Machine tool control device and machine tool control method

Abstract

Provided are a machine tool control device and a machine tool control method capable of alleviating a burden on a user through automatic selection of a shaft to be caused to oscillate in accordance with a request index. A machine tool control device 1 processes a workpiece W while causing a tool T and the workpiece W to oscillate relative to one another. The machine tool includes: a movement command generation unit 8 that generates a movement command for relatively moving the tool T and the workpiece W; a movement command analysis unit 7 that analyzes the movement command; an oscillation condition setting unit 5 that sets an oscillation condition and an oscillation direction of the oscillation; and an oscillation command calculation unit 6 that generates an oscillation command on the basis of the oscillation condition and the oscillation direction. The workpiece W is processed by applying a superposed command in which the oscillation command is superposed on the movement command.

Description

Control device for machine tool and control method for machine tool

[0001] The present disclosure relates to a control device for a machine tool and a control method for a machine tool.

[0002] Conventionally, in order to prevent problems caused by chips continuously generated during machining of a workpiece getting entangled with the workpiece or a cutting tool, swing machining is known in which machining is performed while relatively swinging the tool and the workpiece. According to this swing machining, by setting the tool path, which is the locus of the tool, so that a part thereof overlaps with the previous tool path, an air cut where the tool separates from the surface of the workpiece can be generated to shred the chips. As something in which a technique related to swing machining is described, for example, there is Patent Document 1.

[0003] International Publication No. 2021 / 166974

[0004] Here, if it is only for shredding chips, it is not limited to the feed axis (Z-axis) of the tool, and the purpose can be achieved by swinging any axis of the vertical axis (X-axis) or the longitudinal axis (Y-axis). However, depending on which of the running costs such as the amount of power consumption associated with the swing motion, tool life, etc., and the required indexes such as the surface roughness of the machined surface of the workpiece are emphasized, the axis suitable for the swing motion changes. When the user tries to consider and select this, there is a problem that the burden becomes large.

[0005] The present disclosure has been made in view of the above problems, and an object is to provide a control device for a machine tool and a control method for a machine tool that can reduce the burden on the user by automatically selecting an axis for swinging according to required indexes.

[0006] One aspect of the present disclosure is a control device (1) for a machine tool that processes a workpiece (W) while relatively oscillating a tool (T) and the workpiece (W), comprising: a movement command generation unit (8) that generates movement commands for relatively moving the tool (T) and the workpiece (W); a movement command analysis unit (7) that analyzes the movement commands; a movement condition setting unit (5) that sets the movement conditions and direction of the movement; and a movement command calculation unit (6) that generates movement commands based on the movement conditions and direction, wherein the control device applies a superimposed command, which is a movement command superimposed with the movement command, to process the workpiece (W).

[0007] One aspect of the present disclosure is a control method for a machine tool that processes a workpiece (W) while relatively oscillating a tool (T) and the workpiece (W), comprising: a movement command generation means for generating a movement command for relatively moving the tool (T) and the workpiece (W); a movement command analysis means for analyzing the movement command; an oscillating condition setting means for setting the oscillating conditions and direction of the oscillating motion; and an oscillating command calculation means for generating an oscillating command based on the oscillating conditions and direction of the oscillating motion, wherein the machine tool is processed by applying a superimposed command obtained by superimposing the oscillating command onto the movement command.

[0008] This is an overall diagram of the machine tool. This is a schematic diagram illustrating the concept of oscillating machining. This is a functional block diagram showing the configuration of the control device according to this embodiment. This is a functional block diagram showing the configuration of the control device according to a modified example of this embodiment. This is a functional block diagram showing the configuration of the control device according to a second modified example of this embodiment. This is a functional block diagram showing the configuration of the control device according to a third modified example of this embodiment. This is a schematic diagram illustrating the concepts of oscillating machining and non-oscillating machining. This is a functional block diagram showing the configuration of the control device according to a third modified example of this embodiment. This is a conceptual diagram showing the procedure from rough machining to final machining. This is a flowchart showing the procedure for controlling the machining of the workpiece. This is a schematic diagram showing the relationship between the tool trajectory of the finishing pass and the tool trajectory L of the non-oscillating pass. This is a functional block diagram showing the configuration of the control device according to a fourth modified example of this embodiment. This is a flowchart showing the procedure for workpiece machining control 2. This is a flowchart showing the procedure for workpiece machining control 3. This is a schematic diagram showing the machined surface of the workpiece by the finishing pass. This is a functional block diagram showing the configuration of the control device according to a fifth modified example of this embodiment.

[0009] An example of an embodiment of the present invention will be described below.

