Working machinery

Abstract

To provide a machine tool that improves the convenience of removing burrs. [Solution] The tool post 30 of the machine tool (1) is fitted with a deburring tool TO3 that cuts the periphery C1p of a hole (C1) in the workpiece W1 that intersects the spindle centerline AX1, and rotates the deburring tool TO3 around the deburring tool centerline AX3. The control unit U1 of the machine tool (1) receives commands (CM1~CM4) that instruct whether to perform a down cut on the periphery C1p in which the cutting direction D1 by the rotating deburring tool TO3 is opposite to the relative movement direction D2 of the deburring tool TO3, or to perform an up cut on the periphery C1p in which the cutting direction D1 and the relative movement direction D2 coincide, and controls the cutting of the periphery C1p at the cutting position P1 so as to maintain the cut instructed by the commands (CM1~CM4).

Description

Technical Field

[0001] The present invention relates to a machine tool capable of cutting the periphery of a hole in a direction orthogonal to the spindle center line in a workpiece.

Background Art

[0002] As a machine tool, a numerically controlled (NC) lathe that processes a cylindrical workpiece held by a spindle with a tool is known. When a cross hole is formed in a workpiece with a rotary tool in a direction along a machining center line orthogonal to the spindle center line, burrs occur on the periphery of the cross hole. Therefore, the burrs are removed with a dedicated tool attached to the tool post. The NC lathe can execute a process of removing the burrs on the periphery of the cross hole by controlling the relative cutting position of the workpiece by the dedicated tool in three directions of the X-axis, Y-axis, and Z-axis according to a machining program created by an operator. The machine tool disclosed in Patent Document 1 performs chamfering of the opening edge of the cross hole by moving a conical tool having a conical cutting edge portion in three directions.

Prior Art Documents

Patent Documents

[0003]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0004] As cutting for removing burrs, there are considered a down cut in which the cutting direction by a rotating burr removal tool is opposite to the moving direction of the burr removal tool, and an up cut (also called an upper cut) in which the cutting direction by a rotating burr removal tool and the moving direction of the burr removal tool coincide. However, it is not easy for an operator to create a machining program while being aware of the down cut or the up cut. Furthermore, the aforementioned problems exist not only in lathes but also in various other machine tools such as machining centers.

[0005] This invention discloses a machine tool that improves the convenience of removing burrs. [Means for solving the problem]

[0006] The machine tool of the present invention is The spindle rotates with the workpiece around the center line of the spindle, A deburring tool is attached to the workpiece to cut the periphery of a hole that intersects the spindle centerline, and a tool post rotates the deburring tool around the centerline of the deburring tool, The system includes a control unit that controls the relative positional relationship between the spindle and the tool post, and controls the cutting position of the deburring tool along the circumferential portion, The control unit, A command is obtained to instruct whether to perform a down cut on the periphery in which the cutting direction of the rotating deburring tool is opposite to the relative movement direction of the deburring tool, or to perform an up cut on the periphery in which the cutting direction and the relative movement direction coincide. The present invention includes a configuration in which control is performed to cut the periphery at the cutting position in such a way as to maintain the cut commanded by the command. [Effects of the Invention]

[0007] According to the present invention, it is possible to provide a machine tool that improves the convenience of removing burrs. [Brief explanation of the drawing]

[0008] [Figure 1] This is a schematic front view showing an example of a machine tool configuration. [Figure 2] This is a block diagram schematically showing an example of the configuration of an electrical circuit in a machine tool. [Figure 3]Figure 3A is a schematic plan view showing an example of a cylindrical workpiece with cross holes, Figure 3B is a longitudinal section view at position A1-A1 in Figure 3A, and Figure 3C is a transverse section view at position A2-A2 in Figure 3A. [Figure 4] Figure 4A is a schematic plan view showing an example of a cutting position that changes along the periphery of a cross hole, and Figures 4B and 4C are schematic cross-sectional views showing an example of a deburring tool oriented along the spindle centerline being positioned on the outer surface of a cylindrical workpiece. [Figure 5] Figures 5A and 5B are schematic cross-sectional views showing an example where a deburring tool oriented along the spindle centerline is positioned on the inner surface of a cylindrical workpiece. [Figure 6] This diagram schematically illustrates an example of determining the Z-axis coordinate Zp and C-axis angle Cp corresponding to the cutting position based on the diameter value (CD) of the cross hole and the outer surface value (OD) of the workpiece. [Figure 7] This diagram schematically illustrates an example of determining the Z-axis coordinate Zp and C-axis angle Cp corresponding to the cutting position based on the diameter value of the cross hole (CD) and the inner diameter value of the workpiece (OD). [Figure 8] Figure 8A schematically shows an example of the movement of the cutting position when performing a down cut on the outer surface or an up cut on the inner diameter, and Figure 8B schematically shows an example of the movement of the cutting position when performing an up cut on the outer surface or a down cut on the inner diameter. [Figure 9] This flowchart schematically illustrates an example of a deburring process. [Figure 10] This flowchart schematically illustrates an example of a deburring process. [Figure 11] This diagram schematically illustrates an example of Z-axis movement and C-axis rotation of a workpiece during deburring. [Figure 12] This diagram schematically illustrates an example of Z-axis movement and C-axis rotation of a workpiece during deburring. [Figure 13]FIG. 13A is a diagram schematically showing an example of changing the rotation direction of a deburring tool when performing a down cut on an outer peripheral surface or an up cut on an inner diameter, and FIG. 13B is a diagram schematically showing an example of changing the rotation direction of a deburring tool when performing an up cut on an outer peripheral surface or a down cut on an inner diameter. [Figure 14] It is a flowchart schematically showing an example of a deburring process for switching the rotation direction of a deburring tool. [Figure 15] It is a diagram schematically showing an example of a tool rest to which a right - hand cutting tool and a left - hand cutting tool are attached as deburring tools. [Figure 16] FIG. 16A is a diagram schematically showing an example of switching a deburring tool when performing a down cut on an outer peripheral surface or an up cut on an inner diameter, and FIG. 16B is a diagram schematically showing an example of switching a deburring tool when performing an up cut on an outer peripheral surface or a down cut on an inner diameter. [Figure 17] It is a flowchart schematically showing an example of a deburring process for switching the deburring tool to be used. [Figure 18] It is a diagram schematically showing an example of determining the Z - axis coordinate Zp and the C - axis angle Cp corresponding to a cutting position based on the diameter value (CD) of a long hole, the inner diameter value (OD) of a workpiece, and the center - to - center distance value (LC) of an arc portion. [Figure 19] It is a flowchart schematically showing an example of a deburring process for the peripheral portion of a long hole. [Figure 20] A diagram schematically showing an example where a down cut and an up cut are switched during cutting the peripheral portion of a hole.

Embodiments for Carrying Out the Invention

[0009] Hereinafter, embodiments of the present invention will be described. Of course, the following embodiments are merely illustrative of the present invention, and not all of the features shown in the embodiments are necessarily essential for the solution means of the invention.

[0010] (1) Outline of the aspects included in the present invention: First, an overview of the embodiments included in the present invention will be described with reference to the examples shown in Figures 1 to 20. Note that the figures in this application are schematic examples, and the magnification in each direction shown in these figures may differ, and the figures may not be consistent. Of course, the elements of this embodiment are not limited to the specific examples indicated by the reference numerals.

[0011] [Aspect 1] As illustrated in Figures 1 and 2, a machine tool according to one embodiment (for example, a lathe 1) comprises a spindle 11, a tool post 30, and a control unit U1. The spindle 11 rotates together with the workpiece W1 about the spindle centerline AX1. The tool post 30 is fitted with a deburring tool TO3 that cuts the periphery C1p of a hole (for example, a cross hole C1) in the workpiece W1 that intersects the spindle centerline AX1, and rotates the deburring tool TO3 about the deburring tool centerline AX3. The control unit U1 controls the relative positional relationship between the spindle 11 and the tool post 30 and controls the cutting position P1 by the deburring tool TO3 to change along the periphery C1p. The control unit U1 receives commands (e.g., deburring commands CM1 to CM4) that instruct whether to perform a down cut (e.g., R=0) on the periphery C1p, where the cutting direction D1 of the rotating deburring tool TO3 is opposite to the relative movement direction D2 of the deburring tool TO3, or to perform an up cut (e.g., R=1) on the periphery C1p, where the cutting direction D1 and the relative movement direction D2 coincide. The control unit U1 then controls the cutting of the periphery C1p at the cutting position P1, as illustrated in Figures 8A to 89, while maintaining the cut instructed by the commands (CM1 to CM4).

[0012] As described above, commands (CM1 to CM4) can be used to instruct whether the cutting of the peripheral portion C1p at cutting position P1 should be a down cut or an up cut. Therefore, the above embodiment can provide a machine tool that improves the convenience when removing burrs.

[0013] Here, the control of the relative positional relationship between the spindle and the tool post may be the control of the spindle's position when the tool post does not move, or the control of the tool post's position when the spindle does not move, or the control of the positions of both the spindle and the tool post. The relative movement direction of a deburring tool refers to the relative movement direction of the deburring tool with respect to the position of the workpiece. If the workpiece does not move, the relative movement direction of the deburring tool refers to the direction of movement of the deburring tool. If the deburring tool does not move, the relative movement direction of the deburring tool refers to the direction opposite to the direction of movement of the workpiece. Holes oriented to intersect the spindle centerline include cross holes connecting the outer and inner surfaces of a cylindrical workpiece, lateral holes traversing the workpiece along the machining centerline, and bottomed holes recessed from the outer surface to partway through the workpiece along the machining centerline. The periphery cut by the deburring tool may be either the outer or inner surface of the workpiece. For example, when a cross hole is formed in a cylindrical workpiece, burrs may form on the periphery of both the outer and inner surfaces of the workpiece. A deburring tool only needs to be capable of cutting the periphery of a hole in the workpiece that intersects the spindle centerline, and can be a rotary tool such as an end mill, grinding wheel, or brush. When the cutting position changes along the periphery of the hole, there may be positions where the deburring tool does not move relative to the cutting direction of the rotating deburring tool. The direction of rotation of the deburring tool at these positions can be either clockwise or counterclockwise. The above-mentioned supplementary statement also applies in the following embodiments.

[0014] [Aspect 2] As illustrated in Figures 4B and 5A, the deburring tool TO3 may be mounted on the tool post 30 in an orientation along the spindle centerline AX1. The tool post 30 may rotate the deburring tool TO3 around the deburring tool centerline AX3, which is aligned with the spindle centerline AX1. The control unit U1 may, as illustrated in Figures 8A to 19, control the direction in which the cutting position P1 changes along the circumferential portion C1p (see, for example, Figures 8A to 12), or the direction of rotation of the deburring tool TO3 around the deburring tool centerline AX3 (see, for example, Figures 13 to 17), in order to maintain the cut commanded by the command (CM1 to CM4), during the cutting of the circumferential portion C1p. When the deburring tool TO3 is oriented along the spindle centerline AX1, the relative movement direction D2 of the deburring tool TO3 reverses midway when the cutting position P1 completes a full rotation along the circumferential portion C1p in either a clockwise or counterclockwise direction. Even in this case, the direction in which the cutting position P1 changes along the circumferential portion C1p, or the direction of rotation of the deburring tool TO3 around the deburring tool centerline AX3, automatically changes during the cutting of the circumferential portion C1p, thereby maintaining down-cutting or up-cutting. Therefore, the above embodiment allows for easy deburring while maintaining down-cutting or up-cutting using a deburring tool oriented along the spindle centerline.

[0015] [Aspect 3] As illustrated in Figures 8A to 812, if the relative movement direction D2 of the deburring tool TO3 with respect to the cutting direction D1 is the first direction D21, then the cut commanded by the command (CM1 to CM4) is performed on the circumferential portion C1p. The cutting path PA0 along the circumferential portion C1p may include a first path PA1 and a second path PA2 that go from the first reversal position R1 to the second reversal position R2 without the relative movement direction D2 being the second direction D22 which is the opposite of the first direction D21. The control unit U1 may perform control to change the cutting position P1 in the first path PA1 from the first reversal position R1 to the second reversal position R2, and in the second path PA2 to change the cutting position P1 from the first reversal position R1 to the second reversal position R2. In the above case, down-cutting or up-cutting is maintained without changing the direction of rotation of the deburring tool TO3. Therefore, the above embodiment allows deburring while maintaining down-cutting or up-cutting without being aware of constraints on the direction of rotation of the deburring tool TO3.

[0016] Here, "first," "second," ... in this application are terms used to identify each component included in a group of similar components, and do not imply any order. This supplementary statement also applies to the following embodiments.

[0017] [Aspect 4] As illustrated in Figures 13A to 14, the tool post 30 may be capable of rotating the deburring tool TO3 both clockwise and counterclockwise. The cutting path PA0 along the circumferential portion C1p may include a first path PA1 from a first reversal position R1 to a second reversal position R2 without the relative movement direction D2 of the deburring tool TO3 with respect to the cutting direction D1 being a second direction D22 opposite to the first direction D21, and a second path PA2 from a second reversal position R2 to a first reversal position R1 without the relative movement direction D2 being the first direction D21. The control unit U1 may control the direction of rotation of the deburring tool TO3 in the first path PA1 and the second path PA2 in opposite directions to maintain the cut commanded by the commands (CM1 to CM4). If the deburring tool TO3 can be used in both clockwise and counterclockwise directions, the above embodiment allows for down-cutting or up-cutting without changing the direction in which the cutting position P1 changes along the circumferential portion C1p. Therefore, the above embodiment enables efficient deburring while maintaining down-cutting or up-cutting.

