INTROODUCTION TO METROLOGY

Prehistoric people didn’t have time to measure

METROLOGY: IT IS A SCIENCE OF MEASUREMENT.

ENGINEERING METROLOGY is the measurement of dimensions: length, thickness, diameter, taper, angle, flatness, profiles, and others.

MeasurementIt is the act, or result of a quantitive comparison between a predetermined standard and an unknown magnitude

IT INCLUDE ALL THEORATICAL AND PRACTICAL ASPECTS OF MEASUREMENT.

• Errors of measurement• Measurement method.• Various measuring instrument and devices.• Units of measurement and their standard• Industrial inspection and its different technique.• Measuring instruments care and their accuracy.

TERMS USED IN METROLOGY

SPECIFICATION:

Every product and part have some certain characteristics .It gives certain thoughts of that particular product. Its called specification

STANDARD :

Standard is define as , it is a physical quantity which is established by higher authority or organization .This standard is reliable and acceptable to measure physical quantity. Ex. METER

LENGTH STANDARD

THERE ARE TWO STNDARD SYSTEM TO MEASURE LENGTH

1.BRITISH SYSTEM: INCH,FOOT,YARD

2.METRIC SYSTEM: MM,CM,METER

Need of metrology (inspection).

Importance of metrology:

• To achieve quality control in production• To achieve up to date production.• To reduce rejection with the help of quality control.• To develop inspection procedure .• To calibrate measuring instrument time to time

Objectives of metrology

• To minimise the cost of inspection by effective and efficient use of available facilities

• To minimize the cost of rejection and re-work through through application of SQC technique.

• To maintain the accuracies of measurement.• To do complete evalution of newly developed products.• To standardise the measuring methods.• To make a design for all gauges and special inspection fixtures.

Accuracy vs precision

Accuracy: it refers to the closeness of a measured value to a standard or known value.

Precision: it refers to the closeness of two or more measurement to each other

Accuracy and precision