Working machinery and processing methods

Abstract

The present invention provides a machine tool and a machining method that generate oscillation commands based on the chip thickness commanded in the machining program during continuous oscillation machining. [Solution] The machine tool 10 includes a spindle 20, a workpiece rotating device 24, a storage unit 34 that stores in advance the relative coordinates of the tool and the workpiece W, the rotational speed, the first cutting feed rate and the commanded chip thickness, an oscillation command generation unit 40 that calculates an oscillation frequency at which the first trough of the oscillation waveform at the Nth rotation and the second peak of the oscillation waveform at the N+1th rotation have the same rotational phase, calculates a first amplitude ratio that adjusts the oscillation waveform amplitude so that the minimum distance between the waveforms between the first trough and the second peak matches the commanded chip thickness, and generates a first oscillation command based on the oscillation frequency, the first amplitude ratio and the first cutting feed rate, and a control device 12 that operates the machine device 14 in accordance with the first oscillation command.

Description

[Technical Field]

[0001] The present invention relates to a machine tool and a machining method. [Background technology]

[0002] In turning operations, controlling chip breakage is crucial for maintaining the machine tool and tool in good condition. Therefore, conventional machine tools have been known that perform turning operations by repeatedly performing intermittent cutting, where the tool separates from the workpiece in the cutting feed direction, then contacts it again to cut, thereby breaking the chip. However, such intermittent cutting can lead to tool breakage due to repeated contact between the tool and the workpiece. Therefore, as disclosed in Patent Document 1, a continuous oscillating turning method has been disclosed that allows the chip to be broken by centrifugal force when it is discharged, by changing the chip thickness with each oscillation period while keeping the tool from separating from the workpiece in the cutting feed direction.

[0003] In continuous oscillating turning, it is important to minimize the chip thickness in the thinnest part of the chip in order to facilitate chip breakage by centrifugal force. However, in oscillating turning, thin and thick parts of the chip can occur depending on the rotation phase of the workpiece. Since the surface roughness may increase in the parts of the workpiece corresponding to the thicker chip parts, oscillating turning may result in worse surface roughness compared to non-oscillating turning. Therefore, it is desirable that chip breakage be performed in a manner that allows for adjustment of surface roughness. [Prior art documents] [Patent Documents]

[0004] [Patent Document 1] Japanese Patent Publication No. 2023-141865 [Overview of the Initiative] [Problems that the invention aims to solve]

[0005] In view of the above circumstances, the present invention aims to provide a machine tool and a machining method that generate an oscillation command based on the chip thickness commanded in a machining program in continuous oscillation machining in which the tool oscillates without separating from the workpiece in the cutting feed direction. [Means for solving the problem]

[0006] According to one aspect of the present invention, a machine tool for machining a workpiece is provided, wherein the tool and the workpiece are rotated relative to each other about a first axis and the tool and the workpiece are moved linearly relative to each other while being oscillated in the direction of the first axis, the machine tool comprises a tool mounting section to which the tool is attached, a workpiece mounting section to which the workpiece is attached, a rotation axis for rotating the tool mounting section and the workpiece mounting section relative to each other about a first axis, a linear motion axis for moving the tool mounting section and the workpiece mounting section linearly relative to each other along the direction of the first axis, coordinates indicating the relative positional relationship between the tool and the workpiece during machining, the relative rotational speed between the tool and the workpiece, the relative first cutting feed rate between the tool and the workpiece, and a command chip thickness, which are predetermined A machine tool is provided, comprising: a memory unit for storing data; an oscillation command generation unit that calculates an oscillation frequency based on the rotational speed such that the first trough of the oscillation waveform in the Nth rotation from the start of rotation and the second peak of the oscillation waveform in the N+1th rotation have the same rotational phase; calculates a first amplitude ratio based on a first cutting feed rate and a command chip thickness to adjust the amplitude of the oscillation waveform so that the minimum distance between waveforms, which is the distance between the first trough and the second peak, matches the command chip thickness; and generates a first oscillation command based on the oscillation frequency, the first amplitude ratio, and the first cutting feed rate; and a control device that operates a linear axis and a rotary axis based on coordinates and the first oscillation command.

[0007] Furthermore, according to one aspect of the present invention, a machine tool for processing a workpiece by rotating the tool and the workpiece relative to each other around a first axis and oscillating the tool and the workpiece in the direction of the first axis while oscillating the tool and the workpiece in the direction of the first axis, comprising: a tool mounting section to which the tool is attached; a workpiece mounting section to which the workpiece is attached; a rotation axis for rotating the tool mounting section and the workpiece mounting section relative to each other around a first axis; a linear motion axis for moving the tool mounting section and the workpiece mounting section in the direction of the first axis in the direction of the first axis; a storage section for pre-storing coordinates indicating the relative positional relationship between the tool and the workpiece during processing; the relative rotational speed of the tool and the workpiece; a command chip thickness; a command surface roughness; and an oscillation command generation section, which generates an oscillation command based on the rotational speed, and generates the first trough of the oscillation waveform at the Nth rotation from the start of rotation and the second trough of the oscillation waveform at the N+1th rotation. A machine tool is provided, comprising: an oscillation command generation unit that calculates an oscillation frequency at which two peaks have the same rotational phase; sets the maximum inter-waveform distance, which is the distance between the first peak of the oscillation waveform at the Nth rotation from the start of rotation and the second trough of the oscillation waveform at the N+1th rotation, based on the command surface roughness and the command chip thickness and command surface roughness; calculates the feed amount in the cutting feed direction per rotation of the rotational operation during machining from the maximum inter-waveform distance and the minimum inter-waveform distance, which is the distance between the first trough and the second peak; calculates a third cutting feed rate based on the feed amount and rotational speed; calculates a third amplitude ratio for adjusting the amplitude of the oscillation waveform so that the minimum inter-waveform distance matches the command chip thickness; generates an oscillation command based on the oscillation frequency, the third amplitude ratio and the third cutting feed rate; and a control device that operates a linear axis and a rotary axis based on coordinates and an oscillation command.

