mqa lab report

8/9/2019 MQA Lab Report

1/15

hammad Waleed Tariq2-ME-166

Submitted To

Engr. Muhammad Waqas

Rafque

Metrology and QualityAssurance Lab

Lab Reports 01 to 0


2/15

Lab Session 01

To measure the lengths and diameters of given sample pins by Vernier Caliper

Apparatus

• Sample pins

• Vernier Caliper

Theory

Vernier Caliper A measuring device that consists of a main scale with a fixed jaw and a sliding jaw

with an attached Vernier. It can measure the object with an accuracy of hundreds of

millimeters.

Types of Vernier Caliper

i Inner ! Internal Vernier CaliperThe inner calipers are used to measure the internal si"e of an object.

ii #xternal Vernier Caliper#xternal calipers are used to measure the external si"e of an object.

iii $ivider ! %ointer Vernier CaliperA divider caliper& popularly called a compass& is used in the process of mar'ing

out locations. A divider caliper is also used to measure a distance between two points on

a map. The two caliper(s ends are brought to the two points whose distance is being

measured.

iv $ial ! Analogue Vernier CaliperInstead of using a Vernier mechanism& which re)uires some practice to use& the dial

caliper reads the final fraction of a millimeter or inch on a simple dial.

http://en.wikipedia.org/wiki/Marking_outhttp://en.wikipedia.org/wiki/Marking_outhttp://en.wikipedia.org/wiki/Maphttp://en.wikipedia.org/wiki/Maphttp://en.wikipedia.org/wiki/Marking_outhttp://en.wikipedia.org/wiki/Marking_out


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v $igital Vernier CaliperAn electronic digital display on which the reading is displayed as a single value.

Parts of Vernier Caliper

*. Outside large jaws+ used to measure external diameter or width of an

object

,. Inside small jaws+ used to measure internal diameter of an object

-. Depth probe+ used to measure depths of an object or a hole

. Main scale+ scale mar'ed every mm

/. Main scale+ scale mar'ed in inches and fractions

0. Vernier scale+ gives interpolated measurements to 1.* mm or better

2. Vernier scale+ gives interpolated measurements in fractions of an inch

3. Retainer + used to bloc' movable part to allow the easy transferring of a

measurement

Observations

4east count of Vernier caliper 4.C 5 1.1/ mm

Vernier scale divisions 5 ,14east Count 5 1 mm

Table

Sample in !

Sr. No. Sample Pin Main Sale Vernier Total Total

http://en.wikipedia.org/wiki/Electronicshttp://en.wikipedia.org/wiki/Display_devicehttp://en.wikipedia.org/wiki/Electronicshttp://en.wikipedia.org/wiki/Display_device


4/15

Measurement

s

!ea"in#

mm

Sale

!ea"in#

!ea"in#

mm

!ea"in#

in

* $* ,/ 0 ,/.- 1.660

, $, */ *0 */.3 1.0,,

- $- 6 3 6. 1.-21

7* *, , *,.* 1.20

/ 7, - *6 -.6/ *.2-1

0 7- 2, *2 2,.3/ ,.303

Sample in "

Sr. No. Sample Pin

Measurement

s

Main Sale

!ea"in#

mm

Vernier

Sale

!ea"in#

Total

!ea"in#

mm

Total

!ea"in#

in

* $*8 ,/ ,/., 1.66,

, $,8 */ *0 */.3 1.0,,

- $-8 6 3 6. 1.-21

7*8 *, / *,.,/ 1.3,,

/ 7,8 - *2 -.3/ *.2,0

0 7-8 2, *6 2,.6/ ,.321

Speimen Calulation

#or Sample in !

Total Reading= Main Scale Reading+Vernier Scale Reading× Least Count ± Zero Error

Total Reading=25+6×0.05±0=25.3mm=0.996∈¿

#or Sample in "


5/15

Total Reading=25+4×0.05±0=25.2mm=0.992∈¿

Safety Preautions

i 9hen the jaw of the calipers is opened& a thin metal guide extends from the bottom

of the calipers that could cause injury.

ii The depth probe has the pointy end so must be handle with care.

Comments

i Close the jaws firmly while the object in between them.

ii 4oo' for the smooth surface to close between the jaws.iii :etter loo' the most closely coincident division of the Vernier scale with the main

scale.iv The sample pin may have rough surface that gives different readings.

Conlusions

i Instead of giving the dimensions of the sample& Vernier caliper tells us about thesmoothness of the surface

ii Ta'ing more readings of a dimension leads to more accurate one.

!eferenes

1. Joseph Wickham Roe, English and American tool builders (1916) p. 203

2. http://www.mackinmfg.com/ shows a pict!e of the ca"ipe!s #t $oes not sppo!t the R%& c"aim.

