Machine tool and machining method

Abstract

A machine tool (10) includes: a main shaft (20); a workpiece rotating device (24); a storage unit (34) that stores, in advance, relative coordinates between a tool and a workpiece (W), a rotational speed, a first cutting feed speed, and a commanded chip thickness; an oscillation command generation unit (40) that calculates an oscillation frequency at which a first valley portion of an oscillation waveform in an N-th rotation and a second peak portion of an oscillation waveform in an (N+1)-th rotation are at the same rotational phase, calculates a first amplitude ratio that adjusts an oscillation waveform amplitude such that a minimum distance between waveforms between the first valley portion and the second peak portion coincides with the commanded chip thickness, and generates a first oscillation command on the basis of the oscillation frequency, the first amplitude ratio, and the first cutting feed speed; and a control device (12) that operates a machine device (14) in accordance with the first oscillation command.

Description

Machine tools, processing methods

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

[0002] In turning, controlling chip breakage is important to maintain the condition of the machine tool and the tool. For this reason, conventionally, machine tools have been known that perform turning by repeatedly breaking chips while oscillating the feed shaft at an oscillation frequency, in which the tool separates from the workpiece in the cutting feed direction, misses the workpiece, and then contacts and cuts it again, a process known as intermittent cutting. However, such intermittent cutting can result in damage to the tool due to repeated contact between the tool and the workpiece. Therefore, Patent Document 1 discloses a continuous oscillation turning technique that changes the thickness of the chips with each oscillation cycle while preventing the tool from separating from the workpiece in the cutting feed direction, thereby enabling the chips to be broken by centrifugal force as they are discharged.

[0003] In continuous orbital turning, in order to facilitate chip breaking by centrifugal force, it is important to minimize the thickness of the chips at their thinnest portions. However, orbital turning can result in thin and thick chips depending on the rotation phase of the workpiece. Since the surface roughness of the workpiece corresponding to the thick chips can be large, orbital turning can result in worse surface roughness than non-orbital turning. Therefore, it is desirable to break the chips in a manner that allows for adjustment of the surface roughness.

[0004] Japanese Patent Application Laid-Open No. 2023-141865

[0005] In view of the above circumstances, the present invention aims to provide a machine tool and a machining method that generates a swing command based on the chip thickness commanded in the machining program in continuous swing machining, in which the tool swings in the cutting feed direction without separating from the workpiece.

[0006] According to one aspect of the present invention, there is provided a machine tool that processes a workpiece by relatively rotating a tool and a workpiece about a first axis and relatively linearly moving the tool and the workpiece while swinging them in the first axial direction, the machine tool including a tool mounting portion to which the tool is attached, a work mounting portion to which the workpiece is attached, a rotation axis that relatively rotates the tool mounting portion and the workpiece mounting portion about the first axis, a linear axis that relatively linearly moves the tool mounting portion and the workpiece mounting portion along the first axial direction, coordinates indicating the relative positional relationship between the tool and the workpiece during machining, the relative rotation speed between the tool and the workpiece, a first relative cutting feed rate between the tool and the workpiece, and a command chip thickness, which are set in advance. a swing command generation unit that calculates, based on the rotation speed, a swing frequency at which a first valley of the swing waveform at the Nth rotation from the start of the rotation operation and a second peak of the swing waveform at the N+1th rotation are in the same rotational phase, and calculates, based on the first cutting feed rate and the command chip thickness, a first amplitude ratio for adjusting the amplitude of the swing waveform so that the minimum distance between the waveforms, which is the distance between the first valley and the second peak, matches the command chip thickness, and generates a first swing command based on the swing frequency, the first amplitude ratio, and the first cutting feed rate; and a control device that operates the linear axes and the rotary axes based on the coordinates and the first swing command.

[0007] According to another aspect of the present invention, there is provided a machine tool for machining a workpiece by relatively rotating a tool and a workpiece about a first axis and relatively linearly moving the tool and the workpiece while swinging them in the first axial direction, the machine tool comprising: a tool mounting section to which the tool is attached; a work mounting section to which the workpiece is attached; a rotation axis for relatively rotating the tool mounting section and the workpiece mounting section about the first axis; a linear axis for relatively linearly moving the tool mounting section and the workpiece mounting section along the first axial direction; a storage section for storing 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, a command chip thickness, and a command surface roughness; and a swing command generation section for generating a swing command based on the rotational speed, the first valley of the swing waveform at the Nth rotation from the start of the rotational operation and the second valley of the swing waveform at the N+1th rotation. a swing command generator that calculates a swing frequency at which the first peak of the swing waveform at the Nth rotation from the start of rotation and the second valley of the swing waveform at the (N+1)th rotation based on the command chip thickness and the command surface roughness, sets a maximum inter-wavelength distance, which is the distance between the first peak of the swing waveform at the Nth rotation from the start of rotation and the second valley of the swing waveform at the (N+1)th rotation, based on the command surface roughness, calculates a feed amount in the cutting feed direction per rotation of the rotation operation during machining from the maximum inter-wavelength distance and a minimum inter-wavelength distance, which is the distance between the first valley and the second peak, calculates a third cutting feedrate based on the feed amount and the rotation speed, calculates a third amplitude rate for adjusting the amplitude of the swing waveform so that the minimum inter-wavelength distance matches the command chip thickness, and generates a swing command based on the swing frequency, the third amplitude rate, and the third cutting feedrate; and a control device that operates the linear axis and the rotary axis based on the coordinates and the swing command.