[0008] Furthermore, according to one aspect of the present invention, a machining method is provided for machining a workpiece by rotating the tool and the workpiece relative to each other around a first axis and oscillating the tool and the workpiece in the direction of the first axis while oscillating the tool and the workpiece in a relative linear motion, the machining method comprising: inputting coordinates indicating the relative positional relationship between the tool and the workpiece during machining, the cutting feed rate for the relative linear motion between the tool and the workpiece, the rotational speed for the relative rotational motion between the tool and the workpiece, a commanded chip thickness, and the number of teeth of the tool; calculating an oscillation frequency based on the rotational speed and the number of teeth such that the trough of the oscillation waveform at the Nth rotation from the start of rotation and the peak of the oscillation waveform at the N+1th rotation have the same rotational phase; calculating the amplitude of the oscillation based on the rotational speed, the number of teeth of the tool, the cutting feed rate, and the commanded chip thickness; generating a first oscillation command based on the amplitude and the oscillation frequency; and machining the tool and the workpiece by performing relative rotational and linear motion based on the first oscillation command. [Effects of the Invention]

[0009] According to one aspect of the present invention, a machine tool can store in advance coordinates indicating the relative positional relationship between the tool and the workpiece during machining, the relative rotational speed between the tool and the workpiece, the relative first cutting feed rate between the tool and the workpiece, and the commanded chip thickness. Furthermore, the oscillation command generation unit can calculate an oscillation frequency based on the rotational speed such that the first trough of the oscillation waveform at the Nth rotation from the start of rotation and the second peak of the oscillation waveform at the N+1th rotation have the same rotational phase. Furthermore, the oscillation command generation unit can calculate a first amplitude ratio based on the first cutting feed rate and the commanded chip thickness to adjust the amplitude of the oscillation waveform so that the minimum inter-waveform distance, which is the distance between the first trough and the second peak, matches the commanded chip thickness. Therefore, by making the rotational phases of the first trough and the second peak the same, the minimum inter-waveform distance can be reduced, and the chip thickness can be reduced. Furthermore, since the amplitude of the oscillation waveform can be adjusted using the first amplitude ratio, the minimum distance between waveforms can be made to match the commanded chip thickness. This makes it possible to generate oscillation commands based on the chip thickness commanded in the machining program during continuous oscillation machining. The oscillation command generation unit can also generate a first oscillation command based on the first amplitude ratio and the first cutting feed rate. Therefore, it is possible to adjust both the feed rate per revolution of the workpiece, which can be set by the first cutting feed rate and the relative rotational speed between the tool and the workpiece, and the amplitude of the oscillation waveform, which is adjusted using the first amplitude ratio. This makes it possible to adjust the feed rate per revolution of the workpiece, which affects surface roughness, while adjusting the relationship between the feed rate per revolution of the workpiece and the amplitude of the oscillation waveform, so as not to change the minimum distance between waveforms, thereby enabling chip fragmentation in a manner that allows for surface roughness adjustment.

[0010] Furthermore, according to one aspect of the present invention, the memory unit can pre-store coordinates indicating the relative positional relationship between the tool and the workpiece during machining, the relative rotational speed between the tool and the workpiece, the commanded chip thickness, and the commanded surface roughness. The oscillation command generation unit can calculate the oscillation frequency at which the first trough of the oscillation waveform during the Nth rotation from the start of rotation and the second peak of the oscillation waveform during the N+1th rotation have the same rotational phase, based on the rotational speed. In addition, based on the commanded chip thickness and commanded surface roughness, the maximum inter-waveform distance, which is the distance between the first peak of the oscillation waveform during the Nth rotation from the start of rotation and the second trough of the oscillation waveform during the N+1th rotation, can be set based on the commanded surface roughness. Furthermore, the feed amount in the cutting feed direction per rotation of the rotational operation during machining can be calculated from the maximum inter-waveform distance and the minimum inter-waveform distance, which is the distance between the first trough and the second peak. Furthermore, a third cutting feed rate can be calculated based on the feed rate and rotational speed, and a third amplitude ratio can be calculated to adjust the amplitude of the oscillating waveform so that the minimum distance between waveforms matches the commanded chip thickness. Therefore, by making the rotational phases of the first trough and the second peak the same, the minimum distance between waveforms can be reduced, and the chip thickness can be reduced. In addition, since the amplitude of the oscillating waveform can be adjusted using the third amplitude ratio, the minimum distance between waveforms can be made to match the commanded chip thickness. As a result, in continuous oscillating machining, a third oscillating command can be generated based on the commanded chip thickness and commanded surface roughness commanded in the machining program. Furthermore, the oscillating command generation unit can generate an oscillating command based on the third amplitude ratio and the third cutting feed rate. Therefore, both the feed rate per revolution of the workpiece rotation calculated from the maximum distance between waveforms and the minimum distance between waveforms, and the amplitude of the oscillating waveform adjusted using the third amplitude ratio can be adjusted. This allows for chip fragmentation while adjusting the surface roughness, by adjusting the relationship between the feed rate per revolution of the workpiece and the amplitude of the oscillation waveform, while adjusting the maximum distance between waveforms based on the commanded surface roughness, so as not to change the minimum distance between waveforms.

[0011] Furthermore, according to one aspect of the present invention, the machining method includes a step of inputting coordinates indicating the relative positional relationship between the tool and the workpiece during machining, the cutting feed rate for the relative linear motion between the tool and the workpiece, the rotational speed for the relative rotational motion between the tool and the workpiece, the commanded chip thickness, and the number of teeth of the tool. It also includes a step of calculating the oscillation frequency based on the rotational speed and the number of teeth, such that the trough of the oscillation waveform at the Nth rotation from the start of rotation and the peak of the oscillation waveform at the N+1th rotation have the same rotational phase. Furthermore, it includes a step of calculating the oscillation amplitude based on the rotational speed, the number of teeth of the tool, the cutting feed rate, and the commanded chip thickness. By making the rotational phase of the trough at the Nth rotation and the peak at the N+1th rotation the same, the minimum distance between waveforms, which is the distance between them, can be reduced, and the chip thickness can be reduced. Furthermore, the oscillation amplitude can be adjusted based on the commanded chip thickness. As a result, in continuous oscillation machining, a first oscillation command can be generated based on the calculated amplitude and oscillation frequency. Furthermore, the oscillation command generation unit can generate a first oscillation command based on the oscillation amplitude and the cutting feed rate. This allows adjustment of both the feed rate per revolution of the workpiece, which can be set by the cutting feed rate and the relative rotational speed between the tool and the workpiece, and the oscillation amplitude. This makes it possible to adjust the feed rate per revolution of the workpiece, which affects surface roughness, while adjusting the relationship between the feed rate per revolution of the workpiece and the oscillation amplitude, so as not to change the minimum distance between waveforms, thereby enabling chip fragmentation in a manner that allows for surface roughness adjustment. [Brief explanation of the drawing]

[0012] [Figure 1] Figure 1 shows a block diagram of the machine tool according to this embodiment. [Figure 2] Figure 2 is an explanatory diagram showing the relative relationship between the tool and the workpiece during machining according to this embodiment. [Figure 3] Figure 3 shows the relationship between rotational phase and chip thickness in continuous oscillating turning. [Figure 4]Figures 4(a) and 4(b) show the relationship between rotational phase, chip thickness, and surface roughness in oscillating turning. Figure 4(c) shows the relationship between rotational phase, chip thickness, and surface roughness in non-oscillating turning. [Figure 5] Figure 5(a) shows the relationship between rotational phase and chip thickness when only the commanded chip thickness is satisfied, Figure 5(b) shows the relationship between rotational phase and chip thickness when both the commanded chip thickness and the commanded surface roughness are satisfied, and Figure 5(c) shows a comparison of the relationships shown in Figures 5(a) and 5(b). [Figure 6] Figure 6 shows a flowchart of the machine tool according to this embodiment. [Modes for carrying out the invention]

[0013] The machine tool and machining method according to the embodiment will be described below with reference to the attached drawings. Similar or corresponding elements are denoted by the same reference numerals, and redundant explanations will be omitted. The scale of the drawings may be changed in the explanation to facilitate understanding.

