WO2018135788A1

WO2018135788A1 - Control device of machine tool, machine tool including same, and method for controlling machine tool using same

Info

Publication number: WO2018135788A1
Application number: PCT/KR2018/000326
Authority: WO
Inventors: 하종수
Original assignee: 두산공작기계 주식회사
Priority date: 2017-01-17
Filing date: 2018-01-08
Publication date: 2018-07-26
Also published as: KR20180084359A

Abstract

A control device of a machine tool comprising first and second main axes, which are arranged so as to face each other and clamp both end portions of a structure on the same axial line, comprises: first and second sensors for measuring a phase for a C-axis origin of the first main axis and a phase for a C-axis origin of the second main axis when the structure is clamped by the first and second main axes; a phase calculation device connected to the first and second sensors and calculating the phases of the first and second axes from input values from the first and second sensors; and a system control device for controlling the first and second main axes so as to synchronize phases between the first and second main axes on the basis of the calculated phases.

Description

Control device for machine tool, machine tool including same, and method for controlling machine tool using same

The present invention relates to a control device for a machine tool, a machine tool including the same, and a method for controlling the machine tool using the same. More particularly, the present invention relates to a control device for controlling a machine tool having two spindles arranged opposite to each other, a machine tool including the same, and a method of controlling the machine tool using the same.

In a combined lathe having two main axes, in order to synchronously process a polygonal shaped release material, the phase difference between the main axis and the sub axis is measured using a dial gauge, and the shift amount of the main axis and the sub axis is shifted. Phase synchronization can be performed by entering a machine reference position (CNC) as a computer numerical control (CNC) parameter. However, there is a problem in that the phase synchronizing operation must be repeatedly performed when the workpiece is changed or there is a dimension change of the workpiece.

An object of the present invention is to provide a control device for a machine tool which can shorten the phase synchronization adjustment time and improve the workability.

Another object of the present invention is to provide a machine tool comprising the above-described control device.

Another object of the present invention is to provide a method for controlling a machine tool using the above-described control device.

The control device of the machine tool according to the exemplary embodiments for achieving the object of the present invention, in the machine tool comprising a first and second spindle arranged opposite to each other and clamping both ends of the workpiece on the same axis First and second sensors for measuring a phase with respect to the C-axis origin of the first spindle and a phase with respect to the C-axis origin of the second spindle when the workpiece is clamped by the first and second spindles. A phase calculating device connected to the first and second sensors and calculating phases of the first and second principal axes from input values from the first and second sensors, and the calculated phases. And a system control device for controlling the first and second spindles to synchronize the phase between the first and second spindles based on the same.

In example embodiments, the first sensor may include a first gear that rotates with the first spindle and a first encoder for detecting a rotation angle of the first tooth, wherein the second sensor The second gear that rotates together with the second main axis and a second encoder for detecting the rotation angle of the second gear.

In example embodiments, the first and second encoders may include a pulse coder for generating a pulse from the first and second teeth.

In example embodiments, the phase calculating apparatus may calculate a phase of the C-axis origin of each of the first and second major axes from the number of teeth N of the teeth detected from the pulse.

In example embodiments, the phase calculating device may further include a receiver configured to receive detection signals from the first and second sensors and a first reference to the C-axis origin of the first main axis from the received detection signals. And a calculation unit configured to calculate a phase and a second phase with respect to the C-axis origin of the second main axis, respectively.

In example embodiments, the phase calculating device may further include an interface unit for guiding an automatic phase synchronization function between the first and second main axes.

In an exemplary embodiment, the system control apparatus is a numerical control device for synchronizing the phase difference between the first and second main axes according to a drive program in which the phases of the first and second main axes are written as a phase shift parameter. It may include.

In example embodiments, the workpiece may have a polygonal cross-sectional shape.

