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REV:
02/05/08
SCOPE: This procedure covers the selection and use of precision
measuring equipment for verification of product dimensions. Note:
If there is any question at any point about this procedure,
contact the QC Specialist, QC Manager, Metrologist, or
Machining Department QC
Inspector.
| STEP |
WHO |
WHEN |
INFO TO USE |
WHAT TO DO |
RESULTS |
| 1 |
Anyone (typically QC Inspector) |
As needed to take precision
measurements |
Possibly Production Floor Traveler, Machining Department
Inspection Order, print or inspection sheet |
Determine which measurements are
to be taken and, if appropriate, the frequency with which they are to be taken and any
special sampling or other criteria; determine the accuracy required for the reading (5% of
the tolerance interval, .003" maximum for forging, .002" maximum for machining) |
Clear mental picture of the needs
of the measuring task at hand |
| 2 |
Anyone |
After Step 1 |
Decision from Step 1; Inspection
Order, Machining Department Inspection Order, print or
Part Inspection Sheet |
Choose the correct measuring
equipment to be used per these criteria: 1) Equipment specified by the QC
Forging Supervisor, Metrologist, or QC Specialist, QC Machining Supervisor or
Machine Operator.
2) Equipment specified on the Traveler or noted on the
Part Inspection Sheet. Machining
Department Inspection Order.
3) [Forge Division only] Equipment chosen per the table below. |
Measuring equipment choice |
| 3 |
Anyone |
After Step 2 |
Decision from Step 2 |
Obtain the necessary measuring
equipment (if do not already have ready access to needed equipment, see QC Specialist, QC Forging Supervisor, Metrologist or QC Machining Supervisor; ensure that equipment
has been calibrated/verified per
TOP-CALIB. DO NOT adjust the
equipment so as to invalidate the calibration; when
employees own their own measuring equipment, the selection of equipment is
covered in Step 2 |
Needed measuring equipment ready
to use; equipment not adjusted by unauthorized personnel |
| 4 |
Anyone |
Before tool is used to verify dimension |
Decision from Step 1; Inspection
Order, Machining Department Inspection Order, print or
Part Inspection Sheet |
Record Tool ID Number, Date, and Operator Stamp on Tool Verification Log
Sheet. |
Traceability of tool recorded. |
CRITERIA FOR SELECTION OF LINEAR MEASURING
EQUIPMENT
Typically use standard-issue 8" digital
calipers, unless measuring a dimension with a tolerance interval of less than .060"
or where the configuration of the part indicates one of the following.
For tolerance intervals of less than .060" use
a micrometer or a caliper specifically verified to be accurate to within 1/20 of the
tolerance interval.
For dimensions beyond 8" use longer digital,
dial or vernier calipers.
For an external distance perpendicular to a large,
flat surface, use a height gage on a surface plate.
For measuring the depth of a depression, use a depth
micrometer.
For measuring the thickness of webs, use spring
calipers.
For measuring radii use a
radius gage or CMM.
For measuring angles use
angle plates or CMM.
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