JPH08215981A - Machining method correcting spindle thermal displacement and device thereof - Google Patents

Abstract

PURPOSE: To improve machining efficiency with high machining accuracy by rotating a spindle at usual rotating speed, after rotating the spindle at preliminary heating rotating speed higher than the usual rotating speed until the thermal displacement reaches nearly the same as a target thermal displacement in which the thermall displacement becomes nearly constant in the usual rotating speed used for actual machining. CONSTITUTION: A needed time computing means 56 reads a target thermal displacement from a target displacement setting means 54, and displacement information related to the highest rotating speed in the displacement information stored in a data memory part 52. A rotation lapse time T1 until the thermal displacement becomes nearly equal to a target thermal displacement is computed as a needed time based on the displacement information. Information for the required time is supplied to a spindle rotation control means 50. The spindle rotation control means 50 drives to rotate the spindle at preliminary heating rotating speed prior to actual machining, and when the thermal displacement becomes nearly equal to the target thermal displacement, rotating speed of the spindle is changed to usual rotating speed N. Hereby the thermal displacement of the spindle can be corrected.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method and apparatus for correcting the relative position between a spindle and a workpiece according to the amount of thermal displacement of the spindle to perform machining, and particularly to machining while maintaining high machining accuracy. It is related to technology that improves efficiency.

[0002]

2. Description of the Related Art When machining with an NC machine tool, for example, 2
There are cases where the spindle is rotated at a high rotation speed of 0000 (min ^-1 ) or more to perform cutting, grinding, etc., but when the spindle is rotated at such a high rotation, the temperature of the spindle increases and the axial direction ( It extends in the Z-axis direction), the tool position on the tip side changes, and an error occurs in the machining position. The elongation of the main shaft, that is, the thermal displacement, becomes a substantially steady state after a lapse of a predetermined time, for example, about 30 minutes from the start of rotation, and hardly changes thereafter. Therefore, after the smoothing operation until the steady state is reached, the amount of thermal displacement at that time If the position is corrected only and the machining is started, it is possible to avoid the deterioration of the machining accuracy due to the thermal displacement of the spindle. The amount of thermal displacement of the spindle varies depending on the number of rotations, the length of the spindle, the material, etc.
For example, it is about 40 μm at 20000 (min ⁻¹ ).

On the other hand, the relationship between the elapsed time of rotation of the spindle and the amount of thermal displacement is obtained in advance, and the position correction corresponding to the amount of thermal displacement of the spindle is sequentially performed according to the elapsed time. No. 60-99547. In this case, it is possible to perform the machining while correcting the position immediately after the start of rotation of the spindle, and the machining efficiency is improved by the amount that the leveling operation is unnecessary.

[0004]

However, it is difficult to perform position correction with high accuracy in accordance with the thermal displacement of the main shaft in the course of the thermal displacement of the main spindle, and it is possible to correct the position in micron units in accordance with the sequential position correction. It is unavoidable that a step is generated, and it could not be applied in a field where high processing accuracy in the unit of micron is required.

The present invention has been made in view of the above circumstances, and an object of the present invention is to improve the processing efficiency while maintaining high processing accuracy.

[0006]

In order to achieve the above object, the first invention corrects the relative position between the spindle and the workpiece according to the amount of thermal displacement of the spindle to perform the machining. In the method, the main spindle is rotated at a preheating rotational speed higher than the operating rotational speed until it reaches a thermal displacement that is substantially the same as the target thermal displacement that is substantially constant at the operating rotational speed used for actual machining. After the rotation, the main shaft is rotated at the number of rotations used and the relative position is corrected by the amount of the target thermal displacement to perform the machining.

[0007]

In this case, the spindle is heated at a preheating speed higher than the operating speed until it reaches a thermal displacement that is substantially the same as the target thermal displacement (steady thermal displacement) at which the thermal displacement is substantially constant at the operating speed. Is rotated, and then the spindle is rotated at the number of revolutions used to perform machining in a state where the relative position is corrected by the target thermal displacement amount, so the relative position is sequentially corrected according to the progress of thermal displacement of the spindle. Unlike the conventional case, there is no possibility of causing a step difference of micron unit, and high processing accuracy can be obtained.