[0018] [Aspect 5] As illustrated in Figure 15, the tool post 30 may be fitted with a right-hand rotating tool TO31, which serves as the deburring tool TO3, and a left-hand rotating tool TO32, which serves as the deburring tool TO3. The tool post 30 may rotate the right-hand rotating tool TO31 clockwise around the center line AX31 of the right-hand rotating tool, which serves as the deburring tool center line AX3, or it may rotate the left-hand rotating tool TO32 counterclockwise around the center line AX32 of the left-hand rotating tool, which serves as the deburring tool center line AX3. As illustrated in Figures 16A to 17, the cutting path PA0 along the circumferential portion C1p may include a first path PA1 from a first reversal position R1 to a second reversal position R2 without the relative movement direction D2 of the deburring tool TO3 with respect to the cutting direction D1 being a second direction D22 opposite to the first direction D21, and a second path PA2 from a second reversal position R2 to a first reversal position R1 without the relative movement direction D2 being the first direction D21. The control unit U1 may perform control to cut the circumferential portion C1p in the first path PA1 with one of the right-hand rotary tool TO31 and the left-hand rotary tool TO32, and cut the circumferential portion C1p in the second path PA2 with the other rotary tool, in order to maintain the cut commanded by the commands (CM1 to CM4). If both a right-hand rotary tool TO31 and a left-hand rotary tool TO32 can be used as the deburring tool TO3, then, in the above configuration, down-cutting or up-cutting can be maintained without changing the direction in which the cutting position P1 changes along the circumferential portion C1p. Therefore, in the above configuration as well, deburring can be performed while maintaining down-cutting or up-cutting.

[0019] [Aspect 6] As illustrated in Figures 5A, 5B, etc., the workpiece W1 may be cylindrical in shape. The commands (CM1 to CM4) may include an argument (for example, an argument P) that instructs whether to cut the peripheral portion C1p on the inner circumferential surface W1i of the workpiece W1, or on the outer circumferential surface W1o of the workpiece W1. The control unit U1 may, as illustrated in Figures 8A to 19, perform control to cut the peripheral portion C1p based on the argument, while maintaining the cut instructed by the commands (CM1 to CM4). When the deburring tool TO3 is oriented along the spindle centerline AX1, the type of cut (down-cut or up-cut) depends on whether the cutting surface is the inner circumferential surface W1i or the outer circumferential surface W1o of the workpiece W1. Even in this case, the down-cut or up-cut is performed on the circumferential portion C1p as commanded. Therefore, the above embodiment can provide a machine tool that further improves the convenience of removing burrs.

[0020] (2) Specific examples of machine tool configurations: Figure 1 is a schematic front view illustrating the configuration of a lathe 1 as an example of a machine tool. Figure 2 schematically illustrates the configuration of the electrical circuit of the lathe 1. Figures 3A to 3C schematically illustrate a cylindrical workpiece W1 having a cross hole C1. Here, Figure 3A is a plan view of the workpiece W1, Figure 3B is a longitudinal section view at position A1-A1 in Figure 3A, and Figure 3C is a transverse section view at position A2-A2 in Figure 3A. In Figure 1, the symbol D81 indicates the upward direction, the symbol D82 indicates the downward direction, the symbol D83 indicates the left direction, and the symbol D84 indicates the right direction. These directions are based on the viewing direction of the lathe 1 shown in Figure 1. As shown in Figures 1 and 3, the control axes of the lathe 1 include the X-axis indicated by "X", the Y-axis indicated by "Y", the Z-axis indicated by "Z", and the C-axis indicated by "C". Here, the X-axis, Y-axis, and Z-axis are linear axes, and the C-axis is a rotation axis. The Z-axis direction is along the spindle centerline AX1, which is the rotation center of the workpiece W1, and is horizontal in Figure 1. The X-axis direction is perpendicular to the Z-axis, and is horizontal in Figure 1, but may also be in the up and down directions (upward D81 and downward D82). The Y-axis direction is perpendicular to both the Z-axis and the X-axis. The C-axis is a rotation axis centered on the spindle centerline AX1. Furthermore, the drawings referenced herein are merely examples illustrating the embodiments of the present invention and do not limit the embodiments. The descriptions of the positional relationships of the parts are merely illustrative. Therefore, reversing left and right, or reversing the direction of rotation, etc., are also included in the embodiments of the present invention. Identicality in direction, position, etc., is not limited to strict agreement, but includes deviations from strict agreement due to errors.

[0021] Lathe 1 is an NC lathe equipped with a headstock 10 having a spindle 11 with a gripping part 12, a headstock drive unit 13, a support base 25 having mounting holes 26 for guide bushes 14, a tool post 30, a tool post drive unit 31, an NC device 70, etc. Here, headstock 10 refers collectively to a front headstock 15 and a rear headstock 20, also called an opposing headstock. The front headstock 15 incorporates a front spindle 16 having a gripping part 17 such as a collet. The rear headstock 20 incorporates a rear spindle 21 having a gripping part 22 such as a collet. Spindle 11 refers collectively to the front spindle 16 and the rear spindle 21, also called an opposing spindle. Gripping part 12 refers collectively to the gripping part 17 and the gripping part 22. The headstock drive unit 13 collectively refers to the front headstock drive unit 18, which moves the front headstock 15 along the Z-axis, and the rear headstock drive unit 23, which moves the rear headstock 20 along at least the Z-axis. The lathe 1 shown in Figures 1 and 2 is a spindle-moving type lathe in which the front spindle 16 moves in the Z-axis direction.

[0022] The front spindle 16 grips a cylindrical workpiece W1 inserted, for example, from its rear end 16b, in a releaseable manner by the gripping portion 17, and is rotatable together with the workpiece W1 around the spindle centerline AX1. The front spindle 16 has a through hole 16h that penetrates along the spindle centerline AX1. If the workpiece W1 before processing is a short material, the workpiece W1 may be supplied to the gripping portion 17 from the front end 16a of the front spindle 16. The NC device 70 rotates the front spindle 16 around the spindle centerline AX1 by driving the front spindle rotation drive unit 16c shown in Figure 2, and controls the gripping state of the gripping portion 17 by driving the gripping actuator 17a shown in Figure 2. The gripping portion 17 can be made of, for example, a collet. The front headstock drive unit 18 moves the front headstock 15 in the Z-axis direction according to a command from the NC device 70. Therefore, the workpiece W1, which is held by the front spindle 16, moves in the Z-axis direction.

[0023] The front end 21a of the rear spindle 21 faces the front end 16a of the front spindle 16. The rear spindle 21 grips the workpiece W1, which is being machined and extends forward from the front end 16a of the front spindle 16, in a way that allows it to be released by the gripping part 22, and is rotatable together with the workpiece W1 around the spindle centerline AX1. The NC device 70 rotates the rear spindle 21 around the spindle centerline AX1 by driving the rear spindle rotation drive unit 21c shown in Figure 2, and controls the gripping state of the gripping part 22 by driving the gripping actuator 22a shown in Figure 2. The gripping part 22 can be made of, for example, a collet. The rear headstock drive unit 23 moves the rear headstock 20 in the Z-axis direction, and further moves it in the X-axis direction or the Y-axis direction, according to commands from the NC device 70.

[0024] The guide bush 14 is mounted to the support base 25 with the guide bush 14 inserted into the mounting hole 26 of the support base 25, and supports the workpiece W1 that protrudes from the front spindle 16 toward the rear spindle 21 (rightward D84) so ​​that it can slide in the Z-axis direction. The portion of the workpiece W1 that protrudes from the guide bush 14 toward the rear spindle 21 is machined by the tool TO1. When the guide bush is not used, the front part of the front spindle 16 is inserted into the mounting hole 26, and the portion of the workpiece W1 that protrudes from the front spindle 16 toward the rear spindle 21 is machined by the tool TO1.

[0025] Multiple tools TO1 are mounted on the tool post 30 for machining a workpiece W1 held on at least one of the front spindle 16 and the rear spindle 21. The multiple tools TO1 include cutting tools including parting tools, rotary tools such as rotary drills and end mills, etc. Rotary tools include cross tools TO2 and deburring tools TO3 (e.g., ball end mills) shown in Figure 3B. The tool post 30 shown in Figure 1 refers collectively to the comb-shaped tool post 32 and the tool post 34 for back machining. Although only the deburring tool TO3 is shown on the back machining tool post 34 in Figure 1, tool TO1 refers collectively to the tools mounted on the tool post 30, including the comb-shaped tool post 32 and the back machining tool post 34. Each tool post 30 is equipped with a tool rotation drive unit 30c that rotates the rotary tool around the rotary tool's centerline. Tool TO1 shown in Figure 2 refers to a rotary tool. The tool post 30 may include a turret tool post or the like. The tool post drive unit 31 shown in Figure 1 collectively refers to the comb-type tool post drive unit 33 and the back-machining tool post drive unit 35. The comb-type tool post drive unit 33 moves the comb-type tool post 32 along the X-axis according to a command from the NC device 70, and moves the comb-type tool post 32 along the Y-axis according to a command from the NC device 70. The back-machining tool post drive unit 35 moves the back-machining tool post 34 along the Y-axis according to a command from the NC device 70. The tool post 30 performs front-side machining of the workpiece W1 held on the front spindle 16 with tool TO1, performs parting on the workpiece W1 after front-side machining held on both the front spindle 16 and the back spindle 21 with a parting tool, and performs back-side machining of the workpiece W1 after parting held on the back spindle 21 with tool TO1. In this way, a product is formed from the workpiece W1.

[0026] As shown in Figure 2, the NC device 70 is connected to an operating unit 80, a front spindle drive unit 18, a front spindle rotation drive unit 16c, a gripping actuator 17a, a rear spindle drive unit 23, a rear spindle rotation drive unit 21c, a gripping actuator 22a, a comb-type tool post drive unit 33, a rear machining tool post drive unit 35, a tool rotation drive unit 30c, and the like. The front spindle drive unit 18, the rear spindle drive unit 23, the comb-type tool post drive unit 33, and the rear machining tool post drive unit 35 are each equipped with a servo motor and a servo amplifier (not shown), and change the position of the spindle 11 or the tool post 30 according to commands from the NC device 70. The NC device 70 controls the position of the workpiece W1 or tool TO1 by issuing commands to these elements (18, 23, 33, 35). The front spindle rotation drive unit 16c and the rear spindle rotation drive unit 21c are each equipped with a servo motor (e.g., a built-in motor) and a servo amplifier (not shown), respectively, and change the rotation angle of the spindle 11 according to commands from the NC device 70. The NC device 70 controls the rotation angle of the workpiece W1 around the spindle centerline AX1 by issuing commands to these elements (16c, 21c).

[0027] The NC device 70 includes a processor, a CPU (Central Processing Unit) 71, a semiconductor memory, a ROM (Read Only Memory) 72, a semiconductor memory, a RAM (Random Access Memory) 73, a clock circuit 74, and an I / F (interface) 75 for peripheral elements (80, 18, 16c, 17a, 23, 21c, 22a, 33, 35, 30c). The ROM 72 contains a control program PR1 for interpreting and executing the machining program PR2. The ROM 72 may be a rewritable semiconductor memory. The RAM 73 stores the machining program PR2 created by the operator in a rewritable format. The machining program is also called an NC program. The CPU 71 uses the RAM 73 as a work area and executes the control program PR1 recorded in the ROM 72 to realize the functions of the NC device 70.

[0028] The operation unit 80 comprises an input unit 81 and a display unit 82, and functions as a user interface for the NC device 70. The input unit 81 consists of, for example, keys or a touch panel for receiving operation input from the operator. The display unit 82 consists of, for example, a display that shows the contents of various settings received from the operator and various information related to the lathe 1. The operator can store the machining program PR2 in the RAM 73 using the operation unit 80 or an external computer (not shown).

[0029] In this specific example, the NC device 70, the headstock drive unit 13 (front headstock drive unit 18 and rear headstock drive unit 23), and the spindle rotation drive units (16c, 21c) constitute the control unit U1. The NC device 70 and the headstock drive unit 13 control the relative positional relationship between the spindle 11 and the tool post 30 along the Z-axis parallel to the spindle centerline AX1, and control the cutting position P1 by the deburring tool TO3 along the circumferential portion C1p. The NC device 70 and the spindle rotation drive units (16c, 21c) control the rotation of the spindle 11 along the C-axis centered on the spindle centerline AX1.

[0030] The workpiece W1 shown in Figures 3A to 3C is cylindrical in shape and has a hollow section W1h that penetrates along the spindle centerline AX1. Therefore, the workpiece W1 has an outward-facing outer surface W1o and an inward-facing inner surface W1i. A cross tool TO2, which is a rotary tool for forming a cross hole C1 in the workpiece W1 that connects the outer surface W1o to the hollow portion W1h, is mounted on the tool post 30. A drill or an end mill can be used as the cross tool TO2, and the NC device 70 may be controlled to first form an opening in the workpiece W1 with a drill as the cross tool TO2, and then form the cross hole C1 with an end mill as the cross tool TO2. The cross tool TO2 shown in Figure 3B is positioned with its longitudinal direction oriented in the X-axis direction and is rotatable about the rotary tool centerline AX4 along the X-axis. The rotary tool centerline AX4 is along the machining centerline AX2 of the cross hole C1 and is perpendicular to the spindle centerline AX1 in the XZ plane viewed from the Y-axis direction, as shown in Figure 3B. The cross hole C1 formed by the cross tool TO2 is a hole that penetrates the workpiece W1 so as to connect from the outer surface W1o to the inner surface W1i, with the machining center line AX2 along the X axis as its center. It can be said to be a hole oriented along the machining center line AX2, or a hole centered on the machining center line AX2. In the plan view shown in Figure 3A, the cross hole C1 is circular, and the center C1o of the cross hole C1 lies on the spindle center line AX1.

