I am looking for constructive comments for my first ever procedure. We are IS0 9001 mostly areospace R&D laboratory. We have roughly 2,000 M&TE with about half calibrated in-house. Our current procedures are either non-existent or no longer relevant. Please reply with comments on this:
1.0 Scope
Provide a written procedure for the calibration of outside micrometers appropriate to their utilization.
1.1 Application
This procedure applies to outside micrometers utilized by the X.
1.2 Interval
Calibration shall be required on an annual frequency beginning on the active status date. Micrometers may be appropriately stored (refer to Section 9.0) in a calibrated & inactive state for a period of three years. Anytime during this three year period micrometers may begin an active status calibration interval. After the three year period, micrometers shall be calibrated prior to utilization.
2.0 Description
Micrometers of various models are used to indicate dimensional measurements. This procedure only applies to outside micrometers. The lowest specification/tolerance of this procedure is 0.0001 inches.
3.0 Measurement and Test Equipment used for Calibration
The following table lists the type of equipment required to perform the calibration in accordance with the method used by this procedure. The Minimum Use Specifications column describes the performance characteristics required of the equipment for the calibration and are included to assist in the selection of alternate equipment. The Recommended Equipment column contains items known to be suitable for use in this procedure. All applicable equipment must bear evidence of current calibration and NIST traceability.
4.0 Environmental Conditions
Ensure the M&TE required for this procedure have met the following environmental conditions prior to calibration.
*During the calibration process temperature indications shall be stable to within ±2 ºF of the initial reading.
5.0 Safety
This procedure does require unique safety measures.
6.0 Preliminary Operations
6.1Sealing of micrometers may be used to indicate use over the active calibration interval (Section 9.2a). In cases where the integrity of the seal clearly indicates no use and a three year period without calibration has not been exceeded, the calibration process may be passed over until the next active calibration interval ends. This action shall be appropriately recorded on the calibration report, then proceed to Section 8.0.
6.2 Ensure the temperature specifications of Section 4.0 have been meet. It is a good practice to allow the UUT to stabilize/soak in the same environment as the reference standard.
6.2 Visually inspect the condition of the micrometer for dirt, debris, nicks, burrs and wear. The measurement faces (anvils) should carefully be inspected for cracks or chips.
6.3 Check micrometer spindle for free and smooth movement throughout the range. Micrometer spindle should not exhibit excessive play or backlash.
6.4 Digital micrometers require an operational check of the display and battery. Press the power button and rotate open and closed to ensure the display clearly registers movement. Replace micrometer batteries as needed.
6.5 If a condition is found that affects the proper operation or accuracy of the micrometer a notation shall be made in the calibration report.
7.0 Calibration Process
7.1 Where applicable, ensure the micrometer is set to display measurements in inches.
7.2 Fully close the micrometer. The zero of the thimble and the spindle zero shall coincide. If zero adjustment is performed a notation is required on the calibration report.
7.3 Open and close to recheck zero. In cases where the repeatability of zero is in question the micrometer shall be removed from service until proper repair or replacement is made.
7.4 Micrometer measurement points shall be no less than seven distributed over the calibration range. Measurement points shall follow an ascending then descending sequence, from 0.0 up to the upper range and then back down to 0.0.
Example of thirteen measurement points over a one inch calibration range:
0.0, 0.100, 0.200, 0.400, 0.600, 0.800, 1.000, 0.800, 0.600, 0.400, 0.200, 0.100, 0.0.
7.4a Select the correct gage block/s to achieve the desired measurement point. It is good practice to utilize the fewest number of gage blocks necessary for each measurement point.
7.4b Ensure blocks are wrung together prior to measurement with the micrometer.
7.4c Insert the gage block/s into the open micrometer and rotate closed with uniform pressure. The gage block/s should be inserted into the micrometer with good contact on the measurement surfaces. When available, use of the ratchet stop mechanism is preferred to adjust tension with two soft clicks.
7.4d Record the micrometers indication at each of the desired measurement points.
