Command generation device for machine tool

Abstract

The invention provides a technique capable of improving safety during operation switching and reducing heat generation and power consumption of a drive unit in a command generation device of a machine tool. A command generation device (1) for a machine tool is provided with: a rotational direction acquisition unit (11) that acquires the direction of rotational movement; a translation command generation unit (12) that generates a translation movement command per unit time; a symbol determination unit (13) that determines a symbol of a synchronization ratio for synchronization on the basis of the direction of the translational movement and the direction of the rotational movement acquired by the rotational direction acquisition unit (11); a synchronization ratio determination unit (14) that determines the absolute value of the synchronization ratio in accordance with whether the command for translation is a cutting command or a positioning command; and a rotation command generation unit (15) that generates a rotation movement command on the basis of the translation movement command, the symbol, and the absolute value, and that is capable of changing the synchronization ratio between the translation movement and the rotation movement by means of the cutting command and the positioning command.

Description

Technical Field

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

[0002] Conventionally, in machine tools, there is known a technique for moving a workpiece while synchronizing two axes, a translational axis and a rotational axis, to perform machining (for example, see Patent Documents 1 and 2).

[0003] Prior art literature

[0004] Patent Literature

[0005] Patent Document 1: Japanese Patent Application Laid-Open No. 2005-216135

[0006] Patent Document 2: Japanese Patent Application Laid-Open No. 2015-201968 Summary of the Invention

[0007] Problems to be solved by the invention

[0008] However, when synchronizing the translational axis and the rotational axis, the synchronization ratio between the two axes is fixed. In such a structure, if synchronization is maintained from the cutting action to the positioning action, high-speed rotation or movement in the opposite direction may occur. As a method to avoid this situation, it is considered to cancel the synchronization before positioning, but before the synchronization is canceled, the translational axis must be decelerated and stopped, and the rotational axis must be repeatedly rotated and stopped every time a cutting action is performed. In terms of suppressing the heat generation and power consumption of the drive unit of the rotational axis, the existing technology also has room for improvement.

[0009] The present disclosure has been made in view of the above-mentioned problems, and an object of the present disclosure is to provide a technology capable of improving safety during operation switching and reducing heat generation and power consumption of a drive unit in a command generating device for a machine tool.

[0010] Means for solving problems

[0011] The present invention discloses an instruction generating device, which generates instructions for a machine tool that synchronizes the relative translation and rotational movements of a tool and a workpiece for processing, the instruction generating device comprising: a rotation direction acquiring unit, which acquires the direction of the rotational movement; a translation instruction generating unit, which generates instructions for the translational movement per unit time; a sign determining unit, which determines the sign of the synchronization ratio of the synchronization based on the direction of the translational movement and the direction of the rotational movement acquired by the rotation direction acquiring unit; a synchronization ratio determining unit, which determines the absolute value of the synchronization ratio based on whether the instruction for the translational movement is a cutting instruction or a positioning instruction; and a rotation instruction generating unit, which generates the instruction for the rotational movement based on the instruction for the translational movement, the sign and the absolute value, and is capable of changing the synchronization ratio of the translational movement and the rotational movement by means of a cutting instruction and a positioning instruction.

[0012] Effects of the Invention

[0013] According to the present disclosure, it is possible to provide a technology that can improve safety during operation switching and reduce heat generation and power consumption of a drive unit in a command generation device for a machine tool. BRIEF DESCRIPTION OF THE DRAWINGS

[0014] Figure 1 This is a functional block diagram of a numerical controller for a machine tool according to a first embodiment of the present invention.

[0015] Figure 2 It is a diagram showing an example of a thread cutting program according to the first embodiment.

[0016] Figure 3 This diagram shows the positional relationship between the workpiece and the tool when program instructions are executed.

[0017] Figure 4 This is a flowchart showing an example of a processing flow for command generation by the numerical controller of the machine tool according to the first embodiment.

[0018] Figure 5 This diagram shows the relationship between tool movement and synchronization ratio when executing program commands.

