JPS5988242A - Method for compensating squareness errors in nc machine tool - Google Patents

Abstract

PURPOSE:To compensate for errors in squareness in an NC apparatus, by computing distance errors in the directions other than the reference direction and those in the reference direction and giving driving commands to respective servo mechanisms for the compensation based on the computed errors. CONSTITUTION:The CPU2 in an NC apparatus measures errors in squareness of the Y and Z axes, DELTAXy and DELTAXz, with the guideway in the X axis taken as the reference axis, and the measured errors are stored in the memory 3. Then, distance errors in the X direction of the driven distances in the Y and Z axes are computed from the driven distances in the Y and Z axis and the squareness errors. The distance errors with a minus sign attached, the command for driving the servo mechanism 4 in the X axis, the distance errors in the Y and X axes of the driven distances along the Y and Z axes computed from the earlier mentioned distance errors and the squareness errors, and the commands for driving the servo mechanisms 5, 6 along the Y or Z axes are input to the NC apparatus, whereby the NC apparatus issues commands for compensating the distance errors and the compensation for the errors in squareness can thus be achieved.

Description

DETAILED DESCRIPTION OF THE INVENTION (1) Technical Field of the Invention The present invention relates to a surface angle error correction method for NO (numerically controlled) machine tools. In particular, the 10 angle y made using the NO device
This relates to an I difference correction method.

(2) Technical Background No. Machine tool 1112 is a system that expresses a desired three-dimensional shape as a set of digital quantities using an appropriate coordinate system.
In order to realize this three-dimensional shape on the workpiece, for example, a servo mechanism such as a pulse motor is used to
A machine tool that performs machining by relatively displacing the workpiece and/or tools, etc.

However, since the servo mechanism including the above-mentioned pulse motor etc. is driven along some kind of mechanical guide, if the accuracy of this mechanical guide is poor, the desired iXj degree cannot be obtained during machining. Accuracy of this mechanical guide includes not only straightness accuracy in which the guideways are curved rather than straight, but also squareness accuracy in that the guideways do not intersect with each other at right angles. It goes without saying that the plane angle between the mutually orthogonal X-axis and YIIIllIXz-axis greatly depends on the machining of the machine tool parts, the assembly of the machine tool, and the installation of the machine tool, but it also includes the problems listed below. are doing.

B. There is naturally a certain level of precision in the machining accuracy of machine tool parts, adjustment during assembly of machining PA strips, etc.

In the above-mentioned work, a large number of man-hours are required to improve the accuracy of the squareness.

C. Even if the machining accuracy of the machine tool parts and the assembly accuracy of the machine tool are sufficient, the perpendicularity will deteriorate due to installation, leveling, etc. of the machine tool.

2. During machine tool operation, each part of the machine tool is heated unevenly, and the perpendicularity becomes poor due to thermal displacement.

E. Due to aging, the squareness deteriorates.

Among the above factors, those based on thermal displacement, installation, leveling, etc. have a particularly large influence on machining accuracy.

(B) Prior art and problems The above-mentioned problem of right angle f<i- has been known for some time, but since there was no effective correction method, it is necessary to assemble, adjust, and Installation, leveling, etc. were carried out with precision, but as mentioned above, there were naturally limits to that precision. Also, especially based on thermal displacement < 1lj-
There is no effective method for correcting the deterioration of the angle, and the prior art does not provide a machine tool with the ability to correct squareness errors due to thermal displacement.

However, as mentioned above, squareness is an important element that controls the machining accuracy of machine tools, so in order to improve the machining accuracy of machine tools, it is desirable to develop a method to correct the squareness error of machine tools. It's been a while since I've been in the middle of a long time.

(4) Purpose of the Invention The purpose of the present invention is to provide a method for correcting the 111 angle error of a NO machine tool.

(5) Structure of the Invention The present invention actively utilizes the fact that the No. 1 machine tool originally has an extremely precise servo mechanism.
The NO device has a servo mechanism that drives along guideways that are orthogonal to each other according to commands issued by the NO device.
In a machine tool, the above-mentioned right angle film difference correction is performed using an NO servo mechanism, and the present application includes two independent inventions.

First, the first invention is x −s y %Z i1M+
One axis, one guideway (hereinafter referred to as
- As an example, let the X axis be the reference axis. ) as the reference axis, the other two axes, that is, the other two guideways (Y%2 axis)
Measure the squareness error between and the X axis. In this case, it is assumed that the straightness of each guideway is sufficiently satisfactory, and Y
Let it be expressed by the amount of deviation of axis NZ#I in the X-axis direction with respect to each unit range. In Figs. 1(a) and (b), the x, The axis is an orthogonal 1'H mark 1111+, which is assumed to have no surface angle error.