On the other hand, in the present invention, since the main shaft is rotated at a preheating rotation speed higher than the rotation speed used during actual machining, the time required to reach the same thermal displacement amount as the target thermal displacement amount. However, it is shortened as compared with the case where the main shaft is rotated at the number of rotations used. Therefore, when compared with the case where machining is performed while correcting the position immediately after the start of rotation of the spindle,
Although some waiting time is required before starting machining, the waiting time becomes shorter compared to the case where the spindle is rotated at the number of rotations used from the beginning until the thermal displacement becomes steady. Is improved.

Here, a preferred aspect of the first invention is as follows.
(A) The target thermal displacement is obtained by obtaining the steady-state thermal displacement amount at the rotational speed actually used for machining from the steady-state thermal displacement amount data regarding the machining rotational speed of the spindle and the steady-state thermal displacement amount at which the thermal displacement amount is substantially constant. A target thermal displacement amount setting step as an amount, and (b)
Based on the thermal displacement amount change data representing the relationship between the rotational elapsed time and the thermal displacement amount for the preheating rotational speed higher than the processing rotational speed, the target thermal displacement when the spindle is rotated at the preheating rotational speed. Required time calculation step for obtaining a time required to reach a thermal displacement amount substantially equal to the amount, (c) rotating the spindle at the preheating rotation speed for the required time, and then rotating at the used rotation speed. And a machining control step in which machining is performed in a state where the relative position is corrected by the target thermal displacement amount. In this case, the target thermal displacement amount is set from the steady thermal displacement amount data regarding the processing rotation speed and the steady thermal displacement amount, and the thermal displacement amount change indicating the relationship between the rotation elapsed time and the thermal displacement amount regarding the preheating rotation speed is set. The time required to reach the target thermal displacement is calculated from the data, and the spindle is rotated in advance by the preheating rotation speed for the required time to perform thermal displacement by the same amount as the target thermal displacement. It can easily handle multiple types of machining with different rotational speeds used and achieves high versatility.

The content of the steady-state thermal displacement amount data may be one in which the steady-state thermal displacement amount is determined for each of a plurality of predetermined rotational speeds used, but may be an arithmetic expression or a data map having the rotational speed as a parameter. It is also possible to obtain the steady-state thermal displacement amount at any rotation speed. The thermal displacement amount change data may also be an arithmetic expression, a data map, or the like as long as the rotational elapsed time is represented using the thermal displacement amount as a parameter. These steady-state thermal displacement amount data and thermal displacement amount change data can also be defined by using various influential physical quantities that affect the thermal displacement amount of the spindle such as the environmental temperature around the machine tool as parameters. When the target thermal displacement amount is set from the steady thermal displacement amount data or the required time is obtained from the thermal displacement amount change data, the correction may be performed based on the influential physical quantity.

Further, the relative position between the spindle and the workpiece may be corrected by the target thermal displacement amount at the time when the spindle is rotated at at least the number of rotations in use to machine the workpiece. The position may be corrected in advance before the spindle is rotated at the heating speed. The mode of correction may be, for example, mechanically displacing the spindle of the NC machine tool and the table holding the workpiece, or uniformly changing the data regarding the Z-axis direction (axial direction of the spindle) position of the NC program. Various modes can be adopted, such as

[0012]

As described above, according to the present invention, it is possible to obtain machining accuracy as high as when machining is started by waiting until the thermal displacement reaches a steady state, and the waiting time before machining is started. Shortening improves processing efficiency.