[0019] Figure 6 This is a schematic diagram showing the movement path of the workpiece and tool during thread cutting.

[0020] Figure 7 This is a graph showing the relationship between the Z-axis speed and the C-axis speed in conventional thread cutting.

[0021] Figure 8 This is a functional block diagram of a numerical controller for a machine tool according to a second embodiment of the present invention.

[0022] Figure 9This is a graph showing the relationship among the Z-axis speed, the X-axis speed, and the C-axis speed before adjustment processing.

[0023] Figure 10 This is a graph showing the relationship among the Z-axis speed, the X-axis speed, and the C-axis speed after adjustment.

[0024] Figure 11 This is a graph showing the relationship among the Z-axis speed, the X-axis speed, and the C-axis speed, and the timing of the adjustment process when switching operations. DETAILED DESCRIPTION

[0025] Hereinafter, embodiments of the present disclosure will be described in detail with reference to the accompanying drawings. In the description of the second embodiment and thereafter, the same reference numerals are given to the same components as those of the first embodiment, and their descriptions are omitted as appropriate.

[0026] [First embodiment]

[0027] Figure 1 This is a functional block diagram of a numerical controller 1 for a machine tool according to a first embodiment of the present invention. Figure 1 The numerical controller 1 for a machine tool shown is a command generating device that generates machine tool commands for performing machining by synchronizing relative translation and rotation between a tool and a workpiece. The numerical controller 1 of this embodiment controls a drive unit 3 based on the generated commands.

[0028] The drive unit 3 converts the translational movement instructions and rotational movement instructions from the numerical controller 1 into physical translation and rotation to move the tool and workpiece. In addition, in the following description, for convenience, the drive unit 3 driving multiple feed axes (Z axis and X axis) is described, but this is not limited to the shape of the workpiece. The thread cutting process involved in this embodiment can be applied to situations where more feed axes are required because the workpiece has a tapered portion or an arc-shaped portion on the processing surface, and can also be applied to situations where the workpiece is cylindrical or cylindrical and a specific feed axis (Z axis) is sufficient.

[0029] The numerical controller 1 for a machine tool in this embodiment is configured using, for example, a computer comprising memory such as ROM (read-only memory) and RAM (random access memory), a CPU (control processing unit), and a communication control unit, all interconnected via a bus. The functions and operations of each functional unit described below are implemented through the collaboration of the CPU, memory, and control programs stored in the memory. Furthermore, the numerical controller 1 for a machine tool can be configured using a CNC (Computer Numerical Controller) or a PLC (Programmable Logic Controller), and can also be connected to a host computer that outputs machining conditions such as rotational speed in addition to machining programs.

[0030] like Figure 1 As shown, the numerical controller 1 for a machine tool includes a rotation direction acquisition unit 11 , a translation command generation unit 12 , a sign determination unit 13 , a synchronization ratio determination unit 14 , a rotation command generation unit 15 , and a storage unit 20 .

[0031] The rotation direction acquisition unit 11 acquires the direction of rotational movement based on program instructions. The direction of rotational movement referred to herein is, for example, the rotation direction (positive or negative) of the main shaft (C-axis). The program instructions referenced by the rotation direction acquisition unit 11 may be stored in the storage unit 20, which stores information set by the user, or may be output from an external computer.

[0032] The translation command generation unit 12 generates a translation movement (Z-axis, X-axis) command per unit time.

[0033] The sign determination unit 13 determines the sign of the synchronization ratio based on the direction of the translational movement command and the direction of the rotational movement per unit time. The sign of the synchronization ratio is positive or negative, corresponding to the axial movement direction. When the synchronization ratio is positive, the axial movement direction is also positive (+ direction). When the synchronization ratio is negative, the axial movement direction is also negative (- direction).

[0034] The synchronization ratio determination unit 14 determines the synchronization ratio for the cutting command in the case of a cutting command and the positioning command in the case of a positioning command. The synchronization ratio may be specified by a program instruction or may be pre-set in the storage unit 20 of the numerical controller 1 .