Machine tools according to exemplary embodiments for achieving the another object of the present invention are disposed opposite to each other and equipped with a first spindle and a second spindle for clamping both ends of the workpiece on the same axis, the tool for machining the workpiece A first tool for measuring a phase with respect to the C-axis origin of the first spindle and a phase with respect to the C-axis origin of the second spindle when the workpiece is clamped by the first and second spindles, respectively. And phases of the first and second principal axes connected to second sensors and the first and second sensors, respectively, and from the input values from the first and second sensors, to the calculated phases. And a control device for controlling the first and second spindles to synchronize the phase between the first and second spindles on the basis.

In example embodiments, the first and second encoders may include a pulse coder for generating a pulse from the first and second gears, wherein the control device is configured to control the first and second spindles, respectively. The phase with respect to the C-axis origin of can be calculated from the number of teeth N of the gear detected from the pulse.

In example embodiments, the control device may further include a first phase relative to a C axis origin of the first main axis and the C axis of the second main axis from received detection signals from the first and second sensors. A phase imager for respectively calculating a second phase with respect to an origin, and a numerical control device for controlling the first and second principal axes to compensate for the phase difference between the first and second principal axes based on the calculated phases It may include.

In example embodiments, the machine tool may further include a guide bush disposed between the first and second spindles to support the workpiece therethrough.

In the control method of the machine tool according to the exemplary embodiments for achieving another object of the present invention, one end of the workpiece is clamped to the first spindle. The phase with respect to the C-axis origin of the first main axis is calculated. The other end of the workpiece is clamped to a second spindle arranged opposite to the first spindle on the same axis. The phase with respect to the C-axis origin of the second main axis is calculated. The first and second main axes are controlled to synchronize the phase between the first and second main axes based on the calculated phases.

In exemplary embodiments, calculating the phase with respect to the C-axis origin of the first spindle may include rotating angles of the first tooth that rotate with the first spindle when clamping one end of the workpiece to the first spindle. And detecting a phase with respect to the C-axis origin of the second spindle, wherein the second tooth that rotates with the second spindle when the other end of the workpiece is clamped to the second spindle. Detecting the rotation angle.

In example embodiments, detecting the rotation angles of the first and second teeth, respectively, counts the generated pulses according to the number of teeth of the rotating first and second gears so that the first and second teeth are counted. Computing the phase values for the C-axis origin of the main axis, respectively.

In example embodiments, the control method may further include synchronizing rotation of both ends of the workpiece by synchronizing the speeds of the first and second spindles.

In example embodiments, the controlling of the first and second main axes may include performing a driving program of the CNC in which the calculated phase difference is input as a phase shift parameter.

In exemplary embodiments, the method may further comprise supporting the intermediate portion of the workpiece by a guide bush.

According to the exemplary embodiments, phase values for the C-axis origin of the first and second spindles clamping both ends of the workpiece on the same axis are respectively calculated, and the calculated phase difference is written as a phase shift parameter in the drive program of the CNC. By writing, the phases of the first and second principal axes may be synchronized.

Therefore, when processing a polygonal pillar-shaped release material using two main axes, it is possible to shorten the phase synchronization adjustment time between the two main axes and to improve workability through accurate phase synchronization.

However, the effects of the present invention are not limited to the above-mentioned effects, and may be variously expanded within a range without departing from the spirit and scope of the present invention.

1 is a perspective view illustrating a machine tool according to exemplary embodiments.

FIG. 2 is a perspective view illustrating first and second spindles and a guide bush of the machine tool of FIG. 1.

3 is a block diagram illustrating first and second sensors and a phase calculating device installed on first and second main axes of the machine tool of FIG. 1.

4 is a perspective view illustrating a workpiece clamped to the first and second spindles of FIG. 3.

5 is a block diagram illustrating a control device of the machine tool of FIG. 1.

Fig. 6 is a flow chart illustrating a method of controlling a machine tool according to exemplary embodiments.

Hereinafter, exemplary embodiments of the present invention will be described in detail with reference to the accompanying drawings.

In each of the drawings of the present invention, the dimensions of the structures are shown in an enlarged scale than actual for clarity of the invention.

