INTRODUCTION TO IQC

TOPIC

CONTENTS INTRODUCTION PHYSICAL QUANTITIES MEASUREMENT BASIC METHOD OF MEASUREMENTS CLASSIFICATION OF UNITS SYSTEM OF UNITS STANDARDS FOR MEASUREMENT INTERCHANGEABILITY INTERNATIONAL AND NATIONAL STD. STANDARDS OF MEASUREMENT

INTRODUCTION Inspection is the art of comparing material, product or performance with established standards. Inspection measures the qualities of a product or service in terms of predecided standards. Products quality specified by strength, shape, hardness or by other parameters.

PHYSICAL QUANTITY All quantity in terms of which laws of physics can be expressed and which can be measured directly or indirectly are called physical quantity. Physical Quantity further divided into two types:- Extensive Quantities Intensive Quantities

Extensive Intensive Extensive quantity: its magnitude is additive for subsystems (volume, mass, etc. Extensive quantity Intensive quantity: the magnitude is independent of the extent of the system (temperature, pressure, etc.) Intensive quantity

MEASURMENT Measurement is the presses of comparison of an unknown quantity with a known fixed unit quantity of the similar nature.

Properties of measurement It should be easy to reproduce. It should be easily accessible. It should be commonly acceptable. It should not change with time and from place to place. It should be well defined.

BASIC METHOD OF MEASURMENT These are two types of basic method of measurement:- Direct comparison Indirect comparison

CLASSIFICATION OF UNITS FUNDAMENTAL UNITS DERIVED UNITS

FUNDAMENTAL UNITS A set of fundamental units is a set of units for physical quantities from which every other unit can be generated.unitsphysical quantities In the language of measurement, quantities are quantifiable aspects of the world, such as time, distance, velocity, mass, temperature, energy, and weight, and units are used to describe their measure. Many of these quantities are related to each other by various physical laws, and as a result the units of some of the quantities can be expressed as products (or ratios) of powers of other units (e.g., momentum is mass times velocity and velocity is measured in distance divided by time). These relationships are discussed in dimensional analysis. Those that cannot be so expressed can be regarded as "fundamental" in this sense.measurementquantifiabletimedistancevelocitymasstemperatureenergyweightdimensional analysis

DERIVED UNIT The units of all physical quantities which can be expressed in terms of fundamental units are called derived units.

SYSTEM OF UNITS C.G.S. SYSTEM F.P.S. SYSTEM M.K.S. SYSTEM S.I. UNITS

C.G.S. SYSTEM:-It is also known as “French system”. In this system the unit of length in centimeter, unit of mass is gram and unit of time is second. F.P.S. SYSTEM:-It is also known as “British system”. It uses foot, pound and second.

M.K.S. SYSTEM:-It is also known as “Metric system”.it is a system of measurement in which the fundamental units of measurement of length, mass, and time are meter, kilogram and second respectively. S.I. UNITS:-French name of this system is “System international” units, abbreviated as s.i. unit. This system is an Improved and extended version of M.K.S. system of unit.

Standard for measurment Primary standred- Primary standred are absolute standerds of high accuracy that are used as refrence standred. Secondary standred- Secondary standred are close copies of primary standred and are used in industries for measurment.

Tertiary standred- These are used for refrence purpose in laboratories and workshop. Working standred- Working standred are used as major tools of measurment in ameasurment laboraratory.

INTERCHANGEBILITY Interchangebility refers to assembling a number of mating component taken at random from stock, so as to build up a complete assembly without fitting or adjustment. Types of interchangebility:- I. Full or universal interchangeability II. Selective assembly III. Matched fits

INTERNATIONAL OR NATIONAL STANDRED International standred- The international standred are defined on the basic of international agreement.The international standred are maintained at the international Bureau of weight and international organizatin for standred.(ISO)

NATIONAL STANDRED- The Bureau of indian standred(BIS)is on the same pattern as british standred institution(BSI).Its principal object are: 1. To use for the improvment. 2. To set up standred of quality and dimension. 3. To samplify production and distrbution.

STANDRAD OF MEASURMENT These days two standerd system of linear measurement,English(yard) and metric(meter) are in general use throughout the world. For linear measurement the various standerd known are:- Line standard End standard Wave length standard

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