JP3851046B2 - Straightness correction method for measuring machine and measuring machine - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a straightness correction method for a measuring machine and a measuring machine . For example, the present invention relates to a straightness correction method for a measuring machine and a measuring machine that correct the straightness accuracy of the linear motion mechanism in a measuring device having a linear motion mechanism, such as a roundness measuring device and a roughness measuring device.
[0002]
[Background]
For example, when a workpiece is measured in a measuring machine equipped with a linear motion mechanism as a guide (reference), such as a roundness measuring machine or a roughness measuring machine, the measurement data is the workpiece shape data and the linear motion mechanism machine. Therefore, in order to extract the true workpiece shape, it is necessary to separate and remove the straight accuracy of the linear motion mechanism from the measurement data.
[0003]
Conventionally, Japanese Patent No. 2935603 “Roundness measuring device with straightness measuring function” has been proposed as a method of separating and removing the straightness accuracy of the linear motion mechanism from the measurement data.
This includes a turntable on which a straightness check gauge is mounted, a detector that detects the surface position of one side of the straightness check gauge, and a column that holds the detector movably along the surface of the straightness check gauge. And a first storage means for storing data obtained from the detector as first data, and a straightness check gauge rotated by 180 ° around the rotation axis of the turntable, and the straightness by the detector Second storage means for storing data obtained by detecting the surface position of the same surface as the one side surface of the check gauge as second data, and based on the first data and the second data, And an arithmetic means for calculating a straightness error correction amount.
[0004]
[Problems to be solved by the invention]
The above-mentioned Japanese Patent No. 2935603 “Roundness Measuring Device with Straightness Measurement Function” employs a so-called reversal method, the first measurement (first measurement) and the turntable at 180 °. The second measurement that rotates and measures is necessary, and the measurement trajectory must be exactly the same on the target workpiece surface, and thus has the following problems.
In other words, the setting of the workpiece in the measurement is very difficult and requires skill, and requires a considerable number of man-hours, such as the need to reverse the position of the detector when performing two measurements. In addition, the detector guides are not necessarily the same (for example, in the case of a roundness measuring machine, the amount of the arm holding the detector is not necessarily the same), and there is an overall error. There is a problem that it is easy to generate.
[0005]
An object of the present invention is to provide a straightness correction method for a measuring instrument and a measuring instrument that can eliminate the above-described drawbacks of the inversion method and obtain highly reliable measurement data without improving existing devices. It is in.
[0006]
[Means for Solving the Problems]
Therefore, the straightness correction method of the measuring machine of the present invention employs the following configuration in order to achieve the above object.
The straightness accuracy correction method related to the present invention is a straightness accuracy correction method for a measuring machine having a linear motion mechanism, and the shape data is highly accurate in advance while moving the detector using the linear motion mechanism of the measurement machine. A straight accuracy data calculation step of measuring a master workpiece measured and priced by a measuring device, subtracting the priced shape data from the master workpiece measurement data to obtain straight accuracy data of a linear motion mechanism, and the measuring machine The workpiece measurement data calculation step for measuring the workpiece while obtaining the workpiece measurement data while moving the detector using the linear movement mechanism, and subtracting the straightness accuracy data from the workpiece measurement data to obtain the true value data of the workpiece. A workpiece shape calculation step to be obtained.
[0007]
According to this configuration, in the straightness accuracy data calculation step, the master work to which the shape data is preliminarily measured is measured while moving the detector using the linear motion mechanism of the measuring machine, and the value is calculated from the master work measurement data. The straightness accuracy data of the linear motion mechanism is obtained by subtracting the attached shape data. In the workpiece measurement data calculation step, the workpiece is measured while moving the detector using the linear motion mechanism of the measuring machine, and the workpiece measurement data is obtained. In the workpiece shape calculation step, the true value data of the workpiece is obtained by subtracting the straightness accuracy data from the workpiece measurement data.
Accordingly, in the straight accuracy data calculation step, since only one measurement is required, the disadvantage of the inversion method, that is, the disadvantage of requiring skill and man-hours can be solved. In addition, since the same problem with the detector guide is eliminated, a more accurate correction result can be obtained. In addition, since it is a technique for processing workpiece measurement data, highly reliable measurement data can be obtained without any special work on the measuring machine. Furthermore, straightness data calculation and straightness data correction processing for workpiece measurement data can be performed by an application independent of the measuring machine. For example, master workpiece measurement data averaging processing (same position Data processing such as processing to obtain the average value from multiple masterwork measurement data obtained by repeated measurement under the same measurement conditions) reduces variation in measurement data due to electrical noise and measurement environment, and more Highly accurate correction can be realized.