[0013]

A second aspect of the present invention relates to a processing apparatus capable of suitably implementing the above-mentioned first aspect of the invention.
An apparatus that corrects a relative position between a spindle and a workpiece according to a thermal displacement amount of the spindle to perform machining, wherein: (a) steady-state heat in which the machining rotational speed and the thermal displacement of the spindle are substantially constant. Storage means for storing steady-state thermal displacement amount data relating to the displacement amount and thermal displacement amount change data representing the relationship between the rotation elapsed time and the thermal displacement amount relating to the preheating rotation speed higher than the processing rotation speed thereof; Target thermal displacement amount setting means for obtaining a steady-state thermal displacement amount from the steady-state thermal displacement amount data at a rotational speed used for actual machining to obtain a target thermal displacement amount; and (c) rotating the spindle at the preliminary heating rotational speed. Required time calculating means for obtaining the time required to reach the same thermal displacement amount as the target thermal displacement amount from the thermal displacement amount change data,
(D) Machining control means for performing machining in a state in which the spindle is rotated at the preliminary heating rotation speed for the required time and then at the working rotation speed to correct the relative position by the target thermal displacement amount. And having.

[0014]

In the machining apparatus in which the thermal displacement of the spindle is corrected, first, the steady heat at the rotational speed used for actual machining is used based on the steady thermal displacement data stored in the storage means by the target thermal displacement setting means. The displacement amount is set as the target thermal displacement amount, and the time required for reaching the same thermal displacement amount as the target thermal displacement amount when the spindle is rotated at the preheating rotation speed by the required time calculation device is stored in the storage device. It can be obtained from the generated thermal displacement amount change data. Then, from the machining control means, the main shaft is rotated at the preheating rotational speed for the required time and then at the operating rotational speed, and the workpiece is processed with the relative position corrected by the target thermal displacement amount. .
By rotating the spindle at the preheating rotation speed for the required time, the spindle is thermally displaced by approximately the same amount as the steady thermal displacement amount at the rotation speed used, and in that state the actual machining starts at the rotation speed used. As with the first aspect of the present invention, high machining accuracy is obtained, and the waiting time becomes shorter than that in the case where the spindle is rotated at the number of rotations used from the beginning until the thermal displacement reaches a steady state, and the machining efficiency is improved. improves.

Further, the target thermal displacement amount is set from the steady thermal displacement amount data relating to the machining rotational speed and the steady thermal displacement amount, and the thermal displacement amount representing the relationship between the rotational elapsed time and the thermal displacement amount relating to the preheating rotational speed. The required time to reach the target thermal displacement amount is obtained from the change data, and the spindle is rotated in advance by the preheating rotational speed for the required time in advance to perform the thermal displacement by the same degree as the target thermal displacement amount. It is possible to easily handle multiple types of machining with different rotation speeds used for, and high versatility can be obtained.

[0016]

As described above, according to the present invention, as in the first invention, high machining accuracy can be obtained, and the waiting time until the start of machining can be shortened to improve the machining efficiency. Moreover, it is possible to easily cope with a plurality of types of machining with different rotational speeds used, and high versatility can be obtained.

[0017]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the present invention will be described below in detail with reference to the drawings. The NC machining apparatus 10 shown in FIG. 1 can preferably perform the machining method in which the spindle thermal displacement of the first invention is corrected.
In one example of the processing apparatus of the invention, the position-fixed support member 13 in the machine tool 11 includes a rotary tool 12 such as an end mill.
The main shaft 14 gripping downward is disposed so as to be movable in the substantially vertical Z-axis direction, and is vertically moved by the Z-axis moving device 16 and is rotationally driven around the shaft center by the main-axis drive motor 18. It has become. On the other hand, an X-axis moving table 22 and a Y-axis moving table 24 are provided on the base member 21 so as to overlap with each other.
The workpiece 20 positioned and placed on the shaft moving table 24 can be two-dimensionally moved in a substantially horizontal plane by driving the moving tables 22 and 24. Then, the preset NC program 26 (see FIG.
(See the reference), the Z-axis moving device 16 and X
The spindle and Y-axis moving tables 22 and 24 are respectively driven and the spindle driving motor 18 is rotated, so that the spindle 14 and the workpiece 20 are relatively moved three-dimensionally, and the rotary tool 12 rotates the workpiece. A predetermined cutting process or grinding process is performed on the workpiece 20. NC program 2
6 is a target relative position between the spindle 14 and the work piece 20 (x,
(y, z) is sequentially included, and rotation speed information that commands the rotation speed N of the spindle 14 is included, and is supplied by a storage medium such as a magnetic disk or online.

