JP2008264883A - Machining device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a machining device capable of presuming accurately the distal end position of a machining tool even if the change amount or change rate of the position has a certain magnitude, suppressing the error resulting from a thermal displacement during machining irrespective of the material of the machining tool, its length, rotating speed of a spindle, etc., and shortening the time of warmup operation. <P>SOLUTION: Before machining is started, the spindle is rotated at a rotating speed used in the machining, and the distal end position G1 of the machining tool is obtained on the basis of the signal given by a tool distal end position measuring means, and the thermal displacement amount G2 of the spindle is obtained on the basis of the signal given by a spindle displacement measuring means, and further the correction factor G3 as the ratio of the distal end position G1 to the thermal displacement amount G2 as obtained above is obtained, and after the start of machining, the machining is executed while the control amount of a cut-in motion means is corrected using G3 obtained and the signal given by the spindle displacement measuring means. <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

  The present invention relates to a machining apparatus capable of correcting an error associated with a thermal displacement of a main shaft.

2. Description of the Related Art Conventionally, in a processing apparatus provided with a processing tool at the tip of a main shaft that is rotated by a rotation driving means such as a motor, the processing tool is moved by heat generated by the rotation driving means or heat generated by a bearing portion of the main shaft. It is known that the position of the tip is displaced and an error occurs.
However, in a processing apparatus that processes at the tip of the processing tool, the amount of displacement of the tip position of the processing tool cannot be measured during processing.
Further, during the warm-up operation immediately after starting the rotation of the spindle, the amount of change in temperature is large and the change in amount of thermal displacement is also large. Therefore, the machining is started after the warm-up operation for a certain time is performed and the amount of thermal displacement is stabilized. The predetermined time for performing the warm-up operation is set empirically as a sufficient time until the amount of thermal displacement is stabilized, which may be longer than necessary and may reduce the machining efficiency. Furthermore, the machining tool may be replaced for each workpiece material or machining process (rough machining process, precision machining process, finishing machining process, etc.), and warm-up operation is frequently performed.
Further, the rotational speed of the main spindle may differ depending on the material of the workpiece and the machining process, and the amount of displacement also changes due to the difference in the amount of heat generated by the rotational speed of the main spindle.

  Therefore, in the prior art described in Patent Document 1, a measuring unit capable of measuring the amount of thermal displacement of the main shaft is provided at the rear end portion of the main shaft, and the amount of the main shaft relative to the amount of displacement by the measuring unit according to the rotational speed of the main shaft is determined. The amount of thermal displacement at the front end is previously measured and stored in the storage means. During machining, the amount of thermal displacement at the front end of the main shaft is determined from the amount of thermal displacement at the rear end of the main shaft measured by the measuring means (determined according to the rotational speed of the main shaft, and the amount of thermal displacement at the rear end is calculated. The tip position of the machining tool is corrected by multiplying the correction coefficient to obtain the thermal displacement amount at the tip, and even if the tip position of the machining tool being machined cannot be measured, it depends on the amount of thermal displacement corresponding to the spindle rotation speed. A spindle thermal displacement correction apparatus for machine tools that can suppress errors has been proposed.

In the prior art described in Patent Document 2, the position of the tip of the machining tool is measured during the warm-up operation before machining, and the amount of change or rate of change of the position of the tip of the machining tool is set in advance. A machine tool has been proposed in which it is determined that the warm-up operation has been completed when the position of the tip of the machining tool is stable and the warm-up operation is longer than necessary.
JP-A-1-274951 JP 2004-261934 A