[0031] When a cross hole C1 is formed in the workpiece W1 with the cross tool TO2, burrs may form on the edges of the circumferential portion C1p of the cross hole C1. The term "edge" is used because burrs may form on the circumferential portion C1p on both the outer surface W1o and the inner surface W1i. While it is conceivable to use a dedicated tool to remove the burrs, in this specific example, a general-purpose deburring tool TO3, as illustrated in Figure 4B, is mounted on the tool post 30, for example, the tool post 34 for back machining. The deburring tool TO3 shown in Figure 4B is a ball end mill that can rotate around the deburring tool centerline AX3 and has a spherical cutting portion TO3b at its tip that becomes spherical when rotated. The tool rotation drive unit 30c of the tool post 30 rotates the deburring tool TO3 around the deburring tool centerline AX3. The orientation of the deburring tool centerline AX3 may be along the machining centerline AX2, but in this specific example, it is along the spindle centerline AX1 as shown in Figure 4B. First, we will explain an example of cutting the peripheral portion C1p of a cross hole C1 on the outer surface W1o of workpiece W1 using a deburring tool TO3.

[0032] Figure 4A schematically illustrates the cutting position P1 which changes along the periphery C1p of the cross hole C1. Figure 4B is a longitudinal section corresponding to the position A1-A1 in Figure 3A, schematically illustrating how the deburring tool TO3, oriented along the spindle centerline AX1, is positioned on the outer circumferential surface W1o of the cylindrical workpiece W1. Figure 4C is a cross-sectional view corresponding to the position A2-A2 in Figure 3A, schematically illustrating how the spherical cutting section TO3b is positioned on the outer circumferential surface W1o. In Figure 4A, the cutting position P1 of the circumferential portion C1p by the spherical cutting section TO3b changes along the circumferential portion C1p. If the deburring tool TO3 oriented along the spindle centerline AX1 is a ball end mill, the direction in which the cutting position P1 changes along the circumferential portion C1p changes during the cutting of the circumferential portion C1p so that the down-cut or up-cut commanded by the command is maintained. The details of this will be described later. Here, let θyz be the angle between the line segment connecting the center C1o and the reference position P0 on the spindle centerline AX1 and the line segment connecting the center C1o and the cutting position P1. In this specific example, the NC device 70 rotates the deburring tool TO3 as shown in Figure 4B and reciprocates the workpiece W1 in the Z-axis direction to align it with the cutting position P1, and rotates the workpiece W1 to align it with the cutting position P1 as shown in Figure 4C. As a result, the burrs on the circumferential portion C1p of the cross hole C1 are removed from the outer surface W1o of the workpiece W1. Because the deburring tool TO3 is a ball end mill, the edges of the peripheral C1p are cut in such a way that a constant amount of material is removed across the entire peripheral C1p. Therefore, deburring of the peripheral C1p can be performed using a general-purpose ball end mill instead of a specialized tool.

[0033] Figure 5A is a longitudinal section corresponding to the position A1-A1 in Figure 3A, schematically illustrating how the deburring tool TO3, oriented along the spindle centerline AX1, is positioned on the inner circumferential surface W1i of the cylindrical workpiece W1. Figure 5B is a transverse section corresponding to the position A2-A2 in Figure 3A, schematically illustrating how the spherical cutting section TO3b is positioned on the inner circumferential surface W1i. The cutting position P1 of the circumferential portion C1p by the spherical cutting section TO3b changes along the circumferential portion C1p, as shown in Figure 4A. If the deburring tool TO3, oriented along the spindle centerline AX1, is a ball end mill, the direction in which the cutting position P1 changes along the circumferential portion C1p changes during the cutting of the circumferential portion C1p so that the down-cut or up-cut commanded by the command is maintained. As shown in Figure 5B, the maximum diameter TD of the deburring tool TO3, centered on the deburring tool centerline AX3, in the portion inserted into the cylindrical workpiece W1, is smaller than the inner diameter ID of the workpiece W1. Therefore, as shown in Figure 5A, the NC device 70 rotates the deburring tool TO3 and reciprocates the workpiece W1 in the Z-axis direction to align it with the cutting position P1, and as shown in Figure 5B, rotates the workpiece W1 to align it with the cutting position P1. This removes the burrs from the periphery C1p of the cross hole C1 on the inner circumferential surface W1i of the workpiece W1. Because the deburring tool TO3 is a ball end mill, the edges of the periphery C1p are cut in such a way that a constant amount of material is removed across the entire periphery C1p. Therefore, deburring of the periphery C1p can be performed using a general-purpose ball end mill instead of a dedicated tool.

[0034] Depending on the lathe, it may not be possible to position the deburring tool TO3 in an orientation aligned with the machining centerline AX2. For example, as shown in Figure 1, if the orientation of the tool TO1 mounted on the back machining tool post 34 is limited to aligning with the spindle centerline AX1, and the deburring tool TO3 is required to be mounted on the back machining tool post 34, the deburring tool TO3 will not be oriented aligned with the machining centerline AX2. Furthermore, even if it is possible to position the tool TO1 on the tool post 30 in an orientation aligned with the machining centerline AX2, it may not be possible to mount the deburring tool TO3 on the tool post 30 because another tool is already mounted in a tool mounting location aligned with the machining centerline AX2. In this specific example, deburring can be easily performed using a deburring tool TO3 oriented along the spindle centerline AX1.

[0035] Here, we consider a case where burrs remaining on the periphery C1p of multiple cross holes C1 on the inner circumferential surface W1i of workpiece W1 are removed. If the orientation of the deburring tool TO3 is aligned with the machining centerline AX2, when changing the cross hole C1 to be deburred on the inner circumferential surface W1i, it is necessary to retract the deburring tool TO3 significantly towards the machining centerline. This is because, after inserting the deburring tool TO3 into a certain cross hole C1 to remove the burr from the inner circumferential surface W1i, it is necessary to retract the deburring tool TO3 from that cross hole C1 and then insert the deburring tool TO3 into another cross hole C1 to remove the burr from the inner circumferential surface W1i. The greater the amount of retraction of the deburring tool TO3, the longer the workpiece machining cycle time becomes. On the other hand, if the deburring tool TO3 is oriented along the spindle centerline AX1, the amount of retraction of the deburring tool TO3 is reduced when changing the cross hole C1 to be deburred on the inner surface W1i. This is because, after inserting the deburring tool TO3 into the hollow portion W1h of the workpiece W1 to remove the burr from the inner surface W1i of one cross hole C1, the deburring tool TO3 can be removed from the inner surface W1i of another cross hole C1 while it is still inserted in the hollow portion W1h. As the amount of retraction of the deburring tool TO3 is reduced, the cycle time for workpiece machining is shortened.

[0036] By the way, the task of commanding the cutting position P1 shown in Figure 4A in the three directions of the X, Y, and Z axes is not easy. This is because the edge of the peripheral portion C1p of the cross hole C1 is on the outer surface W1o or inner surface W1i of the workpiece W1, so as the cutting position P1 changes, not only do the Y and Z axis coordinates change, but the X axis coordinate also changes. If the three-dimensional coordinates (X axis coordinate, Y axis coordinate, and Z axis coordinate) of the cutting position P1 are not calculated properly, interference between the deburring tool TO3 and the workpiece W1 may occur, and the peripheral portion C1p may not be cut properly. In this specific example, the aforementioned possibilities are avoided by controlling the relative Z-axis coordinate of the deburring tool TO3 and the C-axis angle of the workpiece W1 based on parameters that can be easily grasped by the operator.

[0037] First, with reference to Figure 6, an example of controlling the cutting position P1 when cutting the peripheral portion C1p of a cross hole C1 on the outer circumferential surface W1o of workpiece W1 will be explained. Figure 6 schematically shows an example of determining the Z-axis coordinate Zp and C-axis angle Cp corresponding to the cutting position P1 based on the diameter value (CD) of the cross hole C1 and the outer diameter value (OD) of workpiece W1. In Figure 6, a plan view 101 of workpiece W1 is shown at the top, a cross-sectional view 102 of workpiece W1 is shown below the plan view 101, and the calculation formulas for the Z-axis coordinate Zp and C-axis angle Cp are shown at the bottom. In the plan view 101, the upward direction is the +Z direction in the Z-axis direction, the downward direction is the -Z direction in the Z-axis direction, the rightward direction is the +Y direction in the Y-axis direction, and the leftward direction is the -Y direction in the Y-axis direction. In the cross-sectional view 102, the upward direction is the +X direction in the X-axis direction, the downward direction is the -X direction in the X-axis direction, the rightward direction is the +Y direction in the Y-axis direction, and the leftward direction is the -Y direction in the Y-axis direction.

[0038] The value CD represents the diameter corresponding to the circumferential portion C1p when the cross hole C1 is viewed from the X-axis direction, which is the machining centerline direction. The value OD represents the diameter corresponding to the circumference, i.e., the outer surface W1o, of the circle passing through the circumferential portion C1p with the spindle centerline AX1 as the center, in a cross section (see cross section 102) that passes through the center C1o of the cross hole C1 and perpendicular to the spindle centerline AX1. The angle θyz is the angle between the line segment connecting the center C1o and the reference position P0 and the line segment connecting the center C1o and the cutting position P1. When the cutting position P1 is the reference position P0, the angle θyz is assumed to be 0° or 360°, and the C-axis angle Cp is assumed to be 0°. Figure 6 also shows point B corresponding to θyz = 90° and point A corresponding to θyz = 270° (or -90°). The rate of change of the angle θyz is determined, for example, based on the feed rate. The angle θxy is the angle between the line segment connecting center point O and point A, which corresponds to the principal axis centerline AX1, and the line segment connecting center point O and point B, in the cross-sectional view 102.

[0039] The Z-axis coordinate Zp is a linear axis coordinate corresponding to the cutting position P1 which changes along the circumferential portion C1p in the Z-axis direction. When the tool post 30 to which the deburring tool TO3 is attached does not move in the Z-axis direction, the Z-axis coordinate Zp corresponds to the Z-axis coordinate of the workpiece W1 held by the spindle 11. The Z-axis coordinate Zp can be expressed by the following formula, using the diameter value CD corresponding to the circumferential portion C1p and the angle θyz. Zp = (CD / 2) × cosθyz …(1) Based on the above, the Z-axis coordinate Zp corresponding to the cutting position P1 which changes along the circumferential portion C1p is determined based on the value CD.

[0040] In the cross-sectional view 102, the radius value r corresponding to the outer surface W1o is half the value OD. r = OD / 2 …(2) The radius value CD / 2 corresponding to the value CD can be expressed by the following formula, using the radius value r and the angle θxy between the line segment between OA and the line segment between OB. CD / 2 = r × sin(θxy / 2) …(3) From equation (3) above, sin(θxy / 2) = CD / 2r, so the angle θxy can be expressed by the following equation. θxy = 2 × arcsin(CD / 2r) …(4) "arcsin" is the inverse function of "sin". -1 It is also written as "". From equation (4) above, the angle θxy is a fixed value calculated from the values ​​CD and OD.

[0041] The C-axis angle Cp is the rotational angle corresponding to the cutting position P1 which changes along the circumferential portion C1p on the C-axis, and is the angle of the workpiece W1 held by the spindle 11 on the C-axis. Since the C-axis angle Cp changes in the range -(θxy / 2)≦Cp≦+(θxy / 2), it can be expressed by the following equation using the angle θxy between the line segment OA and the line segment OB, and the angle θyz corresponding to the cutting position P1. Cp = (θxy / 2) × sinθyz =arcsin(CD / 2r)×sinθyz…(5) Based on the above, the C-axis angle Cp corresponding to the cutting position P1 which changes along the circumferential portion C1p is determined based on the values ​​CD and OD.

[0042] As illustrated in Figure 7, the same concept can be applied when cutting the peripheral portion C1p of a cross hole C1 on the inner circumferential surface W1i of workpiece W1. Figure 7 schematically shows an example of determining the Z-axis coordinate Zp and C-axis angle Cp corresponding to the cutting position P1 based on the diameter value (CD) of the cross hole C1 and the inner diameter value (OD) of workpiece W1. In Figure 7, a plan view 101 of workpiece W1 is shown at the top, a cross-sectional view 102 of workpiece W1 is shown below the plan view 101, and the formulas for calculating the Z-axis coordinate Zp and C-axis angle Cp are shown at the bottom.

[0043] The value CD is the same as when the deburring surface is the outer surface W1o, and represents the diameter corresponding to the circumferential portion C1p when the cross hole C1 is viewed from the X-axis direction. The value OD represents the diameter corresponding to the circumference, i.e., the inner circumferential surface W1i, in a cross section (see cross section 102) that passes through the center C1o of the cross hole C1 and perpendicular to the spindle centerline AX1, with the spindle centerline AX1 as the center and passing through the circumferential portion C1p. Figure 7 also shows point B corresponding to θyz = 90° and point A corresponding to θyz = 270° (or -90°). The angle θxy is the angle between the line segment connecting the center point O and point A, which correspond to the spindle centerline AX1, and the line segment connecting the center point O and point B, in cross section 102.

