305 lab 1

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Metrology Lab #1

Timothy KovacsIE 305, Section 007

December 10, 2012

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Introduction

The purpose behind this lab activity was to get acquainted with the metrology laboratory

instrumentation, learn how to properly use, care for, and read the numerous metrology

instruments and how to wring gage blocks so that measurements and calibrations are as

precise as possible. Included in this group of instruments that were used to learn how to

read inch and metric Vernier scales were a conventional micrometer, digital micrometer,conventional caliper, digital caliper, depth micrometer, and a Vernier height gage. In

addition to the measurement of objects using these instruments, the weights ofmanufactured copper tube components were taken to learn to use the metrology scale. In

todays society, the main use for copper tubing is in homes for water piping as well as

refrigeration systems due to its great thermal conductivity. In addition, copper is

formable, and able to bond very well to solder so that it can be joined to create complexsystems of piping. This tubing can either be rigid as in tempered copper, which is made

in straight lengths, while soft copper(annealed) can be easily bent to create a turn in water

piping, or for use in coils. Copper is made through an extensive process in which it ismined as sulfide and oxide ore and then crushed, concentrated, heated, and refined before

it is drawn to create copper wire or compiled into slabs, billets, and ingots for use incopper pipes and other things.

Methodology

In this lab, four different work pieces were measured using the various instrumentsincluding, conventional micrometer, digital micrometer, conventional caliper, digital

caliper, depth micrometer, and a Vernier height gage. For each of these objects,

depictions of the piece showed the specific dimensions that needed to be taken, as well as

the instrument that was to be used for each dimension measurement. Therefore, forexample the workpiece W_1 has a dimension D_11 that was to be measured using

instrument 3 and 4, which are the conventional and digital calipers respectively. Eachinstrument was then used to make three separate measurements for that specificdimension and the measurements were then averaged to find an average reading for each

instrument for each dimension. This process was then completed for all dimensions for

the four work pieces.

When using the conventional micrometer, there are some important rules to follow when

reading the measurement shown by the instrument. As can be seen in the picture below,

the micrometer is made up of a main bar with a horizontal scale which measures inincrements of 0.1, and a vertical scale which measures in increments of 0.0001. In

addition to the main bar, there is a sleeve that covers the bar and has a vertical scale, on

which the increments are measured to 0.001. To read this instrument, the measurer mustfirst read the measurement of the last fully viewable line on the horizontal scale(0.15).

Then, the measurer must read the vertical scale on the sleeve(0.011)and add that

measurement to the first recorded measurement. Finally the measurer has to read the

measurement of the vertical scale on the main bar(0.0003) and add that measurement tothe first two measurements. These three measurement values are then added(0.15 +

0.011 + 0.0003 = 0.1613)to compute a final value for the measurement of the

dimension.

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Figure 1 - Conventional Micrometer

A Vernier scale is also an important scale that the measurer must learn how to use to read

the measurements for the conventional caliper as well as the height gage. To do this, themeasurer first locates the last line on the main scale that the 0 mark on the Vernier scale

has passed, which according to the image below is 22 mm. Then the measurer finds the

increment on the Vernier scale that matches up exactly with an increment on the mainscale which is read in tenths of a millimeter (0.6mm). The two measurements are then

added together as shown, and the final measurement for this dimension would be 22 + 0.6

= 22.6 mm.

Figure 2 - Conventional Caliper (Vernier Scale)

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Table 1: Tool Precisions

Tool Precision

Conventional Micrometer 0.0001

Digital Micrometer 0.00001

Conventional Caliper 0.001

Digital Caliper 0.001

Depth Micrometer 0.001Vernier Height Gage 0.001

In this lab, gage blocks were used by finding the minimum number of blocks needed tocreate the given reference lengths of 0.8597 and 2.3012. By wringing the blocks

together, these distances could be measured accurately, as there was no longer air or any

other substance between the two gage blocks. The next step in the completion of the lab

was to randomly select 10 copper pieces to be weighed using the very accurate metrologyscale in the metrology lab. The weight of each of the copper pieces was then recorded, as

well as measuring each piece for its diameter and thickness. The data from these

recorded values was then used to compute the mean, standard deviation, and tolerance of

the set of copper pieces.

Results

The instrument numbers indicated in the results are as follows,

1Conventional Micrometer

2Digital Micrometer3Conventional Caliper

4Digital Caliper

5Depth Micrometer6Vernier Height Scale

Table 2 shows the three dimension readings for work piece 1 using the specifiedinstrument as well as the average of the three readings for each instrument and

dimension.

