Verification Regulation of Reading Microscope and Measuring Microscope
Some standard content:
National Metrology Verification Regulation of the People's Republic of China JJG571-—2004
Reading Microscope and Measuring Microscope2004-09-21 Issued
Implementation on 2005-03-21
Issued by the General Administration of Quality Supervision, Inspection and Quarantine JJG571—2004
Verification Regulation of Reading Microscope and Measuring Microscope JJG571—2004
Replaces JJG904——1996
Replaces JJG571-1988
This regulation was approved by the General Administration of Quality Supervision, Inspection and Quarantine on September 21, 2004, and came into effect on March 21, 2005.
Responsible unit: National Technical Committee for Metrology of Geometric Engineering Parameters Main drafting unit: Henan Metrology and Testing Institute, China National Institute of Metrology
Participating drafting unit: The 34th Institute of China Aviation Industry Group I This regulation entrusts the National Technical Committee for Metrology of Geometric Engineering Parameters to be responsible for interpreting this regulation Main drafters:
Zhu Xiaoping
Zhang Weidong
Participating drafters:
Zhao Xinli
Wang Weichen
JJG571-—2004
(China National Institute of Metrology)
(Henan Metrology and Testing Institute)
(China National Institute of Metrology)
(The 304th Institute of China Aviation Industry Group I) (China National Institute of Metrology)
References|| tt||4 Metrological performance requirements
JJG571—2004
Displacement of the circular worktable caused by radial force4.1
Parallelism of the glass tabletop and the moving directions of the longitudinal and transverse slidesStraightness of the longitudinal and transverse slides
Mutual perpendicularity of the longitudinal and transverse slides4.5
Perpendicularity of the glass tabletop in the direction of microscope lifting and loweringIndication error of the circular worktable
Indication error of the microscope
Return error
General technical requirements·
Interaction of various parts·
5.3 Relative position of each scale line of the microscope
Displacement of the image caused by rotation of the prism seat
Coincidence of the center of the spiral graticule and the center of rotation5.5
6 Control of metrological instruments
6.1 Verification conditions.
6.2 Verification items
6.3 Verification methods
6.4 Processing of verification results
6.5 Verification period
Appendix A
Uncertainty analysis of verification results of indication error of reading microscope Appendix B
Uncertainty analysis of verification results of indication error of measuring microscope Appendix C Sample
Verification device for verifying the coincidence of the center of spiral division and its rotation center Appendix D
Verification certificate and verification Format of the inner pages of the result notification (1)
（3）
1 Scope
JJG571—2004
Calibration procedure for reading and measuring microscopes
This procedure is applicable to the initial calibration, subsequent calibration and in-use inspection of reading microscopes with a graduation value not greater than 0.01mm and a measuring range of up to 8mm, and measuring microscopes with a graduation value not greater than 0.01mm and a measuring range of (0~50)mm in the longitudinal direction and (0~13)mm in the lateral direction. References
This specification refers to the following documents:
JJF1001--1998 General metrological terms and definitionsJF1059-1999 Evaluation and expression of measurement uncertaintyJF1094--2002 Evaluation of measuring instrument characteristicsJB/T2369--1993 Reading microscope
JB/T9339--1999 Measuring microscope
When using this specification, attention should be paid to using the current valid versions of the above referenced documents. 3 Overview
The reading microscope and the measuring microscope (hereinafter referred to as the microscope) are both optical mechanical length measuring instruments. The reading microscope is mainly used as the aiming and positioning reading device in the length measuring instrument, and can also be used alone to measure the length of the line width, spacing, etc.; the main purpose of the measuring microscope is to measure the shape and size of the parts by the image method using the rectangular coordinate or polar coordinate principle. The appearance structure of the reading microscope is shown in Figures 1, 2, and 3, and the appearance structure of the measuring microscope is shown in Figure 4.