[0044] The Z-axis coordinate Zp is the same as when the deburring surface is the outer surface W1o, and using the diameter value CD corresponding to the peripheral portion C1p and the angle θyz, it can be expressed by the following formula. Zp = (CD / 2) × cosθyz …(6) In the cross-sectional view 102, the radius value r corresponding to the inner surface W1i is half the value OD. r = OD / 2 …(7) The radius value CD / 2 corresponding to the value CD can be expressed by the following formula, using the radius value r and the angle θxy between the line segment between OA and the line segment between OB. CD / 2 = r × sin(θxy / 2) …(8) From equation (8) above, the angle θxy is expressed by the following equation. θxy = 2 × arcsin(CD / 2r) …(9) Since the C-axis angle Cp varies within the range -(θxy / 2)≦Cp≦+(θxy / 2), it can be expressed by the following equation using the angle θxy between the line segments OA and OB, and the angle θyz corresponding to the cutting position P1. Cp = (θxy / 2) × sinθyz =arcsin(CD / 2r)×sinθyz…(10)

[0045] Based on the above, by determining the Z-axis coordinate Zp and C-axis angle Cp based on the values ​​CD and OD, deburring can be controlled using two-axis control of the Z-axis and C-axis. Therefore, by providing a deburring command CM1 (see Figure 9) suitable for two-axis deburring, deburring can be performed without commanding the cutting position P1 in the three axes of the X-axis, Y-axis, and Z-axis.

[0046] By the way, if the deburring tool TO3 is oriented along the spindle centerline AX1, the relative direction of movement of the deburring tool TO3 will reverse midway as the cutting position P1 completes a full rotation clockwise or counterclockwise along the circumferential portion C1p. If the deburring tool TO3 rotates clockwise, the down cut and up cut will be reversed midway as the cutting position P1 completes a full rotation clockwise or counterclockwise along the circumferential portion C1p.

[0047] Figure 20 schematically illustrates the switching between down-cut and up-cut during the cutting of the periphery C1p of the cross hole C1. The left side of Figure 20 shows a plan view 101 of the workpiece W1 in states 191 to 194, and the right side of Figure 20 shows the cutting state of the workpiece W1 in states 191 to 194. As a premise, the deburring tool TO3 is a right-hand cutting ball end mill, and the deburring tool TO3 rotates clockwise around the deburring tool centerline AX3, causing the cutting position P1 on the outer surface W1o to move clockwise along the periphery C1p. In state 191, where the cutting position P1 is at the reference position P0, the angle θyz is 0°, the workpiece W1 is at a position moved a distance of CD / 2 in the -Z direction, and the C-axis angle Cp is 0°. At this time, in the Y-axis direction along the cutting direction D1 (leftward in Figure 20), which is the rotation direction of the spherical cutting part TO3b, the relative movement direction D2 of the spherical cutting part TO3b is opposite to the cutting direction D1, so a down cut is performed on the periphery C1p at the reference position P0. A down cut can be described as a cut in which the cutting direction D1 by the rotating deburring tool TO3 is opposite to the relative movement direction D2 of the deburring tool TO3.

[0048] When the cutting position P1 reaches state 192, where θyz = 90°, the Z-axis coordinate Zp becomes 0, and the C-axis angle Cp becomes +θxy / 2. At this time, the direction of the relative movement D2 of the spherical cutting section TO3b changes in the Y-axis direction, so the cutting position P1 is at the reversal position of the relative movement direction D2 (which will be called the second reversal position R2 in Figure 20). When the cutting position P1 reaches state 193, where θyz = 180°, the workpiece W1 moves a distance of CD / 2 in the +Z direction, and the C-axis angle Cp becomes 0°. At this time, the relative movement direction D2 of the spherical cutting section TO3b in the Y-axis direction is the same as the cutting direction D1, so an upcut is performed on the circumferential portion C1p. An upcut can be described as a cut where the cutting direction D1 and the relative movement direction D2 coincide.

[0049] When the cutting position P1 reaches state 194, where θyz = 270° (or -90°), the Z-axis coordinate Zp becomes 0, and the C-axis angle Cp becomes -θxy / 2. At this time, the direction of the relative movement D2 of the spherical cutting section TO3b changes in the Y-axis direction, so the cutting position P1 is at the reversal position of the relative movement direction D2 (which will be called the first reversal position R1 in Figure 20). Furthermore, when the cutting position P1 moves counterclockwise along the periphery C1p on the outer circumferential surface W1o, contrary to the above, an up-cut is performed on the periphery C1p at the reference position P0 where θyz=0°, and a down-cut is performed on the periphery C1p at the position where θyz=180°. Also, when the cutting position P1 moves clockwise along the periphery C1p on the inner circumferential surface W1i, contrary to the case of the outer circumferential surface W1o, an up-cut is performed on the periphery C1p at the reference position P0 where θyz=0°, and a down-cut is performed on the periphery C1p at the position where θyz=180°.

[0050] Generally, down-cutting is said to extend the lifespan of rotary tools compared to up-cutting. On the other hand, up-cutting is said to produce a glossier cutting surface and facilitate chip removal compared to down-cutting. If down-cutting and up-cutting are switched midway through the process, the condition of the cutting surface may differ between the down-cut and up-cut sections. Therefore, a mechanism is desired to easily create machining programs while being mindful of down-cutting or up-cutting.

[0051] In this specific example, the lathe 1 automatically performs a down-cut or up-cut on the periphery C1p according to a deburring command that instructs a down-cut or up-cut.

[0052] (3) First specific example of deburring process: Ball end mills come in right-hand and left-hand cutting types, with the right-hand type being the most commonly used. Therefore, it would be advantageous to be able to perform cutting while maintaining down-cut or up-cut while using a right-hand cutting deburring tool, such as the TO3.

[0053] Figure 8A schematically shows an example of the movement of the cutting position P1 when performing a down cut on the outer surface W1o or an up cut on the inner surface W1i. As a premise, the deburring tool TO3 is a right-hand cutting tool, and it is assumed that the deburring tool TO3 rotates clockwise around the deburring tool centerline AX3. As described above, when the cutting position P1 completes a full clockwise rotation along the periphery C1p, the cutting direction changes from a down cut to an up cut at the second reversal position R2 at θyz=90°, and from an up cut to a down cut at the first reversal position R1 at θyz=270° (or -90°). Therefore, the cutting path PA0 along the periphery C1p of the cross hole C1 is divided into a first path PA1 and a second path PA2 at the reversal positions (R1, R2), and the direction in which the cutting position P1 changes along the periphery C1p is changed between the first path PA1 and the second path PA2. Here, the first path PA1 is defined as the path from the first reversal position R1 at θyz=-90°, through the reference position P0 at θyz=0°, to the second reversal position R2 at θyz=90°. The second path PA2 is defined as the path from the first reversal position R1 at θyz=270°, through the intermediate position P2 at θyz=180°, to the second reversal position R2 at θyz=90°. The reason for representing the angle θyz at the first reversal position R1 as -90° and 270° is for the convenience of calculating the Z-axis coordinate Zp and C-axis angle Cp according to the cutting position P1 which changes along the periphery C1p.

[0054] When the cutting position P1 changes along the first path PA1, the relative movement direction D2 of the clockwise rotating spherical cutting section TO3b becomes the +Y direction. As a result, when cutting the outer surface W1o, a down cut is performed in which the cutting direction D1 (see Figure 20) is opposite to the relative movement direction D2, and when cutting the inner surface W1i, an up cut is performed in which the cutting direction D1 coincides with the relative movement direction D2. Even when the cutting position P1 changes along the second path PA2, the relative movement direction D2 of the clockwise rotating spherical cutting section TO3b becomes the +Y direction. As a result, when cutting the outer surface W1o, a down cut is performed in which the cutting direction D1 is opposite to the relative movement direction D2, and when cutting the inner surface W1i, an up cut is performed in which the cutting direction D1 coincides with the relative movement direction D2. When a down cut on the outer circumferential surface W1o or an up cut on the inner circumferential surface W1i is commanded, the direction from the first reversal position R1 to the second reversal position R2 in the Y-axis direction is defined as the first direction D21. When the relative movement direction D2 of the deburring tool TO3 with respect to the cutting direction D1 is the first direction D21, the cut commanded by the deburring command CM1 is performed on the circumferential portion C1p. The first path PA1 and the second path PA2 are paths in which the relative movement direction D2 of the spherical cutting portion TO3b is the first direction D21, and the relative movement direction D2 is not the second direction D22, which is the opposite of the first direction D21.

[0055] In the above case, the NC device 70 performs a "figure eight" control, changing the cutting position P1 from the first reversal position R1 to the second reversal position R2 in the first path PA1, and then changing the cutting position P1 from the first reversal position R1 to the second reversal position R2 in the second path PA2. Figure 8A shows an example of a "figure eight" path in which the cutting position P1 is changed in the first path PA1, then moved from the second reversal position R2 to the first reversal position R1, and then changed in the second path PA2. Of course, the NC device 70 may also change the cutting position P1 in the second path PA2, then move from the second reversal position R2 to the first reversal position R1, and then change the cutting position P1 in the first path PA1. In any case, down-cutting of the outer circumferential surface W1o or up-cutting of the inner circumferential surface W1i is maintained.

[0056] Figure 8B schematically shows an example of the movement of the cutting position P1 when performing an up-cut on the outer surface W1o or a down-cut on the inner surface W1i. Here again, it is assumed that the deburring tool TO3 is a right-handed rotary tool and rotates clockwise around the deburring tool centerline AX3. Note that the first orientation D21 described above is reversed in Figure 8A and Figure 8B, so the first reversal position R1 is at θyz = 90° and the second reversal position R2 is at θyz = 270° (or -90°). In the case of Figure 8B, the first path PA1 is the path from the first inversion position R1 at θyz=90°, through the reference position P0 at θyz=0°, to the second inversion position R2 at θyz=-90°. The second path PA2 is the path from the first inversion position R1 at θyz=90°, through the intermediate position P2 at θyz=180°, to the second inversion position R2 at θyz=270°.

[0057] When the cutting position P1 changes along the first path PA1, the relative movement direction D2 of the clockwise rotating spherical cutting section TO3b becomes the -Y direction. Similarly, when the cutting position P1 changes along the second path PA2, the relative movement direction D2 of the clockwise rotating spherical cutting section TO3b becomes the -Y direction. As a result, when cutting the outer circumferential surface W1o, an up-cut is performed where the cutting direction D1 (see Figure 20) coincides with the relative movement direction D2, and when cutting the inner circumferential surface W1i, a down-cut is performed where the cutting direction D1 is opposite to the relative movement direction D2. When the relative movement direction D2 of the deburring tool TO3 with respect to the cutting direction D1 is the first orientation D21, the cut commanded by the deburring command CM1 is performed on the periphery C1p.

[0058] In the above case as well, the NC device 70 performs a "figure eight" control, changing the cutting position P1 from the first reversal position R1 to the second reversal position R2 in the first path PA1, and changing the cutting position P1 from the first reversal position R1 to the second reversal position R2 in the second path PA2. Figure 8B shows an example of a "figure eight" path in which the cutting position P1 is changed in the first path PA1, then moved from the second reversal position R2 to the first reversal position R1, and then changed in the second path PA2. Of course, the NC device 70 may also change the cutting position P1 in the second path PA2, then move from the second reversal position R2 to the first reversal position R1, and then change the cutting position P1 in the first path PA1. In any case, an up-cut on the outer circumferential surface W1o or a down-cut on the inner circumferential surface W1i is maintained.

[0059] Figures 9 and 10 schematically illustrate the deburring process performed by the NC device 70. Figure 9 also shows the deburring command CM1 included in the machining program PR2. The NC device 70 shown in Figure 2 starts the deburring process when it reads the deburring command CM1 from the machining program PR2. As a prerequisite, the deburring tool TO3 is a right-hand cutting tool, the deburring tool TO3 rotates clockwise around the deburring tool centerline AX3, and the rotational speed of the spindle 11 (in rpm) is pre-commanded.

[0060] The deburring command CM1 shown in Figure 9 has the format "G167 D** X** R** P** F**". "G167" indicates a deburring command to change the direction of cutting along the circumferential portion C1p midway through the cutting process. The argument "**" after D indicates the outer or inner diameter value OD (mm) of the workpiece W1. The argument "**" after X indicates the diameter value CD (mm) corresponding to the circumferential portion C1p when the cross hole C1 is viewed from the X-axis direction. The argument "**" after R indicates whether to perform a down cut or an up cut; "0" means a down cut, and "1" means an up cut. In other words, the deburring command CM1 is a command that instructs whether to perform a down cut or an up cut on the circumferential portion C1p. Hereafter, the argument R may be represented as R=0 or R=1. The argument "**" after P indicates whether to perform internal diameter machining, which cuts the peripheral portion C1p on the inner surface W1i, or external diameter machining, which cuts the peripheral portion C1p on the outer surface W1o. "0" means internal diameter machining, and "1" means external diameter machining. Hereafter, the argument of P may be represented as P=0 or P=1. The argument "**" after F indicates the feed rate per minute, which is distributed between the movement speed of the workpiece W1 along the Z axis and the rotation speed of the workpiece W1 along the C axis. Furthermore, the deburring command CM1 may include an argument indicating the rotational speed of the deburring tool TO3 when it rotates.