Patent Document 1 uses “a ratio (= correction coefficient) between the amount of thermal displacement at the front end of the main shaft and the amount of thermal displacement at the rear end of the main shaft in accordance with the number of rotations of the main shaft”. Since this data is a fixed value stored in advance, the working environment of the machining apparatus (for example, room temperature, type of machining tool) is “the amount of thermal displacement of the spindle tip according to the spindle rotation speed and the spindle rear end. If the ratio of the thermal displacement amount (= correction coefficient) is different from that at the time of sampling, an error occurs. Further, in this regard, Patent Document 1 does not describe correction of the amount of thermal displacement of the machining tool provided at the front end portion of the main shaft. In the same way as the main shaft is thermally displaced, the machining tool is also thermally displaced, and the amount of thermal displacement changes depending on the material and length. Therefore, in order to correct the error more accurately, it is necessary to store the characteristics (graph and the like) of the material and length of the processing tool in advance in the storage means, which is very laborious. Further, since the end of the warm-up operation until the amount of thermal displacement is stabilized is not properly determined, the warm-up operation time may be longer than necessary.
Further, in the prior art described in Patent Document 2, when the tip position of the machining tool is stable (when the change amount or change rate is within a predetermined range), it is determined that the warm-up operation has ended and machining is performed. Although it has started, it still takes a long time to stabilize the tip position of the processing tool.
The present invention has been devised in view of such points, and even when the amount of change or rate of change of the tip position of the processing tool has a certain amount of magnitude, the tip position is determined. It is possible to estimate more accurately, and it is possible to further suppress errors due to thermal displacement during machining regardless of the material and length of the machining tool, the rotation speed of the spindle, etc. It is an object of the present invention to provide a processing apparatus that can be made shorter.

As means for solving the above-mentioned problems, the first invention of the present invention is a processing apparatus as described in claim 1.
The processing apparatus according to claim 1, a main shaft that is rotated by a rotation driving unit, a processing tool that is provided coaxially with the rotation axis of the main shaft, rotates, and processes a workpiece at the tip, and the direction of the rotation axis A cutting movement means capable of moving the position of the workpiece relative to the tip of the machining tool along the cutting edge, and a tool tip position measurement capable of directly detecting the tip position of the machining tool in the rotational axis direction when not machining A spindle displacement amount measuring means capable of detecting a thermal displacement amount of the spindle in the direction of the rotation axis without interfering with the machining tool and a workpiece during machining, and controlling the rotation driving means and the cutting movement means. And a control means for correcting a control amount of the incision moving means during the machining based on a signal from the spindle displacement measuring means. It is the location.
Before starting machining, the control means controls the rotation driving means to rotate the spindle at a rotational speed used for machining, and based on a signal from the tool tip position measuring means, the tip position of the machining tool And obtaining a thermal displacement amount of the spindle based on a signal from the spindle displacement measuring means, obtaining a correction coefficient that is a ratio of the tip position to the obtained thermal displacement amount, and after starting machining, Using the obtained correction coefficient and the signal from the spindle displacement measuring means, machining is performed while correcting the control amount of the cutting movement means.

The second invention of the present invention is a processing apparatus as set forth in claim 2.
The processing apparatus according to claim 2 is the processing apparatus according to claim 1, wherein the control unit obtains the correction coefficient at every predetermined timing before starting the processing, and changes in the correction coefficient. Alternatively, when the rate of change becomes less than the allowable value, it is determined that the warm-up operation has ended, and the machining is started after determining the end of the warm-up operation.

A third aspect of the present invention is a processing apparatus as set forth in the third aspect.
A processing apparatus according to a third aspect is the processing apparatus according to the first aspect, wherein the control means obtains the correction coefficient at every predetermined timing before starting the processing, and the correction coefficient is within an allowable range. When the warming-up operation is finished, it is determined that the warm-up operation has been completed, and the machining is started after determining the end of the warm-up operation.

The fourth invention of the present invention is a processing apparatus as set forth in claim 4.
A processing apparatus according to a fourth aspect is the processing apparatus according to the second or third aspect, wherein the control means determines a change amount or a change rate allowable value of the correction coefficient or an allowable range of the correction coefficient. , Roughing process, fine machining process, finishing process, and switching.

In the machining apparatus according to claim 1, a “ratio” which is the tip position (displacement amount) of the machining tool with respect to the thermal displacement amount of the spindle is used as a correction coefficient, and the correction coefficient and the thermal displacement amount (spindle displacement) of the spindle during machining. The amount of control of the incision moving means is corrected using the quantity obtained from the signal from the quantity measuring means.
Thereby, it is possible to further suppress errors due to thermal displacement during processing regardless of the material and length of the processing tool, the rotation speed of the spindle, and the like. Further, it is not necessary to prepare various correction coefficients in advance according to the material and length of the processing tool, the rotation speed of the spindle, and the like, which is convenient because an optimum correction coefficient can be obtained with an actual machine.