3. http://www.sta!!ett.com/$own"oa$/2'6p1011'.p$f

'. http://www.msi*+iking.com/$igita"ca"ipe!/

Lab Session 0$

$evelop the lengths with the help of bloc' gauges.

Apparatus

i :loc' gauges

ii %etrol for cleaning

iii %etroleum ;elly

Theory

$loc% gauges


6/15

&ses of $loc% gauges

They are used as a reference for the calibration of measuring e)uipment usedin machine shops& such as micrometers& sine bars& calipers& and dial indicators =when used inan inspection role.


7/15

'hy $loc% gauges stic% together

• (ir pressure applies pressure between the bloc's because the air is s)uee"ed

out of the joint.

• Surface tension from oil and water vapor that is present between the bloc's.

• Molecular attraction occurs when two very flat surfaces are brought into

contact. This force causes gauge bloc's to adhere even without surface

lubricants& and in a vacuum.

Observation Table

Sr. @o e)uired 4ength


8/15

Required Reading=Total∑of individualsblock gauges

10.5=5+4+1+0.5

Safety Preautions

i :efore using a gauge& thoroughly wash the gauge and product with gas oil or

'erosene& or wipe them with a clean cloth to remove dust and dirt.ii :efore using a gauge& chec' the gauge for any rust& flaw& burr& etc. If rust&

flaw or burr is found& remove it carefully.

Comments

i ?re)uent use of bloc' gauges ma'e their surface rough and inaccuracy

prevails.

ii 9ash the bloc' gauges before using it.iii 4ow pressure applied on the gauge may result in the not stic'ing of the

gauges.

!eferenes

i oi!on, -e$ John ee!s (2009), -he age "ock an$#ook, %: imensiona" &et!o"og4!op, 5ationa" nstitte of tan$a!$s an$ -echno"og4, pp. 17'

ii 8!ie$e", a+e, W!ing a#i"it4, a!chi+e$ f!om o!igina" on 2010*12*22, !et!ie+e$ 2010*12*22.

iii -he age "ock an$#ook, 5-, p. 13*139iv !a! 200, p. 9.

http://www.nist.gov/calibrations/upload/mono180.pdfhttp://www.nist.gov/calibrations/upload/mono180.pdfhttp://en.wikipedia.org/wiki/Gauge_block#CITEREFKrar2005http://www.nist.gov/calibrations/upload/mono180.pdfhttp://www.nist.gov/calibrations/upload/mono180.pdfhttp://en.wikipedia.org/wiki/Gauge_block#CITEREFKrar2005


9/15

Lab Session 0%

To develop the angle with the help of angle gauges

Apparatusi Angle gauges

ii %etrol for cleaningiii %etroleum ;elly

Theory

(ngle gauges

A series of fixed angles are used for comparative assessment of the angle between

the two surfaces. Important specifications to consider when searching for angle gauges

include angular range and angular resolution. Angle gauges come in sets of bloc's with a

range of standard angles.

Observation Table

Sr.

@o

e)uired Angle


10/15

Speimen Calulation

Requiredangle=∑ of totalanlges of angle gauges

1° 30 =1°+30

Safety Preautions

i :efore using a gauge& thoroughly wash the gauge and product with gas oil or

'erosene& or wipe them with a clean cloth to remove dust and dirt.

ii :efore using a gauge& chec' the gauge for any rust& flaw& burr& etc. If rust&

flaw or burr is found& remove it carefully.

Comments

i ?re)uent use of angle gauges ma'e their surface rough and inaccuracy

prevails.ii 9ash the angle gauges before using it.

iii 4ow pressure applied on the gauge may result in the not stic'ing of thegauges.

!eferenes

i) &et!o"og4 ; &eas!ement 4 ewoo!


11/15

Lab Session 0&

To measure the internal angle with the help of :evel %rotractor

Apparatusi Sample models

ii :evel protractor

Theory

$e)el rotractor

% #e+e" p!ot!acto! is a g!a$ate$ ci!c"a! p!ot!acto! with one pi+ote$ a!m se$ fo! meas!ing o!

ma!king off ang"es. -he #e+e" p!ot!acto! is se$ to esta#"ish an$ test ang"es to +e!4 c"ose to"e!ances.

arts of $e)el rotractor

i $ase+ 9hen measuring an angle& the base is placed on the bottom side of

the angle.

ii $lade+The blade is placed on the opposite side of the angle and can be

released from the bevel protractor using a nut!screw& which allows the

protractor to be moved up and down the length of the blade to fit an angle.