[0035] The rotation command generator 15 generates a rotational movement (C-axis) command per unit time by multiplying the translational movement command by the synchronization ratio having the sign determined by the sign determiner 13. Furthermore, the rotation command generator 15 generates the command so as to maintain the rotational movement speed at the start and end of the positioning operation.

[0036] The storage unit 20 stores various information used for machine tool control and machining. In this embodiment, the storage unit 20 stores machining conditions, etc. Machining conditions include, for example, conditions input by the operator as a program or conditions specified as machine tool parameters. Alternatively, the storage unit 20 may be located externally rather than within the numerical controller 1.

[0037] The above describes the overall configuration of the numerical controller 1. Next, program instructions for thread cutting will be described. Figure 2 It is a diagram showing an example of a thread cutting program according to the first embodiment. Figure 2 The shown program is set by, for example, an operator.

[0038] Figure 2 "X" in the command represents the X coordinate, and "Z" represents the Z coordinate. "G00 X41.0 Z-10.0" is a program block that indicates positioning to the initial position. "M03 S1200" indicates that the spindle is rotating forward, and "M201" indicates synchronization on for executing synchronous control. Synchronization is turned on before the start of thread cutting. In this example, both the ZC axis and the XC axis are synchronously controlled. Among them, the Z axis and the X axis become the master axis (axis that moves in translation), and the C axis becomes the slave axis (axis that moves in rotation) in all cases. In addition, when "M04" is recorded in the program, the spindle's rotation direction is reversed.

[0039] Lines N01 through N12 contain commands for positioning (positioning) and linear movement (cutting) during each stage of thread cutting. "G00" indicates positioning, "G01" indicates linear movement during cutting, and "F" indicates the feed rate. "M200" indicates synchronization off, which stops synchronous control.

[0040] Each stage from N01 to N12 will be described. Figure 3 Schematic diagram showing the positional relationship between the workpiece W and the tool T when executing the program command in the first embodiment. Figure 2 In the case of a program, the generation is performed Figure 3 Instructions for the actions shown.

[0041] exist Figure 3 The moving path of the tool T relative to the workpiece W in each stage of N01 to N12 is shown in FIG. Figure 3In the figure, the solid arrows indicate the movement for positioning, and the dot-dash arrows indicate the movement for thread cutting. The thread cutting lead, which indicates the distance the thread advances in the axial direction when the thread rotates one circle during thread cutting, is set to 1.5 (mm / rev) according to the program instruction. Similarly, the spindle rotation speed S is 1200 (min -1 The feed rate during G01 machining is calculated based on the product of the thread lead specified by the program and the spindle rotation speed.

[0042] The feed rate during G01 positioning uses a value pre-stored in the storage unit 20. In this example, during positioning, feed rates of 5000 (mm / min) in the X-axis direction and 10000 (mm / min) in the Z-axis direction are pre-set in the storage unit 20.

[0043] Figure 3 "N01" in the figure indicates the movement from the initial position to the machining start position, "N02" indicates the linear movement of the cutting tool T from the machining start position to the thread cutting process (cutting action), "N03" indicates the movement of the cutting tool T to the retreat position after machining, and "N05" indicates the movement from the retreat position to the initial position. "N01" to "N05" are the first machining action. The initial position of the cutting tool T in the X-axis direction is 41.0, and the entry position in the X-axis direction during the first machining action is 39.0. Similarly, "N05" to "N08" become the second machining action with the entry position set to 38.7, and "N09" to "N12" become the third machining action with the entry position set to 38.4.

[0044] Next, the generation of commands based on program commands by the numerical control device 1 will be described. Figure 4 This is a flowchart showing an example of the flow of a command generation process of the numerical controller 1 for the machine tool according to the first embodiment.