  Further, in the machining apparatus according to claim 2, even if various correction coefficients (ratio) exist according to the material and length of the machining tool, the rotation speed of the spindle, and the like, the correction coefficient obtained at every predetermined timing It is determined that the warm-up operation has been completed when the amount of change or rate of change in the (ratio) is below the allowable value and is stable. In this case, even when the amount of change or rate of change of the tip position of the machining tool has a certain level (before the tip position of the machining tool becomes stable), the correction coefficient (ratio) Since the value tends to stabilize first, the warm-up operation time can be shortened and appropriately determined (if the correction coefficient (ratio) is stable, the tip position of the machining tool is estimated more accurately) Can start processing).

  In the processing apparatus according to the third aspect, when the correction coefficient (ratio) obtained at every predetermined timing is within the allowable range, it is determined that the warm-up operation is finished. In this case, even when the amount of change or rate of change of the tip position of the machining tool has a certain level (before the tip position of the machining tool becomes stable), the correction coefficient (ratio) Since the value tends to stabilize first, the warm-up operation time can be shortened and appropriately determined (if the correction coefficient (ratio) is stable, the tip position of the machining tool is estimated more accurately) Can start processing).

  Further, in the processing apparatus according to claim 4, in order to satisfy the processing accuracy corresponding to the processing step (a relatively long warm-up time in a process with high required accuracy and a relatively short warm-up time in a process with low required accuracy). Etc.) The end of the warm-up operation can be properly determined, and the processing efficiency can be further improved.

  The best mode for carrying out the present invention will be described below with reference to the drawings. FIG. 1 shows a schematic external view (perspective view) in an embodiment of a processing apparatus 1 of the present invention, and FIG. 2 shows an example of a schematic connection diagram (side view) of the processing apparatus 1. In all the drawings, the Z axis indicates the direction in which the machining tool T cuts into the workpiece W, the Y axis indicates the vertical direction (upward), and the X axis indicates a direction orthogonal to both the Z axis and the Y axis. Show.

● [Appearance and connection of processing equipment 1 (Figs. 1 and 2)]
In the processing apparatus 1 shown in the example of FIG. 1, a spindle housing 12 is fixed to a column 14 placed on a base 2, and a spindle 10 that is rotated by a rotation driving means such as a motor is placed in the spindle housing 12. Provided (see FIG. 3). Further, a processing tool T for processing the workpiece W at the tip portion TS is provided at the tip of the main shaft 10 coaxially with the rotation axis (parallel to the Z-axis direction) of the main shaft 10.
The workpiece W is fixed to the table 20, and a nut portion 22 fitted to the ball screw NZ is connected to the table 20 (see FIG. 2). The Z-axis moving means MZ (which is composed of a motor or the like and corresponds to the cutting movement means) can rotate the ball screw NZ to move the table 20 along the Z-axis direction. The position of the workpiece W relative to the tip portion TS of the processing tool T can be moved forward and backward.

Next, an example of input / output and control of the control means 40 (numerical control device or the like) will be described with reference to FIG.
The control means 40 can detect the position of the table 20 on the processing apparatus 1 based on the signal SA2 from the encoder EZ provided in the Z-axis moving means MZ, and outputs a drive signal SA1 to the Z-axis moving means MZ. Then, the cutting depth of the tool with respect to the workpiece W is controlled by controlling the position of the table 20.
Further, the control means 40 controls the rotation of the main shaft 10 by outputting a drive signal SB1 to the rotation driving means for rotating the main shaft 10. Although not shown, the control means 40 takes in the rotation speed of the rotation drive means using an encoder or the like and controls the rotation speed of the main shaft 10.
Further, the control means 40, based on the signal SB2 from the spindle displacement measuring means SH (see FIG. 3) provided on the spindle 10, the displacement (Z axis) of the spindle 10 at the measurement location of the spindle displacement measuring means SH. Direction displacement amount).
Further, the control means 40 outputs a control signal SC1 to the tool tip detection unit 30 provided on the machining tool side in the table 20, and opens the lid on the upper surface of the tool tip detection unit 30 to thereby measure the tool tip position. 32 (see FIG. 4) is raised, and the position (position in the Z-axis direction) of the tip portion TS of the machining tool T can be directly obtained based on the signal SC2 from the tool tip position measuring means 32.
1 and 2, the moving means for moving the relative position in the X-axis direction and the relative position in the Y-axis direction of the workpiece W with respect to the machining tool T is omitted, but the table 20 or the spindle 10 is not used. X-axis moving means for relatively moving in the X-axis direction and Y-axis moving means for relatively moving the table 20 or the main shaft 10 in the Y-axis direction may be provided.