Figure 1 Reading microscope appearance diagram-
1 objective lens; 2 micrometer scale plate box;
3-eyepiece: 4-micrometer knob: 5-lighting lampFigure 2 Reading microscope appearance diagram 2
1-objective lens; 2-micrometer knob; 3-eyepiece: 4-micrometer scale plate box; 5-zero adjustment knob; 6-lighting lamp1
Figure 3 Reading microscope appearance diagram 3
JJG571-2004
1-mirror base plate; 2-purple solid dart nail: 3-scale plate box: 4-eyepiece; 5-micrometer Drum wheel;
6-objective lens: 7-lens barrel
Metrological performance requirements
4.1 Displacement caused by radial force on circular table Figure 4 Appearance of measuring microscope
1-base; 2-longitudinal micrometer drum wheel; 3, 4-fastening screws: 5-arm; 6-column; 7-microscope lifting knob; 8-calibration seat: 9-eyepiece; 10-microscope tube; 11-glass stage; 12-circular table; 13-transverse micrometer drum wheel: 14-reflector The displacement caused by radial force of 5N on the circular table should not exceed 0.01mm. 4.2 The parallelism between the glass table and the moving direction of the longitudinal and transverse slides should not exceed 0.04mm in the longitudinal length of 50mm; and should not exceed 0.01mm in the transverse length of 13mm. 4.3 Straightness of longitudinal and transverse slides
The straightness of longitudinal and transverse slides (expressed in angular pendulum) should not exceed 25\. 4.4 Mutual perpendicularity of longitudinal and transverse slide movement The mutual perpendicularity of longitudinal and transverse slide movement shall not exceed ±0.003mm/10mm. 4.5
The verticality of microscope lifting direction to glass table surface shall not exceed 5. 4.6 Indication error of circular table
The maximum allowable error of circular table is 6°.
4.7 Indication error of microscope
The maximum allowable error is shown in Table 1.
4.8 Return error
The maximum allowable error is shown in Table 1.
Instrument name
Reading microscope
Measuring microscope
JJG571—2004
Table 1 Requirements for error of magnification, return error and indication error of microscope objective lens Graduation value/mm
5 General technical requirements
5.1 Appearance
Objective lens magnification
Maximum allowable error/um
Return error
Indication error
5+L/15
Measuring length, mm
5.1.1 The instrument shall be marked with the name, model, number, manufacturer name (or factory mark) and M mark. 5.1.2 The working surface of the instrument shall be free of defects such as rust, bruises, obvious scratches, etc., and the coating and plating of the instrument shall not fall off. 5.1.3 The optical system should have a clear image in the entire field of view, and there should be no oil stains, dust, water stains, mildew spots, or other symptoms that affect the use of the instrument.
5.1.4 The lines on the microscope micrometer drum, sleeve, and graticule should be straight, clear, and uniform, without line breakage and paint peeling (or discoloration), and the numbers should also be clear. 5.1.5 There should be no visible parallax between the millimeter scale and the crosshairs of the reading microscope, between the 0.1mm scale and the spiral scale, and between the index line and the micrometer scale. The instruments that are subsequently calibrated and tested in use are allowed to have the above defects that do not affect the metrological performance. 5.2 Interaction of various parts
5.2.1 The movement of each active part of the instrument should be flexible and smooth, without sticking or jumping. The function of the tightening screws should be reliable and effective.
5.2.2 The stroke of the micrometer drum should be greater than the working stroke, and should be greater than 0.3mm in both the initial and final positions. 5.2.3 The distance between the inner edge of the differential cone of the micrometer drum and the scaled surface of the fixed sleeve should not exceed 0.4mm. 5.3 Relative position of each scale line of the microscope
5.3.1 The index line of the reading microscope structure of Figure 1 and Figure 2 should be parallel to the micrometer scale line, and the index line should cover more than 7/10 of the length of the short scale line of the micrometer scale, but should not exceed the length of the short scale line of the micrometer scale. 5.3.2 The parallelism between the movement direction of the micrometer scale of the reading microscope with the structure of Figure 1 and the scale axis should not be greater than 1/5 of the length of the short scale line of the micrometer scale.
5.3.3 There should be no visible skew between the 0.1mm scale and the spiral scale plate of the reading microscope with the structure of Figure 2. When the spiral line is aligned with the 0.5mm scale line on the 0.1mm scale, the deviation of the index line from the zero scale line of the micrometer scale shall not exceed 0.001mm.
JJG571—2004
5.3.4 For the reading microscope with the structure of Figure 3, the vertical line of the crosshairs shall be parallel to the millimeter scale line. When the vertical line of the crosshairs is aligned with the zero scale line of the millimeter scale, the zero position of the micrometer drum wheel should be aligned with the index line, and its offset shall not exceed 1/5 of the scale; when the micrometer drum wheel rotates 100 scales, the vertical line of the crosshairs shall move to the corresponding scale line position, and its offset shall not exceed 1 scale.