[0008] Furthermore, according to one aspect of the present invention, there is provided a machining method for machining a workpiece by relatively rotating the tool and workpiece about a first axis and relatively linearly moving the tool and workpiece while swinging them in the first axial direction, the machining method including the steps of: inputting coordinates indicating the relative positional relationship between the tool and workpiece during machining, a cutting feed rate for the relative linear motion between the tool and workpiece, a rotational speed for the relative rotational motion between the tool and workpiece, a command chip thickness, and the number of teeth of the tool; calculating, based on the rotational speed and the number of teeth, an oscillation frequency at which the valley of the oscillation waveform at the Nth rotation from the start of the rotation operation and the peak of the oscillation waveform at the N+1th rotation are in the same rotational phase; calculating the oscillation amplitude based on the rotational speed, the number of teeth of the tool, the cutting feed rate, and the command chip thickness; generating a first oscillation command based on the amplitude and the oscillation frequency; and machining the tool and workpiece by relatively rotating and linearly moving them based on the first oscillation command.

[0009] According to one aspect of the present invention, the memory unit can pre-store coordinates indicating the relative positional relationship between the tool and workpiece during machining, the relative rotational speed between the tool and workpiece, a first cutting feed rate relative to the tool and workpiece, and a command chip thickness. The swing command generator can calculate, based on the rotational speed, an oscillation frequency at which the first valley of the oscillation waveform at the Nth rotation from the start of the rotation operation and the second peak of the oscillation waveform at the (N+1)th rotation are in the same rotational phase. The swing command generator can also calculate, based on the first cutting feed rate and the command chip thickness, a first amplitude ratio for adjusting the amplitude of the oscillation waveform so that the minimum inter-waveform distance, which is the distance between the first valley and the second peak, coincides with the command chip thickness. Therefore, by matching the rotational phases of the first valley and the second peak, the minimum inter-waveform distance can be reduced, thereby reducing the chip thickness. 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 allows for the generation of an oscillation command based on the chip thickness commanded in the machining program in continuous oscillation machining. The oscillation command generator can also generate a first oscillation command based on the first amplitude ratio and the first cutting feedrate. This allows for the adjustment of both the feed rate per rotation of the workpiece, which can be set by the first cutting feedrate and the relative rotation speed between the tool and the workpiece, and the amplitude of the oscillation waveform, which is adjusted using the first amplitude ratio. This allows for the adjustment of the feed rate per rotation of the workpiece, which affects the surface roughness, while adjusting the relationship between the feed rate per rotation of the workpiece and the amplitude of the oscillation waveform so as not to change the minimum distance between waveforms, thereby enabling chip separation in a manner that allows for the adjustment of surface roughness.

[0010] In a machine tool according to one aspect of the present invention, the memory unit can pre-store coordinates indicating the relative positional relationship between the tool and workpiece during machining, the relative rotational speed between the tool and workpiece, a command chip thickness, and a command surface roughness. The swing command generation unit can calculate, based on the rotational speed, an oscillation frequency at which the first valley of the oscillation waveform at the Nth rotation from the start of the rotation operation and the second peak of the oscillation waveform at the (N+1)th rotation are in the same rotational phase. Based on the command chip thickness and the command surface roughness, a maximum inter-waveform distance, which is the distance between the first peak of the oscillation waveform at the Nth rotation from the start of the rotation operation and the second valley of the oscillation waveform at the (N+1)th rotation, can be set based on the command surface roughness. Furthermore, the feed amount in the cutting feed direction per 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 valley and the second peak. Furthermore, a third cutting feed rate can be calculated based on the feed rate and the rotational speed, and a third amplitude ratio can be calculated to adjust the amplitude of the oscillation waveform so that the minimum distance between waveforms matches the command chip thickness. Therefore, by aligning the rotational phases of the first valley and the second peak, the minimum distance between waveforms can be reduced, thereby reducing the chip thickness. Furthermore, since the amplitude of the oscillation waveform can be adjusted using the third amplitude ratio, the minimum distance between waveforms can be matched to the command chip thickness. This allows the third oscillation command to be generated based on the command chip thickness and command surface roughness commanded in the machining program in continuous oscillation machining. Furthermore, the oscillation command generation unit can generate an oscillation command based on the third amplitude ratio and the third cutting feed rate. Therefore, both the feed rate per rotation of the workpiece calculated from the maximum distance between waveforms and the minimum distance between waveforms and the amplitude of the oscillation waveform adjusted using the third amplitude ratio can be adjusted. This makes it possible to break chips after adjusting the surface roughness, such as by adjusting the relationship between the feed rate per rotation of the workpiece and the amplitude of the oscillating waveform so as not to change the minimum distance between waveforms, while adjusting the maximum distance between waveforms based on the command surface roughness.

[0011] Furthermore, a machining method according to one aspect of the present invention includes a step of inputting coordinates indicating the relative positional relationship between the tool and workpiece during machining, a cutting feed rate for the relative linear motion between the tool and workpiece, a rotational speed for the relative rotational motion between the tool and workpiece, a command chip thickness, and the number of tool teeth. The method also includes a step of calculating, based on the rotational speed and the number of teeth, an oscillation frequency at which the valley of the oscillation waveform at the Nth rotation from the start of the rotational operation and the peak of the oscillation waveform at the N+1th rotation are in the same rotational phase. The method also includes a step of calculating the oscillation amplitude based on the rotational speed, the number of tool teeth, the cutting feed rate, and the command chip thickness. Therefore, by aligning the rotational phases of the valley at the Nth rotation and the peak at the N+1th rotation, the minimum distance between the waveforms, which is the distance between them, can be reduced, thereby reducing the chip thickness. Furthermore, the oscillation amplitude can be adjusted based on the command chip thickness. This allows a first oscillation command to be generated in continuous oscillation machining based on the calculated amplitude and oscillation frequency. Furthermore, the swing command generating unit can generate a first swing command based on the swing amplitude and the cutting feed rate. This allows adjustment of both the swing amplitude and the feed rate per rotation of the workpiece, which can be set based on the cutting feed rate and the relative rotation speed between the tool and the workpiece. This allows for adjustment of the feed rate per rotation of the workpiece, which affects the surface roughness, while adjusting the relationship between the swing amplitude and the feed rate per rotation of the workpiece, so as not to change the minimum distance between waveforms. This makes it possible to break chips in a manner that allows for adjustment of the surface roughness.