● [Configuration of spindle 10 and measuring method of thermal displacement of spindle 10 (FIG. 3)]
FIG. 3 is a sectional view showing the internal structure of the spindle housing 12 (a section taken along the YZ plane passing through the rotation axis of the spindle 10).
The main shaft 10 is fixed in the main shaft housing 12 via a bearing 16 (bearing or the like), and rotates when, for example, the coil 15 is energized.
The main shaft housing 12 is fixed to a column 14, and an arm 18 that is formed separately from the main shaft housing 12 is fixed to the column 14. The tip of the arm 18 is provided with a spindle displacement measuring means SH (gap sensor or the like), and the spindle displacement measuring means SH is spaced at a distance ΔD (gap) from the detection surface M formed on the spindle 10. A corresponding detection signal is output to the control means 40.
The spindle displacement measuring means SH is not limited to the position shown in the example of FIG. 3 as long as it can be measured even when the machining tool T is machining the workpiece W. Can be provided.

● [Direct measurement method of the tip TS of the processing tool T (Fig. 4)]
FIG. 4 shows a view in which the upper end of the tool tip detection unit 30 is opened by the control signal SC1 from the control means 40 (not shown) and the tool tip position measuring means 32 is raised to the position of the machining tool T. Yes. The tool tip position measuring means 32 is a measuring means that can directly and accurately detect the position of the tip portion TS of the processing tool T by shielding the laser beam LA, for example, but the processing tool T processes the workpiece W. Cannot be used inside. As described in the description of FIG. 7 (steps S14 and S24), which will be described later, when the position of the tip TS is detected by the tool tip position measuring means 32, the rotational speed used in machining (step S11). ), The machining tool T is rotating.
The advantage of using the tool tip position measuring means 32 is that the tool tip position measuring means 32 directly detects the tip position of the machining tool T (position of the tip portion TS) on the actual machine and sets the machining start point. Compared to the case where the origin is used as the machining start point, the thermal displacement error of the bed or column can be canceled, and the closer the tool tip position measuring means 32 is to the workpiece W (closer to the actual machining location) The fact that the thermal displacement error between the workpiece W and the tool tip position measuring means 32 can be reduced, and that these can be implemented in the actual machine usage environment (room temperature, type of processing tool, etc.). .

[Relationship between the position of the tip TS of the processing tool T and the amount of thermal displacement of the spindle 10 (FIG. 5)]
In the graph shown in FIG. 5, the horizontal axis is the time axis, and the vertical axis is the displacement amount (graph G1, graph G2) or the correction coefficient (graph G3). This is an example of an actual measurement value when the rotation speed used in the above is set. The graph G1 shows the position of the tip TS of the machining tool T measured based on the signal from the tool tip position measuring means 32, and the graph G2 shows the spindle 10 measured based on the signal from the spindle displacement measuring means SH. The graph G3 indicates “the value of the graph G1 / the value of the graph G2” (= the position of the tip TS of the machining tool T with respect to the displacement of the detection surface M of the spindle 10). ing.
Note that the tool tip position measuring means 32 cannot be used (graph G1) during machining of the workpiece W with the tip portion TS of the machining tool T, but the spindle displacement measuring means SH is being machined. (Graph G2) can be obtained.

As can be seen from the graph of FIG. 5, the value (graph G1) of the position (displacement) of the tip TS of the machining tool T gradually increases after the rotation of the spindle 10 is started (timing Ta). The slope is not constant. Similarly, the displacement amount (graph G2) of the detection surface M of the main shaft 10 gradually increases after the rotation of the main shaft 10, but the inclination thereof is not constant.
However, the position (graph G3) of the tip portion TS of the machining tool T with respect to the displacement amount of the detection surface M of the main spindle 10 becomes substantially constant after a period T1 has elapsed since the rotation of the main spindle 10 has started. I understand that. The value of this graph G3 is used as a thermal displacement correction coefficient. That is, after the period T1 has elapsed, the more accurate position of the tip TS of the machining tool T can be obtained (estimated) from “the amount of displacement of the detection surface M of the spindle 10” × “correction coefficient”.

