MANUFACTURING ENGINEERING LAB 5

(MME 3125)

EXPERIMENT 1

BASIC MEASUREMENT

SECTION 1

GROUP MEMBERS:

WAN EMIRA AZATY BINTI WAN ABDULLAH (0634018)

NOR SURIZA BINTI ZABIDIN (0637428)

EXPERIMENTAL DATE:

TUESDAY- 5TH JANUARY 2010

REPORT DUE DATE:

TUESDAY- 12TH JANUARY 2010

LECTURER:

DR. KONNEH

OBJECTIVES:

1. Introduction to linear and angular method of measurement using vernier caliper, micrometer, depth micrometer, pin gauge set, radius gauge set and so on.

2. To recognize and exposed to the various measuring tools and equipment that are available in the Metrology Lab.

3. To learn how to use the measurement equipment such as steel rule, vernier calipers, height caliper, depth gauge, gauge (pin, black, radius, thickness), depth micrometer etc.

4. To compare the precision and the accuracy of the different measuring instruments.

INTRODUCTION:

In this measurement section, we learned all about the measuring tools which are commonly

used in workshop. Measurement can be using so many instruments such as vernier caliper

micrometer, dial caliper, ruler and other instruments.

EQUIPMENT:

vernier caliper micrometer dial caliper ruler ball bearing NTN 6305NX

PROCEDURE:

1. All the dimension of the ball bearing has been measured. 2. The diameter of the ball bearing must be measured using vernier caliper, micrometer, dial

caliper and ruler.3. The thickness of the piston has been measured by depth micrometer.4. All the measurement should include the proper

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DATA AND ANALYSIS:

VERNIER CALIPER MICROMETER DIAL CALIPER RULER

RESULTS:

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DISCUSSION:

Based on this experiment we can say that, while we are measuring the ball bearing there

are some errors occurred. An ‘error' is a deviation from accuracy or correctness. A ‘mistake' is an

error caused by a fault: the fault being misjudgment, carelessness, or forgetfulness. An error is a

bound on the precision and accuracy of the result of a measurement. These can be classified into

two types: random error and systematic error. Random error is caused by inherently

unpredictable fluctuations in the readings of a measurement apparatus or in the experimenter's

interpretation of the instrumental reading, whereas systematic error is predictable, and typically

constant or proportional to the true value. If the cause of the systematic error can be identified,

then it can usually be eliminated. Such measurement errors can also be referred to as

uncertainties.

The devices of measurement have different accuracy. Steel Ruler has accuracy of 1 mm,

Vernier Caliper has accuracy of 0.05 mm and Vernier micrometer has accuracy of 0.01 mm.

From these devices, Vernier Micrometer has highest accuracy, followed by Vernier Caliper and

Steel Ruler respectively. Actually, accuracy refers to how closely individual measurement agree

with the correct, or “true” value.

No measurement can be made to give an exact dimension. Fundamentally this is because

eventually the numerical value recorded depends upon the human eye reading a scale. The

reading therefore becomes an estimate, the accuracy of which depends on the accuracy of the

scale, the ability of the operator to read the scale, and in some cases the sensitivity of touch or

feel on the part of the operator.

Scale error occurred when we not well calibrating the instrument. This can only be

overcome by calibrating the instrument scale against known standard of length over its whole

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length. Besides, some error occurred when reading the scale. Our eyes do not parallel to the scale

point.

MEASUREMENT METHODS

Vernier Caliper

A Vernier caliper is a device that used to measure inside and outside dimensions and also the

depth gauge measurement. The vernier caliper consist of several part, that is fixed jaw, sliding jaw,

fixed scale, vernier scale, inside measuring surface, outside measuring surface, adjusting clamp and

also the depth gauge.

The vernier caliper measurement dimension is between one division on fixed scale, and one

division on the vernier scale is 0.1mm.

How to use:

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Using Outside and Inside Caliper

Micrometer

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The vernier micrometer is a device that is more precise in reading compare to vernier caliper or even

more the normal steel ruler. Its accuracy is about 0.01mm. The main part of the micrometer is spindle;

thimble, micrometer screw, racet, clamp ring, frame, anvil, measuring faces and etc. the micrometer can

also be use to measure inside and depth.

Steel Ruler

It is a normal ruler, ranging from 150, 300 and 600 mm with precision up to 1 decimal point only.

To provide accurate measurement it is important that the principal of a common datum or reference plane

is adopted. Measurement from the steel ruler depends on the visual alignment against the nearest division

on the scale. Usually, a part of a millimeter will have to be estimated.

ERRORS/ SUGESTIONS:

Every device has the advantages and also weakness. For Steel Ruler, its advantages are

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1. can measure the big length compare to other2. easy to use, easy to handle3. this device difficult to damage

In contrast, their weaknesses are

1. is the least accurate devices (1 mm)2. parallax error can very easily occur when our eye is non-vertical on the scale (refer to the

appendix)

For the Vernier Caliper, their advantages are

1. More accurate than Steel Rule (0.05 mm or 0.02 mm). In addition, it use “meter” for more accurate measurement

2. can ‘clock’ the length that has taken, so, it can prevent the error when we taking measurement

Their weaknesses are

1. Can only measure small object (small distance). Have limitation of measurement2. More sensitive device, and may be, it become damaged if it drops on the floor

For the Vernier micrometer, their advantage is

1. the most accurate device compare to othersIn contrast, their weaknesses are

1. Can measure only for small distance, have measurement limit. That is why we use Hi-Vernier Caliper to measure the length (l) of the cubes

2. More sensitive device, may be can damage if it drop on the floor.

CONCLUSION:

In conclusion, we achieved our objectives of this experiment. Although some errors

occurred that does not much effect our experiment. Now we know how to use the instruments

properly.

REFERENCES:

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Metrology for Engineers by J.F.W.Galyer, 5th edition,ELBS

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