as the second embodiment that performs swing cutting.

[0094] [Sixth Embodiment]

[0095] Fig.10 1E is a functional block diagram of a machine tool control device according to a sixth embodiment. Fig.10As shown, the machine tool control device 1E according to the sixth embodiment is different from the machine tool control device 1 according to the first embodiment in that it further includes an output processing unit 23 , and the other configurations are the same as those of the first embodiment.

[0096] The output processing unit 23 performs display processing for outputting the feed amount information determined by the feed amount control unit 14 to the display unit 16. The display unit 16 displays the feed amount information subjected to the display processing by the output processing unit 23 on the screen. The display unit 16 displays, for example, the feed amount F (mm / rev) per spindle rotation, the spindle speed (rev / min), and the feed amount (mm / min) on the screen as the feed amount information.

[0097] According to the control device 1E for a machine tool according to the sixth embodiment, the following effects are achieved.

[0098] The machine tool control device 1E of the present embodiment further includes an output processing unit 23 that outputs the feed amount information determined by the feed amount control unit 14 to the display unit 16. Thus, the operator can confirm the feed amount information displayed on the display screen of the display unit 16, and can easily confirm safety or production plans.

[0099] In addition, the output processing unit 23 of the sixth embodiment may be added to the configuration of other embodiments such as the second embodiment that performs swing cutting.

[0100] In addition, the present disclosure is not limited to the above-mentioned embodiments, and modifications and improvements within the scope that can achieve the purpose of the present disclosure are included in the present disclosure.

[0101] Explanation of symbols

[0102] 1. Control devices for 1A, 1B, 1C, 1D, 1E machine tools

[0103] 11Surface roughness acquisition unit

[0104] 12Tool surface roughness information acquisition unit

[0105] 13 Swing condition acquisition unit

[0106] 14, 14A, 14B, 14C, 14D Feeding amount control unit

[0107] 16 Display

[0108] 17 Specified feed amount acquisition unit

[0109] 18. Deviation correction value acquisition unit

[0110] 21 Surface roughness correction value acquisition unit

[0111] 22Surface roughness determination

[0112] 23 Output processing unit.

Claims

1. A control device for a machine tool that performs machining while moving a cutting tool and a workpiece relative to each other, characterized in that: The control device has: a surface roughness acquisition unit that acquires a target surface roughness set for the workpiece as a processing object from a processing program; a tool surface roughness information acquisition unit that acquires tool surface roughness information associated with the surface roughness of the cutting tool; as well as A feed amount control unit determines feed amount information associated with a feed amount per relative rotation of the cutting tool and the workpiece based on the tool surface roughness information so that the surface roughness of the workpiece reaches the target surface roughness.

2. The control device for a machine tool according to claim 1, characterized in that: The control device further includes: a swing condition acquisition unit that acquires a swing condition for swing cutting, wherein the swing cutting is to swing the cutting tool and the workpiece relative to each other. The feed amount control unit determines the feed amount information based on the tool surface roughness information and the swing condition so that the surface roughness of the workpiece reaches the target surface roughness.

3. The control device for a machine tool according to claim 2, characterized in that: When the swing condition acquisition unit detects a change in the swing condition, the swing condition acquisition unit acquires the changed swing condition. The feed amount control unit determines the feed amount information again by reflecting the changed swing condition.

4. The control device for a machine tool according to any one of claims 1 to 3, characterized in that: The tool surface roughness information acquisition unit acquires the changed tool surface roughness information when detecting a change in the tool surface roughness information of the cutting tool. The feed amount control unit re-determines the feed amount information by reflecting the changed tool surface roughness information.

5. The control device for a machine tool according to any one of claims 1 to 4, characterized in that: The surface roughness acquisition unit continues to output the target surface roughness acquired last from the machining program to the feed amount control unit until the next target surface roughness is acquired from the machining program.

6. The control device for a machine tool according to any one of claims 1 to 5, characterized in that: The feed amount control unit controls the feed amount per relative rotation of the cutting tool and the workpiece according to the designated feed amount information when acquiring designated feed amount information designating information related to the feed amount per relative rotation of the cutting tool and the workpiece.

7. The control device for a machine tool according to any one of claims 1 to 6, characterized in that: The control device further includes: a deviation correction value acquisition unit that acquires a deviation correction value for correcting a deviation between a theoretical value of surface roughness and an actual value of surface roughness of the workpiece; The feed amount control unit determines the feed amount information with reference to the deviation correction value.

8. The control device for a machine tool according to any one of claims 1 to 7, characterized in that: The control device also has: a surface roughness correction value acquisition unit that acquires a surface roughness correction value for correcting the target surface roughness; and a surface roughness determination unit that determines the surface roughness based on the target surface roughness obtained by the surface roughness acquisition unit and the surface roughness correction value obtained by the surface roughness correction value acquisition unit, The feed amount control unit determines the feed amount information so as to achieve the surface roughness determined by the surface roughness determination unit.

9. The control device for a machine tool according to any one of claims 1 to 8, characterized in that: The control device further includes an output processing unit that outputs the feed amount information determined by the feed amount control unit to a display unit.

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