[0008]
The straightness accuracy correction method related to the present invention is a straightness accuracy correction method for a measuring machine having a linear motion mechanism, and the shape data is highly accurate in advance while moving the detector using the linear motion mechanism of the measurement machine. A straight accuracy data calculation step of measuring a master workpiece measured and priced by a measuring device and subtracting the priced shape data from the master workpiece measurement data to obtain straight accuracy data of the linear motion mechanism, and this straight accuracy Straight accuracy data storage process that stores the straight accuracy data obtained in the data calculation process, and workpiece measurement by measuring the workpiece while moving the detector using the linear motion mechanism of the measuring machine and obtaining the workpiece measurement data A data calculation step, a workpiece measurement data storage step for storing the workpiece measurement data captured in the workpiece measurement data calculation step, and the respective storage Extent by reading the workpiece measurement data and straightness accuracy data stored, characterized in that it comprises a workpiece shape operation step of subtracting the straightness accuracy data from the work measurement data obtaining the true value data of the workpiece.
[0009]
According to this configuration, since a straight accuracy data storing step for storing straight accuracy data and a workpiece measurement data storing step for storing workpiece measurement data are added to the above-described invention , these straight accuracy data are added. It is also possible to obtain and store workpiece measurement data at different points in time, and to obtain true value data of the workpiece by subtracting straightness accuracy data from the workpiece measurement data at any time (when necessary).
[0010]
The straightness accuracy correction method related to the present invention is the straightness accuracy correction method of the measuring machine described above , and in the straightness accuracy data calculation step, a pedestal having a work placement surface and a part of the pedestal or master work are exposed. Using a measuring jig equipped with a reference sphere for origin setting embedded in the state, a prismatic master work is placed on the work placement surface of the pedestal, and in this state, measurement is performed at the apex of the reference sphere After setting the measurement origin by positioning the detector of the machine, the master work is measured while moving the detector along one side of the master work by a linear motion mechanism.
[0011]
According to this configuration, the measurement of the master work is performed using a measurement jig having a base and a reference sphere for setting the origin, and the detector of the measuring machine is attached to the reference sphere for setting the origin. After positioning and setting the measurement origin, measurement of the master work was performed while moving the detector along the measurement surface of the master work using the linear motion mechanism. Since it can be accurately moved to the designated measurement location, the master workpiece can be measured with high accuracy.
[0012]
The straightness correction method related to the present invention is the straightness correction method of the measuring machine described above , wherein the pedestal is formed in a semi-cylindrical shape having a reference vertical surface orthogonal to the workpiece mounting surface, and the reference vertical surface The reference sphere is embedded in a partially exposed state.
According to this configuration, when correcting the straightness accuracy of the roundness measuring machine (straightness accuracy of the column or slider for moving the detector up and down), the pedestal is placed at the center of the rotary table of the roundness measuring machine. Set the pedestal on the rotary table so that the reference vertical plane is located, and then place the master work on the work placement surface of the pedestal so that one side of the master work matches the reference vertical plane of the pedestal. After placement, the detector probe is first brought into contact with the reference sphere, and the position of the detector is adjusted so that the probe captures the apex of the reference sphere both vertically and front and rear. After setting this state as the measurement origin, bring the probe of the detector into contact with a point on the surface of the master work that is a fixed distance away from the measurement origin, and move the detector upward (or downward) from this position. The vertical straightness of the entire length of the master work can be measured.
Therefore, the master work can be positioned on the rotary table using a measuring jig, and the measuring point in the height direction can be set by bringing the measuring point of the detector into contact with the reference sphere. Can be positioned at a fixed position of the master work, and the locus from the fixed position of the master work can be measured.