The Z-axis moving device 16 includes a Z-axis servo motor 28.
And an encoder 30 integrally provided therewith, and outputs a signal corresponding to the position of the spindle 14 in the Z-axis direction, while outputting the X-axis and Y-axis signals.
The axis movement tables 22 and 24 respectively include an encoder 34 integrally with the X-axis servo motor 32 and an encoder 38 integrally with the Y-axis servo motor 36.
A signal corresponding to the position of the workpiece 20 in the axial direction is output. In addition, the spindle drive motor 1
8 integrally includes a rotation speed sensor 40, and the main shaft 14
The number of revolutions (min ^-1 ) is detected.

FIG. 2 is a functional block diagram of the NC processing apparatus 10 including the machine tool 11 described above. X composed of the Z-axis moving device 16 and the moving tables 22 and 24
-Y-Z axis drive means 42 is an XY-axis in NC controller 44 which is a control mechanism including a microcomputer.
Drive control is performed in accordance with the drive signal SD _L output from the Z-axis position control means 46. X-
The YZ axis position control means 46 includes the encoders 30, 3
The position information representing the actual relative position between the spindle 14 and the workpiece 20 is read from the position detecting means 48 constituted by 4, 38, and the route information is read from the NC program 26. The actual relative position between the spindle 14 and the work piece 20 coincides with the target relative position (x, y, z) based on the deviation between the relative position of the workpiece and the target relative position (x, y, z) represented by the route information. The XYZ axis drive means 42 is feedback-controlled so that it may be performed. On the other hand, the spindle drive motor 18 is controlled in rotation speed according to a drive signal SD _M output from the spindle rotation control means 50 in the NC controller 44. The spindle rotation control means 50 reads the signal indicating the actual rotation speed of the spindle 14 from the rotation speed sensor 40 and also reads the rotation speed information from the NC program 26. The actual rotation speed and the rotation speed information are read. The spindle drive motor 18 is feedback-controlled so that the actual rotation speed of the spindle 14 coincides with the used rotation speed N based on the deviation from the used rotation speed N represented by. The NC controller 44 is a CPU for storing programs for performing such feedback control and other functions shown in FIG.
It is configured to include an AM and a ROM.

In the NC processing device 10 as described above,
In recent years, the spindle 14 has been set to, for example, 20,000 (min ⁻¹ ) to 30.
High-efficiency machining may be performed by rotationally driving at a high rotational speed of about 000 (min ⁻¹ ), but when rotationally driven at such a high rotational speed, the temperature of the main shaft 14 rises and the axial direction thereof is increased. Since it extends in the Z-axis direction, the rotary tool 12 is shown in FIG.
Is displaced downwards. FIG. 3 shows the relationship between the elongation of the main shaft 14, that is, the amount of thermal displacement and the elapsed time from the start of rotation for each of three rotation speeds (20,000 min ⁻¹ , 25,000 mi).
It is a figure represented to (n ^-1 , 30,000 min ^-1 ). As is clear from the figure, the displacement of the main shaft 14 becomes a substantially steady state after a lapse of a predetermined time from the start of rotation and hardly changes thereafter, but such a thermal displacement amount is Z relative to the workpiece 20.
It appears as a machining error in the axial direction. The amount of thermal displacement of the main shaft 14 varies depending on the number of revolutions, the length of the main shaft 14, the material, and the like, but is about 40 μm at 20,000 (min ⁻¹ ), for example, and a processing error of the same dimension occurs.