The position of the tip TS is determined by the amount of thermal displacement due to the material (thermal expansion coefficient), length and rotational speed of the main shaft 10, the material (thermal expansion coefficient) and length of the processing tool T, and the inclination thereof is not constant. . In addition, the machining tool T is exchanged for various types depending on the type and machining process of the workpiece W, and even the same workpiece W is exchanged for a machining tool T that is different in the rough machining process and the finishing machining process, and the spindle 10 rotates. The speed may be different for each process.
Further, the amount of displacement of the detection surface M also depends on the material (thermal expansion coefficient), length and rotational speed of the main shaft 10, the position of the detection surface M on the main shaft 10, the material (thermal expansion coefficient) and length of the arm 18, and the like. It is determined by the amount of thermal displacement, and its slope is not constant.
However, as described above, since the correction coefficient is stable after the period T1, the position of the tip TS can be obtained more accurately from “the amount of displacement of the detection surface M of the spindle 10” × “correction coefficient”. it can.
In the processing apparatus 1 described in the present embodiment, the main shaft 10 is rotated at the rotational speed used for processing, the correction coefficient is obtained during the warm-up operation, and the material, length, rotational speed, and processing of the main shaft 10 are determined. Regardless of the material and length of the tool T, the correction coefficient specific to the machining tool T including the spindle 10 can be automatically obtained, so that very high-precision machining can be performed without any trouble.

After time Tb, it is possible to perform processing by obtaining (estimating) the position of the tip TS using a stable correction coefficient. Therefore, this “period T1” is regarded as a “warm-up operation period”. It can be determined that the warm-up operation has been completed at time Tb.
The determination of the end of the warm-up operation according to the prior art determines the end of the warm-up operation when the change amount or change rate of the position of the tip portion TS of the machining tool T falls within a predetermined range. The end of the warm-up operation is determined after time Tc when the amount of change or rate of change in the graph G1 is within a predetermined range. Therefore, in the prior art, the period T2 is determined as the warm-up operation period.
On the other hand, in the machining apparatus 1 described in the present embodiment, the spindle displacement measuring means SH capable of detecting the displacement of the spindle 10 in the rotation axis direction without interfering with the machining tool T and the workpiece W during machining. It has. During the warm-up operation after starting the rotation of the spindle 10, the position (A) of the tip TS based on the signal from the tool tip position detecting means 32 and the signal from the spindle displacement measuring means SH are used. Based on the thermal displacement amount (C) of the main spindle 10 and the position (= A / C) of the tip portion TS with respect to the thermal displacement amount of the main spindle 10 as a correction coefficient, the change amount of the correction coefficient is less than the allowable value. In this case (that is, when the amount of change in the graph G3 is less than the allowable value), it is determined that the warm-up operation has ended.
In the processing apparatus 1 according to the present embodiment, the end determination of the warm-up operation is not “stabilization of the position (absolute position) of the tip portion TS” but “displacement of the tip portion TS with respect to the displacement of the main shaft 10 (= relative ratio). ) Stability ”, a period in which the amount of change in the displacement of the tip TS has a certain magnitude and is conventionally determined to be during the warm-up operation (in the example of FIG. 5, the period from time Tb to time Tc). ), It is possible to determine the end of the warm-up operation from the fact that the correction coefficient is stable, and to start highly accurate machining using the correction coefficient. That is, it is possible to achieve both ensuring of machining accuracy and shortening of the warm-up operation time.

● [Method for correcting thermal displacement by control means 40 (FIG. 6)]
FIG. 6 shows an example of a control block diagram of thermal displacement correction control during machining of the workpiece W by the control means 40.
A signal (analog signal) from the spindle displacement measuring means SH is amplified to a predetermined magnification by the amplifier C10, is input to the A / D converter C30 via the first-order lag converter C20, and is converted into a digital value. .
Then, the signal from the spindle displacement measuring means SH converted into a digital value is multiplied by a correction coefficient by a multiplier C40, and the amount of displacement of the tip TS is obtained. The obtained displacement amount of the tip TS is output from the correction block C50 as the machining device origin offset, and the cutting control amount of the Z-axis moving means MZ is corrected. C50f is a calculation timing instruction for a predetermined time interval output from the correction block C50 to the multiplier C40.