The straightness correction method according to claim 1 is a straightness correction method for a measuring machine having a linear motion mechanism, and the shape data is increased in advance while moving the detector using the linear motion mechanism of the measurement machine. A first straight accuracy data calculation step of measuring a master workpiece measured and priced by an accuracy measuring device, and subtracting the priced shape data from the master workpiece measurement data to obtain straight accuracy data of the linear motion mechanism; Using the linear motion mechanism of the measuring machine, a semi-master work measurement step for measuring a semi-master work that does not require pricing of shape data in advance, and the first straight accuracy measurement data from the measurement values measured by the semi-master work. A true value data storing step for storing the true value data obtained by subtraction, and after the lapse of a certain period, the semi-master work is measured again, and the true data is calculated from the measured data. A second straight accuracy data calculating step for subtracting data to obtain new straight accuracy data; a second straight accuracy data storing step for storing the second straight accuracy data calculated in the second straight accuracy data calculating step; Measure the workpiece while moving the detector using the linear motion mechanism of the measuring machine, save the workpiece measurement data obtained in the workpiece measurement data calculation step, and the workpiece measurement data calculation step to obtain the workpiece measurement data A workpiece shape calculation process for reading workpiece measurement data and the workpiece measurement data and second straightness accuracy data saved in each of the saving steps, and subtracting the second straightness accuracy data from the workpiece measurement data to obtain workpiece true value data And a process.
According to a second aspect of the present invention, the linear motion mechanism is corrected by the straightness accuracy correction method for the measuring machine according to the first aspect.
[0013]
DETAILED DESCRIPTION OF THE INVENTION
Hereinafter, an embodiment of the present invention will be described with reference to the drawings.
The present embodiment is an example applied to a straightness correction method for a roundness measuring machine.
FIG. 1 shows a roundness measuring machine 1 according to this embodiment. The roundness measuring machine 1 includes a base 2, a turntable 3 arranged to be rotatable around an axis (Z axis) perpendicular to the upper surface side (left side) of the base 2, and the base 2. A column 4 disposed parallel to the Z-axis toward the other side (right side) of the upper surface, a slider 5 provided so as to be movable up and down along the column 4 (Z-axis direction), and the column on the slider 5 An arm 6 provided so as to be able to advance and retreat in a direction perpendicular to X 4 (X-axis direction), and a detector 7 attached to the tip of this arm 6 so as to be position-adjustable in the Y-axis direction and having a probe 7A at the tip. It is composed of
[0014]
The rotation angle data of the rotary table 3, the height position of the slider 5 (position data in the Z-axis direction), the advance / retreat amount of the arm 6 (position data in the X-axis direction), the adjustment amount of the detector 7 (in the Y-axis direction) Position data) can be detected by a detection means (not shown).
Further, the column 4 and the slider 5 constitute a linear motion mechanism (guide) that raises and lowers the detector 7 in the vertical direction (Z-axis direction).
[0015]
FIG. 2 shows a data processing device 21 that takes in and processes measurement data from the roundness measuring machine 1. The data processing device 21 includes a control device 22, a storage device 23, and a display device 24.
The control device 22 has a function of executing each process (process) shown in FIGS. 3 to 5 in accordance with a processing program stored in advance. In other words, when a roundness measuring machine 1 measures a master work to which shape data has been priced in advance, the master work measurement data is taken in, and the priced shape data is subtracted from the master work measurement data. Straightness accuracy data calculation step for obtaining straightness accuracy data of the linear motion mechanism, straightness accuracy data storage step (see FIG. 3) for saving the straightness accuracy data obtained in this straightness accuracy data calculation step, and roundness measuring machine 1 , A workpiece measurement data calculation step for fetching the workpiece measurement data when the workpiece is measured, a workpiece measurement data storage step (see FIG. 4) for saving the workpiece measurement data fetched in the workpiece measurement data calculation step, The stored workpiece measurement data and straightness accuracy data are read and straightness accuracy data is read from the workpiece measurement data. By subtracting the data comprises a function of executing the workpiece shape calculation step (see FIG. 5) to determine the true value data of the workpiece.
[0016]
Next, the measurement method of this embodiment will be described.
(Straight accuracy data calculation process and straight accuracy data storage process)
The roundness measuring machine 1 is used to measure a prismatic master work MW (for example, an optical flat) to which shape data has been previously priced, and subtract the price data from the master work measurement data. After obtaining the straight accuracy data of the linear motion mechanism, the straight accuracy data is stored.