In the present invention, terms such as first and second may be used to describe various components, but the components should not be limited by the terms. The terms are used only for the purpose of distinguishing one component from another.

The terminology used herein is for the purpose of describing particular example embodiments only and is not intended to be limiting of the present invention. Singular expressions include plural expressions unless the context clearly indicates otherwise. In this application, the terms "comprise" or "have" are intended to indicate that there is a feature, number, step, action, component, part, or combination thereof described on the specification, and one or more other features. It is to be understood that the present invention does not exclude the possibility of the presence or the addition of numbers, steps, operations, components, components, or a combination thereof.

With respect to the embodiments of the present invention disclosed in the text, specific structural to functional descriptions are merely illustrated for the purpose of describing embodiments of the present invention, embodiments of the present invention may be implemented in various forms and It should not be construed as limited to the embodiments described in.

That is, the present invention may be modified in various ways and may have various forms. Specific embodiments are illustrated in the drawings and described in detail in the text. However, this is not intended to limit the present invention to a specific disclosed form, it should be understood to include all modifications, equivalents, and substitutes included in the spirit and scope of the present invention.

1 is a perspective view illustrating a machine tool according to exemplary embodiments. FIG. 2 is a perspective view illustrating first and second spindles and a guide bush of the machine tool of FIG. 1. 3 is a block diagram illustrating first and second sensors and a phase calculating device installed on first and second main axes of the machine tool of FIG. 1. 4 is a perspective view illustrating a workpiece clamped to the first and second spindles of FIG. 3. 5 is a block diagram illustrating a control device of the machine tool of FIG. 1.

1 to 5, the machine tool 10 is disposed opposite each other on the bed 100 and clamps both ends of the workpiece W and rotates on the same axis a and the second main shaft 112. A first spindle head 110 and a second spindle head 120 each having a spindle 122, a

tool post

140 and 142 on which a plurality of tools for processing the work W are mounted, and first and It may include an automatic phase control device for compensating the phase difference between the second main axis (112, 122).

In exemplary embodiments, the machine tool 10 may be a two spindle opposite composite lathe. The combined lathe may include a main spindle 112 and a sub spindle 122 and

tool posts

140 and 142 facing each other. The complex lathe may be set with a main axis feed coordinate system (A), a sub axis feed coordinate system (B), and a tool bar feed coordinate system, and may be provided with a C-axis control in which the angle of the main axis (and sub axis) is divided and controlled. have.

In the compound lathe, a plurality of spindles (main axis and sub-axis) are synchronously controlled to perform various complex machining. For example, the compound lathe can process a large workpiece while synchronously rotating by clamping both ends of the workpiece in synchronism with the speed and phase of the main shaft and the sub-axis (synchronous processing).

As shown in FIGS. 1 to 3, the bed 100 may be a frame having a cuboid shape. The bed 100 may have a top surface in the horizontal direction and a front surface in the vertical direction. Hereinafter, the vertical direction is referred to as the X-axis direction on the upper surface of the bed 100, the vertical direction is referred to as the Y-axis direction on the front surface of the bed 100, the direction orthogonal to the X-axis direction and the Y-axis direction This is referred to as the Z-axis direction. The Z axis direction may be left and right directions when viewed from the operator.

The first headstock 110 and the second headstock 120 may be disposed opposite to each other on the upper surface of the bed (100). The first headstock 110 may be disposed on the right side from the operator on the upper surface of the bed 100, and the second headstock 120 may be disposed on the left side on the bed 100.

The first spindle base 110 may be installed to be movable in at least one axial direction in the spindle feed coordinate system (X1, Y1, Z1). For example, the first headstock 110 may be movable in the Z1 axis direction on the bed 100 by the first feed motor. In addition, the first headstock 110 may be movable in the X1 axis direction on the bed 100 by the second feed motor.

The first headstock 110 may include a first spindle 112 for rotating the workpiece W in the C1 axis direction. The first collet 114 may be provided at one end of the first spindle 112 to clamp the work W. Therefore, the first headstock 110 may clamp one end of the work W and move the work W in the Z1-axis direction and rotate in the C1-axis direction.