[0061] When the cutting position P1 completes half a turn on the periphery C1p, the total distance traveled by the workpiece W1 along the Z axis is CD (mm), and the total rotational distance of the workpiece W1 along the C axis is θxy (deg). For example, assuming that a rotational distance of 1° corresponds to a travel distance of 1 mm, the time (T (min)) required for the cutting position P1 to complete half a turn on the periphery C1p can be calculated using the following formula. T=(CD 2 +θxy 2 ) 1 / 2 / F …(11) If t (min) is the time elapsed since the cutting position P1 began moving from θyz = -90° to θyz = 90°, then the angle θyz (deg) corresponding to the cutting position P1 can be calculated, for example, using the following formula. θyz = 180 × (t / T) - 90 …(12) Furthermore, if t (min) is the time elapsed since the cutting position P1 began moving from θyz = 270° to θyz = 90°, the angle θyz (deg) corresponding to the cutting position P1 can be calculated, for example, using the following formula. θyz = 270 - 180 × (t / T) …(13) Therefore, by applying the angle θyz corresponding to the cutting position P1 which changes along the circumferential portion C1p, along with the values ​​CD and OD, to the above equations (1) to (10), the Z-axis coordinate Zp and the C-axis angle Cp can be determined.

[0062] Furthermore, if you want to reduce the amount of material removed from the periphery C1p, taking into account the size of the spherical cutting section TO3b of the deburring tool TO3, you may slightly reduce the command value of value CD compared to the actual diameter of the periphery C1p. Conversely, if you want to increase the amount of material removed from the periphery C1p, you may slightly increase the command value of value CD compared to the actual diameter of the periphery C1p. In addition, you can also adjust the amount of material removed from the periphery C1p by adding an argument to the deburring command CM1 that specifies an offset amount for adjusting the amount of material removed from the periphery C1p.

[0063] When the deburring process shown in Figure 9 begins, the NC device 70 obtains the arguments for the deburring command CM1 described above (step S102). Hereafter, the description of "step" will be omitted. Upon obtaining the deburring command CM1, the following are obtained: the diameter value CD corresponding to the circumferential portion C1p as viewed from the X-axis direction, the diameter value OD corresponding to the circumference passing through the circumferential portion C1p as viewed from the Z-axis direction, an argument indicating whether to perform a down cut or an up cut, and an argument indicating whether to perform internal diameter machining or external diameter machining. After receiving the deburring command CM1, the NC device 70 determines the movement path of the cutting position P1 based on the R and P arguments (S104).

[0064] When P=1 (outer diameter machining) and R=0 (down cut), or when P=0 (inner diameter machining) and R=1 (up cut), the NC device 70 determines the movement path of the cutting position P1 so as to change the cutting position P1 along the circumferential portion C1p, as shown in Figure 8A. As a result, the cutting position P1 changes from the first inversion position R1 at θyz=-90° to the second inversion position R2 at θyz=90° in the first path PA1, then moves to the first inversion position R1, and then changes from the first inversion position R1 at θyz=270° to the second inversion position R2 at θyz=90° in the second path PA2. When P=1 (outer diameter machining) and R=1 (up cut), or when P=0 (inner diameter machining) and R=0 (down cut), the NC device 70 determines the movement path of the cutting position P1 so as to change the cutting position P1 along the circumferential portion C1p, as shown in Figure 8B. As a result, the cutting position P1 changes from the first inversion position R1 at θyz=90° to the second inversion position R2 at θyz=-90° in the first path PA1, then moves to the first inversion position R1, and then changes from the first inversion position R1 at θyz=90° to the second inversion position R2 at θyz=270° in the second path PA2.

[0065] After determining the movement path, the NC device 70 controls the Z-axis coordinate Zp and C-axis angle Cp to the first inversion position R1 (S106). For example, the NC device 70 controls the rotation of the deburring tool TO3 around the deburring tool centerline AX3, making the Z-axis coordinate of the workpiece W1 correspond to Zp=0, controlling the C-axis angle of the workpiece W1 to -θxy / 2 or θxy / 2, and controlling the spherical cutting part TO3b of the deburring tool TO3 to come into contact with the first inversion position R1 of the periphery C1p. Note that the rotation of the deburring tool TO3 only needs to start before the spherical cutting part TO3b comes into contact with the reference position P0, so it may start after the Z-axis coordinate of the workpiece W1 is controlled to Zp=0, or after the C-axis angle of the workpiece W1 is controlled to -θxy / 2 or θxy / 2.

[0066] Subsequently, the NC device 70 determines the angle θyz corresponding to the cutting position P1 of the first path PA1 based on the feed rate F, according to equations (11) and (12) above (S108). Furthermore, the NC device 70 determines the Z-axis coordinate Zp and the C-axis angle Cp at angle θyz based on the values ​​CD and OD, according to equations (1) to (10) above (S110). Through the process up to S110, the Z-axis coordinate Zp corresponding to the cutting position P1 that changes along the circumferential portion C1p in the Z-axis, and the C-axis angle Cp corresponding to the cutting position P1 in the C-axis are determined.

[0067] After determining the Z-axis coordinate Zp and the C-axis angle Cp, the NC device 70 controls the relative positional relationship between the workpiece W1 and the deburring tool TO3 to the Z-axis coordinate Zp, and controls the workpiece W1 to the C-axis angle Cp with respect to the spindle centerline AX1 (S112). Subsequently, the NC device 70 determines whether the cutting position P1 has arrived at the second inversion position R2 (S114). If the cutting position P1 has not arrived at the second inversion position R2, the NC device 70 repeats the process from S108 to S114. If the cutting position P1 has arrived at the second inversion position R2, the NC device 70 controls the Z-axis coordinate Zp and the C-axis angle Cp to the first inversion position R1 (S116 in Figure 10). Since the Z-axis coordinate Zp is 0 and the deburring tool TO3 rotates around the deburring tool centerline AX3, the NC device 70 controls the C-axis angle of the workpiece W1 to -θxy / 2 or θxy / 2 and controls the spherical cutting portion TO3b of the deburring tool TO3 to come into contact with the first reversal position R1 of the circumferential portion C1p. As a result, the spherical cutting portion TO3b of the deburring tool TO3 moves away from the circumferential portion C1p and moves from the second reversal position R2 to the first reversal position R1.

[0068] Subsequently, the NC device 70 determines the angle θyz corresponding to the cutting position P1 of the second path PA2 based on the feed rate F, according to equations (11) and (13) above (S118). Furthermore, the NC device 70 determines the Z-axis coordinate Zp and the C-axis angle Cp at angle θyz based on the values ​​CD and OD, according to equations (1) to (10) above (S120). Through the process up to S120, the Z-axis coordinate Zp corresponding to the cutting position P1 that changes along the circumferential portion C1p in the Z-axis, and the C-axis angle Cp corresponding to the cutting position P1 in the C-axis are determined.

[0069] After determining the Z-axis coordinate Zp and the C-axis angle Cp, the NC device 70 controls the relative positional relationship between the workpiece W1 and the deburring tool TO3 to the Z-axis coordinate Zp, and controls the workpiece W1 to the C-axis angle Cp with respect to the spindle centerline AX1 (S122). Subsequently, the NC device 70 determines whether the cutting position P1 has reached the second inversion position R2 (S124). If the cutting position P1 has not reached the second inversion position R2, the NC device 70 repeats the process from S118 to S124. If the cutting position P1 has reached the second inversion position R2, the NC device 70 terminates the deburring process. As described above, the NC device 70 controls the relative positional relationship between the spindle 11 and the tool post 30 in the Z-axis direction to the Z-axis coordinate Zp, and controls the rotation of the spindle 11 to the C-axis angle Cp, so that the cutting position P1 changes along the circumferential portion C1p of the cross hole C1. Then, in order to maintain the cut commanded by the deburring command CM1, the NC device 70 controls the cutting position P1 in the first path PA1 to change from the first reversal position R1 to the second reversal position R2, and in the second path PA2 to change the cutting position P1 from the first reversal position R1 to the second reversal position R2, and cuts the circumferential portion C1p.

[0070] Figures 11 and 12 schematically illustrate the Z-axis movement and C-axis rotation of the workpiece W1 when the deburring command CM1 instructs an up-cut of the inner surface W1i. The left side of Figures 11 and 12 shows a plan view 101 of the workpiece W1 in states 111 to 116, and the right side of Figures 11 and 12 shows a cross-sectional view 102 of the workpiece W1 in states 111 to 116. As a premise, the deburring tool TO3 is a right-hand cutting ball end mill, and the deburring tool TO3 is assumed to rotate clockwise around the deburring tool centerline AX3. In state 111, when the cutting position P1 is at the first inversion position R1 with θyz = -90°, the Z-axis coordinate Zp is 0 and the C-axis angle Cp is -θxy / 2. Subsequently, in the plan view 101, as the cutting position P1 moves clockwise along the first path PA1, the Z-axis coordinate Zp increases, causing the workpiece W1 to move in the -Z direction, and the C-axis angle Cp increases toward 0°.

[0071] When the cutting position P1 reaches state 112, where θyz = 0°, the Z-axis coordinate Zp becomes +CD / 2, so the workpiece W1 moves a distance of CD / 2 in the -Z direction, and the C-axis angle Cp becomes 0°. Subsequently, as the Z-axis coordinate Zp decreases, the workpiece W1 moves in the +Z direction, and the C-axis angle Cp increases toward +θxy / 2. When the cutting position P1 is in the second inversion position R2 at θyz = 90° (state 113), the Z-axis coordinate Zp becomes 0 and the C-axis angle Cp becomes +θxy / 2. At this point, the cutting position P1 is returned to the first inversion position R1. As a result, the spherical cutting portion TO3b of the deburring tool TO3 moves away from the periphery C1p and from the second inversion position R2 to the first inversion position R1. As shown in Figure 12, when the cutting position P1 is in the first inversion position R1 at θyz = 270° (state 114), the Z-axis coordinate Zp becomes 0 and the C-axis angle Cp becomes -θxy / 2. Subsequently, in the plan view 101, as the cutting position P1 moves counterclockwise along the second path PA2, the Z-axis coordinate Zp decreases, causing the workpiece W1 to move in the +Z direction, and the C-axis angle Cp decreases toward 0°.

[0072] When the cutting position P1 reaches state 115, where θyz = 180°, the Z-axis coordinate Zp becomes -CD / 2, so the workpiece W1 moves a distance of CD / 2 in the +Z direction, and the C-axis angle Cp becomes 0°. Subsequently, as the Z-axis coordinate Zp increases, the workpiece W1 moves in the -Z direction, and the C-axis angle Cp increases toward +θxy / 2. When the cutting position P1 is in the second inversion position R2 at θyz = 90°, state 116, the Z-axis coordinate Zp becomes 0 and the C-axis angle Cp becomes +θxy / 2.

[0073] As a result, the edges of the periphery C1p of the cross hole C1 are machined along its entire circumference, and burrs are removed from the outer surface W1o and the inner surface W1i. Although not shown in the diagram, if the deburring command CM1 instructs a down cut of the outer surface W1o, the down cut is maintained by moving the cutting position P1 as shown in Figures 11 and 12. If the deburring command CM1 instructs an up cut of the outer surface W1o or a down cut of the inner surface W1i, the cutting position P1 goes from state 113 to state 112 and then to state 111, and then from state 116 to state 115 and then to state 114. This maintains the up cut of the outer surface W1o or the down cut of the inner surface W1i.

[0074] As described above, the deburring process removes burrs from the periphery C1p of the cross hole C1 based on the value CD representing the diameter of the cross hole C1 as viewed from the machining center line direction, and the value OD representing the outer or inner diameter of the workpiece W1 as viewed from the spindle center line direction. The NC device 70 only needs to control two axes: the Z axis along the spindle center line AX1 and the C axis around the spindle center line AX1, rather than controlling three axes: the X, Y, and Z axes. As the C axis angle Cp of the workpiece W1 is controlled in accordance with the cutting position P1, and the relative Z axis coordinate Zp of the deburring tool TO3 relative to the workpiece W1 is controlled in accordance with the cutting position P1, interference between the deburring tool TO3 and the workpiece W1 can be easily avoided. Therefore, interference between the deburring tool TO3 and the workpiece W1 due to command errors when commanding the movement of the deburring tool TO3 in the three linear axis directions relative to the workpiece W1 can be easily avoided.

[0075] Furthermore, the down-cut or up-cut commanded by the deburring command CM1 is maintained when the cutting position P1 moves from the second reversal position R2 to the first reversal position R1 midway through the process. In particular, when the orientation of the deburring tool TO3 is aligned with the spindle centerline AX1, the relative movement direction D2 of the deburring tool TO3 reverses midway when the cutting position P1 completes a full rotation clockwise or counterclockwise along the circumferential portion C1p. Even in this case, the operator can simply command R=0 or R=1 in the deburring command CM1 to have the lathe 1 perform a down-cut or up-cut along the entire circumference of the circumferential portion C1p, eliminating the need to create a complex machining program PR2. Therefore, the lathe 1 in this specific example is convenient because it can perform deburring while maintaining a down-cut or up-cut even if there are constraints on the direction of rotation of the deburring tool TO3, without the operator having to be aware of these constraints.