[0010] Figure 1 is an overall diagram of the machine tool 50. In the machine tool 50, which is a CNC (Computerized Numerical Control) lathe that processes a workpiece W with a tool T, the chuck 52 that fixes one end of the workpiece W is fixed to the spindle JS which is oriented in the front-to-back direction as shown. The spindle JS is rotationally driven by a spindle motor MS mounted on the upper part of the leg 51. A carriage 53 that reciprocates in the front-to-back direction as shown is also provided on the upper part of the leg 51. The carriage 53 reciprocates by rotationally driving a feed axis JZ (Z axis) which is combined with a ball screw mechanism. The feed axis JZ is rotationally driven by a feed axis motor MZ mounted on the rear of the leg 51.

[0011] A lateral feed table 55 that reciprocates in the left-right direction as shown in the figure is provided on the upper part of the carriage table 53. The lateral feed table 55 reciprocates by rotationally driving the left-right axis JY (Y-axis) which is oriented in the left-right direction as shown in the figure. The left-right axis JY is rotationally driven by the left-right axis motor MY.

[0012] A tool post 54 supporting the tool T is attached to the side of the cross feed table 55. The tool post 54 reciprocates in the vertical direction as shown by rotationally driving a vertical axis JX (X-axis) which is oriented in the vertical direction as shown. The vertical axis JX is rotationally driven by a vertical axis motor MX. In the machine tool 50 according to this embodiment, the tool post 54 is configured to be rotatable relative to the cross feed table 55.

[0013] Behind the cross feed table 55 is a tailstock D, which holds the other end of the workpiece W during machining. The tailstock D reciprocates when the tailstock feed axis JD, which is arranged parallel to the feed axis JZ, is rotationally driven. The tailstock feed axis JD is rotationally driven by the tailstock feed axis motor MD.

[0014] Figure 2 is a schematic diagram illustrating the concept of oscillating machining. Normally, in oscillating machining, the spindle JS, which rotates the tool T and the workpiece W relative to each other, and the feed axis JZ, which moves the tool T relative to the workpiece W, are operated in coordination to rotate the tool T and the workpiece W relative to each other, while simultaneously oscillating the tool T in the feed direction (Z-axis direction) during machining.

[0015] At this time, the tool path L, which is the trajectory of the tool T, is set so that the current path partially overlaps with the previous path. In other words, because the portion that has already been machined by the previous path is partially included in the current path, an air cut occurs in the area of ​​the dashed circle shown in the figure, where the cutting edge of the tool T separates from the surface of the workpiece W, and this shreds the chips.

[0016] Here, if the sole purpose is to shred chips, the objective can be achieved not only by using the Z-axis (feed axis), but also by using the X-axis (vertical axis) or the Y-axis (horizontal axis), which is not shown. The control device of the machine tool according to this embodiment reduces the burden on the user by automatically selecting the axis on which to perform this oscillating motion.

[0017] Figure 3 is a functional block diagram showing the configuration of the control device 1 according to this embodiment. The same reference numerals indicate the same or equivalent parts. The control device 1, which is a numerical control device, can be realized, for example, by loading a predetermined program into a computer having a CPU, memory, etc. In the following, an example is shown in which the axis on which the oscillating motion is executed is automatically selected from the feed axis JZ or the vertical axis JX, but it is also possible to oscillate the left-right axis JY or to oscillate multiple axes simultaneously.

[0018] The movement command analysis unit 7 determines whether or not oscillating motion is necessary based on the machining program and CNC parameters. The position deviation calculation means 3 calculates the position deviation, which is the difference between the movement command issued by the movement command generation unit 8 and the position information of the machine tool 50. The position information of the machine tool 50 is the position information of the spindle motor MS, the feed axis motor MZ, and the vertical axis motor MX. The position information acquired by encoders provided on each motor MS, MZ, and MX is input to the subtractor 2 for position feedback control.

[0019] In this embodiment, the system includes an oscillation condition setting unit 5 that selects the oscillation direction, in other words, the axis on which the oscillation motion is performed (feed axis JZ or vertical axis JX), and sets the oscillation conditions for the oscillation motion. The oscillation command calculation unit 6 calculates an oscillation command consisting of the interval, amplitude, period, etc. of the oscillation motion based on the output of the oscillation condition setting unit 5. The position control unit 9 controls each motor MS, MZ, MX via the speed / current control unit 10 based on a superimposed command obtained by superimposing the oscillation command on the position deviation using an adder 4.