Specifically, as shown in FIG. 3, in step (ST) 1, first, the master work MW is measured. After the master work MW is vertically placed on the rotary table 3, the probe 7A of the detector 7 is brought into contact with one side surface (measurement surface) of the master work MW, and in this state, the slider 5 is moved upward. (See FIG. 6). Then, since the measuring element 7A of the detector 7 is displaced according to the shape of the master work MW and the straightness of the linear motion mechanism, the displacement amount is sent to the control device 22 of the data processing device 21 together with the position data in each axial direction. The control device 22 determines the position of the master work MW from the Z-axis direction position of the slider 5, the advance / retreat amount of the arm 6 (X-axis direction position), the adjustment amount of the detector 7 (Y-axis direction position), and the displacement amount of the measuring element 7A. The position of the measurement surface is calculated, and the master work measurement data is written in the storage device 23.
[0017]
Next, in ST2, straightness accuracy data is obtained by subtracting the shape data previously priced from the master work measurement data. At this time, the shape data of the master work MW is measured by another high-precision measuring device and stored in the storage device 23 in advance. Therefore, the master work measurement data and the shape data priced for the master work MW are read from the storage device 23, and the straightness data is obtained by subtracting the shape data from the master work measurement data.
Next, in ST3, the obtained straight accuracy data is stored in the storage device 23.
[0018]
(Work measurement data calculation process and work measurement data storage process)
After measuring the workpiece W using the roundness measuring device 1 and obtaining the workpiece measurement data, the workpiece measurement data is stored.
Specifically, as shown in FIG. 4, in ST11, the workpiece W is first measured. After the workpiece W is placed vertically on the rotary table 3, the measuring element 7A of the detector 7 is brought into contact with the measurement surface of the workpiece W to perform measurement (see FIG. 7). In this case, measurements such as roundness and cylindricity are performed.
Next, in ST12, workpiece measurement data is stored. That is, since the workpiece measurement data measured in ST11 is sent to the data processing device 21, the workpiece measurement data is stored in the storage device 23.
[0019]
(Work shape calculation process)
The workpiece measurement data and straightness accuracy data stored in each storage step are read, and the workpiece accuracy data is subtracted from the workpiece measurement data to obtain workpiece true value data.
Specifically, as shown in FIG. 5, workpiece measurement data is read from the storage device 23 in ST21.
Next, in ST22, straight accuracy data is read from the storage device 23.
Next, in ST23, the accuracy data of the workpiece is obtained by subtracting the straightness accuracy data from the read workpiece measurement data.
Next, in ST24, the obtained true value data of the work is stored in the storage device 23. That is, the storage device 23 stores the true value data of the workpiece in which the straightness accuracy of the linear motion mechanism is corrected with respect to the workpiece measurement data, so that highly reliable measurement data can be obtained.
[0020]
According to the embodiment described above, in the straightness accuracy data calculation step, the roundness measuring machine 1 is used to measure the master work MW to which the shape data is priced in advance, and the master work measurement data is priced. Separately, the straightness accuracy data of the linear motion mechanism of the roundness measuring machine is obtained by subtracting the measured shape data. Separately from this, in the workpiece measurement data calculation process, the roundness measuring machine 1 is used to measure the workpiece W, The workpiece measurement data is obtained, and after these steps, in the workpiece shape calculation step, the accuracy data of the workpiece is obtained by subtracting the straightness accuracy data from the workpiece measurement data.
[0021]
Therefore, in the straightness accuracy data calculation step, only one measurement is required, so that the disadvantage of the inversion method can be solved. In addition, since the same problem with the detector guide is eliminated, a more accurate correction result can be obtained. In addition, since it is a technique for processing workpiece measurement data, highly reliable measurement data can be obtained without any special work on the measuring machine. Furthermore, straightness data calculation and straightness data correction processing for workpiece measurement data can be performed by an application independent of the measuring machine. For example, master workpiece measurement data averaging processing (same position Data processing such as processing to obtain the average value from multiple masterwork measurement data obtained by repeated measurement under the same measurement conditions) reduces variation in measurement data due to electrical noise and measurement environment, and more Highly accurate correction can be realized.
[0022]
Furthermore, since the straight accuracy data and the workpiece measurement data are separately stored in the storage device 23, the straight accuracy data and the workpiece measurement data are acquired and stored at different points in time, and the workpiece measurement is performed when necessary. The true value data of the workpiece can be obtained by subtracting the straight accuracy data from the data.