[0012] FIG. 1 shows a block diagram of a machine tool according to this embodiment. FIG. 2 shows an explanatory diagram illustrating the relative relationship between the tool and workpiece during machining according to this embodiment. FIG. 3 shows the relationship between rotation phase and chip thickness in continuous orbital turning. FIGS. 4(a) and 4(b) show the relationship between rotation phase and chip thickness and surface roughness in orbital turning. FIG. 4(c) shows the relationship between rotation phase and chip thickness and surface roughness in non-orbital turning. FIG. 5(a) shows the relationship between rotation phase and chip thickness when only the commanded chip thickness is satisfied, FIG. 5(b) shows the relationship between rotation phase and chip thickness when both the commanded chip thickness and commanded surface roughness are satisfied, and FIG. 5(c) shows a comparison of the relationships shown in FIGS. 5(a) and 5(b). FIG. 6 shows a flowchart of the machine tool according to this embodiment.

[0013] Hereinafter, a machine tool and a machining method according to an embodiment will be described with reference to the accompanying drawings. Similar or corresponding elements are designated by the same reference numerals, and duplicated explanations will be omitted. For ease of understanding, the scale of the drawings may be changed.

[0014] 1 shows a block diagram of a machine tool 10 according to this embodiment. The machine tool 10 includes 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 operate a spindle 20, a tool 50, and a cutting insert 52 as part of the tool 50 in accordance with commands of the machining program sent from the control device 12, thereby machining the workpiece W.

[0015] As shown schematically in FIG. 2 , the machine device 14 according to this embodiment is a device for performing turning by moving the tool 50, cutting insert 52, and a rotating workpiece W relative to each other along a feed direction, which is the direction of relative movement. Here, the turning operation is shown with a workpiece rotation speed S, which is the relative rotational speed between the tool 50, cutting insert 52, and workpiece W, a cutting feed rate F, which is the relative linear speed between the tool 50, cutting insert 52, and workpiece W, and a feed rate Fc per rotation of the workpiece W. When the turning operation is not performed, the thickness of the chips generated by the cutting insert 52 turning the workpiece is uniform, regardless of the rotation phase θ (see FIG. 3 ), as shown by the solid line in the figure. On the other hand, when the turning operation is performed with orbital turning, the thickness of the chips generated by the cutting insert 52 turning the workpiece varies depending on the rotation phase θ, as shown by the dashed line in the figure. 3, the vertical axis represents the position (coordinate) in the cutting feed direction, the horizontal axis represents the rotation phase θ of the workpiece W, and the solid lines shown for the Nth and N+1th revolutions represent the cutting edge trajectories. Note that to facilitate understanding of the relationship between various elements, the cutting edge trajectory does not include the feed amount component per revolution.

[0016] As shown in FIG. 1 , the machine 14 includes a bed 16 fixed to the floor of an installation location (such as a factory). A fixed column 18 is erected on the upper surface of the bed 16 on the right side in the Z-axis direction (the horizontal direction on the paper). A spindle 20 serving as a tool mounting unit is disposed on the front side of the column 18, i.e., on the left side of the Z-axis direction, via a saddle (not shown) for moving a tool 50 and a cutting insert 52 along the X-axis direction (perpendicular to the paper) and the Z-axis direction (the vertical direction on the paper). A tool 50 is attached to the tip of the spindle 20. A cutting insert 52 is attached to the tip of the tool 50 as part of the tool 50, and contacts and processes a workpiece W. Here, the cutting insert 52 is a manually replaceable blade. However, various types of blades can be selected instead of the cutting insert 52, such as a blade brazed to the tool 50 or a blade in which the tool 50 itself is machined to form a cutting edge.

[0017] A table 22 is arranged on the upper surface of the bed 16 on the left side in the Z axis direction, and is configured to be movable on the bed 16 via a guide surface. Therefore, the bed 16 is equipped with a Z-axis feed device (not shown) as a linear axis for moving the table 22 along the Z axis direction (direction of the first axis AL), which is the feed direction. The table 22 is also equipped with a workpiece rotation device 24 as a workpiece mounting unit, which includes a workpiece spindle 25 as a rotation axis for mounting the workpiece W and rotating the workpiece W about the first axis AL. This allows the tool 50 and cutting insert 52 attached to the spindle 20 and the workpiece W attached to the workpiece rotation device 24 to move linearly relative to each other in the Z axis direction along the first axis AL, and to rotate relative to each other along the first axis AL. Furthermore, the spindle 20 and the workpiece rotation device 24 can be moved relative to each other in the X axis direction and the Y axis direction, which are the feed directions.