On the other hand, in the present embodiment, the displacement amount information relating to the thermal displacement amount of the spindle 14 and the rotation elapsed time as shown in FIG. 3 is stored in the data storage section 52 of the NC controller 44 as the rotation of the spindle 14. Each number is stored as a data map. The NC controller 44 also includes target thermal displacement amount setting means 54 and required time calculating means 56,
In the target thermal displacement amount setting means 54, the spindle 1 during actual machining is
Displacement amount information regarding the number of revolutions N used, which is the number of revolutions of 4, is read from the data storage unit 52, and the thermal displacement is determined by, for example, whether the change width of the thermal displacement amount within a predetermined time period is a predetermined value or less. The steady-state thermal displacement amount L that makes the amount substantially constant is determined, the steady-state thermal displacement amount L is set as the target thermal displacement amount L1, and the target thermal displacement amount L1 is set as the correction amount ΔZ. In the present embodiment, the processing rotation speeds that can be used for actual processing are 20,000 (min ⁻¹ ) and 25,000 (mi).
n ^-1 ) is determined, and the rotation speed N of the NC program 26 is used.
Is set to any one of the rotational speeds. Data storage unit 52
Of the three pieces of displacement amount information stored in, the machining rotation speed is 20000 (min ⁻¹ ) and 25000 (mi
Those relating to (n ⁻¹ ) correspond to the steady-state thermal displacement amount data.

Here, the value and the number of processing revolutions at which the above-mentioned steady thermal displacement data should be stored are appropriately set according to the actually used revolutions. Also, 30,000 (min ^-1 )
If the steady-state thermal displacement amount L is map-interpolated including the displacement amount information regarding 20,000 (min ⁻¹ ) to 30,000 (mi
It is possible to obtain the steady-state thermal displacement amount L at any rotation speed between n ⁻¹ ) and in that case 20000 (min ⁻¹ ) to 30
Any rotation speed between 000 (min ^-1 ) is used.
Can be set as Further, since the steady-state thermal displacement amount data only needs to know the steady-state thermal displacement amount L for each rotation speed, the data as shown in FIG. 3 is not always necessary. For example, the steady-state thermal displacement amount L is calculated using the rotation speed as a parameter. An arithmetic expression or the like can be used as the steady thermal displacement amount data.

On the other hand, the required time calculation means 56 reads the target thermal displacement amount L1 from the target thermal displacement amount setting means 54, and the highest rotation speed among the displacement amount information stored in the data storage section 52, 300 in this example
The displacement amount information regarding 00 (min ⁻¹ ) is read, and the thermal displacement amount is the target thermal displacement amount L1 based on the displacement amount information.
Is calculated as the required time T1. FIG. 4 shows that the number of rotations N used is 20,000.
Target thermal displacement amount L1 and required time T1 in the case of (min ⁻¹ )
It is a figure which shows the relationship with. 30000 (min ⁻¹ ) corresponds to the preheating rotation speed higher than the processing rotation speed, and of the three displacement amount information stored in the data storage unit 52,
For the number of processing revolutions of 30,000 (min ^-1 ),
This corresponds to thermal displacement amount change data regarding the preheating rotation speed. The data storage unit 52 corresponds to a storage unit that stores the steady thermal displacement amount data and the thermal displacement amount change data. The thermal displacement amount change data can also be set in the form of an arithmetic expression or the like for calculating the required time T1 using the thermal displacement amount as a parameter. Further, the preheating rotation speed is appropriately set in consideration of the processing rotation speed.

Information about the required time T1 is supplied to the spindle rotation control means 50. Spindle rotation control means 50
Is the preheating rotational speed of the spindle 14 of 30,000 (min ⁻¹ ) prior to the actual processing at the operating rotational speed N.
In addition to being rotationally driven by, a timer 58 such as a crystal oscillator provided in the controller 44 measures the elapsed time from the start of rotation. Then, when the elapsed time reaches the required time T1, in other words, when the thermal displacement amount of the spindle 14 becomes substantially the same as the target thermal displacement amount L1, the rotation speed of the spindle 14 is changed to the use rotation speed N. Also, the target thermal displacement L1
The same information regarding the correction amount ΔZ is supplied to the XYZ axis position control means 46, and the XYZ axis position control means 46 adjusts the relative reference position in the Z axis direction by the correction amount ΔZ. Then, relative movement control is performed according to the route information of the NC program 26. This NC program 2
In the relative movement control by 6, the rotational drive speed of the spindle 14 by the spindle rotation control means 50 is at least the number of rotations N used.
Is performed after the change is made to the main shaft rotation control means 50, and the spindle rotation control means 50 outputs to the XYZ axis position control means 46 a signal indicating that the rotation speed has been changed to the used rotation speed N. The spindle rotation control means 50, the XYZ axis position control means 46, and the timer 5
Reference numeral 8 corresponds to processing control means.