The second headstock 120 may be installed to be movable in at least one axial direction in the sub-axis feed coordinate systems X2, Y2, and Z2. For example, the second headstock 110 may be movable in the Z2 axis direction on the bed 100 by the third feed motor. In addition, the second headstock 120 may be movable in the Y2 axis direction on the bed 100 by the fourth feed motor.

The second headstock 120 may include a second spindle 122 for rotating the workpiece W in the C2 axis direction. The second collet 124 may be provided at one end of the second spindle 122 to clamp the work W. Therefore, the second headstock 120 may clamp one end of the work W and move the work W in the Z2 axis direction and rotate in the C2 axis direction.

In exemplary embodiments, the machine tool 10 includes a guide bush 130 that supports an intermediate portion of the workpiece W that is rotated by the first spindle 112 or the first and second spindles 112, 122. ) May be further included. The guide bush 130 may be disposed between the first and

second spindles

110 and 120 on the bed 100 to support the work W therethrough.

The tool post may be a complex tool post composed of a combination of a plurality of

tool posts

140 and 142 installed above and to the side of the guide bush 130 on the bed 100. The composite tool post may include a turning tool post and a milling tool post. The tool posts 140 and 142 may be equipped with a turning tool, a milling tool, a milling rotary tool, and the like.

At least one tool post of the tool posts may be installed to be movable in at least one axial direction in the tool post feed coordinate system. For example, the tool post may be movable on the bed 100 in the X3 axis direction and the Y3 axis direction by the fifth and sixth transfer motors (not shown).

As shown in FIGS. 3 and 4, in exemplary embodiments, the first and second

major axes

112, 122 can clamp the workpiece W and rotate the C axis on the same axis a. have. The first and second

main axes

112 and 122 may be arranged to coincide with the Z1 axis direction and the Z2 axis direction. In addition, the workpiece W may have a cross-sectional shape of a polygon (for example, hexagon, square, octagon, etc.).

Accordingly, the first and

second spindles

112 and 122 may machine the sides of the polygonal columnar workpiece W while clamping both ends of the workpiece W and synchronously rotating the workpiece W to the C axis. .

In example embodiments, the automatic phase control device is adapted to perform the first and

second spindles

112, 122 when the first and

second spindles

112, 122 clamp both ends of the polygonal workpiece W to perform the synchronous machining. The phase between the second

major axes

112 and 122 may be automatically synchronized.

In detail, the automatic phase control apparatus includes a phase and a second spindle 122 with respect to the C-axis origin of the first spindle 112 when the workpiece W is clamped by the first and

second spindles

112 and 122. Are connected to the first and

second sensors

200 and 210 and the first and

second sensors

200 and 210 to measure the phase with respect to the C-axis origin of the first and

second sensors

200 and 210. A phase computing device 300 that calculates phases of the first and second

major axes

112, 122 from input values from 210, and first and second major axes 112 based on the calculated phases. And a system control device 400 for controlling the first and second

main axes

112 and 122 to compensate for the phase difference between the two sides.

The first sensor 200 may include a first gear 202 that rotates together with the first spindle 112, and a first encoder 204 for detecting a rotation angle of the first gear 202. The second sensor 210 may include a second gear 212 rotating together with the second main shaft 122 and a second encoder 214 for detecting a rotation angle of the second gear 212.

The first gear 202 may be directly connected to the first spindle 112 or indirectly through a coupling mechanism such as a belt pulley to rotate together as the first spindle 112 rotates. The second tooth 212 may be directly connected to the second spindle 122 or indirectly through a coupling mechanism such as a belt pulley to rotate together as the second spindle 122 rotates. The first and

second teeth

202 and 212 may have a plurality of teeth around the periphery. For example, the number N of teeth may be 4096.