[0018] The machine 14 also has a tool changer 26 for performing a wide variety of machining operations depending on the machining purpose, and the tool changer 26 is configured to be able to change tools 50 attached to the spindle 20. The machine 14 further includes a plurality of servo motors 28 that drive the spindle 20 and drive a linear motion mechanism and a rotation mechanism that move the spindle 20 relative to the table 22. The machine 14 also includes a servo amplifier 30 that is connected to the servo motors 28 and is configured to supply power and detect the rotation position from an encoder (not shown).

[0019] The control device 12 includes an input unit 32 through which the operator inputs a machining program for continuous orbital turning. The machining program is written as a single block and input to the input unit 32, for example, G01 X_Y_Z_S_F_Q_;. Here, G01 represents a G-code for commanding the cutting feed, X, Y, and Z represent the coordinates at which the spindle 20 or table 22 should be positioned during machining, S represents the workpiece rotation speed of the workpiece rotation device 24, F represents the cutting feed rate, and Q represents the commanded chip thickness. The commanded chip thickness Q is input as zero (0) or a positive value. Furthermore, an M-code for turning on the continuous orbital turning mode is commanded in the block preceding the above block, thereby recognizing the block as continuous orbital turning. In this case, after continuous orbital turning is completed, another M-code is commanded to turn off the mode.

[0020] Furthermore, as will be described later, when performing orbital turning so as to satisfy a commanded surface roughness K in addition to a commanded chip thickness Q, the machining program is written, for example, as 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 cutting edge R (see FIG. 2). Specifically, the tool cutting edge R is the value of the radius of the cutting edge of the tool (here, the cutting edge of the cutting insert 52) ​​that comes into contact with the workpiece W to perform machining. Note that if the tool cutting edge R is not commanded, the information on the tool cutting edge R stored in the memory unit 34 may be referenced for the tool attached to the spindle when the machining program is executed.

[0021] The control device 12 includes a memory unit 34 for storing input contents including an input machining program. The memory unit 34 is configured to store coordinates input by the operator indicating the relative positional relationship between the tool 50 and cutting insert 52 during machining and the workpiece W, the relative rotation 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 a command chip thickness Q.

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

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

[0024] Furthermore, the swing command generating 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 swing waveform, based on the cutting feed rate F, which is the 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 portion TR1 and the second peak portion CR2, matches the command chip thickness Q. The feed swing width WA [mm] satisfies the following relationship with the feed swing 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] means both amplitudes of the oscillation waveform. Also, the minimum distance between the waveforms Tmin [mm] satisfies the following relationship with the feed amount Fc [mm / rev] per rotation of the workpiece W and the feed oscillation width WA [mm]. T ｍｉｎ = Fc - WA (4) Furthermore, the feed amount Fc per rotation of the workpiece W satisfies the following relationship with the cutting feed rate F and the workpiece rotation rate S: Fc = F / S (5) Therefore, using the above formulas (1) to (5), the cutting feed rate amplitude ratio Famp [%] can be calculated as follows: F ａｍｐ =100×π×S×n×m×(F / S-T ｍｉｎ ) / (2 × F) (6)

[0025] The swing command generating unit 40 calculates the cutting feed rate amplitude ratio Famp using the minimum distance between waveforms Tmin as the command chip thickness Q, and generates a swing command as a first swing 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. The point cloud generation unit 42 generates point cloud data based on a predetermined division period of a sine wave and X, Y, and Z coordinates while oscillating the cutting feed rate F input in the machining program based on the calculated cutting feed rate amplitude ratio Famp and oscillation frequency f.

[0027] Once the generation of the point cloud data and the calculation of the machining time are completed, the control device 12 operates the servo amplifier 30, supplies power to the servo motor 28 based on the generated point cloud data, operates the machine device 14, and performs continuous swing turning on the workpiece W. This makes it possible to bring the first valley TR1 of the swing waveform at the Nth rotation from the start of the rotation operation and the second peak CR2 of the swing waveform at the (N+1)th rotation into the same rotational phase θ, and makes it possible to match the minimum distance Tmin between the waveforms, which is the distance between the first valley TR1 and the second peak CR2, with the command chip thickness Q.

[0028] Furthermore, the swing command generation unit 40 is configured to generate a swing command in accordance with a predetermined chip thickness pre-stored in the memory unit 34 when the chip thickness detection unit 36 ​​does not or cannot detect the command chip thickness Q. Here, the predetermined chip thickness may be zero. This allows continuous swing 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 when generating the machining program.

[0029] Furthermore, the swing command generating unit 40 is configured to stop generating a swing command when the chip thickness detecting unit 36 ​​detects a chip thickness that is a negative value. The control device 12 is equipped with a display unit 46 and an informing unit 48, and is configured to display that fact on the display unit 46 when the generation of the swing command has been stopped, and to notify the operator via the informing unit 48. This makes it possible to prevent malfunction of the machine device 14 when the operator mistakenly enters a negative chip thickness when creating a machining program.

[0030] Furthermore, the swing command generating unit 40 is configured to stop generating a swing command when the command chip thickness Q detected by the chip thickness detecting unit 36 ​​is greater than the feed rate Fc per rotation of the workpiece W. In such a case, the control device 12 is configured to display the fact that the swing command has been stopped on the display unit 46 and to notify the operator via the notifying unit 48. This makes it possible to prevent the operator from creating an incorrect machining program.

[0031] Furthermore, the swing command generating unit 40 can generate a swing command that inputs a command surface roughness K in addition to the command chip thickness Q. Generally, the smaller the chip thickness T, the easier it is to break the chip. On the other hand, the smaller the chip thickness T, the worse the surface roughness d. The surface roughness d, which is the maximum height of the unevenness CN created on the surface of the workpiece W by the tool cutting edge R (see FIG. 2 for both), becomes better the larger the tool cutting edge R and the smaller the feed rate Fc per rotation of the workpiece W.