FIG. 5 is a flow chart for explaining an example of control of the machine tool 11 by the NC controller 44. First, in step S1, the rotational speed N (= 20,000 min ⁻¹ or 25,000 mi) used for actual machining is used.
n ⁻¹ ) is read from the NC program 26. Step S
Reference numeral 2 denotes a portion executed by the target thermal displacement amount setting means 54, which reads displacement amount information (steady thermal displacement amount data) regarding the above-described rotational speed N from the data storage unit 52 to obtain a steady thermal displacement amount L, and The steady thermal displacement amount L is set as the target thermal displacement amount L1 and the correction amount ΔZ. This step S2 is a target thermal displacement amount setting step. The following step S3 is a part executed by the required time calculating means 56, which reads displacement amount information (thermal displacement amount change data) regarding the preheating rotation speed 30000 min ⁻¹ from the data storage unit 52,
A required time T1 until the thermal displacement amount reaches the target thermal displacement amount L1 is calculated. This step S3 is a required time calculation step.

In step S4, the drive signal SD for rotating the spindle 14 at the preheating rotational speed of 30,000 (min ^-1 ).
_M is output to the spindle drive motor 18 to start preheating rotation of the spindle 14, and in step S5, the timer 5
Elapsed time T from the start of preheating rotation timed by 8
Is equal to or greater than the required time T1, and when the elapsed time T exceeds the required time T1, the spindle 1
The number of revolutions of 4 is changed to the number of revolutions used N represented by the number of revolutions information of the NC program 26. As a result, the thermal displacement amount of the main shaft 14 is made to substantially match the steady thermal displacement amount L at the operating speed N. These steps S4 to S6 are executed by the spindle rotation control means 50. The required time T1
Alternatively, the elapsed time T or the remaining time (T1−T) can be displayed on a display device (not shown) or the like. Further, since the main shaft 14 does not necessarily have to be positioned at the processing position during the preheating rotation, it may be moved upward and the workpiece 20 may be installed between them.

In step S7, the drive signal SD _L is output to the Z-axis moving device 16 of the XYZ-axis drive means 42, and the drive signal SDL is set in the Z-axis direction by the correction amount ΔZ set in step S2. Correct the reference position. Specifically, the spindle 14
The reference position in the Z-axis direction is changed upward by the target thermal displacement amount L1. In the next step S8, NC program 2
The movement control is performed according to the route information of No. 6, so that the work piece 20 is machined into a predetermined shape by the main shaft 14 that is rotationally driven at the above-described rotational speed N. These steps S7 and S8 are executed by the XYZ axis position control means 46. Further, steps S4 to S8 are processing control steps. Although step S8 is executed at least after step S6 is completed,
Step 7 may be performed at any time after the correction amount ΔZ is set in step S2 and before step S8 is executed. The completion of each step up to step S7 may be displayed on a display device such as a preheating completion lamp, and step S8 may be executed by a switch operation of the operator.

In the NC machining apparatus 10 of the present embodiment as described above, the steady thermal displacement amount L at which the thermal displacement amount is substantially constant at the operating speed N is stored on the basis of the displacement amount information stored in the data storage section 52. The target thermal displacement amount L1 is set, and the time T1 required to reach the thermal displacement amount that is substantially the same as the target thermal displacement amount L1 when rotated at the preheating rotational speed of 30,000 (min ⁻¹ ) is calculated. After rotating the spindle 14 at the preheating rotation speed of 30000 (min ⁻¹ ) for the required time T1, the spindle 14 is rotated at the used rotation speed N and the position of the spindle 14 is set to the target thermal displacement amount L1. Since the machining is performed with the same correction amount ΔZ corrected, the same high machining accuracy as that obtained when the machining is started at the initial rotational speed N until the thermal displacement reaches a steady state is started. Thermal change of spindle There is no possibility of causing a step in the unit of micron as in the case where the relative positions are sequentially corrected corresponding to the progress of the position.

