142503485 Metrology Lab Manual

7/28/2019 142503485 Metrology Lab Manual

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Measurement of Screw thread profile by Profile Projecto

AIM

To measure the thread parameter of given screw thread using Profile projector

APPARATUS REQUIRED

1. Profile projector

PARAMETER TO BE MEASURED

1. Major and Minor diameter

2. Depth and Pitch of thread

THEORY

Minor diameter

It is the diameter of an Imaginary co-axial cylinder which would touch the root of external or internal thread.

Major Diameter

It is the diameter of an imaginary co-axial cylinder which would touch the crest of external or internal thread.

Depth

The distance between the crest and root of the thread is called Depth of Thread Pitch of Thread

The distance measured parallel to the axis from a point on a thread to the Corresponding next point

Pitch angle

The Pitch angle is made by the thread at the pitch line with axis.

PROCEDURE

1. Clean the instrument and its accessories by fine cotton cloth2. Clamp the specimen in between the jaws present in the profile Projector

3. Switch on the power and adjust the degree of magnification in profile projector

4. The magnification depends upon the distance between the Local plane of the lens and the screen

5. Bring the specimen image to the screens axis by adjusting the micrometer and rotation of screen

6. Now the parameters of threads are measured and tabulate the readings.

Tabulation

S.NoMajor

Diameter(mm)

Minor

diameter(mm)

Pitch of

thread(mm)Pitch angle Depth(mm)

1 Major

2

3

4

RESULT:

Thus the thread parameters of given screw thread was found using profile projector


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Measurement of Temperature by Thermocouple.

AIM:

To measure temperature using thermometer and thermocouple apparatus

APPARATUS REQUIRED:

Thermocouple

Thermometer

FORMULA USED:

Error = Ta Ti

% Error = Error

-------------- x 100

Ta

Where Ta is the actual temperature

Ti is the thermocouple indicated temperature

THEORY:

The basic principle of thermocouple is when two dissimilar metals are joined together an e.m.f will exist between the tw

points A and B, which is primarily a function of the junction Temperature. The above principle is called see back effect

The thermocouple consists of one hot junction and one cold junction. The hot junction will be introduced into the place

where temperature is to be measured. The other cold junction is maintained at constant reference temperature. Also one

voltage measuring instrument is connected to the free ends of the thermocouple.

In thermocouple the known temperature is called reference temperature. The temperature which is to be measured isintroduced in the thermocouple hot junction. A common arrangement for establishing the reference temperature is ice b

The reference Temperature is controlled to be at a constant temperature is at 0 C The temperature difference between t

Ice bath and the hot junction temperature will create an e.m.f. This e.m.f production is measured in the mill voltmeter. S

this change in e.m.f rate will give the measure of temperature.

PROCEDURE

1. Clean the instrument and its accessories by fine cotton cloth.

2. Check connection made and switch on the instrument by rocker switch.

3. The display glows to indicate is on.

4. Allow the instruments in on position for 10 minutes for initial warm up.

5. Fill around 3/4th full of water to the kettle and place the thermometer and thermocouple inside the kettle6. Note down the initial water temperature from the thermometer. Adjust the initial set potentiometer in the front pan

till the display reads initial water temperature

7. Switch on the kettle and wait till the water boils note down the thermometer reading and set

8. Potentiometer till the display reads boiling water temperature.

9. Remove the thermometer and temperature sensor from the Kettle and change the water and replace

10. The thermometer reading and set final set potentiometer till the display reads boiling water Temperature

11. Switch on the kettle and note down the reading for every 10 interval and tabulate the readings

12. Plot the graphs between actual reading Vs indicator reading


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Tabulation:

S.No Actual

Temperature(Ta)

Indicated

Temeperature(Ti)

Error % of Error

Result:Thus the performance test on Thermocouple trainer has been performed.


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Measurement of Displacement by using LVDT

AIM:

To measure the displacement by using linear variable differential transformer

APPARATUS REQUIRED:

LVDT setup

Theory:

Linear variable differential transformer is the most popular electro mechanical displacement into electrical signal in ef

is a transformer consisting of three symmetrical spaced coils carefully wounded on insulation. It works on mu

inductance principle and consists of primary coils Wound .AC carried excitation is applied to the primary and

secondary are connected externally in a Series opposition to it. A cylindrical shield of ferromagnetic material is spun o

the washers. The device also becomes extremely rugged and reliable. There is a non contacting magnetic core,

Carefully annealed to improve the stability which moves in the centre of the core varies the mutual Inductance of e

secondary to the primary, which determines the voltage inducted from the primary to the secondary. If the core is cente

in the middle of the two secondary windings if the core is moved off middle position then the mutual inductance of

primary with secondary will be greater than the other and a differential voltage will appear across the secondary in serie

For off center displacement within linear range of operation the output is essential a linear function of core displacemen

Procedure:

1. Check the connection made and switch on the instrument by rocker switch at the front panel the display glows to

indicate is ON.