[0014] Figure 1 shows a block diagram of a machine tool 10 according to this embodiment. The machine tool 10 comprises a machine device 14 for machining a workpiece W and a control device 12 for controlling the machine device 14. The control device 12 executes an input machining program, and the machine device 14 is configured to machine the workpiece W by operating the spindle 20, tool 50, and cutting insert 52 as part of the tool 50 in accordance with the commands of the machining program sent from the control device 12.

[0015] As schematically shown in FIG. 2, the machine device 14 according to the present embodiment is a device for performing turning by relatively moving a tool 50 and a cutting insert 52 and a workpiece W as a rotating machining target along the feed direction as the relative movement direction. Here, the workpiece rotation speed S, which is the relative rotational speed between the tool 50 and the cutting insert 52 and the workpiece W, the cutting feed speed F, which is the relative linear movement speed between the tool 50 and the cutting insert 52 and the workpiece W, and the feed amount Fc per one rotation of the workpiece W are shown in a state where turning is being performed. When the machining does not oscillate, as shown by the solid line in the figure, the chip thickness at which the cutting insert 52 turns the workpiece is uniform regardless of the rotational phase θ (see FIG. 3). On the other hand, when performing oscillatory turning, as shown by the dashed-dotted line in the figure, the chip thickness at which the cutting insert 52 turns the workpiece varies depending on the rotational phase θ. Here, the vertical axis in FIG. 3 is the position (coordinate) in the direction of performing cutting feed, the horizontal axis is the rotational phase θ of the workpiece W, and the solid lines indicated by the Nth and (N + 1)th are the tool edge trajectories. Note that, in order to facilitate understanding of the relationships between various elements, the tool edge trajectories do not include the component of the feed amount per rotation.

[0016] As shown in FIG. 1, the machine device 14 includes a bed 16 fixed to the floor surface of an installation location (such as a factory). A fixed column 18 is erected on the upper surface on the right side in the Z-axis direction (left-right direction of the paper surface) of the bed 16. On the front side of the column 18, that is, on the left side in the Z-axis direction, a spindle head 20 as a tool mounting portion is arranged via a saddle (not shown) for moving the tool 50 and the cutting insert 52 along the X-axis direction (perpendicular direction of the paper surface) and the Z-axis direction (up-down direction of the paper surface). A tool 50 is attached to the tip of the spindle head 20. A cutting insert 52 that contacts the workpiece W and performs machining is attached to the tip of the tool 50 as a part of the tool 50. Here, the cutting insert 52 is a manually replaceable cutting tool (blade), but various styles such as a cutting tool brazed to the tool 50, a cutting tool formed by machining the tool 50 itself to form a tool edge, etc. can be selected instead of the cutting insert 52.

[0017] On the upper surface on the left side of the bed 16 in the Z-axis direction, a table 22 configured to be movable on the bed 16 via a guide surface is arranged. For this reason, the bed 16 includes a Z-axis feed device (not shown) as a linear motion axis for moving the table 22 along the Z-axis direction (the direction of the first axis AL), which is the feed direction. Further, on the table 22, a work rotating device 24 as a work mounting portion is arranged, which includes a work spindle 25 as a rotating axis for mounting a work W and rotating it around the first axis AL. As a result, the tool 50 and the cutting insert 52 attached to the spindle 20 and the work W attached to the work rotating device 24 can be linearly moved relative to each other in the Z-axis direction along the first axis AL and can be rotated relative to each other along the first axis AL. Also, the spindle 20 and the work rotating device 24 can be relatively moved along the X-axis direction and the Y-axis direction, which are the feed directions.

[0018] The machine device 14 also has a tool changing device 26 for performing various types of machining according to the machining purpose, and the tool changing device 26 is configured to be able to change the tool 50 mounted on the spindle 20. Further, the machine device 14 includes a plurality of servo motors 28 that drive the spindle 20 and drive a linear motion mechanism and a rotation mechanism that relatively move the spindle 20 and the table 22. Further, a servo amplifier 30 is provided, which is connected to the servo motor 28, supplies power, and is configured to detect the rotation position from an encoder (not shown).

[0019] The control device 12 includes an input unit 32 for the operator to input a machining program for continuous oscillating turning. The machining program is written as a block and input to the input unit 32, for example, G01 X_Y_Z_S_F_Q_;. Here, G01 is a G code for commanding the cutting feed, XYZ are the coordinates where the spindle 20 or table 22 should be positioned during machining, S is the workpiece rotation speed of the workpiece rotation device 24, F is the cutting feed speed, and Q represents the commanded chip thickness. The commanded chip thickness Q is entered as zero (0) or a positive value. In addition, an M code to turn on the continuous oscillating turning mode is commanded in the blocks preceding the above block, so that the above block is recognized as continuous oscillating turning. In this case, after the continuous oscillating turning is completed, another M code is commanded to turn off the mode.

[0020] Furthermore, as will be described later, when performing oscillating turning to satisfy the commanded surface roughness K in addition to the commanded chip thickness Q, the machining program is written as, for example, G01 X_Y_Z_S_F_Q_K_L_; and input to the input unit 32. Here, K is the commanded surface roughness, and L is the tool tip R (see Figure 2). Specifically, the tool tip R is the numerical value of the radius dimension of the tool tip (in this case, the cutting edge of the cutting insert 52) ​​that contacts the workpiece W and performs machining. If the tool tip R is not commanded, the information on the tool tip R stored in the memory unit 34 regarding the tool mounted on the spindle when executing the machining program may be referred.

[0021] The control device 12 includes a storage unit 34 for storing input content, including the input machining program. The storage unit 34 is configured to store the coordinates indicating the relative positional relationship between the tool 50 and cutting insert 52 and the workpiece W during machining, the relative rotational speed S between the tool 50 and cutting insert 52 and the workpiece W, the relative cutting feed rate F between the tool 50 and cutting insert 52 and the workpiece W, and the commanded chip thickness Q, all of which are input by the operator.