On the other hand, the number of revolutions used N in actual machining
Since the main shaft 14 is rotated at a preheating rotational speed of 30000 min ⁻¹ higher than (= 20000 min ⁻¹ or 25000 min ⁻¹ ), the time T1 required to reach a thermal displacement amount substantially equal to the target thermal displacement amount L1 is , Is shortened as compared with the case where the main shaft 14 is rotated at the used rotation speed N. Therefore, as compared with the case where machining is performed while the position of the spindle 14 is sequentially corrected immediately after the rotation of the spindle 14 is started, a slight waiting time (= T
Although 1) is required, the waiting time is shortened and the machining efficiency is improved as compared with the case where the main shaft 14 is rotated from the beginning at the used rotation speed N and the thermal displacement is waited until it reaches a steady state.

Further, the data storage unit 52 stores displacement amount information regarding a plurality of processing rotation speeds, and sets a target thermal displacement amount L1 according to the used rotation speed N to calculate a required time T1. Therefore, it is possible to deal with a plurality of types of machining having different rotational speeds N and high versatility.

Although one embodiment of the present invention has been described in detail with reference to the drawings, the present invention can be implemented in other modes.

For example, in the above-described embodiment, the machining rotation speed by the machine tool 11 is 20000 min ⁻¹ and 25000 m.
NC with maximum speed of 30,000 min ^-1 at in ^-1
Although it is the case of the processing apparatus 10, the number of rotations thereof can be appropriately changed or added, and the present invention can be applied to other processing apparatuses other than the NC processing apparatus that perform spindle rotation control and relative position control.

When setting the displacement amount information stored in the data storage unit 52, that is, the steady thermal displacement amount data and the thermal displacement amount change data, the thermal displacement of the spindle 14 such as the environmental temperature around the machine tool 11 is set. It is also possible to consider various influential physical quantities that affect the quantity and to determine these influential physical quantities as parameters. When the target thermal displacement amount is set from the steady thermal displacement amount data or the required time is obtained from the thermal displacement amount change data, the correction may be performed based on the influential physical quantity.

In the above embodiment, the maximum rotation speed is 300
While 00min ^-1 has been a preheated rotating speed, since it contains the thermal displacement amount change data in 25000Min ^-1 in the data of FIG. 3, using speed 20000mi
In the case of n ⁻¹ , there is no problem even if the preheating rotational speed is set to 25000 min ⁻¹ . For example, when the desired processing start time can be set, the target thermal displacement amount is reached by the desired processing start time. An appropriate preheating rotation speed may be automatically set.

Further, in the above-mentioned embodiment, the main shaft 14 is simply rotated at the preheating rotational speed for preheating, but a heating means such as a heater is provided as necessary in order to accelerate the temperature rise. It is also possible to further reduce the required time. In that case, the thermal displacement amount change data in the case of using those heating means is stored.

Further, although the above-mentioned embodiment is configured to include the storage means, the target thermal displacement amount setting means, the required time calculating means, and the processing control means in the second invention, the presence or absence of each such means is concerned. First, after rotating the main spindle 14 at a preheating rotational speed N1 higher than the operating rotational speed N until the thermal displacement reaches a thermal displacement amount substantially the same as the target thermal displacement amount L1 at which the thermal displacement amount is substantially constant at the operating rotational speed N, Spindle 14 at speed N
The effect of the first invention can be obtained as long as the machining is performed in a state where the relative position with respect to the workpiece 20 is corrected by the target thermal displacement amount L1 by rotating the.

