Why Controls on measuring instruments?
Controls on measuring instruments – To control, calibrate and maintain inspection, measuring and test instrument to demonstrate the conformance of product to the specified requirements.
How to ensure reliability of measuring instruments?
- The quality inspection, measuring and quality test instrument are properly select. Base on the measurements to be complete and the accuracy require.
- All identify inspection, measuring and quality test instrument shall be calibrate at prescribe intervals. Or prior to use, against certified instrument having a known valid relationship to internationally or nationally recognized standards.
- The Master list of all variable instruments such as micrometer, venire etc. are maintain indicating instrument name, instrument no, make, range, least count, frequency of calibration. Etc.
- The instruments that are calibrate from external agencies are suitably indicated in the list.
- The acceptance criteria of all variable instruments shall be 10 times that of the tolerance. That is the instruments will be used only for such parameters. Where the tolerances exceed the instrument error by at least 10 times.
- The applicable usage of all instruments shall be indicated after calibration in terms of tolerance ranges.
- Lists of attribute gauges such as snap gauges, plug gauges etc. is also maintained indicating gauge name, gauge code, point of use, gauge specifications, acceptance criteria and calibration frequency.
- The inspection, measuring and test instruments are properly selected based on the measurements to be made and the accuracy required.
Measuring instrument calibration
All identified inspection, measuring and test instrument shall be calibrated. At prescribe intervals or prior to use, against certified instrument having a known valid relationship. To internationally or nationally recognized standards. The Master list of all variable instruments such as micrometer, Vernier etc. Should be maintain indicating instrument name, instrument no, make, range, least count, frequency of calibration etc.
The instruments that are calibrate from external agencies should suitably indicates in the list. The acceptance criteria of all variable instruments shall be 10 times that of the tolerance. i.e. the instruments will be use only for such parameters where the tolerances exceed the instrument error by at least 10 times. The applicable usage of all instruments may indicate after calibration in terms of tolerance ranges. Lists of attribute gauges such as snap gauges, plug gauges etc. is also maintain indicating gauge name, gauge code, point of use, gauge specifications, acceptance criteria and calibration frequency.
See example format of: Calibration Standard History Sheet