[0022] The control device 12 includes a chip thickness detection unit 36 ​​for retrieving and detecting a command chip thickness Q that is input to the input unit 32 and stored in the storage unit 34 during oscillating turning, and a surface roughness detection unit 38 for retrieving and detecting a command surface roughness K stored in the storage unit 34.

[0023] The control device 12 includes an oscillation command generation unit 40 for generating oscillation commands based on these machining programs and input content. As shown in Figure 3, the oscillation command generation unit 40 is configured to calculate the oscillation frequency f at which the first trough TR1 of the oscillation waveform in the Nth rotation from the start of rotation and the second peak CR2 of the oscillation waveform in the N+1th rotation have the same rotational phase θ (Ph2 in Figure 3), based on the input rotational speed S. The oscillation frequency f [Hz] can be calculated from the workpiece rotational speed S [1 / min] and the number of cutting edges n of the tool as follows. f = S × n × m / (60 × 2) (1) Here, by setting m to an odd number, we can calculate the oscillation frequency f at which the first trough TR1 of the oscillation waveform during the Nth rotation from the start of rotation and the second peak CR2 of the oscillation waveform during the N+1th rotation have the same rotational phase θ (Ph2 in Figure 3). Furthermore, the feed oscillation angular frequency ω [rad / sec] can be calculated from the oscillation frequency f and radians π [rad] as follows. ω = 2π × f (2)

[0024] Furthermore, the oscillation command generation unit 40 is configured to calculate a cutting feed rate amplitude ratio Famp, which is a first amplitude ratio for adjusting the amplitude of the oscillation waveform, based on the cutting feed rate F, which is a first cutting feed rate, and the command chip thickness Q, so that the minimum inter-waveform distance Tmin, which is the distance between the first valley TR1 and the second peak CR2, matches the command chip thickness Q. The feed oscillation width WA [mm] satisfies the following relationship with the feed oscillation angular frequency ω, the cutting feed rate F [mm / min], and the cutting feed rate amplitude ratio Famp [%]. WA = 2 × F × F amp / (100×60×ω) (3) Here, the feed oscillation width WA [mm] refers to both amplitudes of the oscillation waveform. Furthermore, the minimum distance between waveforms Tmin [mm] satisfies the following relationship with the feed rate Fc [mm / rev] per revolution of the workpiece W and the feed oscillation width WA [mm]. T min =Fc―WA (4) Furthermore, the feed rate Fc per revolution of the workpiece W satisfies the following relationship with the cutting feed rate F and the workpiece rotation speed S. Fc = F / S (5) Therefore, using equations (1) to (5) above, the cutting feed rate amplitude ratio Famp[%] can be calculated as follows. F amp = 100 × π × S × n × m × (F / ST min ) / (2×F) (6)

[0025] The oscillation command generation unit 40 calculates the cutting feed rate amplitude ratio Famp, using the minimum distance Tmin between waveforms as the command chip thickness Q, and generates an oscillation command as the first oscillation command based on this.

[0026] The control device 12 includes a point cloud generation unit 42 that generates point cloud data for operating the machine device 14 in accordance with the generated oscillation command. Based on the calculated cutting feed rate amplitude ratio Famp and oscillation frequency f, the point cloud generation unit 42 generates point cloud data based on a predetermined sine wave division period and XYZ coordinates while oscillating the cutting feed rate F input in the machining program.

[0027] Once the generation of point cloud data and the calculation of processing time are complete, the control device 12 activates the servo amplifier 30, supplies power to the servo motor 28 based on the generated point cloud data, activates the machine device 14, and performs continuous oscillating turning on the workpiece W. This makes it possible to set the first trough TR1 of the oscillating waveform in the Nth rotation from the start of rotation and the second peak CR2 of the oscillating waveform in the N+1th rotation to the same rotational phase θ, and make the minimum inter-waveform distance Tmin, which is the distance between the first trough TR1 and the second peak CR2, to match the command chip thickness Q.

[0028] Furthermore, the oscillation command generation unit 40 is configured to generate an oscillation command according to a predetermined chip thickness pre-stored in the storage unit 34 when the chip thickness detection unit 36 ​​does not detect or is unable to detect the command chip thickness Q. Here, the predetermined chip thickness may be zero. This allows continuous oscillation turning to be performed using the value of the predetermined chip thickness even if the operator forgets to input the command chip thickness Q or fails to input it during the generation of the machining program.

[0029] Furthermore, the oscillation command generation unit 40 is configured to stop generating oscillation commands when the chip thickness detection unit 36 ​​detects a negative chip thickness. The control device 12 includes a display unit 46 and a notification unit 48, and is configured to display on the display unit 46 that it has stopped when it stops generating oscillation commands, and to notify the operator via the notification unit 48. This prevents the machine 14 from malfunctioning if the operator mistakenly inputs a negative value for the chip thickness when creating a machining program.

[0030] Furthermore, the oscillation command generation unit 40 is configured to stop generating oscillation commands when the command chip thickness Q detected by the chip thickness detection unit 36 ​​is greater than the feed rate Fc per revolution of the workpiece W. In such cases, the control device 12 is configured to display the fact that it has stopped on the display unit 46 and to notify the operator via the notification unit 48. This prevents the operator from creating an incorrect machining program.

[0031] Furthermore, the oscillation command generation unit 40 can generate oscillation commands that take the command surface roughness K as input in addition to the command chip thickness Q. Generally, the smaller the chip thickness T, the easier it is to break up the chip. On the other hand, the smaller the chip thickness T, the worse the surface roughness d becomes. The surface roughness d, which is the maximum height of the uneven portion CN created on the surface of the workpiece W by the tool cutting edge R (see Figure 2 in both cases), is better when the tool cutting edge R is large and the feed rate Fc per revolution of the workpiece W is small.