12/15

iii Main Scale+ This is the Bprimary scaleB of the bevel protractor& measuring

angles in =as usual degrees.

iv Vernier Scale+ The Vernier scale is a Bsecondary scaleB and allows the angle

to be measured with a greater degree of accuracy. It is measured in

BminutesB and is read second.

v #ine adjustment %nob+ It is designed to allow the user to move the bladearound with a greater degree of accuracy& especially when trying to ma'e the

final alignment with the object to be measured.

vi Magnifying glass+ Some bevel protractors come with a magnifying glass

attached& which helps when reading the angles more clearly.

Observations

4east count of Vernier scale 5 /8

ero error 5 1o

Table

Sr. @o Sample Dodels Angles* A 62o,/8

30o/8

, : 33o-18

**,o18

- C 26o-/8

61o*/8

$ 6,1

/,1/8

Speimen Calulation

!ngle= Main Scaleangle+vernier scale division× L" C ± Zero error

!ngle=97°+ (5×5) =97°25

Safety Preautions

i 9hile using protractor ma'e sure that nothing struc' the magnifying glass&

otherwise it will get destroyed.

ii The jaws should be firmly tightened with the help of 'nobs with wor' piece in

between them otherwise the wor' piece may lose grip and can createdamage.

Comments

i The structure of the wor' piece does not fit in between the jaws.

ii The jaws are not firmly fixed that gives inaccurate reading.

!eferenesi) 8ines (ecem#e! 1993). ?op"a! &echanics

http://books.google.com/books?id=4eMDAAAAMBAJ&pg=PA76http://books.google.com/books?id=4eMDAAAAMBAJ&pg=PA76


13/15

Lab Session 0'To measure the angle of wedge>shaped model with the help of sine bar.

Apparatus

i Sine barii 9edge>shaped model

iii :loc' gauge

iv $ial gauge

Theory

Sine bar

A sine bar consists of a hardened& precision ground body with two precision ground

cylinders fixed at the ends. The distance between the centers of the cylinders is precisely

controlled& and the top of the bar is parallel to a line through the centers of the two

rollers.

9hen a sine bar is placed on a level surface the top edge will be parallel to that

surface. If one roller is raised by a 'nown distance& usually using gauge bloc's& then the

top edge of the bar will be tilted by the same amount forming an angle that may be

calculated by the application of the sine rule.

• The hypotenuse is a constant dimension

• The height is obtained from the dimension between the bottom of one roller

and the table(s surface.

• The angle is calculated by using the sine rule.

&ses of Sine bar

i Deasuring 'nown angles or locating any wor' to a given angle.

ii Chec'ing of un'nown angles. Dany a times& angle of a component to bechec'ed is un'nown.

http://en.wikipedia.org/wiki/Surface_platehttp://en.wikipedia.org/wiki/Gauge_blockhttp://en.wikipedia.org/wiki/Sine#Right-angled_triangle_definitionhttp://en.wikipedia.org/wiki/Surface_platehttp://en.wikipedia.org/wiki/Gauge_blockhttp://en.wikipedia.org/wiki/Sine#Right-angled_triangle_definition


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iii Chec'ing of un'nown angles of heavy component. In such cases where

components are heavy and can8t be mounted on the sine bar& then sine bar ismounted on the component.

Observation Table

$eflection

h

mm

4ength of

model

l

mm

4ength of

sine bar

4

mm

Thic'ness of

bloc' gauge

used

%

mm

Angle

E

degrees

.* *1*.0 ,/ **.1,/ ,.6o

Speimen Calulation

T#ickness of block gauge ( $ )= %eflection(#)× Lengt#of sine ¯( L ) Lengt# of model(l)

$=4.41× 254

101.6=11.025

sin&= $er'endicular ()'otenuse = $ L =11.025254

=0.0434

&=sin−1 (0.0434 )=2.49 °

Safety Preautions

i A compound angle should not be formed by mis>aligning of wor' piece with

the sine bar. This can be avoided by attaching the sine bar and wor' against

an angle plate.

ii Accuracy of sine bar should be ensured.

iii As far as possible longer sine bar should be used since many errors are

reduced by using longer sine bars.

Comments

i 9hile moving the sine bar& the wor' piece slides thus disturbs the reading.

ii The base of the rollers wear that causes the disturbance in experimentation.

iii The surface of sine bar may wear due to which the angle measures is not

accurate.

iv The surface on which sine bar is placed might not be parallel to the surface of

sine bar.


15/15

!eferenesi) http://what*when*how.com/met!o"og4/sine*p!incip"e*an$*sine*#a!s*met!o"og4/ii) go"$ #ooks (n$ia)

,1*,>D#>*00
http://what-when-how.com/metrology/sine-principle-and-sine-bars-metrology/http://what-when-how.com/metrology/sine-principle-and-sine-bars-metrology/

mqa lab report

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