8.0 Recording and Evaluating the Calibration Results
8.1 Ensure the calibration measurement results were recorded accurately and completely on the calibration report. The calibration report shall be electronically saved in the appropriate M&TE folder on the designated server. The calibration reports document title shall at minimum include the ID# of the UUT and the date of calibration.
8.2 Review the measurement results and ensure they satisfy the tolerances as listed in Section 2.0. If the measurements are within the allowable tolerance proceed to Section 9.0. If the measurements are outside the allowable tolerance disposition of the micrometer shall be agreed upon with the customer.
9.0 Post Calibration Operations
9.1 Clean the micrometer with an appropriate solution and lint free cloth as needed.
9.2 If micrometer status is to be active a calibration label shall be applied. When a calibration label is not able to be properly applied, the label shall be applied to the dedicated case. At minimum the calibration label shall include the micrometers ID# and the calibration interval end date as listed in Section 1.2.
9.2a Micrometers that are calibrated and active may be sealed with wax or other appropriate material in a manner requiring removal prior to use. The integrity of the seal may be used as an indication of no use over the active calibration interval.
9.3 Micrometers that are calibrated and inactive shall be stored in a controlled manner with environmental conditions not to exceed a temperature tolerance of 30 to 100 ºF. Calibrated M&TE that has not been properly stored as stated shall require performing this calibration procedure again prior to utilization. Calibrated M&TE that is appropriately stored will have a valid calibration for a period not to exceed three years.”
10.0 Notes, Definitions, Reference Documents
Digital Micrometers used in the X typically only require battery replacement every other year (odd years).
X
M&TE-Measurement and Test Equipment
UUT- Unit under Test
11.0 Appendix
Calibration Reports and Report Templates are stored electronically here:
X
Routine updates to the templates, reports or their electronic location shall not require a revision of this procedure.
1.0 Scope
Provide a written procedure for the calibration of outside micrometers appropriate to their utilization.
1.1 Application
This procedure applies to outside micrometers utilized by the X.
1.2 Interval
Calibration shall be required on an annual frequency beginning on the active status date. Micrometers may be appropriately stored (refer to Section 9.0) in a calibrated & inactive state for a period of three years. Anytime during this three year period micrometers may begin an active status calibration interval. After the three year period, micrometers shall be calibrated prior to utilization.
2.0 Description
Micrometers of various models are used to indicate dimensional measurements. This procedure only applies to outside micrometers. The lowest specification/tolerance of this procedure is 0.0001 inches.
Manufacturer
Model
Calibration Range
Inches
Specification / Tolerance
Inches
Various
Various
0-6
Lowest marked graduation typically 0.001, no smaller than 0.0001.
3.0 Measurement and Test Equipment used for Calibration
The following table lists the type of equipment required to perform the calibration in accordance with the method used by this procedure. The Minimum Use Specifications column describes the performance characteristics required of the equipment for the calibration and are included to assist in the selection of alternate equipment. The Recommended Equipment column contains items known to be suitable for use in this procedure. All applicable equipment must bear evidence of current calibration and NIST traceability.
Item
Minimum Use Specifications
Recommended Equipment
Gage Blocks
U.S. Federal Specification GGG-G-15C Grade 3 or better.
CS05331- Starrett-Webber Set
CS01131- Mitutoyo Set
4.0 Environmental Conditions
Ensure the M&TE required for this procedure have met the following environmental conditions prior to calibration.
Process
M &T E
Time
Temperature
ºF
Humidity
% R.H.
Stabilization
Gage Blocks
3 Hours
61 to 75
<60
Stabilization
Micrometers-UUT
3 Hours
61 to 75
<60
*Calibration
Gage Blocks
As needed
61 to 75
<60
*Calibration
Micrometers-UUT
As needed
61 to 75
<60
*During the calibration process temperature indications shall be stable to within ±2 ºF of the initial reading.
5.0 Safety
This procedure does require unique safety measures.
6.0 Preliminary Operations
6.1Sealing of micrometers may be used to indicate use over the active calibration interval (Section 9.2a). In cases where the integrity of the seal clearly indicates no use and a three year period without calibration has not been exceeded, the calibration process may be passed over until the next active calibration interval ends. This action shall be appropriately recorded on the calibration report, then proceed to Section 8.0.
