SOP for Operation of Digital Micrometer

OBJECTIVE

To provide a procedure for the Operation of a Digital Micrometer.

SCOPE

This procedure applies to Mitutoyo make a Digital Micrometer.

RESPONSIBILITY

Quality Control Chemist and above

Quality Control Head

PROCEDURE

• The Digital Micrometer is a precision instrument that is used to measure the thickness of packaging materials like PVC film, aluminum foil etc., accurately.
• It can measure a maximum thickness of 25 mm.
• The least count of Digital Micrometer is 0.001 mm.

Precaution

• The Digital Micrometer is a highly heat-sensitive instrument and should be stored at room temperature.
• Hold the Digital Micrometer from its heat-thermally insulating plate whilst handling to prevent heat transfer from the hand of the user to the Digital Micrometer.
• The object to be measured should also be kept at room temperature since this may also affect the reading.

ALSO READ: SOP for Operation and Calibration of Bursting Strength Tester

• Do not overtighten the Digital Micrometer as this can lead to deformation of both the anvil and spindle and the object being measured.
• Store the Digital Micrometer in its appropriate storage compartment to prevent any wearing of the anvil and/or spindle.
• Store the Digital Micrometer with the anvil and spindle not in contact with each other so that any temperature fluctuations will not stress the instrument.
• Measure the desired object three times to ensure that the reading obtained is accurate.
• Do not operate abruptly, drop or strike the Digital Micrometer.
• Digital Micrometer uses a 1.55V button cell battery.
• Do not substitute the used battery.
• Discard the used battery.
• Mitutoyo Digital Micrometer

Operation

• Turn the thimble to gently bring the spindle into contact with the anvil. Apply the rated measuring force using the ratchet stop/friction thimble.
• Press the zero buttons to zero setting to display 0.000 on the screen.
• Rotate the thimble anticlockwise allowing sufficient space between the anvil and the spindle to accommodate the object to be measured.
• Place the object to be measured between the anvil and the spindle.
• Spin the ratchet clockwise until the spindle just meets the object.
• Keep spinning the ratchet gently until 3 clicks are heard.
• Check that both the anvil and the spindle are touching the object evenly.

• Set the Spindle clamp while the micrometer is still on the object.
• Note the reading.
• Remove the object from the micrometer.
• Reset the Spindle clamp to the unlock position.
• Keep the instrument in a box after use.
• Get calibrated Digital Micrometer by an approved outside agency on yearly basis and keep the certificate in the record.

Cleaning

• Rub off any visible dirt, dust, and grit with a lint-free cloth.
• Wipe off the measuring faces of both the anvil and spindle with lint-free paper and set the start (zero) point before measuring.

ABBREVIATIONS

mm: Millimeter

ANNEXURES

Nil

REVISION HISTORY

Nil

ALSO READ: SOP for Operating Procedure of Vernier Caliper