[0032] As shown in Figure 4(c), when turning is performed without oscillation, the chip thickness is always the same as the feed rate Fc per rotation of the workpiece W, and the surface roughness d3 is always constant. In contrast, as shown in Figures 4(a) and 4(b), when turning is performed with oscillation, the surface roughness d varies depending on the rotation phase θ. As shown in Figure 4(a), at the rotation phase θ (Ph1 in Figure 3) where the first peak CR1 of the oscillation waveform at the Nth rotation from the start of rotation and the second valley TR2 of the oscillation waveform at the (N+1)th rotation coincide, the chip thickness Tmax is greatest and the surface roughness d1 is also greatest. 4(b), at the rotation phase θ (Ph2 in FIG. 3) where the first valley TR1 of the oscillation waveform at the Nth rotation from the start of rotation and the second peak CR2 of the oscillation waveform at the (N+1)th rotation coincide, the chip thickness Tmin is at its thinnest and the surface roughness d2 is also at its smallest. The relationship between the surface roughness d, the feed rate Fc per rotation of the workpiece W, and the tool cutting edge R is expressed by the following equation (7). By substituting the feed rate Fc per rotation of the workpiece W for the chip thicknesses Tmax and Tmin, the relationship between the surface roughnesses d1, d2, and d3 and the chip thicknesses Tmax and Tmin can be determined. d = Fc × Fc / (8 × R) (7) Thus, depending on the rotation phase θ of the oscillation turning process, the surface roughness d may be worse than when turning is performed without oscillation.

[0033] Therefore, according to the control device 12 of this embodiment, as shown in Fig. 5, the operator can generate a swing command as a second swing command by inputting not only the command chip thickness Q but also the command surface roughness K. Specifically, the feed amount Fc1 per rotation of the workpiece W that was initially input is used as a tentative feed amount (reference value), and the feed amount Fc2 per rotation of the workpiece W is calculated so as to satisfy both the command chip thickness Q (= Tmin1) and the command surface roughness K (= d).

[0034] 5A shows the relationship between the rotation phase θ and the chip thicknesses Tmax1 and Tmin1 when machining is performed in accordance with a virtual oscillation command (corresponding to the first oscillation command described above) generated from the input feed rate Fc1 per rotation of the workpiece W and the command chip thickness Q. Here, WA1 represents the feed oscillation width. The distance between the first peak CR1 of the oscillation waveform at the Nth rotation and the second valley TR2 of the oscillation waveform that has the same rotation phase θ as the first peak CR1 at the (N+1)th rotation is the maximum inter-waveform distance Tmax1, and the distance between the first valley TR1 and the second peak CR2 is the minimum inter-waveform distance Tmin1. In contrast, the second swing command is generated so that the minimum distance Tmin1 between waveforms based on the command chip thickness Q is kept the same as that of the first swing command, while the maximum distance Tmax2 between waveforms is set, or in this case, is made smaller, so that the surface roughness becomes d based on the command surface roughness K, as shown in Figures 5(b) and 5(c).

[0035] In this way, in order to set the minimum distance between waveforms Tmin1 and the maximum distance between waveforms Tmax2, the feed amount Fc2 per rotation of the workpiece W is calculated so as to satisfy these, separately from the input tentative feed amount Fc1. As shown in Figures 5(b) and 5(c), the sum of the maximum distance between waveforms Tmax2 and the minimum distance between waveforms Tmin1 is twice the feed amount Fc2 per rotation of the workpiece W. T ｍａｘ２ +T ｍｉｎ１ = 2 × Fc2 (8) Furthermore, as shown in the above formula (4), the minimum distance between waveforms Tmin1 [mm] satisfies the following relationship with the feed amount Fc2 [mm / rev] per rotation of the workpiece W and the feed oscillation width WA2 [mm]. T ｍｉｎ１ = Fc2 - WA2 (9) Similarly, the maximum distance between waveforms Tmax2 [mm] satisfies the following relationship with the feed amount Fc2 [mm / rev] per rotation of the workpiece W and the feed oscillation width WA2 [mm]. 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 the corrugations Tmax2 is expressed as follows: d = T ｍａｘ２ ×Tｍａｘ２ / (8×R) (11) Therefore, by substituting equations (9) to (11) into equation (8), the feed amount Fc2 per rotation of the workpiece W can be calculated as follows: Fc2={(8×R×d) １／２ +Tmin1} / 2 (12) Furthermore, from the above equation (5), the cutting feedrate F as the second cutting feedrate can be calculated from the feed amount Fc2 per rotation of the workpiece W and the workpiece rotation speed S. F = Fc2 × S (13) The swing command generation unit 40 calculates a cutting feedrate amplitude ratio Famp as the second amplitude ratio using the minimum distance between waveforms Tmin1 as the command chip thickness Q, and generates a swing command as the second swing command from the swing frequency f, the cutting feedrate amplitude ratio Famp, and the cutting feedrate F. This makes it possible to generate a second swing command so as to satisfy both the command chip thickness Q (= Tmin1) and the command surface roughness K (= d). Then, the point cloud generation unit 42 generates point cloud data based on the generated second swing command, and the servo amplifier 30 supplies power to the servo motor 28 of the machine device 14 based on the generated point cloud data to operate the machine device 14. This allows continuous swing turning to be performed on the workpiece W in accordance with the second swing command.