[0020] In this embodiment, the system comprises a movement command generation unit 8 that generates movement commands for relatively moving the tool T and the workpiece W, a movement command analysis unit 7 that analyzes the movement commands, a swing condition setting unit 5 that sets the swing conditions and swing direction of the swinging motion, and a swing command calculation unit 6 that generates swing commands based on the swing conditions and swing direction. The workpiece W is machined by applying a superimposed command, which is the movement command superimposed with the swing command. As a result, the selection of the axis on which to execute the swinging motion is performed automatically, reducing the burden on the user.

[0021] Figure 4 is a functional block diagram showing the configuration of a control device 1 according to a modified example of this embodiment. The same reference numerals indicate the same or equivalent parts. When selecting an axis for the oscillating motion, the axis suitable for the oscillating motion will change depending on which of the required indicators is given more importance: the amount of power consumption associated with the oscillating motion, running costs such as tool life, or the surface roughness of the machined surface of the workpiece. This modified example is characterized by the inclusion of an evaluation function setting unit 11 for setting an evaluation function as a required indicator, and an evaluation function calculation unit 12 for calculating an evaluation function based on the output of the evaluation function setting unit 11.

[0022] The user can pre-set which requirement indicators to prioritize, or they can change the settings according to the operating status of the machine tool 50, or the system can be configured to automatically change the settings based on output information from various sensors.

[0023] In this modified version, the system includes an evaluation function setting unit 11 for setting an evaluation function for setting the oscillation direction, and an evaluation function calculation unit 12 for calculating the evaluation function. The oscillation condition setting unit 5 sets the oscillation direction based on the calculated evaluation function, so the oscillation direction can be set automatically according to any evaluation function.

[0024] Figure 5 is a functional block diagram showing the configuration of the control device 1 according to a second modified example of this embodiment. The same reference numerals indicate the same or equivalent parts as above. In this second modified example, the control device is equipped with a processing condition / machine information input unit 13 for inputting at least one of the processing conditions and machine information. The evaluation function setting unit 11 sets an evaluation function that indicates the power consumption associated with the oscillating operation based on the input information and oscillating conditions input to the processing condition / machine information input unit 13.

[0025] The power consumption that increases with the oscillating motion can be evaluated based on the inertia of each axis of the machine tool 50 and the amount of movement in the direction of gravity. The evaluation function setting unit 11 sets an evaluation function as the sum of the changes in kinetic energy and potential energy of each axis, and the evaluation function calculation unit 12 calculates the speed and acceleration for the oscillating motion based on the oscillating frequency and amplitude of the oscillating motion notified by the oscillating condition setting unit 5. The oscillating condition setting unit 5 sets the direction of the oscillating motion based on the evaluation function corresponding to the power consumption.

[0026] More specifically, the oscillating motion changes the velocity of the drive unit based on a sine wave, according to the equation v(t) = Vsin(wt). Here, V is the velocity specified in the processing program or other means as a movement command before the oscillating command is superimposed, and w is a constant set by the oscillating conditions. The kinetic energy associated with the oscillating motion is calculated from this velocity V, and the potential energy is calculated from the mass of the drive unit and its position in the direction of gravity.

[0027] The oscillation condition setting unit 5 calculates the kinetic energy associated with the oscillation in the Z-axis direction and the kinetic energy associated with the oscillation in the X-axis direction from the mass and oscillation speed of the tool post 54 of the machine tool 50. Furthermore, by determining the power consumption of motors MZ and MX from the kinetic energy of the oscillation in the Z-axis and X-axis directions, it is possible to select an oscillation direction that consumes less power.

[0028] Figure 6 is a functional block diagram showing the configuration of the control device 1 according to a third modified example of this embodiment. The same reference numerals indicate the same or equivalent parts. In this third modified example, the control device is equipped with an operating status storage unit 14 that stores the operating status of at least one of the machines and peripheral equipment. The evaluation function setting unit 11 sets an evaluation function that indicates the running cost associated with the oscillating operation based on at least one of the input information input to the processing conditions / machine information input unit 13, the oscillating conditions, and the operating status.

[0029] Here, the running costs associated with the oscillating motion are a required indicator related to the machine's lifespan. Because the oscillating motion superimposes a reciprocating motion on the movement command, the number of times the tool T engages with the workpiece W increases, and the cutting distance extends, leading to faster wear of the tool T. In addition, the repeated reciprocating motion increases the load on mechanical parts such as ball screws.

[0030] In contrast, the operating status memory unit 14 can store, for example, the number of times the tool T on each axis engages with the workpiece W. The evaluation function setting unit 11 then compares this with the upper limit number of engagements entered in the machining conditions / machine information input unit 13 and sets a margin for the upper limit number of engagements on each axis as an evaluation function.

[0031] Furthermore, the machine life may be substituted with the number of reversals of each mechanism, based on the user's operating regulations. In this case, the number of reversals of each mechanism can be stored, and a margin against a preset upper limit can be set as an evaluation function. The number of reversals can be determined from the speed of the drive unit according to the oscillation conditions and the position information of the drive unit.