Table 2: Work Piece 1 Dimensions (inches)

Dime

nsion

Instru

mentReading 1 Reading 2 Reading 3

Avera

ge

D_113 1+.7+(50/100) 1+.7+(75/100) 1+.7+(75/100) 1.767

4 1.973 1.972 1.972 1.972

D_12 1

1+.3+.075+(9/1000

)+(1/10,000)

1+.3+.075+(3/1000

)+(1/10,000)

1+.3+.075+(6/100

0)+(1/10,000)

1.3811

4 1.382 1.384 1.381 1.382

D_13 4 0.107 0.107 0.108 0.107

D_14 4 0.152 0.151 0.152 0.152

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Table 3 shows the three dimension readings for work piece 2 using the specified

instrument as well as the average of the three readings for each instrument anddimension.


Dimension Instrument Reading 1 Reading 2 Reading 3 Average

D_21 6 1.978 1.979 1.978 1.9784 2.015 2.009 2.017 2.014

D_223 0.882 0.883 0.882 0.882

2 0.97683 0.9832 0.98225 0.98076

D_23 4 0.878 0.876 0.877 0.877

D_243 1.105 1.104 1.105 1.105

4 1.228 1.228 1.229 1.228

D_25 4 1.129 1.130 1.128 1.129

Table 4 shows the three dimension readings for work piece 3 using the specified

instrument as well as the average of the three readings for each instrument and

dimension.


Dime

nsion

Instr

umen

t

Reading 1 Reading 2 Reading 3Avera

ge

D_31

11+0.8+(3/1000)+(4/

10000)1+0.9+(3/1000)+(6/

10000)1+0.9+(3/1000)+(

5/10000)1.9035

31+0.9+0.025+(6/10

000)1+0.9+0.025+(2/10

000)1+0.9+0.025+(6/1

0000)1.9255

D_321

0+0.8+(21/1000)+(7/10000)

0+0.8+(21/1000)+(7/10000)

0+0.8+(21/1000)+(7/10000) 0.8217

2 0.89665 0.89675 0.896650.8966

8

D_335 0.2+(29/1000) 0.2+(20/1000) 0.2+(24/1000) 0.224

4 0.305 0.302 0.300 0.302

D_341

0+0.7+0.05+(6/100

0)+(2/10000)

0+0.7+0.05+(6/100

0)+(6/10000)

0+0.7+0.05+(6/10

00)+(4/10000)0.7564

2 0.7556 0.7557 0.75565 0.7557

Table 5 shows the three dimension readings for work piece 4 using the specifiedinstrument as well as the average of the three readings for each instrument.


Dimension Instrument Reading 1 Reading 2 Reading 3 Average

D_416 (in scale) 6.375 6.375 6.375 6.375

6 (mm scale) 16.1 16.1 16.1 16.1

D_426 5.410 5.412 5.415 5.412

4 5.418 5.415 5.422 5.418

D_4* 3.4142 3.2438 3.4125 3.3568

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Table 6 shows the weight, diameter, and thickness of each copper piece that was

measured.

Table 6: Copper Pieces Data

Part Number Weight (g) Diameter (inches) Thickness (inches)

1 6.034 0.495 0.062

2 6.001 0.499 0.0633 6.046 0.499 0.068

4 9.314 0.494 0.099

5 5.996 0.493 0.069

6 6.076 0.498 0.068

7 5.994 0.491 0.067

8 5.999 0.496 0.067

9 6.013 0.499 0.069

10 6.025 0.499 0.070

Mean = 6.350 gStandard Deviation = 1.042 g

Tolerance = [3.224,9.476]

Figure 3 - Histogram Distribution of Copper Piece Weights (g)

Figure 3 shows that all of the weights of the copper pieces fall within the specific rangefrom 5.9 to 6.15, except for one outlier weight falling between 9.15 and 9.4.

Table 7: Gage Pieces Used to Achieve Given Reference Lengths

0.8597 inch dimension 2.3012 inch dimension

0.5 2

0.107 0.1003

0.109 0.101

0.15

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Conclusion

In conclusion, this lab taught the importance of precise measurement for multiple

different metrology instruments. The tools used all had different applications in which

they could be used most effectively. For example, a digital micrometer has a much more

accurate measurement when compared to a digital caliper. Because of this, when

measuring dimensions of the work pieces, the digital micrometer was probably moreaccurate in its measurement of the needed dimension. Overall, readings given by

successive measurements using different instruments were comparable and often timesalmost exact, which shows the comparatively accurate reference of each instrument.

Although these measurements were often times very accurate, there was also some

variation when using the instruments. For example, the measured lengths of the gage

blocks did not equal the reference length that was being measured. This is because therewill always be a gap between adjacent gage blocks resulting in some error, as well as the

error that can be associated with the measuring tool. In addition, there was other types of

variation when weighing the copper pieces one piece was an outlier at a weight of9.314g. This happens often times due to the variation in production of the copper pipes

when they are being drawn into shape, more or less material can be used, resulting in apiece that should be rejected, but may sometimes be included as an accurate product as

seen in this lab. Generally, all measuring instruments have some sort of error and it isalmost impossible to have an exact measurement, as there will always be error in

measurement, due to both controllable and uncontrollable factors.

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305 lab 1