The parallelism between the movement direction of the cross-hair graticule and the axis of the millimeter scale should not be greater than 1/10 of the length of the millimeter scale line. 5.3.5 For the measuring microscope with the structure of Figure 4, when the zero line of the micrometer drum on the longitudinal reading device is aligned with the index line, the offset of the millimeter scale line to the index line should not exceed 0.1mm; when the zero line of the differential cylinder on the transverse reading device is aligned with the longitudinal line of the fixed sleeve, the end face of the cone surface of the differential cylinder should be tangent to the right edge of the millimeter scale line of the fixed sleeve, and the offline difference should not be greater than 0.1mm or the pressure line should not be greater than 0.05mmo
5.4 Displacement of the image caused by rotation of the prism seat
The displacement of the image caused by rotation of the prism seat should not exceed 1/6 of the diameter of the field of view. 5.5 Coincidence of the center of the spiral graticule and the center of rotation There should be no visible offset in the coincidence of the center of the spiral graticule and the center of rotation. 6 Measuring instrument control
Measuring instrument control includes initial calibration, subsequent calibration and inspection during use. 6.1 Calibration conditions
6.1.1 Calibration environment conditions are shown in Table 2.
Table 2 Calibration environment conditions
Instrument name
Reading microscope
Measuring microscope
Graduation value/mm
6.1.2 Calibration equipment
Main calibration equipment are shown in Table 3.
6.2 Calibration items
Room temperature/℃
20 ± 5
20 ± 3
20 ±5
Each calibration item and calibration category are shown in Table 3.
6.3 Calibration method
6.3.1 Appearance
Visual observation.
6.3.2 Interaction of various parts
Room temperature change/(℃/h)
Time for the instrument under test to balance the temperature in the room/h3
JJG571—2004
Table 3 Verification items, verification categories and verification categories of main verification equipment
Verification items
Interaction of various parts
Relative position between the lines of the microscope
Image displacement caused by the rotation of the prism seat
Radial influence of the circular worktable Displacement caused by force
Parallelism of the glass table and the longitudinal and transverse sliding plate
Straightness of the longitudinal and transverse sliding plate
Mutual perpendicularity of the longitudinal and transverse sliding plate
Verticality of the glass
table in the direction of microscope lifting and lowering
Indication error of the circular worktable
Coincidence of the center of the spiral graticule and the center of rotation
Indication error of the microscope
Return error||tt| |Main calibration equipment
0.4mm grade II feeler gauge
cross-line scale
cross-line scale,
division value ≤0.1N dynamometer
0-grade micrometer
1\autocollimator
±3\cube scale with division value
0.002mm lever micrometer
cross-line scale,
40mm parallel flat crystal
2-grade knife-edge square
division value 0. 01mm, measuring range (0~1)mm, U=0.2μm (k=3) special glass scale; graduation value is 0.1mm, measuring range (0)10)mm, U=0.5μm (k=3) special glass scale; second-class standard glass line ruler and reading microscope calibration equipment 1. "+" in the table means calibration is required, "_" means calibration is not required. First calibration Subsequent calibration In-use inspection Description of calibration items Reading microscope Measurement display 2. Due to different instrument structures, if the instrument does not have the functions involved in a certain calibration item, the item can be not calibrated. "×" indicates that the item is not involved, and "△" indicates that the item is involved. Visual observation and manual test. The distance between the inner edge of the cone surface of the differential cylinder of the micrometer drum and the scaled surface of the fixed sleeve is measured by a feeler gauge in four directions evenly distributed within one rotation of the differential cylinder. 6.3.3 Relative position between the scaled lines of the microscope 5
Visual observation and manual test.
6.3.4 Image displacement caused by rotation of the prism seat JJG571-2004
Put the crosshair scale plate flat on the glass workbench, and adjust the microscope with the help of the microscope's lifting knob so that a clear crosshair image can be seen in the eyepiece field of view. Rotate the prism seat for one circle and observe the maximum displacement of the crosshair image as the measurement result.