Therefore, the surface angle error is the deviation in the X-axis direction corresponding to the distance #a (y, or phrase) from the X-axis or zIIqII. With ΔXy or ΔX, or ΔXy/Y
It is expressed as l or ΔXZ/Zl. Next, when the Y-axis or two-axis servo mechanism of the No. 1 machine tool operates, the distance jump 11 (Y2 or Distance 1il indicated by Zl
ll:) and the right angle film difference ΔXa or ΔXz or Δ”
Distance difference in the X-axis direction (lIJΔXy-Y2 or approximately ΔX2・z2 or approximately Y2・ΔXy/Yt
or approximately 22·Δx2/z,) with a negative sign, a command to drive the servo mechanism along the X-axis, and the above distance A1. i difference (approximately ΔXy-Y2 or approximately ΔX2・
z2 or approximately Y2・ΔXy/Yl or z2・ΔXz
/Z+) and surface angle error (Δx2 or ΔXy/Y, or ΔXz/Zl), the distance error in the Y-axis or X-axis direction (approximately ΔXy
2 or about ΔX2' or about ΔXy"/Y+ or about ΔXz"/Zl) along the Y-axis or the Z-axis. ! /The command to drive the No device i′￥
input to this NO device 1″1 to output the above two hq: +ia error correction commands as correction commands along with the command (Y2 or Zz) as an external command, and adjust the X-axis according to the sum of these commands. This operates the servo mechanism for the Y-axis and two axes.

As mentioned above, it is not always easy to measure the surface angle error of j, but based on the first fact that the difference in right angle machining is reflected on the processed product, the dimensional error of the processed product is determined as 11i1i, and the horizontal angle error is calculated. It is possible to estimate and is a convenient method in practice.

Next, the second invention is the above-mentioned N having at least one temperature measuring element at one appropriate location of the machine tool.

For machine tools, after installation of the machine tool is completed,
The relationship between the perpendicular coating difference between the M guideway and the YSZ-axis guideway and temperature was measured, and N.

When the Y-axis or two-axis servo mechanism of a machine tool operates, the ability to be driven along the Y-axis or Z-axis (first
In Figures (a) and (b), Y2 or z2 is shown as the Motte distance μm.
distance error in the X-axis direction (approximately ΔXy 'Y2 or ΔX2・z2
or about y2-ΔXy/Yl or about z2-Δ
The servo mechanism is built along the mx axis with a negative sign for x2/z, )! 171.1 and the above W detuning difference (
Approximately ΔXa・Y2 or approximately ΔX2・z2 or approximately Y2・
ΔXy / Yl or approximately z2・ΔXz / Z
+) and the detected temperature (with a distance error in the Y-axis or X-axis direction (approximately Δ
xy2 or about ΔXz2 or about Δxy2/y2
Or approximately ΔXz"/Zl) A command to drive the servo mechanism along the Y-axis or Z-axis is input to the No device, and the above command as a correction command is sent to this No device along with the command (Y2 or 22) as an external command. The two distance error correction commands are output, and the servo mechanisms for the two axes, the X-axis and the Y-axis, are operated according to the sum of these commands.

(6) The fruit of invention 1! Examples Hereinafter, actual examples of each of the two inventions of the present application will be further explained with reference to the drawings.

Invention of Bo 1 Using the X-axis guideway as a reference axis, the right angle coating difference between the Y and Z-axis guideways is measured. In this case, the 11th yen + (
As shown in a) and (b), the deviation amount ΔXy or Δx2 on X'il+(b) corresponding to the degree distance (Y+ or Zt) of YXZIIilIl represents the surface angle error.This right angle coating difference ΔXy % ΔXz is no-dressing h'
Write it down in It's memory. Figure 2 shows the first embodiment of the present invention.
It is a block diagram of the No system used for blood. In the figure, l is an input device, which inputs to the process unit 2 a command representing a desired three-dimensional shape as a set of digital AI7 using an appropriate coordinate system. Process unit 2
Based on the command input through the input device 1, extracts the necessary 'rH information from the memory 3, executes calculations etc. based on the command, and outputs the results as X and Y.

The output is output to the z-axis pulse motor 4.5.6 to drive the desired distance in each axis direction.

When the Y-axis or 2-axis servo mechanism operates, the input device jF
Based on the moving distance Y2 or z2 included in the command given by Jl and the surface angle error ΔXy or Δx2 stored in the memory 3, the movement command in the Y-axis or two-axis direction is calculated. A distance error occurring in the X-axis direction during execution is calculated in the process unit 2. This value is approximately ΔXy−Y2 or ΔX2・z2
It is clear that To correct this error,
It is a good idea to give this error value a negative sign and input it to the X-axis direction servo mechanism.

