Metrology Metrology is the science of measurement It

Tolerances Price ? Rs 30 Roundness 25 µ Rs 200 Roundness 5 µ Rs

Geometric Tolerances A B B as a Datum, Parallelism = 0. 05 mm A

Accuracy & Repeatability 100 shafts of diameter 50 mm were manufactured using different manufacturing

Accuracy & Repeatability Accuracy and Repeatability

Accuracy and Resolution Shafts Y and Z of diameter 50 mm manufactured using a

Metrology Shafts of diameter 50 mm were manufactured using a process and needs to

Metrology Mechanical Comparator (Option B)

Metrology 79. 352 = 75 + 1+ 1. 3 + 1. 05 + 1.

Metrology Snap Gauge/Go-Nogo Gauge (Option C)

CMM Cylindricity Flatness Roundness CMM – Coordinate Measuring Machine

CMM Flatness – 6 Parallelism – 3 Squareness – 12

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Metrology • Metrology is the science of measurement. It includes all theoretical and practical aspects of measurement. • It is derived from Greek word metros which means “measure”. • Should not be confused with meteorology which deals with study of the atmosphere that focuses on weather processes and climate forecasting. • The subject of metrology has changed since the introduction of concept called Interchangeable parts by Eli Whitney.

Tolerances Courtesy: ANSI/ISO

Tolerances Price ? Rs 30 Roundness 25 µ Rs 200 Roundness 5 µ Rs 6000 Roundness 0. 5 µ

Tolerances Clearance Fit

Geometric Tolerances

Geometric Tolerances A B B as a Datum, Parallelism = 0. 05 mm A B A as a Datum, Parallelism = 0. 02 mm

Geometric Tolerances Courtesy: ANSI/ISO

Accuracy & Repeatability 100 shafts of diameter 50 mm were manufactured using different manufacturing processes. When manufactured by process A the diameter of shafts were in the range of 49. 994 to 50. 005 (Accuracy=0. 006) When manufactured by process B the diameter of shafts were in the range of 49. 978 to 50. 024 (Accuracy=0. 024) Process A has better accuracy than Process B When manufactured by process C the diameter of shafts were in the range of 49. 979 to 49. 981 (Accuracy=0. 021) Process C has better repeatability than Process A Accuracy and Repeatability

Accuracy & Repeatability Accuracy and Repeatability

Accuracy and Resolution Shafts Y and Z of diameter 50 mm manufactured using a process were measured using three different instruments. Shaft Y Shaft Z Steel Rule 49. 5 mm 50. 0 mm Vernier Caliper 49. 41 mm 49. 89 mm Micrometer 49. 408 mm 49. 892 mm Resolution of steel rule is 0. 5 mm, vernier is 0. 01 mm and micrometer is 0. 001 mm. Accuracy and Resolution

Metrology Shafts of diameter 50 mm were manufactured using a process and needs to be inspected for meeting tolerances. Micrometer (Option A)

Metrology Mechanical Comparator (Option B)

Metrology 79. 352 = 75 + 1+ 1. 3 + 1. 05 + 1. 002 Slip Gauges

Metrology Snap Gauge/Go-Nogo Gauge (Option C)

CMM Cylindricity Flatness Roundness CMM – Coordinate Measuring Machine

CMM Flatness – 6 Parallelism – 3 Squareness – 12

CMM yi y = a + bx ei = yi – (a + b xi ) a + b xi CMM – Coordinate Measuring Machine

Straightness

CMM – Coordinate Measuring Machine