The first encoder 204 may be a proximity sensor disposed on one side of the first gear 202, and the second encoder 214 may be a proximity sensor disposed on one side of the second gear 212. The first and

second encoders

204, 214 may include a pulse coder that generates a pulse when the first and

second teeth

202, 212 rotate. The pulse coder may generate pulses according to the number of teeth counted when the gear rotates.

The phase calculating device 300 detects from the interface unit 310 and the first and

second sensors

200 and 210 for guiding an automatic phase synchronization function between the first and

second spindles

112 and 122. The receiver 320 receiving the signals and the first phase with respect to the C-axis origin of the first main axis 112 and the second phase 122 with respect to the C-axis origin of the second main axis 122 from the received detection signals. It may include a calculation unit 330 for calculating and outputting each.

The interface unit 310 may provide the operator with the phase automatic synchronization HMI screen, and the operator may input an execution command and a condition of the automatic phase synchronization function through the HMI screen. When the interface unit 310 receives an execution command from the operator, the receiver 320 receives a pulse signal from the first and

second encoders

204 and 214 of the first and

second sensors

200 and 210. The number of received pulses can be counted.

The phase calculating device 300 may further include a memory unit for storing a condition input from an operator, the number of first and second gears, a C-axis origin position, and the like. Before executing the automatic phase synchronization function, the receiver 320 counts the number of teeth of the first and

second gears

202 and 212 according to one rotation of the first and

second spindles

112 and 122. The calculator 320 may set the respective C-axis origin positions. For example, when the first spindle 112 is rotated by CNC control, the pulses of the number of teeth of the first gear 202 are counted and an arbitrary position at that time is referred to the reference origin C of the first spindle 112. Axis origin) position, and when the second spindle 122 is rotated by CNC control, the pulses of the number of teeth of the second gear 212 are counted and any position at that time is set to the second spindle 122. Can be set as the reference origin (C axis origin) position. The memory unit may store the counted number of teeth as a reference value and store the C-axis origin position.

When one end of the polygonal columnar workpiece W is clamped by the first main shaft 112, one side of the workpiece W is rotated by a predetermined angle with respect to the reference surface, and the receiver 320 rotates the first gear ( The number of pulses generated from 202 may be detected, and the calculator 330 may calculate a first phase Ф1 with respect to the C-axis origin of the first main axis 112 by Equation 1 below.

Phase (Ф) = 360 (Degrees) / Number of Gears (N) ---- Equation (1)

Subsequently, when the second headstock 120 is moved relative to the first headstock 110 so that the other end of the polygonal column-shaped workpiece W is clamped by the second headstock 122, the receiver 320 The number of pulses generated from the second gear 212 may be detected, and the calculator 330 may calculate a second phase Ф2 of the C-axis origin of the second main axis 122 by Equation 1 above.

The system controller 400 compensates for the difference between the calculated first phase Ф1 and the second phase Ф2 input from the calculator 330, and thus phases of the first and second

main axes

112 and 122. Can be synchronized.

The system control apparatus 400 controls the first and second

main axes

112 and 122 according to a control code created by the phase shift parameter of the phase difference between the first phase Ф1 and the second phase Ф2. It may include. The phase association device 300 may be provided in the numerical control device. The phase difference is created as a phase shift parameter of the driving program, and the numerical controller may synchronize the phase difference between the first and second

main axes

112 and 122 according to the written program.

As described above, the control device of the machine tool provides an interface for guiding the automatic phase synchronization function of the C axis of the main axis and the C axis of the sub axis, and calculates and calculates the phase difference between the C axis of the main axis and the C axis of the sub axis. The phase difference may be written to the CNC as a phase shift parameter to synchronize the phase of the main axis and the sub axis.

Hereinafter, a method of synchronizing a phase between a first main axis and a second main axis using the above-described control device of a machine tool will be described.

1 to 6, first, one end of the workpiece W may be clamped to the first spindle 112 (S100), and the phase of the first axis 112 of the C axis origin may be calculated (S100). S110).