[0045] When a program instruction is read into the numerical controller 1, first, the rotation direction acquisition unit 11 acquires the rotation direction (step S1). The rotation direction can be acquired by reading the program instruction. Figure 2 The rotation direction of the spindle can be obtained by using "M03" in the program, which indicates the rotation direction of the spindle. In this example, the positive direction of the C-axis, which serves as the driven axis, is obtained as the rotation direction. The method for obtaining the rotation direction is not limited to this. For example, the rotation direction can also be obtained based on feedback information from the spindle at the time synchronization is turned on.

[0046] After the process of step S1 , the sign determination unit 13 determines the sign of the synchronization ratio based on the movement direction per unit time of the translational motion (Z axis, X axis) and the direction of the rotational motion (step S2 ).

[0047] Here, refer to Figure 5 An example of setting the synchronization ratio will be described. Figure 5 This is a diagram showing the relationship between the movement of the tool T and the synchronization ratio when executing program instructions. Figure 5 In FIG. 1 , a dotted arrow indicates an operation of setting the synchronization ratio to a negative value by the sign determination unit 13 , and a solid arrow indicates an operation of setting the synchronization ratio to a positive value by the sign determination unit 13 .

[0048] exist Figure 5 In the example, the synchronization ratios for "N01" and "N02" in the first operation, "N05" and "N06" in the second operation, and "N09" and "N10" in the third operation are set to negative. Then, the synchronization ratios for "N03" and "N04" after the first operation, "N07" and "N08" after the second operation, and "N11" and "N12" after the third operation are set to positive.

[0049] After processing in step S2, the synchronization ratio determination unit 14 determines whether the operation in the program instruction is a positioning operation (G00) or a cutting operation (G01) (step S3). If it is a positioning operation (G00), the synchronization ratio determination unit 14 advances the processing to step S4 (step S3; G00), and if it is a cutting operation (G01), the synchronization ratio determination unit 14 advances the processing to step S5 (step S3; G01).

[0050] In step S4, the synchronization ratio determination unit 14 sets the synchronization ratio for the positioning operation. The synchronization ratio for the positioning operation can be calculated based on (360 × spindle rotation speed) / positioning speed. In this example, since the feed speed is set to 5000 (mm / min) in the X-axis direction and 10000 (mm / min) in the Z-axis direction, the synchronization ratio for the positioning operation is set as follows.

[0051] ZC synchronization ratio: R ZC =(360×1200) / 10000=43.2

[0052] XC Sync Ratio: R XC =(360×1200) / 5000=86.4

[0053] In step S5, the synchronization ratio determination unit 14 sets the synchronization ratio for the cutting command. The synchronization ratio for the cutting command can be calculated based on synchronization ratio = 360 / feed rate per rotation (pitch). In the case of a single thread, the pitch and the thread lead can be considered equal. Since the thread cutting lead during each cutting operation is F = 1.5, the synchronization ratio for the cutting command is set as follows.

[0054] ZC synchronization ratio: C ZC =360 / F=240

[0055] - XC Sync Ratio: C XC =360 / F=240

[0056] exist Figure 5 In the example, in the X-axis positioning operations from the initial position to the start of machining, namely "N01", "N05", and "N09", the absolute value of the synchronization ratio R XC =86.4, synchronization ratio <0. In the linear motion in the Z-axis direction for thread cutting, i.e., "N02", "N06", and "N10", the absolute value of the synchronization ratio C ZC = 240, synchronization ratio < 0. In the X-axis direction movement to the retreat position after processing, that is, in "N03", "N07", and "N11", the absolute value of the synchronization ratio R XC =86.4, synchronization ratio>0. In the Z-axis direction movement from the retreat position to the initial position, that is, "N04", "N08", and "N12", the absolute value of the synchronization ratio R ZC =43.2, synchronization ratio>0.

[0057] After executing step S4 or step S5, the rotation command generator 15 generates a rotational movement (C-axis) command per unit time based on the translational movement command and the synchronization ratio with the sign determined by the sign determination unit 13 (step S6). The rotation command generator 15 calculates the rotational movement command by, for example, multiplying the synchronization ratio with the sign determined by the sign determination unit 13 by the translational movement command. As described above, the command is generated so as to maintain the rotational movement speed at the start and end of the positioning operation.