Furthermore, it can be seen from Figure 3 that the operation of the Y-axis or two-axis servo mechanism generates errors in the Y-axis or Z-axis direction, in addition to the error in the y-axis (reference axis) direction described above. it is obvious. That is, according to the command, it should move to point A (along the hypothetical coordinate axis y-axis) in a direction perpendicular to the reference axis (y-axis), but in reality, it moves perpendicular to the reference axis J! Since it is supposed to be moving to point B along the Y axis along the guideway with L error, in addition to the error (ΔXa・Yz,) in the y axis (reference axis) direction mentioned above, An error should have occurred in the y-axis direction by a distance indicated by 0. This error always occurs in the negative direction, and its widest value, that is, the distance, is . In order to correct this error, it is sufficient to drive the servo mechanism in the Y-axis direction by this amount. More precisely, additional movement should be made in the y-axis direction, but there is no means for driving in this direction, and even if correction is made in the y-axis direction, generally satisfactory results can be obtained.

Correction of the error in the y-axis direction due to the operation of the two-axis servo mechanism may be performed in the same manner as described above.

Therefore, when this calculation means is stored in the memory 3 and the servo mechanism in the Y-axis or Z-axis direction is operated, this correction command is also sent to the X%Y% Z-axis pulse motor 4.5. .6 should be output.

Second Invention As mentioned above, it is inevitable that the machine tool is heated unevenly and causes thermal changes as the machine tool operates, so the surface of the guideway in each coordinate direction of the machine tool is avoided. At least one temperature measuring element is provided at a convenient position for detecting the angle error, and the relationship between the temperature at the position where the temperature measuring element is provided and the surface angle error is measured and stored in the memory 3 described above.
During processing, the detection value of the temperature measuring element described above is input to the process unit 2 one after another, and the surface angle error at that time is calculated based on this value, as in the case of the first invention. Similarly, by operating the pulse motors 4.5.6 for the X, Y, and Z axes, it is possible to correct the ia angle error based on nonuniform heating that occurs during operation of the machine tool.

(C) As described in detail, the present invention can provide a method for correcting the squareness difference of NO machine tools.

[Brief explanation of the drawing]

1(a) and 1(b) are auxiliary diagrams for explaining the present invention in detail, and FIG. 2 is an auxiliary diagram for explaining the present invention in detail.
This is a block diagram of the O system, and FIG. 3 is an auxiliary diagram for explaining the present invention in detail. 1... Input device, 2... Process unit, 3... Memo 1'', 4.
5.6...X% YN 7 points in the z-axis direction. Patent applicant Makoto Samukawa, agent for FANUC Co., Ltd., patent attorney - Figure 2 Figure 3

Claims (3)

[Claims] (1) In the squareness correction method of a No. machine tool that has a servo mechanism that drives along mutually orthogonal guideways according to commands issued by the No. device, one of the guideways is used as the reference axis. , the surface angle error of another guideway with respect to the reference axis is measured, and when driving the servo mechanism for the second guideway, the driven distance and the squareness t! a distance given a negative sign to the distance error in the direction of the reference axis calculated based on the difference; a command to drive the servo mechanism along the reference axis; and the distance l! 1. The distance in one direction of the other guideway calculated based on the error and the surface angle error! ! lIF error A command to drive the servo mechanism along the other guideway is input to the No device, and based on the command issued by the No device, the servo mechanism in the reference axis direction and the servo mechanism in one direction of the other guideway are input. This is a surface angle error correction method for No. 1 machine tool, which is achieved by driving a servo mechanism. (2) The surface angle error is measured by measuring the dimensional error of the broken body machined using the No. machine tool,
A surface angle error correction method for an NG machine tool according to claim 1. (3) In a surface angle error correction method for a No. machine tool, which has a servo mechanism that drives along mutually orthogonal guideways according to commands issued by No. device a, and has at least one temperature measuring element. , ifi After the installation of the machine tool is completed, the relationship between the surface angle error and temperature of the l guideway selected as the reference axis and the other guideways is measured, and the servo mechanism for the new guideway is measured. When driving, a negative sign is given to the distance error in the reference axis direction, which is calculated based on the temperature detected by the temperature measurement element and the relationship between the surface angle error and temperature. distance, a command to drive the servo mechanism along the reference axis, a distance error in one direction of the other guideway calculated based on the Dtf distance error and the surface angle error at the detected temperature; a command to drive the servo mechanism along the
A right angle coating of a No. machine tool, characterized in that the servo mechanism in the reference axis direction and the servo mechanism in the other axis direction are driven based on the command issued by the NO device +11. Difference correction method.