● [Processing procedure for determining the end of warm-up operation and obtaining the correction coefficient (Fig. 7)]
Next, with reference to the flowchart shown in FIG. 7, the procedure for determining the end of the warm-up operation and determining the correction coefficient for correcting the position of the tip TS accompanying the thermal displacement will be described. The control means 40 performs the processing shown in the flowchart of FIG. 7 to obtain the correction coefficient, and then performs control according to the control block diagram shown in the example of FIG. 6 to correct the cutting control amount of the Z-axis moving means MZ. While processing the workpiece W.

In step S10, tool change is performed. The tool change may be performed by the processing apparatus 1 or an operator.
In step S11, the control means 40 controls the rotation driving means to start the rotation of the main spindle 10 at the rotation speed used for machining, and proceeds to step S12.
In step S12, the sampling number (n) is set to the initial value (1), and the process proceeds to step S14.
In step S14, the position _An (in this case, A ₁ ) of the tip portion TS of the machining tool T is obtained based on the signal from the tool tip position measuring means 32, and the process proceeds to step S16.
In step S16, the displacement amount C _n (C _{1 in} this case) of the detection surface M of the spindle 10 is obtained based on the signal from the spindle displacement measuring means SH, and the process proceeds to step S18.
In step S18, the correction coefficient α ₁ (= A ₁ / C ₁ ) is obtained using the obtained position A ₁ of the tip TS and the displacement amount C ₁ of the detection surface M, and the process proceeds to step S20.

In step S20, the process waits until a preset sampling time (Ts) elapses. When the standby is completed, the process proceeds to step S22.
In step S22, the sampling number (n) is updated (n = n + 1), and the process proceeds to step S24.
In step S24, obtains a position A _n of the tip portion TS of the working tool T on the basis of a signal from the tool tip position measuring means 32, the process proceeds to step S26.
In step S26, the displacement amount C _n of the detection surface M of the spindle 10 is obtained based on the signal from the spindle displacement measuring means SH, and the process proceeds to step S28.
At step S28, obtains a correction coefficient _{α n (= A n / C} n) by using the displacement amount C _n positions A _n and the detection plane M of the calculated tip TS, the process proceeds to step S30.

In step S30, a change amount (Δα) of the correction coefficient is obtained from the difference between the correction coefficient α _n obtained this time and the correction coefficient α _n-1 obtained last time, and whether or not the obtained change amount is less than an allowable value. Determine. The allowable value is set as appropriate, and the absolute value of the difference between the correction coefficient α _n obtained this time and the correction coefficient α _n-1 obtained last time is changed (Δα = | α _n −α _n-1 |). It is good. When the amount of change is equal to or greater than the allowable value (No), it is determined that the warm-up operation period is in progress because the correction coefficient is not yet stable, and the process returns to step S20. When the amount of change is less than the allowable value (Yes), it is determined that the correction coefficient is stable and the warm-up operation period has ended, and the process proceeds to step S32.
In step S32, the value of the obtained correction coefficient α _n is set in the correction coefficient (H) used in the multiplier C40 in the control block diagram shown in FIG. 6, and the process proceeds to step S34.
In step S34, the measurement by the tool tip position measuring unit 32 is terminated, the tool tip position measuring unit 32 is accommodated in the tool tip detection unit 30, preparation for machining the workpiece W is performed, and the process proceeds to step S40.
In step S40, machining of the workpiece W is started while correcting the spindle thermal displacement (control according to the control block diagram of FIG. 6 is started).

