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REV:
04/15/09
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 Supervisor, 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, CMM Programmer/Operator, 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,
Calibrations Clerk, 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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