[0032] Furthermore, the machine life can be substituted with the travel distance of guide members such as ball screws. In this case, the travel distance of the guide members can be stored, and a margin relative to a preset upper limit can be set as an evaluation function. When setting the evaluation function based on machine life, the oscillation direction can be set so that the load is concentrated on parts with a long lifespan or low cost, thereby optimizing running costs.

[0033] Furthermore, since each axis of the machine tool 50 is equipped with multiple mechanical parts such as ball screw mechanisms, if the replacement timing of each mechanical part is spread out, it will result in a decrease in the operating rate of the machine tool 50 and an increase in maintenance costs. To address this, an evaluation function may be set using the replacement timing of the mechanical parts as an indicator. In this case, the lifespan of each mechanical part can be set based on the number of reversals of the oscillating motion, and a margin against a predetermined upper limit can be set as the evaluation function.

[0034] The movement command analysis unit 7 then determines whether a predetermined timing has been reached so that the margins corresponding to each mechanism are evenly distributed. If it is determined that the predetermined timing has been reached, it determines whether or not a swinging motion is necessary. The swinging condition setting unit 5 readjusts the swinging direction according to the result of the determination of whether or not a swinging motion is necessary. This makes it possible to control the timing of replacement of the mechanism parts.

[0035] Figure 7 is a schematic diagram illustrating the concepts of oscillating and non-oscillating machining. Figure 8 is a functional block diagram showing the configuration of the control device 1 according to a third modified example of this embodiment, and Figure 9 is a conceptual diagram showing the procedure from rough machining to final machining. The same reference numerals indicate the same or equivalent parts.

[0036] Referring to Figure 7, in oscillating machining, the tool path L, which is the trajectory of the tool T, is set so that it partially overlaps with the previous tool path L, thereby generating an air cut that causes the tool T to separate from the surface of the workpiece W and shredding the chips. This third modified example is characterized in that, as STEP 1, after cutting to the finish pass (n passes) with oscillating cutting, a non-oscillating pass (n+1 passes) without oscillating motion is added as STEP 2. In oscillating cutting, the distance between the previous tool path L and the current tool path L is at most Va, but by adding a non-oscillating pass at the end where the distance between the previous tool path L and the current tool path L is a constant distance Vb, it is possible to reduce the amount of material left uncut.

[0037] The movement command analysis unit 7 determines whether or not an oscillating motion is necessary, and also determines whether or not the pass to be executed is a finishing pass. If the pass to be executed is a finishing pass, the movement command generation unit 8 adds one non-oscillating pass with the same depth of cut as the finishing pass. The oscillating command calculation unit 6 calculates an oscillating command if it determines that an oscillating motion is necessary, and sets the oscillating command to zero if it determines that an oscillating motion is unnecessary. By adding this non-oscillating pass, it becomes possible to improve the surface roughness of the workpiece W to the same level or higher than before the application of oscillating machining.

[0038] One of the indicators that determines the surface roughness of the workpiece W is the distance between adjacent tool paths, or in other words, the feed rate of the axis performing the oscillating motion. In oscillating machining, the maximum speed during which the feed rate is repeatedly varied is more than twice that of normal machining, so the amount of material left uncut increases and the surface roughness tends to decrease. If this decrease in surface roughness is significant, it becomes necessary to reduce the feed rate of the finishing pass B, which increases the machining time.

[0039] Referring to Figure 9, the machining of the workpiece W can be performed as follows: the 1st to n-1st (th)th passes are rough machining A with oscillating motion; the nth pass is finishing pass B with oscillating motion in a different direction from rough machining A; and the n+1st pass is a non-oscillating pass C without oscillating motion. In this modified example, by performing one finishing pass B with X-axis oscillating motion after the rough machining A with Z-axis oscillating motion, and then adding one non-oscillating pass C, it is possible to further improve the surface roughness of the workpiece W.

[0040] That is, the movement command analysis unit 7 determines whether the command to be executed is the finish path B. When it is determined that the command to be executed is the finish path B, the movement command generation unit 8 sets the swing direction of the finish path B in a direction different from that of the rough machining A, and adds a non-swing path C to which the same cutting amount as that of the finish path B is applied after the finish path B.

[0041] FIG. 10 is a flowchart showing the procedure of the machining control 1 of the workpiece W. In step S1, it is determined whether a swing operation is required. If the determination in step S1 is affirmative, the process proceeds to step S2, where it is determined whether the command to be executed is the finish path B. If the determination in step S2 is affirmative, the process proceeds to step S3, where the finish path B is generated.