[0058] By executing a series of processes in each program block between the start and end of the program synchronization, movement commands for the entire machining process are generated. Furthermore, the translational movement commands within these movement commands are generated based on the program. The numerical controller 1 controls the drive unit 3 based on these generated movement commands. This flowchart is merely an example; the order and content of the processes can be modified as appropriate.

[0059] Next, refer to Figure 6 and Figure 7 , illustrating the effect of this embodiment relative to the prior art. Figure 6 Schematic diagram showing the movement paths of the workpiece W and the tool T during thread cutting. Figure 7 This is a graph showing the relationship between the Z-axis speed and the C-axis speed in the thread cutting process of the prior art. Figure 6 as well as Figure 7, the movement paths of the tool T corresponding to serial numbers N1 to N7 are shown. The solid lines of serial numbers N1 to N6 correspond to the movement paths during machining, and the dashed-dotted line of N7 corresponds to the movement from the retreat position to the initial position.

[0060] Conventional technology also multiplies the movement command of the master axis (the axis that moves translationally) by a predetermined ratio to generate the movement command of the synchronous driven axis (the axis that moves rotationally). In this thread cutting process, the master axis is set as the Z axis and the driven axis is set as the C axis, so that the main spindle rotates in a manner corresponding to the movement of the Z axis. Through this synchronous control, even if the speed of the Z axis fluctuates for some reason, as in the movement path corresponding to serial numbers N2 to N4, processing can be carried out without disrupting synchronization. The "some reason" mentioned here includes, for example, changes that cause override or the inability to analyze and process small line segments in time.

[0061] However, if the tool T is operated sequentially from cutting to positioning while maintaining synchronization, the C-axis may move at high speed or in the opposite direction, which can be dangerous (e.g., N7). On the other hand, if synchronization is canceled before positioning, the Z-axis or X-axis must be stopped before canceling synchronization. This causes the C-axis to repeatedly rotate and stop during each cutting operation, increasing heat generation and power consumption in the C-axis drive unit.

[0062] In this regard, according to the numerical controller 1 for a machine tool according to the first embodiment described above, the following effects are achieved.

[0063] A numerical control device 1 for a machine tool includes: a rotational direction acquisition unit 11 that acquires the direction of rotational movement; a translational command generation unit 12 that generates a translational movement command per unit time; a sign determination unit 13 that determines the sign of a synchronization ratio based on the direction of translational movement and the direction of rotational movement obtained by the rotational direction acquisition unit 11; a synchronization ratio determination unit 14 that determines the absolute value of the synchronization ratio based on whether the translational movement command is a cutting command or a positioning command; and a rotational command generation unit 15 that generates a rotational movement command based on the translational movement command, its sign, and its absolute value. The synchronization ratio between translational movement and rotational movement can be changed using cutting and positioning commands. This prevents the C-axis from rotating at high speed or reversing during positioning operations, thereby improving safety. Furthermore, the time during which the C-axis speed can be maintained constant can be extended, reducing heat generation and power consumption in the drive unit 3.

[0064] Furthermore, the rotation command generator 15 of this embodiment generates rotational movement commands in a manner that maintains the speed of the rotational movement at the start and end of the positioning operation. This increases the proportion of time the C-axis maintains a constant speed, further reducing heat generation and power consumption by the drive unit 3. Furthermore, even when multiple cutting commands are issued consecutively, the rotational movement speed is limited at the start and end of the positioning operation, thus preventing the occurrence of defective threads caused by maintaining the rotational movement speed.

[0065] In addition, the processing in which translation and rotation are synchronized in this embodiment is thread cutting. In thread cutting in which cutting and positioning operations are repeated, the configuration in which the synchronization ratio is not fixed in this embodiment is particularly suitable.

[0066] The numerical controller 1 for a machine tool according to the first embodiment has been described above, but the present invention is not limited to the configuration of the above embodiment.