In exemplary embodiments, first, the C-axis origin of the first spindle 112 is set, and then one end portion of the workpiece W is synchronized with the first spindle 112 to synchronously process the polygonal column-shaped workpiece W. After clamping to the first collet 114 of), it is possible to calculate the phase with respect to the C-axis origin of the first main axis (112). At this time, the intermediate portion of the workpiece (W) may be supported by the guide bush 130.

In the C-axis origin adjustment of the first spindle 112, the first encoder 204 of the first sensor 200 is the number of teeth of the first gear 202 according to one rotation of the first spindle 112. According to the present invention, the phase calculator 300 may count the generated pulses and set an arbitrary position at that time as the C-axis origin of the first main axis 112.

Subsequently, after clamping one end of the workpiece W to the first collet 114 of the first spindle 112, the first phase value of the first spindle 112 of the C axis origin may be calculated. When one end of the polygonal columnar workpiece W is clamped by the first main shaft 112, one side of the workpiece W is rotated by a predetermined angle with respect to the reference surface, and the receiver 320 rotates the first gear ( The number of pulses generated from 202 may be detected, and the calculator 330 may calculate a first phase value with respect to the C-axis origin of the first main axis 112.

Subsequently, the other end of the workpiece W may be clamped to the second main shaft 122 (S120), and the phase of the C-axis origin of the second main shaft 122 may be calculated (S130).

In example embodiments, the second spindle 122 may be disposed on the same axis a as the first spindle 112. First, after setting the C-axis origin of the second spindle 122, the other end of the workpiece (W) is clamped to the second collet 124 of the second spindle 122, then the second spindle 122 The phase with respect to the C-axis origin can be calculated.

In adjusting the C-axis origin of the second spindle 122, the second encoder 214 of the second sensor 210 has the number of teeth of the second tooth 212 according to one rotation of the second spindle 122. According to the present invention, the phase calculating device 300 may set the C-axis origin of the second main axis 122 by counting the generated pulses. Subsequently, after clamping the other end of the work W to the second collet 124 of the second main shaft 122, the second phase value of the second main shaft 122 with respect to the C-axis origin can be calculated. .

Subsequently, after synchronizing the phases of the first and

second spindles

112 and 122 based on the calculated difference value (phase difference) between the first and second phase values (S140), the side surface of the work W Machining may be carried out on at least one side of these.

In example embodiments, the phase difference may be written as a phase shift parameter of a drive program of the CNC, and may synchronize the phase difference between the first and second

main axes

112 and 122 according to the drive program.

Subsequently, the speeds of the first and

second spindles

112 and 122 may be synchronized to rotate both ends of the work W to perform machining on another side surface.

Although the above has been described with reference to the embodiments of the present invention, those skilled in the art will be able to variously modify and change the present invention without departing from the spirit and scope of the present invention as set forth in the claims below. It will be appreciated.

10: machine tool 100: bed

110: first headstock 112: first headstock

114: first collet 120: second headstock

122: second spindle 124: second collet

130: guide bush 140, 142: tool bar

200: first sensor 202: first gear

204: First encoder 210: Second sensor

212: second gear 214: second encoder

300: phase calculator 310: interface unit

320: receiver 330: calculator

400: system control unit

Claims

A machine tool comprising first and second spindles disposed opposite one another and clamping both ends of a workpiece on the same axis, the machine tool comprising:

First and second sensors for measuring the phase with respect to the C-axis origin of the first spindle and the phase with respect to the C-axis origin of the second spindle when the workpiece is clamped by the first and second spindles. ;

A phase computing device coupled to the first and second sensors and calculating phases of the first and second principal axes from input values from the first and second sensors; And

And a system control device for controlling the first and second spindles to synchronize the phase between the first and second spindles based on the calculated phases.
The method of claim 1, wherein the first sensor comprises a first gear for rotating with the first main axis and a first encoder for detecting the rotation angle of the first gear,