[0042] In the subsequent step S4, it is determined whether the swing operation by the finish path B has been completed. If the determination is affirmative, the process proceeds to step S5, where the non-swing path C is generated. In the subsequent step S6, it is determined whether the operation of the non-swing path C has been completed. If the determination is affirmative, the series of machining controls is terminated.

[0043] On the other hand, if the determination in step S2 is negative, that is, if it is determined that the command to be executed is not the finish path B, the process proceeds to step S7, where a swing path as the rough machining A is generated. In the subsequent step S8, it is determined whether the swing operation by the rough machining A has been completed. If the determination is affirmative, the series of controls is terminated, and if the determination is negative, the process returns to the determination in step S8. Also, if the determination in step S1 is negative, the process proceeds to step S9, where the non-swing path C is generated. In the subsequent step S10, it is determined whether the operation of the non-swing path C has been completed. If the determination is affirmative, the series of controls is terminated, and if the determination is negative, the process returns to the determination in step S10.

[0044] FIG. 11 is a schematic diagram showing the relationship between the tool path L of the finish path B and the tool path La of the non-swing path C. FIG. 12 is a functional block diagram showing the configuration of the control device 1 according to the fourth modification of the present embodiment, and FIG. 13 is a flowchart showing the procedure of the machining control 2 of the workpiece W. The same reference numerals as above indicate the same or equivalent parts.

[0045] Referring to FIG. 11, in order to neatly remove the remaining material by the non-oscillating path C and improve the surface roughness, it is preferable that the tool path La of the non-oscillating path C passes through the midpoint of the remaining material range N. As shown in FIG. 12, the non-oscillating path start phase calculation unit 15 calculates the start phase for minimizing the surface roughness when machining is performed using the added non-oscillating path C. The movement command generation unit 8 generates a movement command for the non-oscillating path C based on the start phase calculated by the non-oscillating path start phase calculation unit 15.

[0046] The finish path start phase calculation unit 16 calculates the spindle phase of the cutting start point of the finish path B. This spindle phase can be calculated based on the position information acquired by the encoders provided in each of the motors MS, MZ, MX, or can also be calculated based on the command from the movement command analysis unit 7.

[0047] FIG. 11 shows the case where the oscillation frequency magnification is 1.5 times. In this case, the maximum distance at which the distance of the tip of the tool T is farthest apart and the spindle phase at that time are calculated. Then, a tool path La that passes through the position obtained by bisecting this maximum distance is calculated. In other words, the start phase of the non-oscillating path C is calculated based on the tool path L of the finish path B and the feed rate set by the user's designation, machining program, or the like.

[0048] Referring to the flowchart of FIG. 13, in step S11, it is determined whether the oscillation operation is necessary. If an affirmative determination is made in step S11, the process proceeds to step S12, and it is determined whether the command to be executed is the finish path B. If an affirmative determination is made in step S12, the process proceeds to step S13, and the finish path B is generated.

[0049] In the subsequent step S14, it is determined whether the oscillation operation by the finish path B has been completed. If an affirmative determination is made, the process proceeds to step S15. In step S15, a non-oscillating path C that passes through the midpoint of adjacent finish paths B is generated. In the subsequent step S16, it is determined whether the operation of the non-oscillating path C has been completed. If an affirmative determination is made, a series of machining controls is terminated.

[0050] On the other hand, if step S12 is rejected, that is, if it is determined that the command to be executed is not finish pass B, the process proceeds to step S17, where an oscillating pass as rough machining A is generated. In the following step S18, the oscillating motion due to rough machining A is executed. In the following step S19, the spindle phase at the start of the oscillating motion is calculated, and the series of controls is terminated.

[0051] Furthermore, if the result in step S11 is negative, the process proceeds to step S20, where a non-oscillating path C is generated. In the following step S21, it is determined whether the operation of the non-oscillating path C has been completed. If the result is negative, the process returns to the determination in step S21; on the other hand, if the result is positive, the series of controls is terminated.

[0052] Figure 14 is a flowchart showing the procedure for machining control 3 of the workpiece W. As described above, the oscillation condition setting unit 5 sets the oscillation direction of the oscillation operation, and at this time, the oscillation direction of rough machining A and the oscillation direction of finishing pass B can be made different. Specifically, a finishing pass B can be executed by oscillating an axis in a direction perpendicular to the oscillation direction of rough machining A. In this embodiment, during rough machining A, the feed axis ZJ is oscillated, and when it is determined that the command to be executed is a finishing pass B, the system is set to execute the finishing pass B by oscillating the vertical axis XJ which is perpendicular to the feed axis ZJ.