[0067] [Second embodiment]

[0068] Next, a numerical controller 1A according to a second embodiment will be described. Figure 8 This is a functional block diagram of a numerical controller for a machine tool according to a second embodiment of the present invention. The second embodiment differs from the numerical controller 1 in that it further includes a synchronization error calculation unit 16 and a translational motion adjustment unit 17. The remaining configurations are identical.

[0069] The synchronization error calculation unit 16 calculates the synchronization error between translation and rotation at the start and end of translation. The synchronization error based on translation can be calculated using the synchronization ratio as follows. The synchronization ratio here is the value set by the synchronization ratio determination unit 14.

[0070] Synchronous error = rotational movement command / synchronization ratio - translation movement command

[0071] The translational motion adjustment unit 17 performs an adjustment process to adjust the start timing of the translational motion based on the synchronization error calculated by the synchronization error calculation unit 16. During the adjustment process, the translational motion adjustment unit 17 calculates so that the cumulative value of the synchronization error becomes a value obtained by adding a predetermined constant to an integer multiple of one rotation. For example, in the case of N threads, the cumulative value of the synchronization error is calculated as an integer multiple of one rotation + 360 degrees / N. For two threads, the value becomes 180 degrees, and a predetermined constant is determined, such as 540 degrees or 900 degrees.

[0072] The adjustment process performed by the synchronization error calculation unit 16 and the translational motion adjustment unit 17 according to the second embodiment will be described. Figure 9 This is a graph showing the relationship among the Z-axis speed (Vz), the X-axis speed (Vx), and the C-axis speed (Vc) before adjustment processing.

[0073] like Figure 9 As shown, when calculating the movement command per unit time for the rotational motion (C-axis), the C-axis also accelerates and decelerates during the acceleration and deceleration of the translational motion. To reduce heat generation, it is preferable to maintain a constant speed for the C-axis, which serves as the main axis. However, if the C-axis speed is constant, synchronization deviations between the translational motion and the rotational motion may occur. In other words, if the C-axis speed is kept constant, the C-axis position may advance.

[0074] Therefore, in the second embodiment, the rotation command generating unit 15 generates a movement command so that the speed of the C axis is constant during acceleration and deceleration of the X axis and the Z axis, and then performs the adjustment process. First, the synchronization error calculating unit 16 calculates the advance amount indicating how much the C axis advances based on the acceleration and deceleration time constant of the X axis or the Z axis or the overlap time between program blocks. Figure 9 In the calculation, the lead amount is calculated as the area based on the acceleration / deceleration time and the overlap time.

[0075] Figure 9 The X-axis movement in N1 is 2.0 (mm) in movement, 5000 (mm / min) in speed, and 64 (ms) in acceleration and deceleration time. The Z-axis movement in N2 is 20.0 (mm) in movement, F×S=1800 (mm / min) in speed, and 80 (ms) in acceleration and deceleration time. In addition, the C-axis as the main axis has a speed of 360×S=360×1200 (deg / min). Figure 9 In the example of , the overlap time is 16 ms, and the synchronization error calculation unit 16 calculates the C-axis lead amount as 417.6 (deg).

[0076] Next, the translation operation adjustment unit 17 performs adjustment processing to delay the start of the cutting block so that the advance amount of the C axis calculated by the synchronization error calculation unit 16 becomes an integral multiple of 360 degrees. Figure 10 This is a graph showing the relationship among the Z-axis speed, X-axis speed, and C-axis speed after adjustment. Figure 10 In the example of FIG. 1 , the translation motion adjustment unit 17 performs adjustment processing to delay the start of N2 indicating the cutting command by 36 (ms) so that the advance amount of the C axis becomes 720 (deg) as an integral multiple of 360 degrees.

[0077] In the second embodiment, to reduce non-cutting time, the synchronization error calculation unit 16 calculates the synchronization error between the two blocks: from the cutting action to the positioning action and from the positioning action to another positioning action. However, the adjustment process is performed so that the start of the block is not delayed. In other words, when adjusting the start timing of the translation movement, the translation movement is limited to the cutting instruction immediately following the positioning instruction.