[0023]
In the above embodiment, the measurement is performed by placing the master work MW or the work W directly on the turntable 3, but for example, as shown in FIG. The master work MW may be placed via the tool 11.
The measurement jig 11 has a pedestal 12. The pedestal 12 has a semi-cylindrical shape in which a short cylinder is cut in half from the center, a work placement surface 13 is formed on the upper surface, and a reference sphere 15 is embedded in half at the center position of the cut reference vertical surface 14. It is. The master work MW is fixed to the work placement surface 13 by close contact (ringing).
[0024]
In measuring the master work MW, after placing the master work MW on the work placing surface 13 of the pedestal 12 so that one side surface (measurement surface) of the master work MW coincides with the reference vertical surface 14, first, The probe 7A of the detector 7 is brought into contact with the reference sphere 15, and the position of the detector 7 is adjusted so that the probe 7A can catch the apex of the reference sphere 15 both vertically and front and rear. After this, the height counter (position detector in the Z-axis direction) is set to “0” (origin setting), and then the probe 7A of the detector 7 is placed on the surface of the master work MW away from the measurement origin by a certain amount. This is brought into contact with one point (for example, the lowermost position), and the detector 7 is moved upward from this position to measure the vertical straightness accuracy of the entire length of the master work MW.
[0025]
If the straightness of the master work MW is measured using such a measuring jig 11, the trajectory from the determined position of the master work MW can be measured. That is, the master work MW can be positioned on the rotary table 3 using the measurement jig 11 and the origin of the height direction can be set by bringing the probe 7A of the detector 7 into contact with the reference sphere 15. Since the probe 7A of the detector 7 can always be positioned at the fixed position of the master work MW, the trajectory from the determined position of the master work MW can be measured.
[0026]
Further, when this measuring jig 11 is used, it is possible to easily perform the verification of the straightness accuracy data obtained in the straightness accuracy data calculation step by the inversion method.
For example, in the state shown in FIG. 9A (the same state as FIG. 8), one side of the master work MW is measured and the measurement data is stored.
Next, as shown in FIG. 9B, after rotating the rotary table 3 by 180 degrees, the measurement origin is set and measured in the same manner as described above, and the measurement data is stored. Even if the turntable 3 is rotated 180 degrees, one side surface of the master work MW is located on the central axis of the turntable 3, so that one side face of the master work MW can be turned on without requiring skill or manpower. 3 on the central axis. In this case, the orientation of the probe 7A of the detector 7 is set inward.
Finally, the first measurement data measured first and the second measurement data measured next are calculated to separately determine the straightness of the master work MW and the straightness of the linear motion mechanism.
[0027]
In the above-described embodiment, either the straightness accuracy data calculation step or the workpiece measurement data calculation step may be performed first. For example, the workpiece W is measured first and workpiece measurement data is obtained and stored, then the master workpiece MW is measured to obtain straight accuracy data, and the workpiece measurement data is corrected with the straight accuracy data at any time. You may do it.
In addition, the correction result (workpiece true value data) obtained by correcting the straightness accuracy data with respect to the workpiece measurement data is not limited to being stored as a separate file from the workpiece measurement data. The correction result (workpiece true value data) obtained by correcting the above may be replaced and stored as work measurement data.
[0028]
Further, in the measurement jig 11 described above, the reference sphere 15 for setting the origin is embedded in the reference vertical surface 14 of the pedestal 12. However, the present invention is not limited to this, and it is the same if the reference sphere is embedded in the master work MW. Can be expected.
Moreover, although embodiment mentioned above demonstrated the roundness measuring machine, this invention is applicable not only to this but general measuring machines which have a linear motion mechanism, such as a roughness measuring machine.
[0029]
Furthermore, the present invention can also be applied to the correction of the aging of the straightness accuracy of the measuring machine as follows.
In general, since a straight accuracy standard (master work) that can be used as a master work is expensive, it is difficult for general users to prepare for calibration of a measuring machine. In particular, a large straightness accuracy standard (in this embodiment, an optical flat) that can be used for straightness correction of a measuring instrument with a long stroke is extremely expensive.