Further, in the correction of the relative position between the spindle 14 and the workpiece 20 in the above embodiment, the spindle 14 is corrected by a correction amount ΔZ.
(= L1), the Z-axis component z at the target relative position (x, y, z) of the NC program 26 was uniformly set before the start of the machining. Position correction means 4
It is also possible to correct the zero point of the Z-axis position coordinate at 8.

Further, in the above-mentioned embodiment, although the thermal displacement of the rotary tool 12 is not particularly mentioned, the thermal displacement of the rotary tool 12 is also taken into consideration so that the relative position with respect to the workpiece 20 is corrected. It is also possible.

Further, in the above embodiment, the position correction in the Z-axis direction which is the thermal displacement direction of the main shaft 14 is performed by the XYZ-axis position control means 46, but the Z-axis direction relating to the thermal displacement amount is corrected. Z-axis correction control means for instructing correction of only the above is provided separately, or a fine adjustment device for moving the amount of thermal displacement is provided between the Z-axis moving device 16 and the support member 13 in FIG. It doesn't matter if you do.

Further, although the storage means, the target thermal displacement amount setting means, the required time calculation means and the like are provided in the NC controller 44 in the above embodiment, the storage means and the like are provided separately from the existing NC controller and the like. A controller for thermal displacement correction may be provided.

Although not individually exemplified, the present invention can be carried out in various modified and improved modes based on the knowledge of those skilled in the art.

[Brief description of drawings]

FIG. 1 is a schematic diagram illustrating an example of a processing apparatus according to claim 2, which can suitably carry out the processing method according to claim 1.

FIG. 2 is a functional block diagram including a control system of the NC processing apparatus of FIG.

FIG. 3 is a diagram illustrating displacement amount information of a spindle stored in a data storage unit of FIG.

FIG. 4 is a diagram for explaining the operation of the required time calculating means of FIG.

5 is an example of a flowchart illustrating an operation of the NC controller of FIG.

[Explanation of symbols]

 10: NC machining device (machining device in which thermal displacement of the spindle is corrected) 14: Spindle 20: Workpiece 46: XYZ axis position control means (machining control means) 50: Spindle rotation control means (machining control means) 52: data storage unit (storage unit) 54: target thermal displacement amount setting unit 56: required time calculation unit 58: timer (processing control unit) N: number of revolutions used L1: target thermal displacement amount T1: required time

Claims (2)

[Claims] 1. A method of performing machining by correcting the relative position between the spindle and a workpiece according to the amount of thermal displacement of the spindle, wherein the amount of thermal displacement is substantially the same at the rotational speed used for actual machining. After rotating the main shaft at a preheating rotational speed higher than the operating speed until the thermal displacement amount is approximately the same as the target thermal displacement amount that becomes constant, the main shaft is rotated at the operating speed to rotate the relative position. A machining method in which the spindle thermal displacement is corrected, wherein the machining is performed in a state where the amount of the target thermal displacement is corrected. 2. An apparatus for performing processing by correcting the relative position between the spindle and a workpiece according to the amount of thermal displacement of the spindle, wherein the machining rotational speed and the amount of thermal displacement of the spindle are substantially constant. A storage unit that stores steady-state thermal displacement amount data regarding the steady-state thermal displacement amount, and thermal displacement amount change data that represents a relationship between the rotation elapsed time and the thermal displacement amount regarding the preheating rotational speed higher than the processing rotational speed, and the stationary state. Target thermal displacement amount setting means for obtaining a steady-state thermal displacement amount at a use rotational speed used for actual machining from the thermal displacement amount data and setting the target thermal displacement amount, and when the main spindle is rotated at the preliminary heating rotational speed. Required time calculating means for obtaining the time required to reach the same thermal displacement amount as the target thermal displacement amount from the thermal displacement amount change data, and after rotating the spindle at the preliminary heating rotation speed for the required time, The number of rotations used Processing apparatus to correct the spindle thermal displacement, characterized in that it comprises a processing control means for processing the relative position is rotated in a state of being corrected by the target thermal displacement amount.