In the above description, an example has been described in which it is determined that the warm-up operation period has ended when the amount of change in the correction coefficient is less than the allowable value, and machining is started, but the correction coefficient is used instead of the amount of change in the correction coefficient. May be used, or an allowable range of the correction coefficient is set in advance for each machining tool T, and it is determined that the warm-up operation period has ended when the correction coefficient falls within the allowable range. Processing may be started.
In any case, since it is possible to appropriately determine the end of the warm-up operation period, it is possible to prevent the warm-up operation time from becoming longer than necessary.
Further, the change amount or change rate allowable value of the correction coefficient, or the allowable range of the correction coefficient may be switched for each step of the roughing process, the fine processing process, and the finishing process, which are sequentially performed. In this case, by setting the allowable value (or allowable range) to gradually decrease as the grinding amount decreases from the roughing process to the finishing process, it is warm in the roughing process where the required machining accuracy is relatively low. The machine operation period can be shortened, and the machining efficiency can be further improved while ensuring the final workpiece machining accuracy.

The processing apparatus 1 of the present invention is not limited to the appearance, configuration, processing, and the like described in the present embodiment, and various modifications, additions, and deletions can be made without changing the gist of the present invention.
Further, the above (≧), the following (≦), the greater (>), the less (<), etc. may or may not include an equal sign.

It is a figure explaining one embodiment (schematic appearance figure (perspective view)) of processing device 1 of the present invention. It is a figure explaining one embodiment (schematic connection diagram (side view)) of processing device 1 of the present invention. It is a figure explaining the measuring method of the structure of the main axis | shaft 10, and the thermal displacement amount of the main axis | shaft 10. FIG. It is a figure explaining the direct measuring method of front-end | tip part TS of the processing tool T. FIG. 3 is a diagram for explaining the relationship between the position of a tip portion TS of a machining tool T and the amount of thermal displacement of a main shaft 10. FIG. 4 is a control block diagram for explaining a method of correcting a thermal displacement amount by a control means 40. FIG. It is a flowchart explaining the process sequence which calculates | requires completion | finish determination and a correction coefficient of warm-up operation.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Processing apparatus 2 Base 10 Spindle 12 Spindle housing 14 Column 15 Coil 16 Bearing 18 Arm 20 Table 30 Tool tip detection unit 32 Tool tip position measurement means 40 Control means MZ Z axis movement means EZ Encoder LA Laser light M Detection surface SH Spindle Displacement measuring means T Machining tool TS Tip W Work α _n , H Correction coefficient

Claims (4)

A spindle that is rotated by a rotation drive means;
A machining tool that is provided coaxially with the rotation axis of the main shaft and rotates and works a workpiece at the tip;
A cutting movement means capable of moving forward and backward relative to the tip of the processing tool along the rotational axis direction;
Tool tip position measuring means capable of directly detecting the tip position in the rotational axis direction of the machining tool at the time of non-machining;
Spindle displacement measuring means capable of detecting the amount of thermal displacement of the spindle in the direction of the rotation axis without interfering with the machining tool and a workpiece during machining;
Control means for controlling the rotation driving means and the cutting movement means,
In the processing device for correcting the control amount of the incision moving means during processing based on the signal from the spindle displacement amount measuring means in the control means,
The control means includes
Before starting machining, the spindle is rotated at a rotational speed used in machining by controlling the rotation driving means, and the tip position of the machining tool is obtained based on a signal from the tool tip position measuring means, and Obtaining a thermal displacement amount of the spindle based on a signal from the spindle displacement measuring means, obtaining a correction coefficient which is a ratio of the tip position to the obtained thermal displacement amount;
After starting processing, using the obtained correction coefficient and the signal from the spindle displacement measuring means, processing while correcting the control amount of the cutting movement means,
Processing equipment. The processing apparatus according to claim 1,
The control means includes
Before starting the processing, the correction coefficient is obtained at every predetermined timing, and when the change amount or change rate of the correction coefficient is less than the allowable value, it is determined that the warm-up operation is finished,
Start processing after determining the end of the warm-up operation,
Processing equipment. The processing apparatus according to claim 1,
The control means includes
Before starting machining, determine the correction coefficient at every predetermined timing, and determine that the warm-up operation has ended when the correction coefficient falls within an allowable range,
Start processing after determining the end of the warm-up operation,
Processing equipment. It is a processing apparatus of Claim 2 or 3, Comprising:
The control means includes
The permissible value of the change amount or rate of change of the correction coefficient, or the permissible range of the correction coefficient is switched in each step of the roughing process, the fine machining process, and the finishing process.
Processing equipment.

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