2. Allow the instrument in ON position for 10 minutes.

3. Rotate the micrometer till it reads 20

4. Adjust the CAL potentiometer at the front panel so the display reads the 20.

5. Rotate the core of the micrometer till it reaches the 10 and adjust the zero potentiometer

6. Rotate back the micrometer core upto 10

7. As the core of the LVDT moves the display reads the displacement

8. Rotate the core of micrometer in steps of 2mm and tabulate the readings

9. Plot the graphs between actual reading Vs indicator reading, Actual reading

Vs error and Display the results.

S.No Actual

Displacement(Da)

Indicated

Displacement (Di)

Error % of Error

RESULT:

Thus the Performance test on LVDT was conducted


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CALIBRATION OF PRECISION MEASURING INSTRUMENTAim:

To study and calibrate the precision measuring instruments like Vernier caliper,Micrometer,

Apparatus Required:Surface plate, Vernier caliper, Micrometer and Slip gauges.

Specification:Vernier caliper Range: L. C:Micrometer Range: L. C:Study:

1.) Vernier caliper:

The Vernier caliper has one L shaped frame with a fixed jaw on which Vernier scaleattached. The principle of Vernier is that when two scale divisions slightly different in sizes

can be used to measure the length very accurately.Least Count is the smallest length that can be measured accurately and is equal to tdifference between a main scale division and a Vernier scale division.

LEAST COUNT = 1 Main scale division 1 Vernier scale division

Uses:It is used to measure the external diameter, the internal diameter and the length of

given specimen.

2.) Micrometer:The micrometer has an accurate screw having about 10 to 20 threads/cm and revolv

in a fixed nut. The end of the screw is one tip and the other is constructed by a stationaryanvil.

LEAST COUNT = Pitch scale division / Number of threadsPitch scale division = Distance moved / number of rotation

Uses:Outside micrometer is used to measure the diameter of solid cylinder.Inside micrometer is used to measure the internal diameters of hollow cylinders and

spheres.

3.) Slip gauges:

They are rectangular blocks hardened and carefully stabilized. The surfaces are highpolished to enhance wringing. It is used as a reference standard for transferring thedimensions of unit of length from primary standard. It is generally made up of high carbon,high chromium hardened steel.Uses:

These are accurate and used as comparator.

5.) Surface plate:


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The foundation of all geometric accuracy and indeed of all dimensional measuremenin workshop is surface plate. It is a flat smooth surface sometimes with leveling screwsat tbottom.

Uses:It is used as a base in all measurements.

Procedure For Calibration:1.) The range of the instruments is noted down.2.) Within that range, slip gauges are selected.3.) The measuring instrument is placed on the surface plate and set for zero and the sli

gauges are placed one by one between the measuring points4.) The slip gauge (actual) readings and the corresponding (observed) readings in the

measuring instruments are noted down and tabulated.

S.No

Slip GaugeReading

(Actual)In mm

Precision Measuring Instruments Reading (Observedl) in mm

Vernier Caliper Micro Meter

MSR(mm)

VSR(div)

TR(mm)

Error(mm)

PSR(mm)

HSR(div)

TR(mm)

Error(mm)

1

2

Result:

The precision measuring instruments are studied and calibrated.


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TORQUE MEASUREMENTAim:

To measure the torque using shear type load cell.

Apparatus Required:

1. Torque measurement equipment2. Stand3. lever4. stain gauge5. Weight.

Formula Used:

Calculated Torque = Load x Distance (kg-m)

Description:

Torque is the tangential force to set a body in rotation. It is represented as a vecof a force for a rigged body undergoing force rotation about a single axis.

Torque = DX,D = Moment of inertia of body about the axis.X = Angular acceleration.

Thus torque is the essential tensional twisting about its axis of rotation. In this se

shear type load is used to measure the torque a inverse method of measuring the load wit

the output immune to side load and bending moment is based on measurement of shearcomponents. The load cell is balancing a beam supported on both ends.

Procedure:

1. Fix the main frame of transducers rigidity.2. Connect the cantilever beam with weight pan.3. Connect transducer wire socket to rear side of indicator.4. Connect digital indicator at 230V, AC supply.5. Set zero on indicator, by zero adjust pan provides indicator.6. Now apply the load gradually and note down reading in upward & downward

trend.

Sl.no Weight added (Kg)Observed torque

(Kg-m)Calculated Torque

(Kg-m)1234


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5Model Calculation:

Calculated Torque =Load x Distance (kg-m)

Result:

Thus measurement of torque using shear type load cell has been carried o

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142503485 Metrology Lab Manual