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MEM560MEM560Manufacturing ProcessesManufacturing ProcessesTopic 2Topic 2
Rahani Abdul RahmanCo-ordinator: PM Yusof MohdFKM
Topic 2Topic 2
2.0 Introduction2.1 Tolerance, Limits and Fit2.2 Linear Measurement Using Tools and such
as Digital Gauges, Micrometer and Calipers2.3 Angular Measurement Using Profile
Projector2.4 Straightness, Flatness, and Roundness
Measurement2.5 Surface Roughness Measurement2.6 Measurement Using GO and NO GO
ConceptTopic 2 2
Introduction to Metrology Introduction to Metrology and Instrumentation and Instrumentation Science of measurement –
experimental and theoretical with certain level of uncertainties.
i.e: Length – Mass – Flatness – Profiles – taper
Why is it important?
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With a universal meaningWith a defined
uncertaintiesWith a judicious standardizationWith/using good and correct
technique
Tolerance, Limits and FitTolerance, Limits and Fit
2.1 Introduction2.2 Linear Measurement Using Tools and
such as Digital Gauges, Micrometer and Calipers
2.3 Angular Measurement Using Profile Projector
2.4 Straightness, Flatness, and Roundness Measurement
2.5 Surface Roughness Measurement2.6 Measurement Using GO and NO GO
ConceptTopic 2 4
StandardsStandardsWho are the respective parties
responsible to maintain standards of a universally agreed set of guidelines for interoperability.
Local : SIRIMInternational : ISODoing an inspection? With/without Doing a measurement? – With
equipment/ apparatus (attributes – Yes/No OR variables – dimensional wise)
Differentiate the Metric (SI) and Imperial System measurement.
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Category Name Abbv
Length Metre m
Mass kilogram Kg
Time Second S
Electric current
Ampere A
Temperature
Kelvin K
Amount of substance
Mole Mol
Luminous intensity
Candela cd
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Derivations;
-Farad (F)-Hertz (Hz)-Joule (J)-Newton (N)-Ohm (Ω)-Pascal (Pa)-Volt (V)-Watt (w)
Accurate
Allowances
Tolerances
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4.25 +0.01 / - 0.01(BILATERAL)
4.25 +0.01 / -0.00(UNILATERAL)
4.2495 / 4.2505 LIMIT DIMENSIONS
Clearance fit & loose fit / free fit Interference fit
Errors With all dimension inspected, tendency for errors are
great with 3 major categories namely;1. Systematic error- Due to quality of equipment: causes consistent signs
(+ve or –ve)- Due to ambient conditions : temperature, humidity, CO2
or pressure of work piece or instrument2. Accidental error- Due to the smallest gradient in equipment or - Inexperience of equipment user3. Illegitimate error
Calibration- Equipment is compared to;1. primary standard2. Secondary standard (with higher accuracy than the
equipment itself)3. Known input source
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2.2 Linear Measurement Using Tools 2.2 Linear Measurement Using Tools and such as Digital Gauges, and such as Digital Gauges, Micrometer and CalipersMicrometer and Calipers
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Digital Caliper Dial Caliper Vernier Caliper
Point Micrometer
Dual Point Micrometer
Outside Micrometer
Jaw
Nibs
Anvil
Spindle
Frame
Thimble
Sleeve
Ratchet stop
2.3 Angular Measurement Using 2.3 Angular Measurement Using Profile ProjectorProfile Projector
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Main criteria for a PP/optical comparison ;-Diascopic (behind) / episcopic (above) illumination-Measuring stroke-Contour illumination system-Standard equipped turret-X and Y wheel-Digital displays-Focusing (motor-driven or manual)-Bulbs-Overlay Charts-Resolutions-Data processing unit
Angle measurement;Protractor : measuring angle via displacement method in reading of degrees
2.4 Straightness, Flatness, and 2.4 Straightness, Flatness, and Roundness MeasurementRoundness Measurement
Straightnessi.e Laser beamFlatnessi.e reference of surface (3 points)
onto new reference plane (3 points)i.e use of calibrated granite tableRoundnessi.e use of dial indicator with object
set on V-block, error in roundness can be directly known by comparing the peak height as measured by the dial gauge.
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2.5 Surface Roughness 2.5 Surface Roughness MeasurementMeasurement
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Characteristic of a surface is its structure, texture and roughness.-Structured : microscopic level - effect of processes that the raw material had gone through.-Texture : repetitive and/or random deviations from the nominal surface of an object (roughness, waviness, form, lays and flaws).surface profile = error of form + waviness + roughness-Roughness : surface profile (peaks and valley)-Integrity : sub-surface alterations produced due to manufacturing.
2.6 Measurement Using GO and 2.6 Measurement Using GO and NO GO ConceptNO GO ConceptGauges : device that measures the dimension of an
object or to measure the dimension of produced part if it is within specified limits.
: gauge of a numeric scale for metal thickness
GO-NO-GO and GO gaugesGauges that gives categorical data on one or
more dimension of a work piece is within specification.
Limit Gauges / Attribute gauges
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