[0053] This axis switching control allows for a distribution of the load on the mechanism and tool T compared to performing roughing and finishing passes while maintaining the same oscillation direction. Alternatively, the finishing pass B may be executed using the left / right axis YJ, or the roughing A may be executed using the up / down axis XJ.

[0054] Figure 15 is a schematic diagram showing the machined surface of the workpiece W by the finishing pass B. Figure 16 is a functional block diagram showing the configuration of the control device 1 according to a fifth modified example of this embodiment. The same reference numerals indicate the same or equivalent parts. As shown in Figure 9, when the finishing pass B (n passes) is oscillating along the X axis, shallow grooves F remain on the machined surface by the finishing pass B, which are cut radially inward along the tip shape of the tool T. In order to reduce these grooves F and further improve the surface roughness of the workpiece W, it is preferable to set the tool trajectory of the non-oscillating pass C to pass through the lowest point Fa of the groove F.

[0055] Referring to Figure 16, the finishing pass start phase calculation unit 16 calculates the spindle phase at the cutting start point of the finishing pass B. This spindle phase can be calculated based on position information acquired by encoders provided on each motor MS, MZ, MX, or based on a command from the movement command analysis unit 7. When the command to be executed is the finishing pass B, the movement command generation unit 8 adds one non-oscillating pass C with the same depth of cut as the finishing pass B, and generates a movement command that matches the start phase of the non-oscillating pass C to the spindle position calculated by the finishing pass start phase calculation unit 15.

[0056] Specifically, the movement command analysis unit 7 is equipped with a finishing pass start phase calculation unit 15 that acquires position information of the drive body for moving the tool T and workpiece W, and calculates the start phase of the finishing pass B based on the position information and machining conditions, and the movement command generation unit 8 is set to generate movement commands based on the start phase of the non-oscillating pass C. This makes it possible to further improve the surface roughness of the workpiece W after machining.

[0057] Furthermore, the shape of the workpiece is not limited in the oscillating machining according to one aspect of this disclosure. For example, multiple feed axes may be required to form tapered or arc-shaped portions on the machined surface of the workpiece, or the workpiece may be cylindrical or cylindrical and only one feed axis may be sufficient.

[0058] As described above, the control device for the machine tool according to this embodiment reduces the burden on the user by automatically selecting and changing the axis on which the oscillating motion is performed, depending on which of the multiple evaluation elements is given more importance.

[0059] A machine tool control system can consist of one or more control units and memory units. Here, the control unit is a processor such as a CPU (Central Processing Unit), and it realizes various functions by executing programs stored in the memory unit. The memory unit consists of a ROM (Read Only Memory) or RAM (Random Access Memory) that stores the OS (Operating System) and application programs, and a storage device such as a hard disk drive or SSD (Solid State Drive) that stores various other information.

[0060] According to the above-described control device for a machine tool, a control method for a machine tool can be obtained in which the movement command generation unit 8 is used as a movement command generation means, the movement command analysis unit 7 is used as a movement command analysis means, the oscillation condition setting unit 5 is used as an oscillation condition setting means, and the oscillation command calculation unit 6 is used as an oscillation command calculation means.

[0061] The control devices and control methods for the machine tools described above can be implemented by hardware, software, or a combination thereof. Here, implementation by software means that it is implemented by a computer loading and executing a program.

[0062] Programs can be stored and supplied to a computer using various types of non-transitor computer-readable media. Non-transitor computer-readable media include various types of tangible storage media. Examples of non-transitor computer-readable media include magnetic recording media (e.g., hard disk drives), magneto-optical recording media (e.g., magneto-optical disks), CD-ROMs (Read Only Memory), CD-Rs, CD-R / Ws, and semiconductor memory (e.g., mask ROMs, PROMs (Programmable ROMs), EPROMs (Erasable PROMs), flash ROMs, and RAMs (random access memory)).

[0063] Furthermore, while the embodiments described above are preferred embodiments of the present invention, the scope of the present invention is not limited to these embodiments alone. Various modifications can be made to the present invention without departing from its spirit.

[0064] While this disclosure has been described in detail, it is not limited to the individual embodiments described above. These embodiments can be added, replaced, modified, partially deleted, etc., in any way that does not depart from the gist of this disclosure or from the spirit of this disclosure derived from the claims and their equivalents. These embodiments can also be implemented in combination. For example, the order of operations and processes in the embodiments described above are given as examples only and are not limited thereto.

[0065] The control device and control method for machine tools described herein can be applied to various machine tools and industrial machinery.