And said second sensor comprises a second gear that rotates with said second spindle and a second encoder for detecting a rotation angle of said second gear.
3. The control apparatus of claim 2, wherein the first and second encoders comprise a pulse coder for generating a pulse from the first and second teeth.
4. The control device of a machine tool according to claim 3, wherein the phase calculating device calculates a phase with respect to the C-axis origin of each of the first and second main axes from the number of teeth (N) of the teeth detected from the pulse.
The apparatus of claim 1, wherein the phase calculating device

A receiver configured to receive detection signals from the first and second sensors; And

And a calculation unit for calculating a first phase with respect to the C-axis origin of the first main axis and a second phase with respect to the C-axis origin of the second main axis, respectively, from the received detection signals.
6. The apparatus of claim 5, wherein the phase computing device further comprises an interface for guiding an automatic phase synchronization function between the first and second major axes.
The apparatus of claim 1, wherein the system control apparatus comprises a numerical control apparatus for synchronizing a phase difference between the first and second main axes according to a drive program in which the phases of the first and second main axes are written as phase shift parameters. Control equipment for machine tools.
The apparatus of claim 1, wherein the workpiece has a polygonal cross-sectional shape.
First and second spindles disposed opposite each other and clamping both ends of the workpiece on the same axis;

A tool post on which tools for machining the workpiece are mounted;

First and second sensors for measuring the phase with respect to the C-axis origin of the first spindle and the phase with respect to the C-axis origin of the second spindle when the workpiece is clamped by the first and second spindles, respectively. field; And

Connected to the first and second sensors, respectively, calculating phases of the first and second principal axes from input values from the first and second sensors and based on the calculated phases; A control device for controlling said first and second spindles to synchronize phases between said second spindles.
10. The method of claim 9, wherein the first sensor comprises a first gear for rotating with the first spindle and a first encoder for detecting a rotation angle of the first gear,

The second sensor includes a second gear that rotates with the second spindle and a second encoder for detecting a rotation angle of the second tooth.
11. The apparatus of claim 10, wherein the first and second encoders comprise a pulse coder for generating a pulse from the first and second gears,

And the control device calculates the phase with respect to the C-axis origin of each of the first and second main axes from the number of teeth (N) of the teeth detected from the pulse.
The method of claim 9, wherein the control device

A phase associating device for calculating a first phase with respect to the C-axis origin of the first main axis and a second phase with respect to the C-axis origin of the second main axis from the received detection signals from the first and second sensors, respectively ; And

And a numerical control device that controls the first and second spindles to compensate for the phase difference between the first and second spindles based on the calculated phases.
10. The machine tool of claim 9, wherein the workpiece has a polygonal cross-sectional shape.
10. The machine tool of claim 9, further comprising a guide bush disposed between the first and second spindles to support the workpiece therethrough.
Clamp one end of the workpiece to the first spindle;

Calculating a phase with respect to the C-axis origin of the first main axis;

Clamping the other end of the workpiece to a second spindle disposed opposite to the first spindle on the same axis;

Calculating a phase with respect to the C-axis origin of the second main axis; And

Controlling the first and second spindles to synchronize the phase between the first and second spindles based on the calculated phases.
16. The method of claim 15, wherein calculating the phase with respect to the origin of the C axis of the first spindle detects the rotation angle of the first gear that rotates with the first spindle when clamping one end of the workpiece to the first spindle. Including doing it,

Calculating the phase with respect to the C-axis origin of the second main axis includes detecting a rotation angle of a second tooth that rotates with the second main axis when clamping the other end of the workpiece to the second main axis. Control method of the machine.
17. The method of claim 16, wherein detecting the rotation angles of the first and second teeth, respectively, counts pulses generated according to the number of teeth of the rotating first and second teeth to determine the first and second major axes. Calculating a phase value with respect to the C-axis origin respectively.
16. The method of claim 15, further comprising synchronizing rotation of both ends of the workpiece by synchronizing the speeds of the first and second spindles.
16. The method of claim 15, wherein the controlling of the first and second spindles comprises performing a drive program of the CNC in which the calculated phase difference is input as a phase shift parameter.
The method of claim 15, further comprising supporting an intermediate portion of the workpiece by a guide bush.