[0036] Since the swing command generating unit 40 can generate the second swing command using both the command chip thickness Q and the command surface roughness K as inputs as described above, it can generate a swing command as a third swing command using the same procedure as generating the second swing command even when the cutting feedrate is not input. That is, by setting the minimum inter-waveform distance Tmin1 as the command chip thickness Q and the surface roughness d as the command surface roughness K, the feed rate Fc3 per rotation of the workpiece W can be calculated from the above equation (12), and by substituting this into equation (13), the cutting feedrate F can be calculated as the third cutting feedrate. Therefore, by substituting these into the above equation (6), the cutting feedrate amplitude rate Famp as the third amplitude rate can be calculated, and a swing command as the third swing command can be generated from the swing frequency f, the cutting feedrate amplitude rate Famp, and the cutting feedrate F.

[0037] The effects of the machine tool 10 according to this embodiment will be described below through an explanation of the swing cutting process of the workpiece W using the flowchart of the machine tool 10 shown in FIG.

[0038] First, the process proceeds to step S10, where the machining process is started, and then to step S20, where a machining program including a swing command is input to the input unit 32 of the control device 12, and the swing command is stored in the memory unit 34. Then, the process proceeds to step S30, where the chip thickness detection unit 36 ​​detects the commanded chip thickness Q from the memory unit 34, and then to step S40. Here, if the chip thickness detection unit 36 ​​detects the commanded chip thickness Q, the process proceeds to step S50.

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

[0040] When the chip thickness detection unit 36 ​​detects the command chip thickness Q and the process 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 alarm 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 ends the machining process.

[0041] In step S50, if the command chip thickness Q confirmed by the chip thickness detection unit 36 ​​is zero or a positive value, the process proceeds to step S60, where it is confirmed whether the command chip thickness Q detected by the chip thickness detection unit 36 ​​is greater than the feed rate Fc per rotation of the workpiece W. If the command chip thickness Q is greater than the feed rate Fc per rotation of the workpiece W, the process proceeds to step S70, where the control device 12 activates the alarm 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, where the machining process ends.

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

[0043] When the process proceeds to step S100, it is confirmed whether the surface roughness detection unit 38 has detected the command surface roughness K. If the surface roughness detection unit 38 has not detected the command surface roughness K, the process proceeds to step S150, where the provisional swing command generated in step S80 or step S90 is determined to be the official swing command.

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

[0045] In step S110, if the command surface roughness K is a value (zero) specifying the predetermined surface roughness, the process proceeds to step S130 (step Y2 in FIG. 6), where the surface roughness detection unit sets the predetermined surface roughness as the surface roughness set value, and the process proceeds to step S140. The predetermined surface roughness may be set to be the same as the surface roughness d3 in turning without oscillation (see FIG. 4(c)), for example. In this way, even if the operator cannot specify the surface roughness, by specifying zero as the predetermined surface roughness, it is possible to ensure the same surface roughness d3 as in the case without oscillation.

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

[0047] In step S140, if the swing command generating unit 40 determines that the command surface roughness cannot be satisfied with the tentative swing command, the swing command generating unit 40 adjusts the tentative swing command so as to satisfy the command surface roughness K (second swing command). The swing command generating unit 40 calculates the cutting feedrate amplitude ratio Famp as the second amplitude ratio using the minimum inter-waveform distance Tmin1 as the command chip thickness Q using the above equations (8) to (13), and generates a second swing command from the swing frequency f, the cutting feedrate amplitude ratio Famp, and the cutting feedrate F, and determines it as a formal swing command. Once the second swing command has been generated, the process proceeds to step S170.

[0048] In step S170, the point cloud generator 42 generates point cloud data based on the determined or generated swing command. After the point cloud data is generated, the process proceeds 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. When the machining is completed, the process proceeds to step S190, where the machining process ends.

[0049] According to the machine tool 10 and machining method of this embodiment, the swing command generation unit 40 can calculate, based on the workpiece rotation speed S, a swing frequency f at which the first valley TR1 of the swing waveform at the Nth rotation from the start of the rotation operation and the second peak CR2 of the swing waveform at the (N+1)th rotation are at the same rotational phase θ. Furthermore, based on the cutting feed rate F and the command chip thickness Q, the swing command generation unit 40 can calculate an amplitude ratio Famp for adjusting the amplitude WA of the swing waveform so that the minimum inter-waveform distance Tmin, which is the distance between the first valley TR1 and the second peak CR2, coincides with the command chip thickness Q. Therefore, by making the rotational phase θ of the first valley TR1 and the second peak CR2 the same, the minimum inter-waveform distance Tmin can be reduced, thereby reducing the chip thickness. Furthermore, since the amplitude WA of the swing waveform can be adjusted using the amplitude ratio Famp, the minimum inter-waveform distance Tmin can be made to coincide with the command chip thickness Q. This allows the first swing command to be generated based on the chip thickness Q commanded in the machining program in continuous swing machining. The swing command generator 40 can also generate the first swing command based on the amplitude ratio Famp and the cutting feed rate F. This allows adjustment of both the feed rate Fc per rotation of the workpiece W, which can be set based on the cutting feed rate F and the workpiece rotation speed S, and the amplitude WA of the swing waveform, which is adjusted using the amplitude ratio Famp. This allows for adjustment of the feed rate Fc per rotation of the workpiece W, which affects the surface roughness d, while adjusting the relationship between the feed rate Fc per rotation of the workpiece W and the amplitude WA of the swing waveform, so as not to change the minimum inter-waveform distance Tmin. This enables chip breaking in a manner that allows for adjustment of the surface roughness.