[0032] As shown in Figure 4(c), when turning is performed without oscillating motion, the chip thickness is always equal to the feed rate Fc per revolution of the workpiece W, and the surface roughness d3 is always constant. In contrast, as shown in Figures 4(a) and 4(b), when oscillating turning is performed, the surface roughness d varies depending on the rotational phase θ. As shown in Figure 4(a), at the rotational phase θ (Ph1 in Figure 3) where the first peak CR1 of the oscillating waveform in the Nth rotation from the start of rotation coincides with the second trough TR2 of the oscillating waveform in the N+1th rotation, the chip thickness Tmax is the thickest, and the surface roughness d1 is also the largest. Also, as shown in Figure 4(b), at the rotational phase θ (Ph2 in Figure 3) where the first trough TR1 of the oscillating waveform in the Nth rotation from the start of rotation coincides with the second peak CR2 of the oscillating waveform in the N+1th rotation, the chip thickness Tmin is the thinnest, and the surface roughness d2 is also the smallest. The relationship between the surface roughness d, the feed rate Fc per revolution of the workpiece W, and the tool tip R is given by equation (7) below. By replacing the feed rate Fc per revolution of the workpiece W with chip thicknesses Tmax and Tmin, the relationship between the above surface roughnesses d1, d2, and d3 and chip thicknesses Tmax and Tmin can be understood. d = Fc × Fc / (8 × R) (7) Thus, depending on the rotational phase θ of the oscillating turning process, the surface roughness d may be worse compared to when turning is performed without oscillating motion.

[0033] Therefore, according to the control device 12 of this embodiment, as shown in Figure 5, the operator can generate an oscillation command as a second oscillation command by taking the commanded chip thickness Q and the commanded surface roughness K as inputs. Specifically, the feed rate Fc1 per revolution of the workpiece W that is initially input is a provisional feed rate (reference value), and the feed rate Fc2 per revolution of the workpiece W is calculated so as to satisfy both the commanded chip thickness Q (=Tmin1) and the commanded surface roughness K (=d).

[0034] Figure 5(a) shows the relationship between the rotational phase θ and the chip thickness Tmax1 and Tmin1 when machining according to a provisional oscillation command (corresponding to the first oscillation command described above) generated from the input feed rate Fc1 per revolution of the workpiece W and the commanded chip thickness Q. Here, WA1 represents the feed oscillation width. The distance between the first peak CR1 of the oscillation waveform in the Nth rotation and the second trough TR2 of the oscillation waveform that has the same rotational phase θ as the first peak CR1 in the N+1th rotation is the maximum inter-waveform distance Tmax1, and the distance between the first trough TR1 and the second peak CR2 is the minimum inter-waveform distance Tmin1. In contrast, as shown in Figures 5(b) and 5(c), the second oscillation command is generated to set the maximum inter-waveform distance Tmax2 to be smaller, while keeping the minimum inter-waveform distance Tmin1 based on the commanded chip thickness Q the same as the first oscillation command, so that the surface roughness d is based on the commanded surface roughness K.

[0035] Thus, in order to set the minimum inter-waveform distance Tmin1 and the maximum inter-waveform distance Tmax2, the feed rate Fc2 per revolution of the workpiece W is calculated separately from the input provisional feed rate Fc1 to satisfy these conditions. As shown in Figures 5(b) and 5(c), the sum of the maximum inter-waveform distance Tmax2 and the minimum inter-waveform distance Tmin1 is twice the feed rate Fc2 per revolution of the workpiece W. T max2 +T min1 = 2 × Fc² (8) Furthermore, as shown in equation (4) above, the minimum distance between waveforms Tmin1 [mm] satisfies the following relationship with the feed rate Fc2 [mm / rev] and the feed oscillation width WA2 [mm] of the workpiece W. T min1 =Fc2 ― WA2 (9) Similarly, the maximum distance between waveforms Tmax2 [mm] satisfies the following relationship with the feed per revolution Fc2 [mm / rev] and the feed oscillation width WA2 [mm] of the workpiece W per revolution. T max2 =Fc2 + WA2 (10) Furthermore, as shown in the above formula (7), the relationship between the surface roughness d [mm] and the maximum distance between waveforms Tmax2 is expressed as follows. d = T max2 ×T max2 / (8 × R) (11) Therefore, by substituting formulas (9) to (11) into formula (8), the feed per revolution Fc2 of the workpiece W can be calculated as follows. Fc2 = {(8 × R × d) 1 / 2 + Tmin1} / 2 (12) Also, from the above formula (5), the cutting feed rate F as the second cutting feed rate can be calculated from the feed per revolution Fc2 of the workpiece W and the workpiece rotation speed S. F = Fc2 × S (13) The oscillation command generation unit 40 calculates the cutting feed rate amplitude ratio Famp as the second amplitude ratio with the minimum distance between waveforms Tmin1 as the commanded chip thickness Q, and generates an oscillation command as the second oscillation command from the oscillation frequency f, the cutting feed rate amplitude ratio Famp, and the cutting feed rate F. As a result, the second oscillation command can be generated so as to satisfy both the commanded chip thickness Q (= Tmin1) and the commanded surface roughness K (= d). Then, the point cloud generation unit 42 generates point cloud data based on the generated second oscillation command, and the servo amplifier 30 supplies power to the servo motor 28 of the mechanical device 14 based on the generated point cloud data to operate the mechanical device 14. As a result, continuous oscillatory turning machining can be performed on the workpiece W along the second oscillation command.

[0036] As described above, the oscillation command generation unit 40 can generate a second oscillation command using both the command chip thickness Q and the command surface roughness K as inputs. Therefore, even if the cutting feed rate is not input, it can generate an oscillation command as a third oscillation command using the same procedure as for generating the second oscillation command. That is, by setting the minimum distance between waveforms Tmin1 as the command chip thickness Q and the surface roughness d as the command surface roughness K, the feed amount Fc3 per revolution of the workpiece W can be calculated from equation (12) above, and by substituting this into equation (13), the cutting feed rate F as the third cutting feed rate can be calculated. Therefore, by substituting these into equation (6) above, the cutting feed rate amplitude ratio Famp as the third amplitude ratio can be calculated, and an oscillation command as the third oscillation command can be generated from the oscillation frequency f, the cutting feed rate amplitude ratio Famp, and the cutting feed rate F.

[0037] The effects and advantages of the machine tool 10 according to this embodiment will be explained below through an explanation of the oscillating cutting process of the workpiece W using the flowchart of the machine tool 10 shown in Figure 6.

[0038] First, the process moves to step S10 to start the machining process, then to step S20 where the machining program including the oscillation command is input to the input unit 32 of the control device 12, and the storage unit 34 stores the oscillation command. Furthermore, the process moves to step S30 where the chip thickness detection unit 36 ​​detects the commanded chip thickness Q from the storage unit 34, and then to step S40. If the chip thickness detection unit 36 ​​has detected the commanded chip thickness Q, the process moves to step S50.

[0039] If the chip thickness detection unit 36 ​​has not detected the command chip thickness Q, the process proceeds to step S90, where the oscillation command generation unit 40 generates a provisional oscillation command based on the predetermined chip thickness, and the process proceeds to step S100.