6.2 Ensure the temperature specifications of Section 4.0 have been meet. It is a good practice to allow the UUT to stabilize/soak in the same environment as the reference standard.
6.2 Visually inspect the condition of the micrometer for dirt, debris, nicks, burrs and wear. The measurement faces (anvils) should carefully be inspected for cracks or chips.
6.3 Check micrometer spindle for free and smooth movement throughout the range. Micrometer spindle should not exhibit excessive play or backlash.
6.4 Digital micrometers require an operational check of the display and battery. Press the power button and rotate open and closed to ensure the display clearly registers movement. Replace micrometer batteries as needed.
6.5 If a condition is found that affects the proper operation or accuracy of the micrometer a notation shall be made in the calibration report.
7.0 Calibration Process
7.1 Where applicable, ensure the micrometer is set to display measurements in inches.
7.2 Fully close the micrometer. The zero of the thimble and the spindle zero shall coincide. If zero adjustment is performed a notation is required on the calibration report.
7.3 Open and close to recheck zero. In cases where the repeatability of zero is in question the micrometer shall be removed from service until proper repair or replacement is made.
7.4 Micrometer measurement points shall be no less than seven distributed over the calibration range. Measurement points shall follow an ascending then descending sequence, from 0.0 up to the upper range and then back down to 0.0.
Example of thirteen measurement points over a one inch calibration range:
0.0, 0.100, 0.200, 0.400, 0.600, 0.800, 1.000, 0.800, 0.600, 0.400, 0.200, 0.100, 0.0.
7.4a Select the correct gage block/s to achieve the desired measurement point. It is good practice to utilize the fewest number of gage blocks necessary for each measurement point.
7.4b Ensure blocks are wrung together prior to measurement with the micrometer.
7.4c Insert the gage block/s into the open micrometer and rotate closed with uniform pressure. The gage block/s should be inserted into the micrometer with good contact on the measurement surfaces. When available, use of the ratchet stop mechanism is preferred to adjust tension with two soft clicks.
7.4d Record the micrometers indication at each of the desired measurement points.
8.0 Recording and Evaluating the Calibration Results
8.1 Ensure the calibration measurement results were recorded accurately and completely on the calibration report. The calibration report shall be electronically saved in the appropriate M&TE folder on the designated server. The calibration reports document title shall at minimum include the ID# of the UUT and the date of calibration.
8.2 Review the measurement results and ensure they satisfy the tolerances as listed in Section 2.0. If the measurements are within the allowable tolerance proceed to Section 9.0. If the measurements are outside the allowable tolerance disposition of the micrometer shall be agreed upon with the customer.
9.0 Post Calibration Operations
9.1 Clean the micrometer with an appropriate solution and lint free cloth as needed.
9.2 If micrometer status is to be active a calibration label shall be applied. When a calibration label is not able to be properly applied, the label shall be applied to the dedicated case. At minimum the calibration label shall include the micrometers ID# and the calibration interval end date as listed in Section 1.2.
9.2a Micrometers that are calibrated and active may be sealed with wax or other appropriate material in a manner requiring removal prior to use. The integrity of the seal may be used as an indication of no use over the active calibration interval.
9.3 Micrometers that are calibrated and inactive shall be stored in a controlled manner with environmental conditions not to exceed a temperature tolerance of 30 to 100 ºF. Calibrated M&TE that has not been properly stored as stated shall require performing this calibration procedure again prior to utilization. Calibrated M&TE that is appropriately stored will have a valid calibration for a period not to exceed three years.”
10.0 Notes, Definitions, Reference Documents
Digital Micrometers used in the X typically only require battery replacement every other year (odd years).
X
M&TE-Measurement and Test Equipment
UUT- Unit under Test
11.0 Appendix
Calibration Reports and Report Templates are stored electronically here:
X
Routine updates to the templates, reports or their electronic location shall not require a revision of this procedure.
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