[0050] Furthermore, according to the machine tool 10 and machining method of this embodiment, the memory unit 34 can store the command surface roughness K in advance. Therefore, the swing command generation unit 40 can generate a swing command that satisfies both the chip thickness and the surface roughness. Specifically, based on the first swing command and the command surface roughness K, the swing command generation unit 40 can set, based on the command surface roughness K, a maximum inter-waveform distance Tmax, which is the distance between the first peak portion CR1 of the swing waveform at the Nth rotation from the start of the rotation operation and the second valley portion TR2 of the swing waveform that has the same rotational phase θ as the first peak portion CR1 at the (N+1)th rotation. Furthermore, the swing 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 valley portion TR1 and the second peak portion CR2. Furthermore, the swing command generating unit 40 can calculate the cutting feed rate F based on the feed rate Fc2 and the workpiece rotation speed S, and can calculate the amplitude ratio Famp for adjusting the amplitude WA of the swing waveform based on the feed rate Fc2 and the cutting feed rate F so that the minimum distance between waveforms Tmin coincides with the command chip thickness Q. The swing command generating unit 40 can generate a second swing command based on the amplitude ratio Famp and the cutting feed rate F calculated in this way so as to satisfy both the command chip thickness Q and the command surface roughness K. This makes it possible to break the chips after adjusting the surface roughness d.

[0051] Furthermore, with the machine tool 10 and machining method according to this embodiment, even when there is no input of the cutting feed rate F, the oscillation command generation unit 40 can calculate, based on the workpiece rotation rate S, an oscillation frequency f at which the first valley TR1 of the oscillation waveform at the Nth rotation from the start of the rotation operation and the second peak CR2 of the oscillation waveform at the (N+1)th rotation have the same rotational phase θ. Furthermore, based on the command chip thickness Q and the command surface roughness K, the maximum inter-waveform distance Tmax, which is the distance between the first peak CR1 of the oscillation waveform at the Nth rotation from the start of the rotation operation and the second valley TR2 of the oscillation waveform at the (N+1)th 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 valley TR1 and the second peak CR2. Furthermore, the cutting feed rate F can be calculated based on the feed rate Fc3 and the workpiece rotation speed S, and the amplitude ratio Famp can be calculated to adjust the amplitude WA of the oscillation waveform so that the minimum inter-waveform distance Tmin coincides with the command chip thickness Q. Therefore, by making the rotation phase θ of the first valley portion TR1 and the second peak portion CR2 the same, the minimum inter-waveform distance Tmin can be reduced, thereby reducing the chip thickness. Furthermore, since the amplitude WA can be adjusted using the amplitude ratio Famp, the minimum inter-waveform distance Tmin can be matched with the command chip thickness Q. As a result, in continuous oscillation machining, a third oscillation command can be generated based on the chip thickness Q commanded in the machining program. Furthermore, the oscillation command generation unit 40 can generate a third oscillation command based on the amplitude ratio Famp and the cutting feed rate F. Therefore, it is possible to adjust both the feed rate 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 oscillation waveform, which is adjusted using the amplitude ratio Famp. This makes it possible to adjust the maximum distance between waveforms Tmax based on the command surface roughness K while adjusting the relationship between the feed rate Fc3 per rotation of the workpiece W and the amplitude WA of the oscillation waveform so as not to change the minimum distance between waveforms Tmin, thereby making it possible to break chips after adjusting the surface roughness d.

[0052] Furthermore, in the machine tool 10 according to this embodiment, the swing command generation unit 40 is configured to generate a swing command in accordance with a predetermined chip thickness pre-stored in the memory unit 34 when the chip thickness detection unit 36 ​​does not or cannot detect the command chip thickness Q. Here, the predetermined chip thickness may be zero. This makes it possible to perform continuous swing 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, in the machine tool 10 according to this embodiment, the swing command generating unit 40 is configured to stop generating a swing command when the chip thickness detecting unit 36 ​​detects a chip thickness that is a negative value. The control device 12 is equipped with a display unit 46 and an informing unit 48, and is configured such that when the generation of the swing command is stopped, the display unit 46 indicates that the command has been stopped and the operator is notified via the informing unit 48. This makes it possible to prevent malfunction of the machine device 14 when the operator mistakenly enters a negative chip thickness when creating a machining program.

[0054] Furthermore, the machine tool 10 according to this embodiment is configured to stop generating a swing command when the chip thickness Q detected by the chip thickness detection unit 36 ​​is greater than the feed rate Fc per rotation of the workpiece W. Even in such a case, the control device 12 is configured to display the fact that the operation 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 a swing command based on the chip thickness Q commanded in the machining program during continuous swing machining in which the cutting insert 52 swings in the cutting feed direction without moving away from the workpiece W.

[0056] The control device 12 also includes a machining time calculation unit 44 (see FIG. 1 ) for calculating the machining time. The machining time calculation unit 44 calculates the machining time of the turning process executed by the machining program based on the generated point cloud data. When a swing command is generated to satisfy the command surface roughness K, the feed rate Fc per rotation of the workpiece W changes, resulting in a corresponding change in machining time. However, the correlation between the command surface roughness K and machining time is difficult for operators to intuitively understand. Therefore, the control device 12 includes the machining time calculation unit 44, which can calculate in advance the machining time required for a block containing the command chip thickness Q and command surface roughness K, i.e., the degree to which the machining time varies from the previous prediction, and display this information on the display unit 46 of the control device 12. This allows the operator to confirm the changed machining time and change the machining conditions in consideration of the impact on the production plan.