6.3.5 Displacement of the circular workbench caused by radial force Place the crosshair scale plate on the glass workbench and adjust the microscope so that a clear crosshair image can be seen in the eyepiece. Rotate the micrometer drum of the longitudinal and transverse reading device to align the crosshair image with the crosshair in the eyepiece, and record the longitudinal and transverse micrometer drum readings a, and b,. Apply a radial force of 5N to the side of the circular table. After removing the external force, rotate the micrometer drum to align the two crosshairs again, and record the longitudinal and transverse micrometer drum readings a, and b2. The displacement 1 caused by the radial force on the circular table is calculated according to formula (1). l=/(a2 - ar)2 + (b2 - b,)
Where: a1, a2 are the longitudinal micrometer drum readings, mm; b,, bz are the transverse micrometer drum readings, mm6.3.6 Parallelism between the glass table and the longitudinal and transverse sliding plate moving directions (1)
Fix the micrometer on the objective cylinder of the microscope with the help of a table stand, and adjust the micrometer so that its measuring axis is perpendicular to the table surface. Lift and lower the microscope so that the probe of the meter contacts the glass table and indicates a certain measured value in the middle of the stroke. Move the longitudinal and transverse slides respectively throughout the working stroke, observe the change in the indication of the micrometer, and take the maximum change in the indication in each direction as the measurement result.
6.3.7 Straightness of the movement of the longitudinal and transverse slides After installing the instrument to be tested and the autocollimator on the same flat plate, place a reflector on the circular work surface. Adjust the autocollimator and the reflector so that their optical axes are parallel to the moving direction of one slide. Then, move the slide within the entire working stroke, and record the maximum change in the indication of the slide in the horizontal and vertical directions respectively, and take the maximum change as the angular pendulum of the moving slide. Measure the angular pendulum of the other slide in the same way. 6.3.8 Mutual perpendicularity of the movement of the longitudinal and transverse slides Place the cube flat on the glass table and fix it. At the same time, fix the lever micrometer on the microscope objective cylinder with the help of a clamp. Adjust the measuring axis of the lever micrometer so that it is parallel to the moving direction of the transverse slide. Move the horizontal slide to make the lever micrometer probe contact with one of the working surfaces of the cube. Adjust the cube so that the working surface is parallel to the moving direction of the longitudinal slide, and then change the measuring direction of the lever micrometer so that its measuring axis is perpendicular to and in contact with the adjacent working surface of the cube. Move the horizontal slide 10 mm, and record the change in the indication of the lever micrometer a as the measurement result.
6.3.9 When measuring the verticality of the glass table in the direction of microscope lifting and lowering, fix the crosshair scale plate on the glass table, and raise and lower the microscope until a clear crosshair image is seen in the eyepiece. Adjust the circular worktable so that the crosshairs of the crosshair scale plate are parallel to the moving direction of the longitudinal and transverse slides, and turn the longitudinal and transverse micrometer drum wheels to align the crosshair image with the crosshairs in the eyepiece, and record the longitudinal and transverse readings a and b. Lift the microscope, place the parallel flat crystal on the crosshair graticule, raise and lower the microscope until a clear crosshair image is seen in the eyepiece, turn the longitudinal and transverse micrometer drum wheels to align the crosshair image with the crosshairs in the eyepiece again, and record the longitudinal and transverse readings a2 and b2. Calculate the verticality △ of the microscope lifting direction to the glass table according to formula (2). . 3438n(az-a)+（bz-b,)2
L(n-1)
Where: △. Verticality of the microscope lifting direction to the glass table, (\); L-—the size of the parallel flat crystal, mm;
n——the glass refractive index of the parallel flat crystal;
ai,a2——the indication of the longitudinal reading device at two positions, mm; 6i,b2—the indication of the transverse reading device at two positions, mm. This item can also be measured by other methods that meet the uncertainty requirements. 6.3.10 Indication error of the circular table
First align the indication of the circular table to the zero position ao, place the knife-edge square flat on the glass table and focus. Adjust the square so that the image of one edge is parallel to the horizontal line (or vertical line) of the crosshairs in the eyepiece, and then rotate the circular table to 90°, 180°, and 270° in sequence, so that the image of the working edge of the square is alternately parallel to the horizontal line (or vertical line) of the crosshairs in the eyepiece, and record the indications of the circular table ag0, α180, and α270. Calculate the error of each measuring point relative to the zero position according to formula (3). The difference between the maximum and minimum values of the error of each point to the zero position is the indication error of the circular table.
g=（aa)-α
Where: α;—take the values of 90°, 180°, and 270% respectively. 6.3.11 Coincidence of the center of the spiral graticule and the center of rotation (3)
Install the reading microscope on the calibration device (see Appendix Figure C1), place the special glass scale on the workbench of the calibration device, focus until the millimeter scale is clearly imaged in the field of view of the reading microscope, make one of the millimeter scales tangent to the auxiliary circle (or the end point of the micrometer scale) in the spiral graticule, and rotate the spiral graticule for one circle to observe whether there is any relative displacement between the auxiliary circle (or the end point of the micrometer scale) and the millimeter scale. 6.3.12 Indication error of the microscope
6.3.12.1 Reading microscope
For reading microscopes with graduation values of 0.0025mm, 0.001mm, and 0.0005mm, use a special glass scale with a graduation value of 0.01mm for measurement; for reading microscopes with graduation values of 0.01mm and 0.005mm, use a special glass scale with a graduation value of 0.1mm for measurement.
