MM322 lab 1 report.pdf

7/27/2019 MM322 lab 1 report.pdf

1/5

MM322-Metrology and Instrumentation

Lab1: Linear Measurement Page 1

The University of the South PacificSchool of Engineering and Physics

MM 322 Metrology and Instrumentation

Lab 1: Linear Measurement

Name : Jowesh Avisheik GoundarID: S11076586

AIM To determine the accuracy of vernier caliper and micrometer when used for linearmeasurement.

EQUIPMENT

Five Specimens with variable dimensions 2 different types of vernier caliper [manual and digital] 2 different type of micrometer

INRODUCTION A measurement is an act of assigning a specific value to a physical variable and thisphysical system is the measured variable. Linear measurement is simply the distancebetween two points in a straight line which can be measured with meters, inches,millimetres kilometers.

In this lab, it will be seen the accuracy of vernier caliper and micrometer when used tomeasure different specimens properties such as internal diameter, external diameterand the specimens length. It will also discuss the use of uncertainties and types of errorsduring the duration of the experiment.

Figure 1: The instruments utilized in this experiment.


2/5



EXPERIMENTAL SET UP

Figure 2: Measuring of a specimen using Micrometer

RESULTS AND DISCUSSIONVernier Caliper 1Table 1: Results for Internal Diameter

SampleNo.

Test 1 Test 2 Test 3 Test 4 Test 5 MeanStandardDeviation

%Uncertainty

1 12.1 11.95 12.15 12.05 11.95 12.04 0.089442719 0.742 20.5 20.05 20.5 20.5 20.3 20.37 0.198746069 0.98

3 20.9 20.9 21.05 20.9 20.9 20.93 0.067082039 0.324 26.9 26.8 26.85 27.1 27.05 26.94 0.129421791 0.485 23.5 23.55 24.8 24.8 24.8 24.29 0.698569968 2.88

Table 2: Results for External Diameter

SampleNo.


%Uncertainty

1 18.65 18.6 18.6 18.6 18.65 18.62 0.027386128 0.152 31.1 31.05 31.05 31.1 31.4 31.14 0.147478812 0.473 30.05 30.05 30.9 30.9 30.9 30.56 0.465564174 1.52

4 40 39.85 39.9 39.95 39.9 39.92 0.057008771 0.145 44.95 45.44.95 44.95 44.95 45 44.9625 0.025 0.06

Table 3: Results for Length

SampleNo.


%Uncertainty

1 35.9 35.9 35.9 35.9 35.9 35.9 0 0.002 37.5 37.4 37.3 37.5 37.35 37.41 0.089442719 0.243 33.85 34.2 33.9 34.05 34.2 34.04 0.163554272 0.484 49.3 49.3 49.25 49.15 49.35 49.27 0.075828754 0.15

5 48 47.95 48 48 48 47.99 0.02236068 0.05


3/5



Vernier Caliper 2 [Digital]Table 4: Results for Internal Diameter

SampleNo.


%Uncertainty

1 11.93 11.78 11.75 11.84 11.9 11.84 0.076485293 0.652 20.45 20.44 20.43 20.28 20.45 20.41 0.073143694 0.363 20.91 21.02 21.04 21.02 20.89 20.976 0.070213959 0.334 26.92 27.18 27.08 27.14 27.1 27.084 0.099398189 0.375 23.31 23.28 23.45 23.38 23.33 23.35 0.06670832 0.29

Table 5: Results for External Diameter

SampleNo.


%Uncertainty

1 18.81 18.78 18.8 18.83 18.81 18.806 0.018165902 0.102 31.25 31.23 31.2 31.18 31.19 31.21 0.029154759 0.093 30.19 30.17 30.14 30.15 30.15 30.16 0.02 0.074 40.07 40.08 40.1 40.05 40.05 40.07 0.021213203 0.055 44.28 44.29 44.37 44.27 44.2 44.282 0.060580525 0.14

Table 6: Results for Length

SampleNo.


%Uncertainty

1 36.04 36 36.01 36.02 36.02 36.018 0.014832397 0.042 37.39 37.4 37.39 37.4 37.42 37.4 0.012247449 0.033 34.17 34.18 34.15 34.2 34.2 34.18 0.021213203 0.064 49.4 49.39 49.39 49.38 49.4 49.392 0.0083666 0.025 48.22 48.3 48.22 48.23 48.16 48.226 0.049799598 0.10

Micrometer 1Table 7: Results for Internal Diameter

SampleNo.


%Uncertainty

1 21.12 21.12 21.09 21.04 21.13 21.1 0.036742346 0.172 20.44 20.48 20.47 20.57 20.45 20.482 0.051672043 0.253 27.13 27.2 27 27.15 27.13 27.122 0.073959448 0.274 - - - - - - -5 23.88 23.83 23.85 23.79 23.9 23.85 0.043011626 0.18


4/5


5/5



Therefore,

DISCUSSION Standard deviation simply shows that how close or far the values of the data are from themean value or simply the distribution of data. If it is near 0, this showed that the dataobtained are accurate and precise and from the results it was seen that for somemeasurements the data were distributed close to each other thus the uncertainty orpercentage error was not so much. The maximum error was found to be 1.52%. Thisshowed that the data collected were good and accurate. Since the data were multilple thebest estimation for error was done from the standard deviation since there were alsodigital instruments present, but for some instruments the accuracy was given such as forvernier caliper the accuracy was given to be Some data were not able to becollected for micrometer values since the instrument had limited measurement size thusthe specimens could not be fit into the measuring size of the instrument. The valuesobtained had some differences and this was due to errors such as systematic error forexample the sensitivity of the digital vernier caliper could not be adjusted while somewere operator error to read accurate and precise results from the measuring device.

CONCLUSION

From this experiment, it could be observed the accuracy and precision of severalmeasuring devices. The main prospective was to learn how to use the instrumentscorrectly and derive the uncertainty or the error of the device, and this task wassuccessfully learnt and completed. It was noted that in comparison to many device of same purpose and usage has different level of accuracy and precision but this is not onlydependent on the device but the operator also. How precise and accurately the operatorcould read out the measurements from the device is the most important task to reduceand minimize errors and uncertainties in the results. The results differed mainly due tothis error [operator error] while other means of error caused during this experiment were systematic whereby the instruments sensitivity and resistance could not beadjusted.

REFERENCEUncertainties & Error Analysis Tutorial. (2012). Retrieved August 06, 2013, from Physics education:

https://www.google.com/url?sa=t&rct=j&q=&esrc=s&source=web&cd=4&cad=rja&ved=0CEAQFjAD&url=http%3A%2F%2Fphysics.wustl.edu%2Fintrophys%2FPhys117_118%2FLab_Manual%2FTutorials%2FErrorAnalysisTutorial.pdf&ei=95MHUsXwJOuuiQf19IGYCQ&usg=AFQjCNEC--VUCxqR4etiII9Dz

Figliola, R. S., & Beasley, D. E. (2011). Theory and Design of Mechanical Measurements. United Statesof America: John Wiley and Sons, Inc.

Documents

MM322 lab 1 report.pdf