[0076] (4) A second specific example of deburring process: When using a rotary tool that can be used both clockwise and counterclockwise, such as a grinding wheel or brush, as the deburring tool TO3, it is possible to maintain down-cut or up-cut without having to move the cutting position P1 from the second reversal position R2 to the first reversal position R1 midway through the process. The machining program PR2 may include a deburring command CM2 (see Figure 14) suitable for rotary tools that can be used both clockwise and counterclockwise. The tool post 30 is designed to allow the deburring tool TO3 to rotate both clockwise and counterclockwise.

[0077] Figure 13A schematically shows an example of changing the rotation direction of the deburring tool TO3 when performing a down cut on the outer surface W1o or an up cut on the inner surface W1i. It is assumed that the cutting position P1 completes a full clockwise rotation along the periphery C1p of the cross hole C1. In the second specific example, the cutting path PA0 along the circumferential portion C1p includes a first path PA1 from a first reversal position R1 at θyz = -90° to a second reversal position R2 at θyz = 90°, and a second path PA2 from a second reversal position R2 at θyz = 90° to a first reversal position R1 at θyz = 270°. The first path PA1 is a path in which the relative movement direction D2 of the deburring tool TO3 with respect to the cutting direction D1, which is the rotation direction of the spherical cutting portion TO3b, is the first direction D21, not the second direction D22. The second path PA2 is a path in which the relative movement direction D2 with respect to the cutting direction D1 is the second direction D22, not the first direction D21. Therefore, the second path PA2 shown in Figure 13A has a different movement direction of the cutting position P1 than the second path PA2 shown in Figure 8A.

[0078] The NC device 70 rotates the deburring tool TO3 clockwise in the first path PA1 and counterclockwise in the second path PA2. As the cutting position P1 changes along the first path PA1, the relative movement direction D2 of the clockwise rotating spherical cutting section TO3b becomes the +Y direction. As a result, when cutting the outer surface W1o, a down cut is performed in which the cutting direction D1 (see Figure 20) is opposite to the relative movement direction D2, and when cutting the inner surface W1i, an up cut is performed in which the cutting direction D1 coincides with the relative movement direction D2. When the cutting position P1 arrives at the second reversal position R2, the NC device 70 controls the rotation direction of the deburring tool TO3 from clockwise to counterclockwise. Subsequently, as the cutting position P1 changes along the second path PA2, the relative movement direction D2 of the counterclockwise rotating spherical cutting section TO3b becomes the -Y direction. As a result, when cutting the outer surface W1o, a down cut is performed in which the cutting direction D1 is opposite to the relative movement direction D2, and when cutting the inner surface W1i, an up cut is performed in which the cutting direction D1 coincides with the relative movement direction D2.

[0079] Figure 13B schematically shows an example of changing the rotation direction of the deburring tool TO3 when performing an upcut on the outer circumferential surface W1o or a downcut on the inner circumferential surface W1i. Here again, it is assumed that the cutting position P1 completes one full rotation clockwise along the circumferential portion C1p. The cutting path PA0 shown in Figure 13B also includes a first path PA1 and a second path PA2, similar to those in Figure 13A. The first path PA1 shown in Figure 13B differs from the first path PA1 shown in Figure 8B in the direction of movement of the cutting position P1.

[0080] The NC device 70 rotates the deburring tool TO3 counterclockwise in the first path PA1 and clockwise in the second path PA2. As the cutting position P1 changes along the first path PA1, the relative movement direction D2 of the counterclockwise rotating spherical cutting section TO3b becomes the +Y direction. As a result, when cutting the outer surface W1o, an up-cut is performed where the cutting direction D1 (see Figure 20) coincides with the relative movement direction D2, and when cutting the inner surface W1i, a down-cut is performed where the cutting direction D1 is opposite to the relative movement direction D2. When the cutting position P1 arrives at the second reversal position R2, the NC device 70 controls the rotation direction of the deburring tool TO3 from counterclockwise to clockwise. Subsequently, as the cutting position P1 changes along the second path PA2, the relative movement direction D2 of the clockwise rotating spherical cutting section TO3b becomes the -Y direction. As a result, when cutting the outer surface W1o, an up-cut is performed where the cutting direction D1 coincides with the relative movement direction D2, and when cutting the inner surface W1i, a down-cut is performed where the cutting direction D1 is opposite to the relative movement direction D2.

[0081] Figure 14 schematically illustrates a deburring process that switches the rotation direction of the deburring tool TO3. Figure 14 also shows the deburring command CM2 included in the machining program PR2. The NC device 70 shown in Figure 2 starts the deburring process when it reads the deburring command CM2 from the machining program PR2. As a prerequisite, it is assumed that the cutting position P1 completes one full rotation clockwise along the periphery C1p of the cross hole C1, and that the rotation speed of the spindle 11 has been commanded in advance.

[0082] The deburring command CM2 shown in Figure 14 has the format "G168 D** X** R** P** S** R** F** B**". "G168" indicates a deburring command to change the rotation direction of the deburring tool TO3 midway. The argument "**" after D indicates the outer or inner diameter value OD (mm) of the workpiece W1. The argument "**" after X indicates the diameter value CD (mm) corresponding to the circumferential portion C1p when the cross hole C1 is viewed from the X-axis direction. The argument "**" after R, which indicates the third argument, indicates whether to perform a down cut or an up cut; "0" means a down cut, and "1" means an up cut. The argument "**" after P indicates whether to perform an inner diameter machining operation, where the circumferential portion C1p is cut on the inner circumferential surface W1i, or an outer diameter machining operation, where the circumferential portion C1p is cut on the outer circumferential surface W1o; "0" means inner diameter machining, and "1" means outer diameter machining. The argument "**" after S indicates the rotational speed (rpm) when the deburring tool TO3 rotates clockwise. The argument "**" after R, which indicates the sixth argument, indicates the rotational speed (rpm) when the deburring tool TO3 rotates counterclockwise. If the rotational speed of the deburring tool TO3 is predetermined, the argument indicating the rotational speed of the deburring tool TO3 may be omitted. The argument "**" after F indicates the feed rate per minute, which is distributed between the movement speed of the workpiece W1 along the Z axis and the rotation speed of the workpiece W1 along the C axis when the deburring tool TO3 rotates clockwise. The argument "**" after B indicates the feed rate per minute, which is distributed between the movement speed of the workpiece W1 along the Z axis and the rotation speed of the workpiece W1 along the C axis when the deburring tool TO3 rotates counterclockwise.

[0083] When the deburring process shown in Figure 14 begins, the NC device 70 obtains the arguments of the deburring command CM2 (S202) and determines the direction of rotation of the deburring tool TO3 based on the arguments R (third argument) and P (S204). If P=1 (outer diameter machining) and R=0 (down cut), or if P=0 (inner diameter machining) and R=1 (up cut), the NC device 70 determines the direction of rotation of the deburring tool TO3 to be clockwise in the first path PA1 and counterclockwise in the second path PA2, as shown in Figure 13A. If P=1 (outer diameter machining) and R=1 (up cut), or if P=0 (inner diameter machining) and R=0 (down cut), the NC device 70 determines the direction of rotation of the deburring tool TO3 to be counterclockwise in the first path PA1 and clockwise in the second path PA2, as shown in Figure 13B.

[0084] After determining the direction of rotation of the deburring tool TO3, the NC device 70 controls the Z-axis coordinate Zp and C-axis angle Cp to the first reversal position R1 (S206). For example, the NC device 70 controls the rotation of the deburring tool TO3 at the commanded rotational speed S or R (sixth argument), making the Z-axis coordinate of the workpiece W1 correspond to Zp=0, controlling the C-axis angle of the workpiece W1 to -θxy / 2, and controlling the spherical cutting portion TO3b of the deburring tool TO3 to come into contact with the first reversal position R1 of the circumferential portion C1p. Subsequently, the NC device 70 determines the angle θyz corresponding to the cutting position P1 based on the feed rate F or B according to equations (11) and (12) above (S208). When the argument B is applied to the feed rate, the argument B is applied to the feed rate F in equation (11) above. Furthermore, the NC device 70 determines the Z-axis coordinate Zp and the C-axis angle Cp at angle θyz based on the values ​​CD and OD according to equations (1) to (10) above (S210).

[0085] After determining the Z-axis coordinate Zp and the C-axis angle Cp, the NC device 70 controls the relative positional relationship between the workpiece W1 and the deburring tool TO3 to the Z-axis coordinate Zp, and controls the workpiece W1 to the C-axis angle Cp with respect to the spindle centerline AX1 (S212). Subsequently, the NC device 70 determines whether the cutting position P1 has reached the second reversal position R2 (S214). If the cutting position P1 has not reached the second reversal position R2, the NC device 70 repeats the processes from S208 to S214. If the processes from S216 onwards have not been performed, the down cut or up cut commanded in the first path PA1 is performed on the peripheral portion C1p. If the cutting position P1 has reached the second reversal position R2, the NC device 70 reverses the rotation of the deburring tool TO3 at the commanded rotational speed R (sixth argument) or S (S216). In S216, the NC device 70 may control the process by slightly separating the rotating spherical cutting part TO3b from the peripheral part C1p at the second reversal position R2, then reversing the rotation of the deburring tool TO3 at rotational speed R (sixth argument) or S, and then bringing the spherical cutting part TO3b to contact the second reversal position R2 of the peripheral part C1p. By separating the spherical cutting part TO3b from the peripheral part C1p within the hollow part W1h of the workpiece W1, the time during which cutting of the peripheral part C1p is temporarily interrupted at the second reversal position R2 is reduced. The distance at which the spherical cutting part TO3b is separated from the peripheral part C1p is sufficient as long as the spherical cutting part TO3b does not come into contact with the peripheral part C1p, and may be as small as 1 mm or less. Subsequently, the NC device 70 determines whether the cutting position P1 has returned to the first reversal position R1 (S218). If the cutting position P1 has not reached the first reversal position R1, the NC device 70 repeats the processes S208 to S218. After the determination process in S218, the down cut or up cut commanded in the second path PA2 is performed on the peripheral portion C1p. If the cutting position P1 has reached the first reversal position R1, the NC device 70 terminates the deburring process.

[0086] Therefore, when the deburring command CM2 instructs a down cut on the outer surface W1o or an up cut on the inner surface W1i, the deburring tool TO3 rotates clockwise in the first path PA1 and counterclockwise in the second path PA2. As a result, the cutting position P1 completes a full clockwise rotation along the circumferential portion C1p while maintaining the down cut or up cut instructed by the deburring command CM2. When the deburring command CM2 instructs an up cut on the outer surface W1o or a down cut on the inner surface W1i, the deburring tool TO3 rotates counterclockwise in the first path PA1 and clockwise in the second path PA2. As a result, the cutting position P1 completes a full clockwise rotation along the circumferential portion C1p while maintaining the down cut or up cut instructed by the deburring command CM2. Furthermore, the ridge of the peripheral portion C1p of the cross hole C1 is machined along its entire circumference, and burrs are removed from the outer surface W1o and the inner surface W1i. In this specific example, since down-cutting or up-cutting is maintained without changing the direction in which the cutting position P1 changes along the peripheral portion C1p, deburring while maintaining down-cutting or up-cutting can be performed efficiently. Furthermore, even when the cutting position P1 completes a counterclockwise rotation along the circumferential portion C1p, deburring can be performed while maintaining either a down-cut or up-cut by reversing the direction of rotation of the deburring tool TO3 midway through the process.

[0087] (5) A third specific example of deburring process: Even with a deburring tool TO3 that has constraints on the direction of rotation, such as a ball end mill, it is possible to perform deburring while maintaining down-cut or up-cut by using both a right-hand cutting tool TO3 and a left-hand cutting tool TO3. The machining program PR2 may include a deburring command CM3 (see Figure 17) that is suitable for using both a right-hand cutting tool TO3 and a left-hand cutting tool TO3.

[0088] Figure 15 schematically illustrates a tool post 30 (for example, a tool post 34 for back machining) to which a right-hand rotary tool TO31 and a left-hand rotary tool TO32 are attached as deburring tools TO3. As shown in Figure 15, the tool post 30 is equipped with a right-hand rotary tool TO31 and a left-hand rotary tool TO32. The tool post 30 rotates the right-hand rotary tool TO31 clockwise around the centerline AX31 of the right-hand rotary tool, which serves as the deburring tool centerline AX3, and rotates the left-hand rotary tool TO32 counterclockwise around the centerline AX32 of the left-hand rotary tool, which also serves as the deburring tool centerline AX3.

[0089] Figure 16A schematically shows an example of switching the deburring tool TO3 when performing a down cut on the outer surface W1o or an up cut on the inner surface W1i. It is assumed that the cutting position P1 completes a full clockwise rotation along the periphery C1p of the cross hole C1. The cutting path PA0 shown in Figure 16A is the same as the cutting path PA0 shown in Figure 13A. The NC device 70 controls the right-hand rotating tool TO31 to rotate clockwise in the first path PA1 to cut the periphery C1p, and controls the left-hand rotating tool TO32 to rotate counterclockwise in the second path PA2 to cut the periphery C1p. As the cutting position P1 changes along the first path PA1, the relative movement direction D2 of the right-hand rotating tool TO31, which rotates clockwise, becomes the +Y direction. As a result, when cutting the outer circumferential surface W1o, a down cut is performed in which the cutting direction D1 (see Figure 20) is opposite to the relative movement direction D2, and when cutting the inner circumferential surface W1i, an up cut is performed in which the cutting direction D1 coincides with the relative movement direction D2. When the cutting position P1 arrives at the second reversal position R2, the NC device 70 controls the deburring tool TO3 to switch from the right-hand rotating tool TO31 to the left-hand rotating tool TO32. Subsequently, as the cutting position P1 changes along the second path PA2, the relative movement direction D2 of the left-hand rotating tool TO32, which rotates counterclockwise, becomes the -Y direction. As a result, when cutting the outer surface W1o, a down cut is performed in which the cutting direction D1 is opposite to the relative movement direction D2, and when cutting the inner surface W1i, an up cut is performed in which the cutting direction D1 coincides with the relative movement direction D2.