The reading microscope with a graduation value of 0.001mm and 0.0005mm is first installed on the calibration device (see Appendix Figure C.1), and then the scale is placed on the workbench of the calibration device. The focus is adjusted so that the scale lines of the special glass scale are clearly imaged in the field of view of the reading microscope, and the axis of the special glass scale is parallel to the axis of the 0.1mm scale of the reading microscope, and they are arranged in series. With the help of the workbench of the calibration device, the zero scale line of the special glass scale is at the zero position of the 0.1mm scale of the reading microscope, and the double scale line (or spiral line) is used for positive alignment. The positive reading is repeated twice and the average value is recorded as a10. Then, with the help of the workbench of the calibration device, the special glass scale is moved so that the 0.12mm scale line is aligned with the zero scale line of the 0.1mm scale of the reading microscope, and the double scale line (or spiral line) of the reading microscope is used for positive alignment with the zero scale line of the special glass scale. The positive reading is repeated twice and the average value is recorded as a1. Use the same method to measure the points to be inspected as specified in Table 4 and record the readings. After appropriate overtravel, perform reverse measurements in turn and record the readings b1. Repeat the above forward and reverse travel measurements to obtain the readings α2. and bz. Take the average of the two forward readings (a, a2:) as the forward indication c; of the i-th measuring point, and take the average of the two reverse readings (b, b2t) as the reverse indication c: of the i-th measuring point. Then the forward or reverse indication error of each inspected point relative to the starting point is calculated according to formula (4): = [(c-co)-L1x1000
Where: 8—indication error of each inspected point, um; ci, co—forward or reverse indication of each inspected point and the zero point of the instrument, mm; L—actual size of the special glass scale at the i-th inspected point relative to the zero point, mm. Table 4 Distribution of inspection points
Instrument name
Reading microscope
Measuring microscopebzxz.net
Graduation value
Distribution of inspection points
0,1,1.2,2,2.4,3,3.6,4,4.8,5，6,7,80,0.2,0.4,0.6,0.8,1,2,3
0，0.05，0.1，0.25，0. 5, 0.75, 10, 0.12, 0.34, 0.56, 0.88, 1
Measure at 5mm intervals
3, 5, 8, 10, 13
For reading microscopes with graduation values of 0.01mm, 0.005mm, and 0.0025mm, first install and adjust according to the above method, so that the axis direction of the special glass scale is consistent with the moving direction of the crosshairs in the field of view of the reading microscope. Then align the zero scale line of the micrometer drum wheel of the reading microscope with the index line, and align the vertical line of the crosshair scale plate with the zero scale line of the special glass scale, aim forward and record the reading an. Then rotate the micrometer drum wheel to move the crosshairs according to the inspection point specified in Table 4, and align the vertical line with the corresponding scale line on the special glass scale in the forward direction, and record the readings a1i respectively. After appropriate overtravel, reverse measurement is carried out in sequence to record the reading b1. Repeat the above forward and reverse travel measurements to obtain the readings α2 and b2i. The average of the two forward readings (al, a2) is taken as the forward indication of the i-th measuring point, and the average of the two reverse readings (b1, bz) is taken as the reverse indication of the i-th measuring point. The forward or reverse indication error of each inspected point to the starting point is calculated according to formula (4).