[0066] With respect to the above embodiments and modifications, the following additional notes are disclosed. (Addendum 1) A control device (1) for a machine tool that processes a workpiece (W) while relatively oscillating a tool (T) and the workpiece (W), comprising: a movement command generation unit (8) that generates movement commands for relatively moving the tool (T) and the workpiece (W); a movement command analysis unit (7) that analyzes the movement commands; a movement condition setting unit (5) that sets the movement conditions and direction of the oscillating motion; and a movement command calculation unit (6) that generates movement commands based on the movement conditions and direction, wherein the control device for a machine tool processes the workpiece (W) by applying a superimposed command obtained by superimposing the movement command onto the movement command.

[0067] (Note 2) A control device for a machine tool as described in Note 1, comprising: an evaluation function setting unit (11) for setting an evaluation function for setting the oscillation direction; and an evaluation function calculation unit (12) for calculating the evaluation function, wherein the oscillation condition setting unit (5) sets the oscillation direction based on the calculated evaluation function.

[0068] (Note 3) A control device for a machine tool as described in Note 2, comprising a machining condition / machine information input unit (13) for inputting at least one of machining conditions and machine information, and the evaluation function setting unit (11) sets an evaluation function indicating the power consumption associated with the oscillating operation based on the input information and the oscillating conditions.

[0069] (Note 4) A control device for a machine tool as described in Note 2, comprising: a processing condition / machine information input unit (13) for inputting at least one of processing conditions and machine information; and an operating status storage unit (14) for storing the operating status of at least one of the machine and peripheral equipment, wherein the evaluation function setting unit (11) sets an evaluation function indicating the running cost associated with the oscillating operation based on at least one of the input information, the oscillating conditions, and the operating status.

[0070] (Note 5) The control device for a machine tool as described in Note 1, wherein the movement command analysis unit (7) determines whether or not a predetermined timing has been reached, and if it is determined that the predetermined timing has been reached, it determines whether or not a swinging motion is necessary, and the swinging condition setting unit (5) resets the swinging direction according to the result of the determination of whether or not a swinging motion is necessary.

[0071] (Note 6) The control device for a machine tool as described in Note 1, wherein the movement command analysis unit (7) determines whether the command to be executed is a finishing pass (B), and the movement command generation unit (8), when it is determined that the command to be executed is a finishing pass (B), adds a non-oscillating pass (C) after the finishing pass (B) to which the same depth of cut as the finishing pass (B) is applied.

[0072] (Note 7) The control device for a machine tool as described in Note 6, wherein the movement command analysis unit (7) acquires position information of a drive body for moving the tool (T) and the workpiece (W), and comprises a finishing pass start phase calculation unit (15) that calculates the start phase of the finishing pass (B) based on the position information and the machining conditions, and a non-oscillating pass start phase calculation unit (16) that calculates the start phase of the non-oscillating pass (C) based on the start phase of the finishing pass (B), and the movement command generation unit (8) generates the movement command based on the start phase of the non-oscillating pass (C).

[0073] (Note 8) A control device for a machine tool as described in Note 6, applicable to a machine tool (50) having a plurality of axes including a spindle (SJ) that rotates the workpiece (W) and the tool (T) relative to each other, and a feed axis (ZJ) that feeds the workpiece (W) and the tool (T) relative to each other, wherein the oscillation condition setting unit (5) oscillates the feed axis (ZJ) when rough machining (A) of the workpiece (W), and when it is determined that the command to be executed is a finishing pass (B), it oscillates axes (XJ, YJ) that are oriented in a direction different from the feed axis (ZJ).

[0074] (Note 9) The control device for a machine tool as described in Note 8, wherein the oscillation condition setting unit (5) oscillates the feed axis (ZJ) when rough machining (A) of the workpiece (W), and when it is determined that the command to be executed is a finishing pass (B), it oscillates the axes (XJ, YJ) perpendicular to the feed axis (ZJ).

[0075] (Note 10) The control device for a machine tool according to Note 8 or 9, wherein the movement command analysis unit (7) acquires position information of a drive body for moving the tool (T) and the workpiece (W), and the finishing pass start phase calculation unit (15) calculates the start phase of the finishing pass (B) based on the position information and the machining conditions, and the movement command generation unit (8) generates the movement command based on the start phase of the non-oscillating pass (C).

[0076] (Note 11) A control method for a machine tool that processes a workpiece (W) while the tool (T) and the workpiece (W) are oscillating relative to each other, comprising: a movement command generation means for generating a movement command for moving the tool (T) and the workpiece (W) relative to each other; a movement command analysis means for analyzing the movement command; a movement condition setting means for setting the movement conditions and direction of the oscillating motion; and a movement command calculation means for generating a movement command based on the movement conditions and direction of the oscillating motion, wherein the machine tool is processed by applying a superimposed command obtained by superimposing the movement command onto the movement command.