[0078] Figure 11 This is a graph showing the relationship between the Z-axis speed, X-axis speed, and C-axis speed, and the timing of the adjustment process when switching between operations. Figure 11 In the example shown in FIG, adjustment processing to delay the start timing of the cutting operation is performed only when switching from positioning to cutting from N1 to N2 and from positioning to cutting from N5 to N6. In other words, adjustment processing is performed so that the lead amount (area) of the C-axis when switching from N1 to N2 becomes an integer multiple of 360 degrees.

[0079] Furthermore, the adjustment process from N5 to N6 is performed based on the synchronization errors for the switch from cutting to positioning (N2 to N3), the switch from positioning to other positioning (N3 to N4), and the switch from N4 to N5, and the switch from positioning to cutting (N1 to N2) (N5 to N6). Specifically, the adjustment process is performed so that the sum of the lead amount (area) when switching from N2 to N3, the lead amount (area) when switching from N3 to N4, the lead amount (area) when switching from N4 to N5, and the lead amount (area) when switching from N5 to N6 (total area) is an integer multiple of 360 degrees. In this example, the adjustment process to delay the start timing of the next action is not performed when switching from N2 to N5; only the synchronization error is calculated.

[0080] The numerical controller 1 for a machine tool according to the second embodiment described above provides the following advantages. In addition to a rotation direction acquisition unit 11, a translation command generation unit 12, a sign determination unit 13, a synchronization ratio determination unit 14, and a rotation command generation unit 15, the numerical controller 1 further includes a synchronization error calculation unit 16 that calculates the synchronization error between translation and rotation at the start and end of positioning operations, and a translation adjustment unit 17 that adjusts the start timing of translation so that the cumulative value of the calculated synchronization error equals a value obtained by adding a predetermined constant to an integer multiple of one rotation of rotation. This avoids any synchronization deviation between translation and rotation that might otherwise occur when the C-axis speed is constant, enabling more stable machining operations.

[0081] In this embodiment, the translational motion adjustment unit 17 adjusts the start timing only for the translational movement of the cutting command immediately following the positioning command. This allows for stable machining by adjusting the C-axis phase at the start of machining, which has a significant impact. Adjustment is not performed when switching to other operations where phase stabilization is less necessary. Consequently, compared to delaying all start timings, non-cutting time can be shortened, effectively suppressing increases in cycle time.

[0082] Above, in the second embodiment, an example of performing adjustment processing only when switching from a positioning action to a cutting action is described, but the adjustment processing can also be configured to be applied to all of the switching times from a cutting action to a positioning action, from a positioning action to other positioning actions, and from a positioning action to a cutting action.

[0083] In addition, in the above embodiment, an example of thread cutting is described, but the present invention is not limited to this configuration. For example, the numerical controller 1 of this embodiment can also be applied to a machine tool that performs gear cutting.

[0084] In the above embodiment, the numerical controller 1 or 1A that controls the driver 3 is described as an example of a command generating device, but the present invention is not limited to this configuration. For example, the present invention can also be applied to a computer that only generates commands.

[0085] The present disclosure has been described in detail, but the present disclosure is not limited to the above-mentioned embodiments. These embodiments can be variously added, replaced, changed, partially deleted, etc. without departing from the scope of the present disclosure, or without departing from the scope of the present disclosure derived from the contents recorded in the scope of the patent protection requested and its equivalents. In addition, these embodiments can also be implemented in combination. For example, in the above-mentioned embodiment, the order of each action and the order of each processing are shown as an example and are not limited to this. In addition, the same applies to the case where numerical values or mathematical formulas are used in the description of the above-mentioned embodiments.

[0086] The following supplementary notes are further disclosed regarding the above-mentioned embodiment and modifications.