[0090] Figure 16B schematically shows an example of switching the deburring tool TO3 when performing an upcut on the outer surface W1o or a downcut on the inner surface W1i. Here again, it is assumed that the cutting position P1 completes a full clockwise rotation along the circumferential portion C1p. The cutting path PA0 shown in Figure 16B also includes a first path PA1 and a second path PA2, similar to those in Figure 16A. The NC device 70 controls the left-hand rotary tool TO32 to rotate counterclockwise in the first path PA1 to cut the periphery C1p, and controls the right-hand rotary tool TO31 to rotate clockwise in the second path PA2 to cut the periphery C1p. As the cutting position P1 changes along the first path PA1, the relative movement direction D2 of the left-hand rotary tool TO32, which rotates counterclockwise, becomes the +Y direction. As a result, when cutting the outer circumferential surface W1o, an up-cut is performed where the cutting direction D1 (see Figure 20) coincides with the relative movement direction D2, and when cutting the inner circumferential surface W1i, a down-cut is performed where the cutting direction D1 is opposite to the relative movement direction D2. When the cutting position P1 arrives at the second reversal position R2, the NC device 70 controls the deburring tool TO3 to switch from the left-hand rotary tool TO32 to the right-hand rotary tool TO31. Subsequently, as the cutting position P1 changes along the second path PA2, the relative movement direction D2 of the right-hand rotating tool TO31, which rotates clockwise, becomes the -Y direction. As a result, when cutting the outer surface W1o, an up-cut is performed where the cutting direction D1 coincides with the relative movement direction D2, and when cutting the inner surface W1i, a down-cut is performed where the cutting direction D1 is opposite to the relative movement direction D2.

[0091] Figure 17 schematically illustrates an example of a deburring process that switches the deburring tool TO3 used. Figure 17 also shows the deburring command CM3 included in the machining program PR2. The NC device 70 shown in Figure 2 starts the deburring process when it reads the deburring command CM3 from the machining program PR2. As a prerequisite, it is assumed that the cutting position P1 completes one full rotation clockwise along the periphery C1p of the cross hole C1, and that the rotational speed of the spindle 11 has been commanded in advance.

[0092] The deburring command CM3 shown in Figure 17 has the format "G169 D** X** R** P** T** T** S** S** F** F**". "G169" indicates a deburring command for switching the deburring tool TO3 midway through the process. The argument "**" after D indicates the outer or inner diameter value OD (mm) of the workpiece W1. The argument "**" after X indicates the diameter value CD (mm) corresponding to the circumferential portion C1p when the cross hole C1 is viewed from the X-axis direction. The argument "**" after R indicates whether to perform a down cut or an up cut; "0" means a down cut, and "1" means an up cut. The argument "**" after P indicates whether to perform an inner diameter machining operation, where the circumferential portion C1p is cut on the inner circumferential surface W1i, or an outer diameter machining operation, where the circumferential portion C1p is cut on the outer circumferential surface W1o; "0" means inner diameter machining, and "1" means outer diameter machining. The argument "**" after T, which indicates the fifth argument, indicates the number of the right-hand cutting tool TO31. For example, when using the right-hand cutting tool TO31 with the T2100 tool, it is written as "T2100". The argument "**" after T, which indicates the sixth argument, indicates the number of the left-hand cutting tool TO32. For example, when using the left-hand cutting tool TO32 with the T2200 tool, it is written as "T2200". The argument "**" after S, which indicates the seventh argument, indicates the rotational speed (rpm) when the right-hand cutting tool TO31 rotates clockwise. The argument "**" after S, which indicates the eighth argument, indicates the rotational speed (rpm) when the left-hand cutting tool TO32 rotates counterclockwise. The argument "**" after F, which indicates the ninth argument, indicates the feed rate per minute that is distributed between the movement speed of the workpiece W1 along the Z axis and the rotational speed of the workpiece W1 along the C axis when the right-hand cutting tool TO31 is used. The argument "**" after F, which indicates the tenth argument, represents the feed rate per minute, which is distributed between the movement speed of the workpiece W1 along the Z axis and the rotation speed of the workpiece W1 along the C axis when a left-hand rotary tool TO32 is used.

[0093] When the deburring process shown in Figure 17 begins, the NC device 70 obtains the arguments of the deburring command CM3 (S302) and determines the deburring tool TO3 to be used based on the R and P arguments (S304). If P=1 (outer diameter machining) and R=0 (down cut), or P=0 (inner diameter machining) and R=1 (up cut), the NC device 70 determines the deburring tool TO3 to be used as the right-hand rotary tool TO31 in the first path PA1 and the left-hand rotary tool TO32 in the second path PA2, as shown in Figure 16A. If P=1 (outer diameter machining) and R=1 (up cut), or P=0 (inner diameter machining) and R=0 (down cut), the NC device 70 determines the deburring tool TO3 to be used as the left-hand rotary tool TO32 in the first path PA1 and the right-hand rotary tool TO31 in the second path PA2, as shown in Figure 16B.

[0094] After determining which deburring tool TO3 to use, the NC device 70 controls the Z-axis coordinate Zp and C-axis angle Cp of the determined rotary tool (TO31 or TO32) to the first inversion position R1 (S306). For example, the NC device 70 controls the rotary tool (TO31 or TO32) to rotate at a rotational speed S (seventh or eighth argument), sets the Z-axis coordinate of the workpiece W1 to Zp=0, controls the C-axis angle of the workpiece W1 to -θxy / 2, and controls the spherical cutting part TO3b of the rotary tool (TO31 or TO32) to come into contact with the first inversion position R1 of the circumferential part C1p. Subsequently, the NC device 70 determines the angle θyz corresponding to the cutting position P1 based on the feed rate F or B, according to equations (11) and (12) above (S308). Furthermore, the NC device 70 determines the Z-axis coordinate Zp and the C-axis angle Cp at angle θyz based on the values ​​CD and OD, according to equations (1) to (10) above (S310).

[0095] After determining the Z-axis coordinate Zp and the C-axis angle Cp, the NC device 70 controls the relative positional relationship between the workpiece W1 and the rotary tool (TO31 or TO32) to the Z-axis coordinate Zp, and controls the workpiece W1 to the C-axis angle Cp with respect to the spindle centerline AX1 (S312). Subsequently, the NC device 70 determines whether the cutting position P1 has reached the second reversal position R2 (S314). If the cutting position P1 has not reached the second reversal position R2, the NC device 70 repeats the processes from S308 to S314. If the processes from S316 onwards have not been performed, the down cut or up cut commanded in the first path PA1 is performed on the peripheral portion C1p. If the cutting position P1 has reached the second reversal position R2, the NC device 70 controls the switching of the deburring tool TO3 to be used (S316). If the right-hand rotary tool TO31 was used in the first path PA1, the deburring tool TO3 to be used is switched to the left-hand rotary tool TO32. If the left-hand rotary tool TO32 is used in the first path PA1, the deburring tool TO3 used is switched to the right-hand rotary tool TO31. In S316, the NC device 70 separates the spherical cutting portion TO3b of the rotary tool in use (TO31 or TO32) from the peripheral portion C1p, rotates the unused rotary tool (TO32 or TO31) at rotational speed S (seventh or eighth argument), and then controls the spherical cutting portion TO3b of the unused rotary tool (TO32 or TO31) to come into contact with the second inversion position R2 of the peripheral portion C1p. Subsequently, the NC device 70 determines whether the cutting position P1 has returned to the first reversal position R1 (S318). If the cutting position P1 has not reached the first reversal position R1, the NC device 70 repeats the processes from S308 to S318. After the determination process in S318, the down cut or up cut commanded in the second path PA2 is performed on the peripheral portion C1p. If the cutting position P1 has reached the first reversal position R1, the NC device 70 terminates the deburring process.

[0096] Therefore, when the deburring command CM3 instructs a down cut on the outer surface W1o or an up cut on the inner surface W1i, the right-handed rotary tool TO31, which rotates clockwise, is used in the first path PA1, and the left-handed rotary tool TO32, which rotates counterclockwise, is used in the second path PA2. As a result, the cutting position P1 completes a full clockwise rotation along the circumferential portion C1p while maintaining the down cut or up cut instructed by the deburring command CM3. When the deburring command CM3 instructs an up cut on the outer surface W1o or a down cut on the inner surface W1i, the left-handed rotary tool TO32, which rotates counterclockwise, is used in the first path PA1, and the right-handed rotary tool TO31, which rotates clockwise, is used in the second path PA2. As a result, the cutting position P1 completes a full clockwise rotation along the circumferential portion C1p while maintaining the down cut or up cut instructed by the deburring command CM3. Furthermore, the edges of the periphery C1p of the cross hole C1 are machined all the way around, and burrs are removed from the outer surface W1o and the inner surface W1i.

[0097] As explained above, the NC device 70 controls the cutting of the periphery C1p in the first path PA1 using one of the right-hand rotary tool TO31 and left-hand rotary tool TO32, in order to maintain the cut commanded by the deburring command CM3, and cutting of the periphery C1p in the second path PA2 using the other rotary tool. In this specific example as well, since down-cutting or up-cutting is maintained without changing the direction in which the cutting position P1 changes along the periphery C1p, deburring can be performed while maintaining down-cutting or up-cutting. Furthermore, even when the cutting position P1 moves counterclockwise around the periphery C1p, deburring can be performed while maintaining either a down-cut or up-cut by switching the deburring tool TO3 midway through the process.

[0098] (6) Variations: Various modifications of this invention are conceivable. For example, the machine tool is not limited to a lathe; it could also be a machining center or similar. Lathe 1 may be a spindle-fixed type lathe in which the front spindle 16 does not move in the Z-axis direction. At least some of the processes S102-S110, S114-S120, and S124 shown in Figures 9 and 10 may be performed on an external computer or other device other than the lathe 1. At least some of the processes S202-S210 and S214-S218 shown in Figure 14 may also be performed on a device other than the lathe 1, and at least some of the processes S302-S310 and S314-S318 shown in Figure 17 may also be performed on a device other than the lathe 1. The D argument (OD) in the deburring commands CM1 to CM3 is not limited to a diameter value; it can also be a radius value, etc. The X argument (CD) in the deburring commands CM1 to CM3 is not limited to a diameter value; it can also be a radius value, etc. In the specific example described above, deburring was performed by controlling the Z-axis coordinate Zp and the C-axis angle Cp. However, even when deburring is performed by controlling the relative cutting position of the workpiece in three directions—the X-axis, Y-axis, and Z-axis—down-cutting or up-cutting as commanded by the deburring process can be achieved.

[0099] Even if the orientation of the deburring tool centerline AX3 is aligned with the machining centerline AX2, the NC device 70 can perform control to cut the periphery C1p in accordance with the deburring command, maintaining either a down-cut or up-cut. For example, suppose the deburring tool TO3 is a right-hand cutting ball end mill and rotates clockwise around the deburring tool centerline AX3. If the deburring command is R=0 (down-cut), the NC device 70 can achieve a down-cut over the entire circumference of the periphery C1p by rotating the spherical cutting portion TO3b of the deburring tool TO3 counterclockwise along the periphery C1p. If the deburring command is R=1 (up-cut), the NC device 70 can achieve an up-cut over the entire circumference of the periphery C1p by rotating the spherical cutting portion TO3b of the deburring tool TO3 clockwise along the periphery C1p.

[0100] The machining centerline AX2 does not need to be perpendicular to the spindle centerline AX1, as long as it intersects with it. Even if the machining centerline AX2 intersects the spindle centerline AX1 at an angle, the down cut or up cut commanded by the deburring command can still be achieved. The holes to be deburred are not limited to cross holes C1, but may also be bottomed holes recessed from the outer surface W1o to partway down the workpiece W1 along the machining centerline AX2, or horizontal holes for solid workpieces, etc. A hole, such as a cross hole C1, as viewed from the direction of the machining centerline, can have any shape that includes a portion that can be called a diameter, and may be an elongated hole C2, etc., which includes a straight portion in addition to an arc-shaped portion, as illustrated in Figure 18.

[0101] Figure 18 schematically shows an example of determining the Z-axis coordinate Zp and C-axis angle Cp corresponding to the cutting position P1 based on the diameter value (CD) of the elongated hole C2, the inner diameter value (OD) of the workpiece W1, and the center-to-center distance value (LC) of the arc portion. In Figure 18, a plan view 101 of the workpiece W1 is shown at the top, a cross-sectional view 102 of the workpiece W1 is shown below the plan view 101, and the formulas for calculating the Z-axis coordinate Zp and C-axis angle Cp are shown at the bottom. As shown in the plan view 101, the peripheral portion C1p of the elongated hole C2 includes, when viewed from the X-axis direction, a first arc-shaped portion C21 in the range Zp > 0, a second arc-shaped portion C22 in the range Zp < 0, and a straight portion C23 connecting the first arc-shaped portion C21 to the second arc-shaped portion C22.