[0040] If the chip thickness detection unit 36 ​​detects the command chip thickness Q and proceeds to step S50, the chip thickness detection unit 36 ​​checks whether a negative value has been input as the command chip thickness Q. If the command chip thickness Q is a negative value, the process proceeds to step S70, and the control device 12 activates the notification unit 48 to sound an alarm so that the operator can be aware of it. After sounding the alarm, the control device 12 proceeds to step S190 and terminates the machining process.

[0041] In step S50, if the command chip thickness Q detected by the chip thickness detection unit 36 ​​is zero or a positive value, the process proceeds to step S60, where the chip thickness detection unit 36 ​​checks whether the command chip thickness Q detected is greater than the feed rate Fc per revolution of the workpiece W. If the command chip thickness Q is greater than the feed rate Fc per revolution of the workpiece W, the process proceeds to step S70, where the control device 12 activates the notification unit 48 to sound an alarm so that the operator can recognize it. After sounding the alarm, the control device 12 proceeds to step S190 and terminates the machining process.

[0042] In step S60, if the command chip thickness Q detected by the chip thickness detection unit 36 ​​is smaller than the feed rate Fc per revolution of the workpiece W, the process proceeds to step S80, where the oscillation command generation unit 40 generates a provisional oscillation command (the first oscillation command described above) based on the command chip thickness Q, and the process proceeds to step S100.

[0043] When the process moves to step S100, it is checked whether the surface roughness detection unit 38 has detected the commanded surface roughness K. If the surface roughness detection unit 38 has not detected the commanded surface roughness K, the process moves to step S150, and the provisional oscillation command generated in step S80 or step S90 is officially determined as the oscillation command.

[0044] In step S100, if the surface roughness detection unit 38 detects a commanded surface roughness K, the process proceeds to step S110 (step X1 in the figure), where the surface roughness detection unit 38 determines whether the commanded surface roughness K is a positive value or a value that specifies a predetermined surface roughness (which is zero in this embodiment). If the commanded surface roughness K is a positive value, the process proceeds to step S120 (step Y1 in Figure 6), where the surface roughness detection unit 38 sets the commanded surface roughness K as the surface roughness setting value and proceeds to step S140.

[0045] In step S110, if the commanded surface roughness K is a value that specifies a predetermined surface roughness (zero), the process proceeds to step S130 (step Y2 in Figure 6), where the surface roughness detection unit sets the predetermined surface roughness as the surface roughness setting value, and proceeds to step S140. The predetermined surface roughness may be set to be the same as, for example, the surface roughness d3 in a non-oscillating turning process (see Figure 4(c)). This ensures that even if the operator cannot command the surface roughness, by specifying zero as the predetermined surface roughness, the same surface roughness d3 as in the non-oscillating case can be secured.

[0046] When the process moves to step S140, the oscillation command generation unit 40 determines whether the surface roughness set value can be met when machining is performed according to the provisional oscillation command. If it is determined that the commanded surface roughness can be met with the provisional oscillation command, the provisional oscillation command is set as the formal oscillation command and the process moves to step S170. At this time, the provisional oscillation command may be adjusted to shorten the machining time by increasing the feed rate Fc and feed oscillation width WA per revolution of the workpiece W, within a range that satisfies the commanded surface roughness K and commanded chip thickness Q.

[0047] In step S140, if the oscillation command generation unit 40 determines that the command surface roughness cannot be satisfied with the provisional oscillation command, the oscillation command generation unit 40 adjusts the provisional oscillation command to satisfy the command surface roughness K (second oscillation command). Using equations (8) to (13) above, the oscillation command generation unit 40 calculates the cutting feed rate amplitude ratio Famp as the second amplitude ratio, with the minimum distance between waveforms Tmin1 as the command chip thickness Q, and generates the second oscillation command from the oscillation frequency f, the cutting feed rate amplitude ratio Famp, and the cutting feed rate F, and formally determines it as the oscillation command. Once the second oscillation command is generated, the process proceeds to step S170.

[0048] When the process moves to step S170, the point cloud generation unit 42 generates point cloud data based on the determined or generated oscillation command. Once the point cloud data is generated, the process moves to step S180, where the servo amplifier 30 supplies power to the servo motor 28 of the machine device 14 based on the generated point cloud data, and the machine device 14 performs turning on the workpiece W. Once the machining is complete, the process moves to step S190 and ends.

[0049] According to the machine tool 10 and machining method of this embodiment, the oscillation command generation unit 40 can calculate an oscillation frequency f based on the workpiece rotation speed S such that the first trough TR1 of the oscillation waveform in the Nth rotation from the start of rotation and the second peak CR2 of the oscillation waveform in the N+1th rotation have the same rotational phase θ. Furthermore, the oscillation command generation unit 40 can calculate an amplitude ratio Famp based on the cutting feed rate F and the command chip thickness Q so that the minimum inter-waveform distance Tmin, which is the distance between the first trough TR1 and the second peak CR2, matches the command chip thickness Q. Therefore, by making the rotational phase θ of the first trough TR1 and the second peak CR2 the same, the minimum inter-waveform distance Tmin can be reduced, and the chip thickness can be reduced. In addition, since the amplitude WA of the oscillation waveform can be adjusted using the amplitude ratio Famp, the minimum inter-waveform distance Tmin can be made to match the command chip thickness Q. This allows for the generation of a first oscillation command in continuous oscillation machining based on the chip thickness Q commanded by the machining program. The oscillation command generation unit 40 can also generate a first oscillation command based on the amplitude ratio Famp and the cutting feed rate F. Therefore, it is possible to adjust both the feed amount Fc per revolution of the workpiece rotation, which can be set by the cutting feed rate F and the workpiece rotation speed S, and the amplitude WA of the oscillation waveform, which is adjusted using the amplitude ratio Famp. This makes it possible to adjust the feed amount Fc per revolution of the workpiece W rotation, which affects the surface roughness d, while adjusting the relationship between the feed amount Fc per revolution of the workpiece W rotation and the amplitude WA of the oscillation waveform, so as not to change the minimum distance Tmin between waveforms, thereby enabling chip fragmentation in a manner that allows for surface roughness adjustment.