[0087] (Note 1)

[0088] A command generating device 1, 1A, which generates commands for a machine tool for synchronizing the relative translational movement and rotational movement of a tool T and a workpiece W for processing, the command generating device 1, 1A comprising: a rotation direction acquisition unit 11, which acquires the direction of the rotational movement; a translation command generating unit 12, which generates a command for the translational movement per unit time; a sign determination unit 13, which determines the sign of the synchronization ratio of the synchronization based on the direction of the translational movement and the direction of the rotational movement obtained by the rotation direction acquisition unit; a synchronization ratio determination unit 14, which determines the absolute value of the synchronization ratio based on whether the command for the translational movement is a cutting command or a positioning command; and a rotation command generating unit 15, which generates the command for the rotational movement based on the command for the translational movement, the sign, and the absolute value, and is capable of changing the synchronization ratio of the translational movement and the rotational movement by means of a cutting command and a positioning command.

[0089] (Note 2)

[0090] In the command generating devices 1 and 1A for the machine tool described above, the rotation command generating unit 15 generates a rotational movement command so as to maintain the speed of the rotational movement when starting and ending the positioning operation.

[0091] (Note 3)

[0092] The above-mentioned machine tool instruction generating device 1A is further provided with: a synchronization error calculation unit 16, which calculates the synchronization error between the translational movement and the rotational movement at the beginning and end of the positioning action; and a translational action adjustment unit 17, which adjusts the start timing of the translational movement so that the calculated cumulative value of the synchronization error becomes a value obtained by adding a predetermined constant to an integer multiple of one rotation of the rotational movement.

[0093] (Note 4)

[0094] In the above-mentioned machine tool command generating device 1A, the translational movement adjustment unit 17 starts adjusting the translational movement timing only for the cutting command immediately following the positioning command.

[0095] (Note 5)

[0096] In the above-described machine tool command generating devices 1 and 1A, the machining in which the translational movement and the rotational movement are synchronized is thread cutting.

[0097] Explanation of symbols

[0098] 1. Numerical control device of 1A machine tool,

[0099] 11 Rotation direction acquisition unit,

[0100] 12 translation instruction generation unit,

[0101] 13. Symbol determination unit,

[0102] 14 synchronization ratio determination unit,

[0103] 15 rotation instruction generating unit,

[0104] 16 Synchronous error calculation unit,

[0105] 17 translational motion adjustment unit.

Claims

1. A machine tool command generation device for generating machine tool commands for performing machining by synchronizing relative translational and rotational movements of a tool and a workpiece, characterized in that: The instruction generating device comprises: a rotation direction acquiring unit configured to acquire the direction of the rotational movement; a translation instruction generating unit that generates an instruction for the translation movement per unit time; a sign determination unit that determines a sign of the synchronization ratio of the synchronization based on the direction of the translational movement and the direction of the rotational movement acquired by the rotational direction acquisition unit; a synchronization ratio determination unit that determines an absolute value of the synchronization ratio according to whether the translation movement instruction is a cutting instruction or a positioning instruction; as well as a rotation instruction generating unit that generates the rotation instruction based on the translation instruction, the sign, and the absolute value; The synchronization ratio between the translational movement and the rotational movement can be changed by a cutting command and a positioning command.

2. The machine tool command generating device according to claim 1, characterized in that: The rotation command generating unit generates a rotational movement command so as to maintain a speed of the rotational movement when starting and ending the positioning operation.

3. The machine tool command generating device according to claim 2, characterized in that: The instruction generating device further comprises: a synchronization error calculation unit that calculates a synchronization error between the translational movement and the rotational movement at the start and end of the positioning operation; and The translation movement adjustment unit adjusts the start timing of the translation movement so that the calculated cumulative value of the synchronization error becomes a value obtained by adding a predetermined constant to an integral multiple of one rotation of the rotation movement.

4. The machine tool command generating device according to claim 3, characterized in that: The translational movement adjustment section adjusts the translational movement start timing only for a cutting command immediately following a positioning command.

5. The machine tool command generating device according to any one of claims 1 to 4, characterized in that: The machining process in which the translational movement is synchronized with the rotational movement is a thread cutting process.

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