[0030]
Therefore, straight accuracy data (this is defined as straight accuracy data 1) is created by the master work shown in the present embodiment only for the first time. Unnecessary: Semi-master work) is prepared and measured to obtain workpiece measurement data (this is called workpiece measurement data 1), and straight accuracy data 1 is subtracted from this to determine the trueness of this straightness standard (semi-master work). Value data is obtained and stored in the storage device 23. In other words,
(Work measurement data 1)-(straightness accuracy data 1) = true value data is obtained and stored in the storage device 23.
Next, after elapse of a certain period (usually about one year), the straightness standard (semi-master work) is measured again, and the true value data is subtracted from the work measurement data (this is called work measurement data 2). New straight accuracy data (this is defined as straight accuracy data 2) is obtained. In other words,
(Work measurement data 2)-(True value data) = Straightness accuracy data 2
Ask for.
The straightness accuracy data 2 obtained in this way is stored in the storage device 23 and used as straightness accuracy data until the next calibration time.
[0031]
According to such a method, the master work can be measured only once at the first time using the high-precision straightness standard, and then the high-precision straightness data is obtained by the inexpensive straightness standard (semi-masterwork). Since it can be obtained at any time, periodic straightness calibration of the measuring machine can be performed at low cost.
[0032]
【The invention's effect】
According to the straightness correction method for a measuring instrument of the present invention, the disadvantages of the inversion method can be eliminated, and highly reliable measurement data can be obtained without improving existing devices.
[Brief description of the drawings]
FIG. 1 is a perspective view of a roundness measuring machine showing an embodiment of the present invention.
FIG. 2 is a block diagram showing a data processing apparatus according to the embodiment.
FIG. 3 is a flowchart showing a straightness accuracy data calculation step and a straightness accuracy data storage step in the embodiment;
FIG. 4 is a flowchart showing a workpiece measurement data calculation step and a workpiece measurement data storage step in the embodiment.
FIG. 5 is a flowchart showing a workpiece shape calculation step in the embodiment.
FIG. 6 is a diagram showing a relationship between a master work and a measuring element of a detector in a straightness accuracy data calculation step.
FIG. 7 is a diagram showing a relationship between a master work and a detector probe in the work measurement data calculation step.
FIG. 8 is a perspective view showing a state in which measurement is performed using a measurement jig in a straightness accuracy data calculation step.
FIG. 9 is a diagram showing a procedure for verifying straightness accuracy data using the measuring jig of FIG. 8;
[Explanation of symbols]
1 Roundness measuring machine 4 Column (elements constituting linear motion mechanism)
5 Slider (element that constitutes linear motion mechanism)
7 Detector 11 Measuring jig 12 Pedestal 13 Workpiece mounting surface 14 Reference vertical surface 15 Reference sphere MW Master work W Workpiece

Claims (2)

A straightness correction method for a measuring machine having a linear motion mechanism,
While moving the detector using the linear motion mechanism of the measuring machine, measure a master work in which shape data is measured and priced in advance by a high-precision measuring device, and the priced shape is measured from the master work measurement data. A first straight accuracy data calculation step for subtracting the data to obtain straight accuracy data of the linear motion mechanism;
A quasi-master work measuring step for measuring a quasi-master work that does not require pricing of shape data in advance using the linear motion mechanism of the measuring machine,
A true value data storing step for storing true value data obtained by subtracting the first straight accuracy measurement data from the measured value measured by the quasi-master work;
A second straight accuracy data calculating step of measuring the semi-master work again after a certain period of time and subtracting the true value data from the measured data to obtain new straight accuracy data;
A second straight accuracy data storage step for storing the second straight accuracy data calculated in the second straight accuracy data calculation step;
While measuring the workpiece using the linear motion mechanism of the measuring machine, the workpiece is measured, and workpiece measurement data calculating step for obtaining the workpiece measurement data,
A workpiece measurement data storage step for storing workpiece measurement data obtained in the workpiece measurement data calculation step;
A workpiece shape calculation step of reading the workpiece measurement data and the second straightness accuracy data saved in each of the saving steps, and subtracting the second straightness accuracy data from the workpiece measurement data to obtain true value data of the workpiece. Straightness correction method for measuring machines.   A measuring machine, wherein the linear motion mechanism is corrected by the straightness accuracy correcting method of the measuring machine according to claim 1.

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