[0050] Furthermore, according to the machine tool 10 and machining method of this embodiment, the memory unit 34 can store the commanded surface roughness K in advance. Therefore, the oscillation command generation unit 40 can generate oscillation commands that satisfy both chip thickness and surface roughness. Specifically, based on the first oscillation command and the commanded surface roughness K, the oscillation command generation unit 40 can set the maximum inter-waveform distance Tmax, which is the distance between the first peak CR1 of the oscillation waveform in the Nth rotation from the start of rotation and the second trough TR2 of the oscillation waveform that has the same rotational phase θ as the first peak CR1 in the N+1th rotation, based on the commanded surface roughness K. In addition, the oscillation command generation unit 40 can calculate the feed amount Fc2 in the cutting feed direction per rotation of the workpiece W being machined from the maximum inter-waveform distance Tmax and the minimum inter-waveform distance Tmin, which is the distance between the first trough TR1 and the second peak CR2. Furthermore, the oscillation command generation unit 40 can calculate the cutting feed rate F based on the feed amount Fc2 and the workpiece rotation speed S, and calculate the amplitude ratio Famp for adjusting the amplitude WA of the oscillation waveform based on the feed amount Fc2 and the cutting feed rate F, so that the minimum distance Tmin between waveforms matches the commanded chip thickness Q. Based on the amplitude ratio Famp and the cutting feed rate F calculated in this way, the oscillation command generation unit 40 can generate a second oscillation command that satisfies both the commanded chip thickness Q and the commanded surface roughness K. This makes it possible to break up the chip after adjusting the surface roughness d.

[0051] Furthermore, according to the machine tool 10 and machining method of this embodiment, even when there is no input of cutting feed rate F, the oscillation command generation unit 40 can calculate the oscillation frequency f in which the first trough TR1 of the oscillation waveform in the Nth rotation from the start of rotation and the second peak CR2 of the oscillation waveform in the N+1th rotation have the same rotational phase θ, based on the workpiece rotation speed S. In addition, based on the command chip thickness Q and command surface roughness K, the maximum inter-waveform distance Tmax, which is the distance between the first peak CR1 of the oscillation waveform in the Nth rotation from the start of rotation and the second trough TR2 of the oscillation waveform in the N+1th rotation, can be set based on the command surface roughness K. Furthermore, the feed amount Fc3 in the cutting feed direction per rotation of the workpiece W being machined can be calculated from the maximum inter-waveform distance Tmax and the minimum inter-waveform distance Tmin, which is the distance between the first trough TR1 and the second peak CR2. Furthermore, the cutting feed rate F is calculated based on the feed amount Fc3 and the workpiece rotation speed S, and the amplitude ratio Famp is calculated to adjust the amplitude WA of the oscillating waveform so that the minimum distance between waveforms Tmin matches the commanded chip thickness Q. Therefore, by making the rotational phase θ of the first valley TR1 and the second peak CR2 the same, the minimum distance between waveforms Tmin can be reduced, and the chip thickness can be reduced. In addition, since the amplitude WA can be adjusted using the amplitude ratio Famp, the minimum distance between waveforms Tmin can be made to match the commanded chip thickness Q. As a result, in continuous oscillating machining, a third oscillating command can be generated based on the chip thickness Q commanded in the machining program. Furthermore, the oscillating command generation unit 40 can generate a third oscillating command based on the amplitude ratio Famp and the cutting feed rate F. Therefore, both the feed amount Fc3 per rotation of the workpiece W, which is calculated from the maximum distance between waveforms Tmax and the minimum distance between waveforms Tmin, and the amplitude WA of the oscillating waveform, which is adjusted using the amplitude ratio Famp, can be adjusted. This allows for chip fragmentation after adjusting the surface roughness d, by adjusting the relationship between the feed rate Fc3 per revolution of the workpiece W and the amplitude WA of the oscillating waveform, while keeping the minimum distance Tmin between waveforms unchanged, and by adjusting the maximum distance Tmax between waveforms based on the commanded surface roughness K.

[0052] Furthermore, according to the machine tool 10 of this embodiment, the oscillation command generation unit 40 is configured to generate an oscillation command according to a predetermined chip thickness that has been stored in the storage unit 34 in advance, when the chip thickness detection unit 36 ​​does not detect or is unable to detect the command chip thickness Q. Here, the predetermined chip thickness may be zero. This makes it possible to perform continuous oscillation turning using the value of the predetermined chip thickness even if the operator forgets to input the command chip thickness Q or fails to input it when generating the machining program.

[0053] Furthermore, according to the machine tool 10 of this embodiment, the oscillation command generation unit 40 is configured to stop generating oscillation commands when the chip thickness detection unit 36 ​​detects a negative chip thickness. The control device 12 includes a display unit 46 and a notification unit 48, and is configured to display on the display unit 46 that it has stopped when it stops generating oscillation commands, and to notify the operator via the notification unit 48. This prevents malfunction of the machine device 14 when the operator mistakenly inputs a negative value for the chip thickness when creating a machining program.

[0054] Furthermore, according to the machine tool 10 of this embodiment, the chip thickness detection unit 36 ​​is configured to stop generating the oscillation command when the chip thickness Q detected is greater than the feed rate Fc per revolution of the workpiece W. In such cases, the control device 12 is configured to display the fact that it has stopped on the display unit 46 and to notify the operator via the notification unit 48. This prevents the operator from creating an incorrect machining program.

[0055] As described above, the machine tool 10 and machining method according to this embodiment can generate an oscillation command based on the chip thickness Q commanded by the machining program in continuous oscillation machining in which the cutting insert 52 oscillates without separating from the workpiece W in the cutting feed direction.

[0056] Furthermore, the control device 12 includes a machining time calculation unit 44 (see Figure 1) for calculating the machining time. Based on the generated point cloud data, the machining time calculation unit 44 calculates the machining time for the turning operation performed by the machining program. When an oscillation command is generated to satisfy the commanded surface roughness K, the feed rate Fc per revolution of the workpiece W changes, and consequently, the machining time also changes. However, the correlation between the commanded surface roughness K and the machining time is not intuitively understandable to the operator. Therefore, the control device 12 includes a machining time calculation unit 44 that can calculate in advance how much machining time is required for a block containing the commanded chip thickness Q and the commanded surface roughness K, that is, how much the machining time will change from the prior prediction, and display it on the display unit 46 of the control device 12. This allows the operator to check the changed machining time and change the machining conditions in consideration of the impact on the production plan.

[0057] Although the explanation here has assumed that the machining is a turning process, the concept of this invention is not limited to turning and can also be applied to hole drilling. A machine tool for hole drilling may be constructed by replacing the cutting edge of a turning tool with the cutting edge of a boring tool or drill tool used for hole drilling.

[0058] Furthermore, the commanded surface roughness may be commanded not only in units of the maximum height Rz indicated by the theoretical finished surface roughness, but also in units of the arithmetic mean roughness Ra. In this case, the machine tool has the function of calculating the maximum height Rz that can satisfy the commanded arithmetic mean roughness Ra and generating the various oscillation commands described above.