[0077] 1 Machine tool control device 5 Oscillation condition setting unit 6 Oscillation command calculation unit 7 Movement command analysis unit 8 Movement command generation unit 11 Evaluation function setting unit 12 Evaluation function calculation unit 13 Machining condition / machine information input unit 14 Operating status storage unit 15 Non-oscillation pass start phase calculation unit 16 Finishing pass start phase calculation unit 50 Machine tool A Rough machining B Finishing pass C Non-oscillation pass JS Spindle JZ Feed axis (Z axis) JX Up / down axis (X axis) JY Back / forward axis (Y axis) W Workpiece T Tool

Claims

1. A control device for a machine tool that processes a workpiece while the tool and the workpiece are relatively oscillating, comprising: a movement command generation unit that generates movement commands for relatively moving the tool and the workpiece; a movement command analysis unit that analyzes the movement commands; an oscillating condition setting unit that sets the oscillating conditions and direction of the oscillating motion; and an oscillating command calculation unit that generates oscillating commands based on the oscillating conditions and direction of the oscillating motion, wherein the control device for a machine tool processes the workpiece by applying a superimposed command obtained by superimposing the oscillating command onto the movement command.

2. A control device for a machine tool according to claim 1, comprising: an evaluation function setting unit for setting an evaluation function for setting the oscillation direction; and an evaluation function calculation unit for calculating the evaluation function, wherein the oscillation condition setting unit sets the oscillation direction based on the calculated evaluation function.

3. A control device for a machine tool according to claim 2, comprising a machining condition / machine information input unit for inputting at least one of machining conditions and machine information, wherein the evaluation function setting unit sets an evaluation function indicating the power consumption associated with the oscillating operation based on the input information and the oscillating conditions.

4. A control device for a machine tool according to claim 2, comprising: a processing condition / machine information input unit for inputting at least one of processing conditions and machine information; and an operating status storage unit for storing the operating status of at least one of the machine and peripheral equipment, wherein the evaluation function setting unit sets an evaluation function indicating the running cost associated with the oscillating operation based on at least one of the input information, the oscillating conditions, and the operating status.

5. The control device for a machine tool according to claim 1, wherein the movement command analysis unit determines whether or not a predetermined timing has been reached, and if it is determined that the predetermined timing has been reached, it determines whether or not a swinging motion is necessary, and the swinging condition setting unit resets the swinging direction according to the result of the determination of whether or not a swinging motion is necessary.

6. The control device for a machine tool according to claim 1, wherein the movement command analysis unit determines whether the command to be executed is a finishing pass, and the movement command generation unit, when it determines that the command to be executed is a finishing pass, adds a non-oscillating pass after the finishing pass, to which the same depth of cut as the finishing pass is applied.

7. The control device for a machine tool according to claim 6, wherein the movement command analysis unit acquires position information of a drive body for moving the tool and the workpiece, and comprises a finishing pass start phase calculation unit that calculates the start phase of the finishing pass based on the position information and the machining conditions, and a non-oscillating pass start phase calculation unit that calculates the start phase of the non-oscillating pass based on the start phase of the finishing pass, and the movement command generation unit generates the movement command based on the start phase of the non-oscillating pass.

8. A control device for a machine tool according to claim 6, applicable to a machine tool having a plurality of axes including a spindle for rotating the workpiece and the tool relative to each other, and a feed axis for feeding the workpiece and the tool relative to each other, wherein the oscillation condition setting unit oscillates the feed axis when rough machining of the workpiece, and when it is determined that the command to be executed is a finishing pass, it oscillates an axis oriented in a direction different from the feed axis.

9. The control device for a machine tool according to claim 8, wherein the oscillation condition setting unit oscillates the feed axis when rough machining of the workpiece, and when it is determined that the command to be executed is a finishing pass, it oscillates an axis perpendicular to the feed axis.

10. The control device for a machine tool according to claim 8 or 9, wherein the movement command analysis unit acquires position information of a drive body for moving the tool and the workpiece, and the finishing pass start phase calculation unit calculates the start phase of the finishing pass based on the position information and the machining conditions, and the movement command generation unit generates the movement command based on the start phase of the non-oscillating pass.

11. A control method for a machine tool that processes a workpiece while the tool and the workpiece are oscillating relative to each other, comprising: a movement command generation means for generating a movement command for moving the tool and the workpiece relative to each other; a movement command analysis means for analyzing the movement command; a movement condition setting means for setting the movement conditions and direction of the oscillating motion; and a movement command calculation means for generating a movement command based on the movement conditions and direction, wherein the machine tool processes the workpiece by applying a superimposed command obtained by superimposing the movement command onto the movement command.

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