The difference between the maximum and minimum forward indication errors is taken as the forward stroke indication error. The reverse stroke indication error is calculated in the same way, and the larger value of the forward and reverse stroke indication errors is taken as the measurement result. 6.3.12.2 Measuring microscope
Use a standard glass ruler to measure the longitudinal and transverse reading devices respectively according to the inspection point distribution requirements in Table 4. Place the standard glass ruler on the glass table and rotate the micrometer drum so that the indication in the inspected coordinate direction is approximately at zero. Adjust the ruler axis to be parallel to the longitudinal movement direction, and align its zero line with the crosshairs in the eyepiece. Then rotate the micrometer drum in the forward direction to align the zero line of the ruler with the crosshairs in the eyepiece, and record the reading a1o. Then rotate the micrometer drum in the forward direction and align the corresponding scale lines of the glass scale with the crosshairs in the eyepiece according to the distribution requirements of the inspection points in Table 4, and record the reading an. After an appropriate overrun, perform reverse measurement in turn and record the reading bu. Repeat the above 8 steps.1), then place the scale on the workbench of the calibration device, adjust the focus so that the scale lines of the special glass scale are clearly imaged in the field of view of the reading microscope, and make the axis of the special glass scale parallel to the axis of the 0.1mm scale of the reading microscope, and arrange them in series. With the help of the workbench of the calibration device, make the zero scale line of the special glass scale at the zero position of the 0.1mm scale of the reading microscope, use the double scale line (or spiral line) to align it positively, repeat the reading in the positive direction twice, and take the average value, which is recorded as a10. Then move the special glass scale with the workbench of the calibration device, align the 0.12mm scale line with the zero scale line of the 0.1mm scale of the reading microscope, use the double scale line (or spiral line) of the reading microscope to align it positively with the zero scale line of the special glass scale, repeat the reading in the positive direction twice, and take the average value, which is recorded as a1. Use the same method to measure the points to be inspected as specified in Table 4 and record the readings. After appropriate overtravel, perform reverse measurements in turn and record the readings b1. Repeat the above forward and reverse travel measurements to obtain the readings α2. and bz. Take the average of the two forward readings (a, a2:) as the forward indication c; of the i-th measuring point, and take the average of the two reverse readings (b, b2t) as the reverse indication c: of the i-th measuring point. Then the forward or reverse indication error of each inspected point relative to the starting point is calculated according to formula (4): = [(c-co)-L1x1000
Where: 8—indication error of each inspected point, um; ci, co—forward or reverse indication of each inspected point and the zero point of the instrument, mm; L—actual size of the special glass scale at the i-th inspected point relative to the zero point, mm. Table 4 Distribution of inspection points
Instrument name
Reading microscope
Measuring microscope
Graduation value
Distribution of inspection points
0,1,1.2,2,2.4,3,3.6,4,4.8,5，6,7,80,0.2,0.4,0.6,0.8,1,2,3
0，0.05，0.1，0.25，0. 5, 0.75, 10, 0.12, 0.34, 0.56, 0.88, 1
Measure at 5mm intervals
3, 5, 8, 10, 13
For reading microscopes with graduation values of 0.01mm, 0.005mm, and 0.0025mm, first install and adjust according to the above method, so that the axis direction of the special glass scale is consistent with the moving direction of the crosshairs in the field of view of the reading microscope. Then align the zero scale line of the micrometer drum wheel of the reading microscope with the index line, and align the vertical line of the crosshair scale plate with the zero scale line of the special glass scale, aim forward and record the reading an. Then rotate the micrometer drum wheel to move the crosshairs according to the inspection point specified in Table 4, and align the vertical line with the corresponding scale line on the special glass scale in the forward direction, and record the readings a1i respectively. After appropriate overtravel, reverse measurement is carried out in sequence to record the reading b1. Repeat the above forward and reverse travel measurements to obtain the readings α2 and b2i. The average of the two forward readings (al, a2) is taken as the forward indication of the i-th measuring point, and the average of the two reverse readings (b1, bz) is taken as the reverse indication of the i-th measuring point. The forward or reverse indication error of each inspected point to the starting point is calculated according to formula (4).