[0102] The value CD represents the diameter corresponding to the circumferential portion C1p when the first and second circular arc sections C21 and C22 are viewed from the X-axis direction. The value OD represents the diameter corresponding to the circumference, i.e., the inner circumferential surface W1i, in a cross section perpendicular to the principal axis centerline AX1 between the centers C1o (see cross section 102), with the principal axis centerline AX1 as the center and passing through the circumferential portion C1p. Figure 18 also shows point B corresponding to θyz=90° in the first circular arc section C21, point D corresponding to θyz=90° in the second circular arc section C22, point C corresponding to θyz=270° in the second circular arc section C22, and point A corresponding to θyz=-90° in the first circular arc section C21. The value LC, which represents the distance between the center C1o corresponding to the first circular arc section C21 and the center C1o corresponding to the second circular arc section C22, is also shown in Figure 18.

[0103] The Z-axis coordinate Zp can be expressed by the following formula, using the diameter CD corresponding to the circumferential portion C1p, the angle θyz, and the center-to-center distance LC, when the cutting position P1 is at the first circular arc portion C21. Zp=(CD / 2)×cosθyz+(LC / 2) …(14) If the cutting position P1 is in the second arc section C22, it can be expressed by the following formula. Zp=(CD / 2)×cosθyz-(LC / 2) …(15) When the cutting position P1 is in the first circular arc section C21 or the second circular arc section C22, the radius value CD / 2 corresponding to the value CD can be expressed by the following formula, using the radius value r = OD / 2 and the angle θxy. CD / 2 = r × sin(θxy / 2) …(16) From equation (16) above, the angle θxy is expressed by the following equation. θxy = 2 × arcsin(CD / 2r) …(17) Since the C-axis angle Cp varies within the range -(θxy / 2)≦Cp≦+(θxy / 2), it can be expressed by the following equation using the angle θxy and the angle θyz corresponding to the cutting position P1. Cp = (θxy / 2) × sinθyz =arcsin(CD / 2r)×sinθyz…(18)

[0104] Based on the above, by determining the Z-axis coordinate Zp and C-axis angle Cp for the first arc section C21, the second arc section C22, and the straight section C23, respectively, based on the values ​​CD, OD, and LC representing the distance between centers, deburring can be controlled using two-axis control of the Z-axis and C-axis. By providing a deburring command CM4 (see Figure 19) suitable for this two-axis controlled deburring, deburring can be performed without commanding the cutting position P1 in the three axes of the X-axis, Y-axis, and Z-axis. Furthermore, regarding the straight section C23, regardless of whether the deburring tool TO3 rotates clockwise or counterclockwise, the cutting process does not fit into either the concepts of down-cutting or up-cutting. Therefore, the direction of rotation of the deburring tool TO3 can be switched at any point in the straight section C23.

[0105] Figure 19 schematically illustrates a deburring process for cutting the peripheral portion C1p of an elongated hole C2, using the deburring tool TO3 as an example where it can rotate both clockwise and counterclockwise. Figure 19 also shows the deburring command CM4 included in the machining program PR2. When the NC device 70 shown in Figure 2 reads the deburring command CM4 from the machining program PR2, it starts the deburring process. The deburring command CM4 shown in Figure 19 has "L**" added to it. The argument "**" after L represents the value LC (mm) which represents the distance between the centers of the arc sections (C21, C22). Furthermore, by adding "L**" to the deburring command CM1 shown in Figure 9 and the deburring command CM3 shown in Figure 17, it is possible to deburr the peripheral portion C1p of the elongated hole C2.

[0106] When the cutting position P1 is in the straight section C23, the speed of the cutting position P1 moving in the Z-axis direction is, for example, the feed rate F or B. The time required (Tc(min)) for the cutting position P1 to move along the first arc section C21 or the second arc section C22 can be calculated using the following formula. Tc=(CD 2 +θxy 2 ) 1 / 2 / F …(19) Furthermore, when the argument B is applied to the feed rate, the argument B shall be applied to the feed rate F in equation (19) above. If tc(min) is the time it took for the cutting position P1 to move from position A at θxy = -90° in a direction where the angle θxy increases, and to be located on the arc section (C21, C22), then the angle θyz(deg) corresponding to the cutting position P1 can be calculated, for example, using the following formula. θyz = 180 × (tc / Tc) - 90 …(20) Therefore, by applying the angle θyz corresponding to the cutting position P1, which changes along the circumferential portion C1p, along with the values ​​CD, OD, and LC, to equations (14) to (18) above, the Z-axis coordinate Zp and C-axis angle Cp can be determined when the cutting position P1 is in the arc portion (C21, C22). When the cutting position P1 is in the straight portion C23, the C-axis angle Cp is +θxy / 2 or -θxy / 2, and the Z-axis coordinate Zp changes according to the feed rate F or B.

[0107] When the deburring process begins, the NC device 70 obtains the arguments of the deburring command CM4 described above (S402) and determines the direction of rotation of the deburring tool TO3 based on the arguments R (third argument) and P (S404). Next, the NC device 70 controls the Z-axis coordinate Zp and C-axis angle Cp to the first inversion position R1 (for example, position A or C) (S406). After that, the NC device 70 determines the angle θyz corresponding to the cutting position P1 based on the feed rate F or B according to equations (19) and (20) above (S408). If the cutting position P1 is in an arc section (C21, C22), the NC device 70 determines the Z-axis coordinate Zp and C-axis angle Cp at angle θyz based on the values ​​CD and OD according to equations (14) to (18) above (S410). If the cutting position P1 is in the straight section C23, the NC device 70 determines the Z-axis coordinate Zp based on the feed rate F or B (S412).

[0108] After determining the Z-axis coordinate Zp and the C-axis angle Cp, the NC device 70 controls the relative positional relationship between the workpiece W1 and the deburring tool TO3 to the Z-axis coordinate Zp, and controls the workpiece W1 to the C-axis angle Cp with respect to the spindle centerline AX1 (S414). Subsequently, the NC device 70 determines whether the cutting position P1 has reached the second reversal position R2 (for example, position D or B) (S416). If the cutting position P1 has not reached the second reversal position R2, the NC device 70 repeats the process from S408 to S416. If the cutting position P1 has reached the second reversal position R2, the NC device 70 reverses the rotation of the deburring tool TO3 at the commanded rotational speed (S418). Subsequently, the NC device 70 determines whether the cutting position P1 has returned to the first reversal position R1 (S420). If the cutting position P1 has not reached the first reversal position R1, the NC device 70 repeats the process from S408 to S420. If the cutting position P1 has reached the first reversal position R1, the NC device 70 terminates the deburring process.

[0109] As described above, the NC device 70 controls the relative positional relationship between the spindle 11 and the tool post 30 in the Z-axis direction to the Z-axis coordinate Zp, and controls the rotation of the spindle 11 to the C-axis angle Cp, so that the cutting position P1 changes along the circumferential portion C1p of the elongated hole C2. Therefore, in the example shown in Figures 18 and 19, interference between the deburring tool TO3 and the workpiece W1 can be easily avoided during deburring of the circumferential portion C1p of the elongated hole C2. Furthermore, the operator can have the lathe 1 perform a down cut or up cut along the entire circumference of the circumferential portion C1p simply by commanding R=0 or R=1 in the deburring command CM1, eliminating the need to create a complex machining program PR2. Therefore, even if there are constraints on the direction of rotation of the deburring tool TO3, deburring can be performed while maintaining a down cut or up cut without being aware of these constraints.

[0110] Furthermore, although the elongated hole C2 described above is a vertically elongated hole in which the size along the Z axis is larger than the size along the C axis, the elongated hole may also be a horizontally elongated hole in which the size along the C axis is larger than the size along the Z axis. If the elongated hole is a horizontally elongated hole, the NC device 70 can control the part of the circumference that is not an arc by changing the C axis angle Cp without changing the Z axis coordinate Zp. Furthermore, the diameter corresponding to the first arc and the diameter corresponding to the second arc may be different. In this case, the NC device 70 can control the part of the circumference connecting the arcs by changing the Z-axis coordinate Zp at a constant speed and changing the C-axis angle Cp at a constant rotational speed.

[0111] (7) Conclusion: As described above, according to the present invention, various embodiments can provide configurations for machine tools and the like that improve the convenience of removing burrs. Of course, even embodiments consisting only of the constituent elements of the independent claims can obtain the basic functions and effects described above. Furthermore, configurations obtained by substituting or changing the combinations of each configuration disclosed in the above-mentioned examples, configurations obtained by substituting or changing the combinations of each configuration disclosed in the prior art and the above-mentioned examples, etc., are also possible. The present invention also includes these configurations, etc. [Explanation of Symbols]

[0112] 1… Lathe (an example of a machine tool), 10...headstock, 11...main spindle, 12...gripping section, 13...headstock drive section, 15...Front headstock, 16...Front spindle, 16c...Front spindle rotation drive unit, 20... Rear spindle head, 21... Rear spindle, 21c... Rear spindle rotation drive unit, 30...Tool post, 30c...Tool rotation drive unit, 31...Tool post drive unit, 32...comb-shaped tool post, 34...tool post for back processing, 70...NC device, AX1...Spindle center line, AX2...Machining center line, AX3... Deburring tool centerline, AX4... Rotary tool centerline, AX31...Centerline of right-hand rotary tool, AX32...Centerline of left-hand rotary tool C1...cross hole, C1o...center, C1p...periphery, C2...elongated hole, CM1~CM4... Deburring command, D1...Cutting direction, D2...Relative movement direction, D21...First direction, D22...Second direction P0...Reference position, P1...Cutting position, PA0…Cutting path, PA1…First path, PA2…Second path PR1...Control program, PR2...Machining program, R1...First inversion position, R2...Second inversion position, TO1...Tool, TO2...Cross tool, TO3...Deburring tool, TO3b...Spherical cutting part TO31...Right-hand cutting rotary tool, TO32...Left-hand cutting rotary tool U1... Control unit, W1...workpiece, W1h...hollow section, W1i...inner surface, W1o...outer surface

Claims

1. The spindle rotates with the workpiece around the center line of the spindle, A deburring tool is attached to the workpiece to cut the periphery of a hole that intersects the spindle centerline, and a tool post rotates the deburring tool around the centerline of the deburring tool, The system includes a control unit that controls the relative positional relationship between the spindle and the tool post, and controls the cutting position of the deburring tool along the circumferential portion, The control unit, A command is obtained to instruct whether to perform a down cut on the periphery in which the cutting direction of the rotating deburring tool is opposite to the relative movement direction of the deburring tool, or to perform an up cut on the periphery in which the cutting direction and the relative movement direction coincide. A machine tool that performs control to cut the periphery at the cutting position so as to maintain the cut commanded by the command.

2. The deburring tool is mounted on the tool post in an orientation along the center line of the spindle. The tool post rotates the deburring tool around the deburring tool's center line, which is aligned with the spindle's center line. The machine tool according to claim 1, wherein the control unit controls the direction in which the cutting position is changed along the circumferential portion, or the direction of rotation of the deburring tool about the center line of the deburring tool, to change during cutting of the circumferential portion, in order to maintain the cut commanded by the command.

3. If the relative movement direction of the deburring tool with respect to the cutting direction is the first orientation, then the cut commanded by the command is performed on the periphery, The cutting path along the circumferential portion includes a first path and a second path that go from a first reversal position to a second reversal position without the relative movement direction being a second direction opposite to the first direction, The machine tool according to claim 2, wherein the control unit controls the cutting position in the first path to change it from the first reversal position to the second reversal position, and controls the cutting position in the second path to change it from the first reversal position to the second reversal position.

4. The tool holder is capable of rotating the deburring tool both clockwise and counterclockwise. The cutting path along the circumferential portion includes a first path from a first reversal position to a second reversal position, where the relative movement direction of the deburring tool with respect to the cutting direction is not a second direction opposite to the first direction, and a second path from the second reversal position to the first reversal position, where the relative movement direction is not the first direction. The machine tool according to claim 2, wherein the control unit controls the direction of rotation of the deburring tool in the first path and the second path in opposite directions so as to maintain the cut commanded by the command.

5. The tool post is equipped with a right-hand rotating tool for deburring and a left-hand rotating tool for deburring. The tool post rotates the right-hand rotating tool clockwise around the center line of the right-hand rotating tool, which serves as the center line of the deburring tool, and rotates the left-hand rotating tool counterclockwise around the center line of the left-hand rotating tool, which serves as the center line of the deburring tool. The cutting path along the circumferential portion includes a first path from a first reversal position to a second reversal position, where the relative movement direction of the deburring tool with respect to the cutting direction is not a second direction opposite to the first direction, and a second path from the second reversal position to the first reversal position, where the relative movement direction is not the first direction. The machine tool according to claim 2, wherein the control unit controls the machine tool to cut the periphery in the first path using one of the right-bladed rotary tool and the left-bladed rotary tool, and cut the periphery in the second path using the other rotary tool, in order to maintain the cut commanded by the command.

6. The aforementioned workpiece is cylindrical in shape, The deburring tool is mounted on the tool post in an orientation along the center line of the spindle. The tool post rotates the deburring tool around the deburring tool's center line, which is aligned with the spindle's center line. The command includes an argument that instructs whether to cut the periphery on the inner surface of the workpiece or on the outer surface of the workpiece, The machine tool according to claim 1, wherein the control unit performs control to cut the periphery in such a way as to maintain the cut commanded by the command, based on the argument.

Images