[0059] Although embodiments of the machine tool 10 have been described above, the present invention is not limited to the above embodiments. For example, instead of a horizontal machine tool with a horizontal spindle, a vertical machine tool with a vertical spindle may be used. In addition to the above, it is expected that those skilled in the art will understand that various modifications of the above embodiments are possible. [Explanation of Symbols]

[0060] 10 Machine tools 12 Control device 14 Mechanical equipment 20. Main spindle (tool mounting section) 24. Workpiece Rotation Device (Workpiece Mounting Section) 25 Workpiece spindle (rotating axis) 34 Storage section 40 Oscillation command generation unit 50 tools 52 Cutting Inserts AL First axis F Cutting feed rate (1st to 3rd cutting feed rates) Famp cutting feed rate amplitude ratio (amplitude ratio of 1st to 3rd) Fc feed rate Fc1 feed rate Fc2 feed rate Fc3 feed rate Double job

Claims

1. A machine tool that processes a workpiece by rotating the tool and the workpiece relative to each other around a first axis, and also oscillating the tool and the workpiece in the direction of the first axis while moving them in a linear motion relative to each other, A tool mounting section to which the aforementioned tool is attached, A workpiece mounting section to which the workpiece is attached, A rotating shaft that causes the tool mounting portion and the workpiece mounting portion to rotate relative to each other around the first axis, A linear motion axis that moves the tool mounting portion and the workpiece mounting portion in a linear motion relative to each other along the first axial direction, A storage unit that pre-stores coordinates indicating the relative positional relationship between the tool and the workpiece during machining, the relative rotational speed between the tool and the workpiece, the relative first cutting feed rate between the tool and the workpiece, and the commanded chip thickness. Oscillating command generation unit, based on the rotation speed, The oscillation frequency at which the first trough of the oscillation waveform during the Nth rotation from the start of rotation and the second peak of the oscillation waveform during the N+1th rotation have the same rotational phase is calculated. Based on the first cutting feed rate and the commanded chip thickness, a first amplitude ratio is calculated to adjust the amplitude of the oscillation waveform so that the minimum inter-waveform distance, which is the distance between the first trough and the second peak, matches the commanded chip thickness. A oscillation command generation unit generates a first oscillation command based on the oscillation frequency, the first amplitude ratio, and the first cutting feed rate, A control device that operates the linear axis and the rotary axis based on the coordinates and the first oscillation command, Machine tools, including those mentioned above.

2. The machine tool according to claim 1, wherein the oscillation command generation unit generates the first oscillation command according to a predetermined chip thickness that has been stored in advance when the command chip thickness is not stored in the storage unit.

3. The machine tool according to claim 1, wherein the oscillation command generation unit stops generating the first oscillation command when the command chip thickness is a negative value.

4. The machine tool according to claim 1, wherein the oscillation command generation unit stops generating the first oscillation command when the command chip thickness is greater than the tool feed amount per revolution of the workpiece, which is calculated from the relative rotational speed with respect to the workpiece and the cutting feed rate.

5. The memory unit stores the commanded surface roughness in advance. The oscillation command generation unit generates the oscillation command based on the first oscillation command and the command surface roughness, The maximum inter-waveform distance, which is the distance between the first peak of the oscillation waveform during the Nth rotation from the start of rotation and the second trough of the oscillation waveform that has the same rotational phase as the first peak during the N+1th rotation, is set based on the commanded surface roughness, and the feed amount in the cutting feed direction per rotation of the rotational movement during machining is calculated from the maximum inter-waveform distance and the minimum inter-waveform distance, which is the distance between the first trough and the second peak. A second cutting feed rate is calculated based on the feed amount and the rotational speed. Based on the feed rate and the second cutting feed rate, a second amplitude ratio is calculated to adjust the amplitude of the oscillation waveform so that the minimum distance between waveforms matches the commanded chip thickness. A second oscillation command is generated based on the oscillation frequency, the second amplitude ratio, and the second cutting feed rate. The control device operates the linear axis and the rotary axis based on the coordinates and the second oscillation command. The machine tool according to claim 1.

6. A machine tool that processes a workpiece by rotating the tool and the workpiece relative to each other around a first axis, and also oscillating the tool and the workpiece in the direction of the first axis while moving them in a linear motion relative to each other, A tool mounting section to which the aforementioned tool is attached, A workpiece mounting section to which the workpiece is attached, A rotating shaft that causes the tool mounting portion and the workpiece mounting portion to rotate relative to each other around the first axis, A linear motion axis that moves the tool mounting portion and the workpiece mounting portion in a linear motion relative to each other along the first axial direction, A storage unit that pre-stores coordinates indicating the relative positional relationship between the tool and the workpiece during machining, the relative rotational speed between the tool and the workpiece, a commanded chip thickness, and a commanded surface roughness. Oscillating command generation unit, based on the rotation speed, The oscillation frequency at which the first trough of the oscillation waveform during the Nth rotation from the start of rotation and the second peak of the oscillation waveform during the N+1th rotation have the same rotational phase is calculated. Based on the commanded chip thickness and the commanded surface roughness, The maximum inter-waveform distance, which is the distance between the first peak of the oscillation waveform at the Nth rotation from the start of rotation and the second trough of the oscillation waveform at the N+1th rotation, is set based on the commanded surface roughness, and the feed amount in the cutting feed direction per rotation of the rotational movement during machining is calculated from the maximum inter-waveform distance and the minimum inter-waveform distance, which is the distance between the first trough and the second peak. A third cutting feed rate is calculated based on the feed amount and the rotational speed. A third amplitude ratio is calculated to adjust the amplitude of the oscillation waveform so that the minimum distance between the waveforms matches the commanded chip thickness. A oscillation command generation unit generates an oscillation command based on the oscillation frequency, the third amplitude ratio, and the third cutting feed rate, A control device that operates the linear axis and the rotation axis based on the coordinates and the oscillation command, Machine tools, including those mentioned above.

7. A machining method for processing a workpiece by rotating the tool and the workpiece relative to each other around a first axis, and oscillating the tool and the workpiece in the direction of the first axis while moving them in a linear motion relative to each other, A process of inputting coordinates indicating the relative positional relationship between the tool and the workpiece during machining, the cutting feed rate for the relative linear motion between the tool and the workpiece, the rotational speed for the relative rotational motion between the tool and the workpiece, the commanded chip thickness, and the number of teeth of the tool. A step of calculating the oscillation frequency at which the trough of the oscillation waveform during the Nth rotation from the start of rotation and the peak of the oscillation waveform during the N+1th rotation have the same rotational phase, based on the rotational speed and the number of blades. A step of calculating the amplitude of oscillation based on the rotational speed, the number of teeth of the tool, the cutting feed rate, and the commanded chip thickness, A step of generating a first oscillation command based on the amplitude and the oscillation frequency, A process of machining by causing the tool and the workpiece to rotate and move in a linear motion relative to each other based on the first oscillation command, Processing methods, including those mentioned above.

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