METROLOGY
DPT 312
PREPARED BY:
CIK ROSHALIZA HAMIDON
roshaliza@unimap.edu.my
0194754105
049852639
ROSHALIZA HAMIDONMETROLOGY-010809
CHAPTER 1
INTRODUCTION TO
METROLOGY &
QUALITY
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OUTLINE
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Overview
Metrology & Measurement
The uses of measurement
Quality
Measure of Quality
Inspection
What to inspect??
Why we need for Quality and inspection?
Metrology and Quality Control
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Overview
• The old saying ‘ measure it twice and cut it
once’…….
• The measurements we make with
accuracy and precision will reduce the
waste of materials and will further
contribute to the production of high
quality items
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Metrology and Measurement
• Metrology comes from Greek word ‘metron’ (measure)
and –logy.
• Metrology is the science of measurement and
measurement is the language of science (language to
communicate about size, quantity, position,
condition and time
• Metrology includes all theoretical and practical
aspects of measurement
• Measurement is a procedure in which an unknown
quantity compared to a known standard, using an
accepted and consistent system of units
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Figure 1.1 This derivation of the Vitruvian Man by Leonardo da Vinci,
depicts nine historical units of measurement: the Yard, the Span, the
Cubit, the Flemish Ell, the English Ell, the French Ell, the Fathom, the
Hand , and the Foot. The Vitruvian man was drawn to scale, so the units
depicted are displayed with their proper historical ratios.
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Figure 1-2 Without metrology there is no science. This principle has been recognize
since the early years of human history, as these examples of fundamental quantities
show. Each era produced its equivalent.
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Metrology and Measurement
(cont’)
• In manufacturing, metrology is defined as
the measurement of dimensions: length,
thickness, depth, diameter, angle, flatness,
straightness, roundness and surface roughness
• Why we need measurement??
1. To make things
2. To control the way other people to make
things
3. For scientific description
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The uses of measurement
To make things
To control manufacture
For progress
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Quality
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Quality is a very important aspect of manufacturing.
Definition of quality
i. Deming - “non-faulty systems”
ii. Juran - “fitness for use”
iii. Crosby - “conformance to requirements”
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Customer’s view (more subjective)
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Producer’s view
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the quality of the design (look, feel, function)
product does what’s intended and lasts
conformance to requirements (Crosby)
costs of quality (prevention, scrap, warranty)
increasing conformance raises profits
Government’s view
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products should be safe
not harmful to environment
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Measure of Quality
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Inspection
• An inspection is, most generally, an organized
examination or formal evaluation exercise.
• It involves the measurements, tests, and gauges
applied to certain characteristics in regard to an
object or activity.
• The results are usually compared to specified
requirements and standards for determining
whether the item or activity is in line with these
targets
(wikipedia)
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What to inspect?
• Inspection specific to PRODUCTS
 Electronic parts (circuits, chips, etc.)
 Machine elements (engines, brakes, gears, etc.)
 Heat and thermodynamic components (engines, fuel injectors
 Medical and Bio-related products (implants, dental
devidevices, surgical parts, etc.)
• Inspection specific to PROCESSES
 Chip removal processes (turning, milling, drilling, etc.)
 Chipless manufacturing (casting, molding, forging, etc.)
 Non-traditional methods (EDM, ECM, ultrasonics, etc.)
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Why We Need for Quality and
Inspection??
• Quality is a very important aspect of
manufacturing.
• Needed for interchangeable manufacturing.
• Basic concept of standardization and mass
production
• Components of a product must fit together,
assemble properly and be replaceable
• Quality should be built into a product.
• Prevention of defects is a major goal
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Metrology and quality control
• Certification to ISO 9000 standards has become a
primary requirement for both manufacturing and service
oriented organization
• Calibration and control of test, measurement and inspection
equipment is one of the more important requirements
given in standard
• Requirement of ISO 9001: 2000
• Metrology, the science of measurement, plays an
important roles in checking if specifications are met, and
is needed to develop experimental data for analyzing a
process
• The quality of goods and services offered is highly dependent on
reliable measurement.
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References
• C.l.Dotson, Fundamentals of
Dimensional Metrology, Thomson
Delmar Learning, 2006
• A. T. Bozdana, PP, Engineering
Metrology and Quality Control,
Mechanical Engineering University of
Gaziantep
• Analysis of Material Removal
• G.M.S de Silva, Basic Metrology for
ISO 9000 certification, Butterworth
Heinemann, 2002
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