[0057] Although the machining described here is turning, the concept of the present application is not limited to this and can also be applied to hole drilling. A machine tool for hole drilling may be configured by replacing the cutting edge of a turning tool with the cutting edge of a boring tool or drilling tool used for hole drilling.

[0058] Furthermore, the command surface roughness may be commanded not only in units of the maximum height Rz indicated by the theoretically 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 swing commands described above.

[0059] Although an embodiment of the machine tool 10 has been described above, the present invention is not limited to the above embodiment. 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, those skilled in the art will understand that various modifications of the above embodiment are possible.

[0060] REFERENCE SIGNS LIST 10 Machine tool 12 Control device 14 Machine device 20 Spindle (tool mounting portion) 24 Workpiece rotation device (workpiece mounting portion) 25 Workpiece spindle (rotation axis) 34 Memory unit 40 Swing command generation unit 50 Tool 52 Cutting insert AL First axis F Cutting feedrate (first to third cutting feedrates) Famp Cutting feedrate amplitude ratio (first to third amplitude ratio) Fc Feed amount Fc1 Feed amount Fc2 Feed amount Fc3 Feed amount W Workpiece

Claims

1. A machine tool that processes a workpiece by rotating a tool and a workpiece relatively about a first axis and linearly moving the tool and the workpiece relatively while swinging them in the first axial direction, comprising: a tool mounting section to which the tool is attached; a work mounting section to which the workpiece is attached; a rotation axis that rotates the tool mounting section and the workpiece relatively about the first axis; a linear axis that linearly moves the tool mounting section and the workpiece relatively along the first axial direction; a memory section that stores in advance coordinates indicating the relative positional relationship between the tool and the workpiece during machining, the relative rotation speed between the tool and the workpiece, a first cutting feed rate relative to the tool and the workpiece, and a command chip thickness; and a swing command generation section that generates a swing command based on the rotation speed. a swing command generating unit that calculates a swing frequency at which a first valley of the swing waveform at the Nth rotation from the start of rotation and a second peak of the swing waveform at the N+1th rotation are in the same rotational phase, and calculates a first amplitude ratio based on the first cutting feed rate and the command chip thickness to adjust the amplitude of the swing waveform so that a minimum distance between the waveforms, which is a distance between the first valley and the second peak, matches the command chip thickness; and a swing command generating unit that generates a first swing command based on the swing frequency, the first amplitude ratio, and the first cutting feed rate. A machine tool comprising: a swing command generating unit that generates a first swing command based on the swing frequency, the first amplitude ratio, and the first cutting feed rate; and a control unit that operates the linear axis and the rotary axis based on the coordinates and the first swing command.

2. A machine tool as described in claim 1, wherein the swing command generating unit generates the first swing command in accordance with a predetermined chip thickness that has been stored in advance when the command chip thickness is not stored in the memory unit.

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

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

5. The storage unit stores a command surface roughness in advance, and the swing command generation unit, based on the first swing command and the command surface roughness, sets a maximum inter-waveform distance, which is the distance between a first peak of the swing waveform at the Nth rotation from the start of rotation and a second valley of the swing waveform that has the same rotational phase as the first peak at the N+1th rotation, based on the command surface roughness, calculates a feed amount in the cutting feed direction per rotational operation during machining from the maximum inter-waveform distance and the minimum inter-waveform distance, which is the distance between the first valley and the second peak, calculates a second cutting feedrate based on the feed amount and the rotational speed, calculates a second amplitude ratio for adjusting the amplitude of the swing waveform so that the minimum inter-waveform distance matches the command chip thickness, based on the feed amount and the second cutting feedrate, The machine tool according to claim 1 , wherein the control device operates the linear axis and the rotary axis based on the coordinates and the second swing command.

6. A machine tool that processes a workpiece by rotating a tool and a workpiece relatively about a first axis and linearly moving the tool and the workpiece relatively while swinging them in the first axial direction, comprising: a tool mounting section to which the tool is attached; a work mounting section to which the workpiece is attached; a rotation axis that rotates the tool mounting section and the workpiece relatively about the first axis; a linear axis that linearly moves the tool mounting section and the workpiece relatively along the first axial direction; a storage section that stores 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, a command chip thickness, and a command surface roughness; and a swing command generation section that calculates, based on the rotational speed, an oscillation frequency at which a first valley of an oscillation waveform at the Nth rotation from the start of rotation and a second peak of an oscillation waveform at the N+1th rotation are in the same rotational phase, a swing command generating unit that generates a swing command based on the swing frequency, the third amplitude rate, and the third cutting feed rate; and a control device that operates the linear motion axis and the rotary axis based on the coordinates and the swing command.

7. A machining method for machining a workpiece by rotating a tool and a workpiece relative to each other about a first axis and linearly moving the tool and the workpiece relative to each other while swinging the tool in the first axial direction, comprising the steps of: inputting coordinates indicating the relative positional relationship between the tool and the workpiece during machining, a cutting feed rate for the relative linear motion between the tool and the workpiece, a rotational speed for the relative rotational motion between the tool and the workpiece, a command chip thickness, and the number of teeth of the tool; calculating, based on the rotational speed and the number of teeth, an oscillation frequency at which the valley 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 are in the same rotational phase; calculating an oscillation amplitude based on the rotational speed, the number of teeth of the tool, the cutting feed rate, and the command chip thickness; generating a first oscillation command based on the amplitude and the oscillation frequency; and performing machining by rotating and linearly moving the tool and the workpiece relative to each other based on the first swing command.

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