The difference between the maximum and minimum forward indication errors is taken as the forward stroke indication error. The reverse stroke indication error is calculated in the same way, and the larger value of the forward and reverse stroke indication errors is taken as the measurement result. 6.3.12.2 Measuring microscope
Use a standard glass ruler to measure the longitudinal and transverse reading devices respectively according to the inspection point distribution requirements in Table 4. Place the standard glass ruler on the glass table and rotate the micrometer drum so that the indication in the inspected coordinate direction is approximately at zero. Adjust the ruler axis to be parallel to the longitudinal movement direction, and align its zero line with the crosshairs in the eyepiece. Then rotate the micrometer drum in the forward direction to align the zero line of the ruler with the crosshairs in the eyepiece, and record the reading a1o. Then rotate the micrometer drum in the forward direction and align the corresponding scale lines of the glass scale with the crosshairs in the eyepiece according to the distribution requirements of the inspection points in Table 4, and record the reading an. After an appropriate overrun, perform reverse measurement in turn and record the reading bu. Repeat the above 8 steps.1), then place the scale on the workbench of the calibration device, adjust the focus so that the scale lines of the special glass scale are clearly imaged in the field of view of the reading microscope, and make the axis of the special glass scale parallel to the axis of the 0.1mm scale of the reading microscope, and arrange them in series. With the help of the workbench of the calibration device, make the zero scale line of the special glass scale at the zero position of the 0.1mm scale of the reading microscope, use the double scale line (or spiral line) to align it positively, repeat the reading in the positive direction twice, and take the average value, which is recorded as a10. Then move the special glass scale with the workbench of the calibration device, align the 0.12mm scale line with the zero scale line of the 0.1mm scale of the reading microscope, use the double scale line (or spiral line) of the reading microscope to align it positively with the zero scale line of the special glass scale, repeat the reading in the positive direction twice, and take the average value, which is recorded as a1. Use the same method to measure the points to be inspected as specified in Table 4 and record the readings. After appropriate overtravel, perform reverse measurements in turn and record the readings b1. Repeat the above forward and reverse travel measurements to obtain the readings α2. and bz. Take the average of the two forward readings (a, a2:) as the forward indication c; of the i-th measuring point, and take the average of the two reverse readings (b, b2t) as the reverse indication c: of the i-th measuring point. Then the forward or reverse indication error of each inspected point relative to the starting point is calculated according to formula (4): = [(c-co)-L1x1000
Where: 8—indication error of each inspected point, um; ci, co—forward or reverse indication of each inspected point and the zero point of the instrument, mm; L—actual size of the special glass scale at the i-th inspected point relative to the zero point, mm. Table 4 Distribution of inspection points
Instrument name
Reading microscope
Measuring microscope
Graduation value
Distribution of inspection points
0,1,1.2,2,2.4,3,3.6,4,4.8,5，6,7,80,0.2,0.4,0.6,0.8,1,2,3
0，0.05，0.1，0.25，0. 5, 0.75, 10, 0.12, 0.34, 0.56, 0.88, 1
Measure at 5mm intervals
3, 5, 8, 10, 13
For reading microscopes with graduation values of 0.01mm, 0.005mm, and 0.0025mm, first install and adjust according to the above method, so that the axis direction of the special glass scale is consistent with the moving direction of the crosshairs in the field of view of the reading microscope. Then align the zero scale line of the micrometer drum wheel of the reading microscope with the index line, and align the vertical line of the crosshair scale plate with the zero scale line of the special glass scale, aim forward and record the reading an. Then rotate the micrometer drum wheel to move the crosshairs according to the inspection point specified in Table 4, and align the vertical line with the corresponding scale line on the special glass scale in the forward direction, and record the readings a1i respectively. After appropriate overtravel, reverse measurement is carried out in sequence to record the reading b1. Repeat the above forward and reverse travel measurements to obtain the readings α2 and b2i. The average of the two forward readings (al, a2) is taken as the forward indication of the i-th measuring point, and the average of the two reverse readings (b1, bz) is taken as the reverse indication of the i-th measuring point. The forward or reverse indication error of each inspected point to the starting point is calculated according to formula (4).
The difference between the maximum and minimum forward indication errors is taken as the forward stroke indication error. The reverse stroke indication error is calculated in the same way, and the larger value of the forward and reverse stroke indication errors is taken as the measurement result. 6.3.12.2 Measuring microscope
Use a standard glass ruler to measure the longitudinal and transverse reading devices respectively according to the inspection point distribution requirements in Table 4. Place the standard glass ruler on the glass table and rotate the micrometer drum so that the indication in the inspected coordinate direction is approximately at zero. Adjust the ruler axis to be parallel to the longitudinal movement direction, and align its zero line with the crosshairs in the eyepiece. Then rotate the micrometer drum in the forward direction to align the zero line of the ruler with the crosshairs in the eyepiece, and record the reading a1o. Then rotate the micrometer drum in the forward direction and align the corresponding scale lines of the glass scale with the crosshairs in the eyepiece according to the distribution requirements of the inspection points in Table 4, and record the reading an. After an appropriate overrun, perform reverse measurement in turn and record the reading bu. Repeat the above 8 steps.
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