Calibration of dial gauge

CONTENT 1.0 Title……………………………………2 2.0 Objectives……………………………..2 3.0 Introduction……………………………2 4.0 Apparatus………………………………8 4.1 Industrial Apparatus……………….8 5.0 Experimental Procedure……………….9 6.0 Results & Data Analysis………………10 7.0 Discussion of Results…………………. 8.0 Conclusion……………………………. 9.0 Recommendation…………………… 10.0 References

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1.0 TITLE CALIBRATION OF A DIAL GAUGE

2.0 OBJECTIVES 1. To calibrate a Dial Gauge using Calibration Tester and Computerised Calibrator ( Optimar 100 ) 2. To find the error on each reading of the dial gauge 3. To obtain accuracy of the gauge 4. To analyse and compare the values of error obtained by Calibration Tester and Computerised Calibrator ( Optimar 100 )

3.0 INTRODUCTION A dial gauge is the most commonly used mechanical type comparator. It is used to make a relative measurement between the work piece and gauge block from the same reference plane. Usually comparators are used to compare a measurement with a known standard with a high degree of accuracy. The dial gauge has some basic components which are a small clock and a plunger (stylus probe). This gauge works when there is very slight upward pressure applied on the plunger that causes it moves upward. The upward movement of the plunger is converted into the rotary movement of an indicator on the dial gauge. Besides, the dial gauge is widely used in all types working industries as it has excellent accuracy in measurement. This is because the dial is divided into 100 divisions and one complete revolution of the indicator corresponds to 1mm linear movement of plunger. This means that each division on the dial indicates a movement of 0.01mm.

Dial Gauge 2

In addition, there are some advantages and disadvantages of dial gauge:-

Advantages  Relatively inexpensive  Some systems can perform all five dial indicator measurement techniques  Little chance of distorted readings  Highest accuracy compared to others equipment  Easily repaired Disadvantages  Needs to be carefully adjusted before use  User must know how to read and take a reading  Need to handle carefully to avoid damage on components

Dial gauge is basically well known as it is widely used around the world. There are many applications of dial gauge that available and commonly used for some several functions. i.

It usually is used to check the out of roundness of a part on a lathe machine. The dial gauge is clamped in a holder which in turn is mounted in a lathe tool holder. Any roundness variation on a work piece is detected by slowly rotating the work piece and bringing this contact with the dial gauge contact point.

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The dial gauge is preferred extensively for inside, outside and depth measurement. For example is dial calliper gauge.

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Dial bore gauge is another type of application of dial gauge. It is used for checking engine block cylinders for size, taper, bell mouth and ovality. It may be used to test the holes for true size and to check other surface irregularities such as concentricity (out of roundness).

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Dial indicating snap gauges are used for determining the acceptance of a work piece as per the specified tolerances.

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Actually, there are also many different types of dial gauge available and each of them have their own characteristics and functions. Types of Dial Gauge

Picture

Plunger Type Dial Gauge  A dial gauge that is robust and sturdy  Fitted with Swiss brass bush bearings  A dial gauge with strong and smooth metal bezel  It is also supplied with tolerance pointers  Has tungsten carbide ball anvil  Metric gauges conform to IS2092-1983 and for the European market to DIN878-1983  Inch gauges conform to ASME B89.1.10M2001  Each gauge carries a calibration certificate that gives the actual values  0.001mm x 1mm dial gauge which is fitted with 8 jewels and conforms to JIS B-75031997  It also was exported to 46 countries all over the world

Lever Type of Dial Gauge  It has auto reversal mechanism  Has been fitted with jewels and Swiss miniature ball bearings for smoother operation  A device that has highly sensitive at the same time and also suitable for workshop use  Inch gauges conform to ASME B89.1.10M2001  Metric gauges conform to IS 11498-1985 and for the European market to DIN 2270-1985  Each of gauge carries a calibration certificate that giving actual values  Commonly in two bezel diameters- 28mm and 38 mm  The metric gauges have 2 mm tungsten carbide ball stylus while for inch gauges have 0.08inch tungsten carbide ball stylus. Both of them are supplied with 8 mm spigot assembly as standard supply

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Bore Gauges  It has carbide-tipped stationary and moving anvils that make it high wear resistance  Also has small bores from 10mm to 18mm  In addition, highly versatile 18-50mm bore gauge can cover a large range for which one needs to generally purchase 2 bore gauges having ranges Ø 18-35mm and Ø 35-60mm  While the third bore gauge covers a range of 50-150 mm and it is used in Automobile, Aircraft, Engine and Pump manufacturers  It has extra wide bridge which ensures automatic centering in the bore. Selfcentralising feature of this bore gauge also can make that the measurement can be done with minimum of skill  Bore gauge is furnished in a sleek wooden case containing measurement anvils and extension rods with necessary tools

Thickness Gauges  Can be found in different throat depths, thus suitable for different measurement requirements.  Usually can be used for quick measurement of thickness of sheets, paper and leather  It is supplied with 10 mm anvil as standard. 20 mm and larger available on request  It is designed in different readings and travels.  In series J130, J138/L, and J142, measurement pressure is independent of the user, resulting in accurate readings of thickness without personal bias.  J138. 'Push Down Type' thickness gauge is particularly useful where fine measurement is not required  This gauge quietly easy to use for the measurement as it has well-balanced balanced frames and handgrips coupled with lightweight  Thickness gauges also has fulfil the requirements of AGD standard available for the American market

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Depth Gauges  It can be used for measurement of wide variety of depths as it is supplied with a set of extension rods  It also has Tungsten Carbide contact point for longer life  Not only that, it is used for quick and easy measurements of bore depths  Depth Gauges Base with 80 mm length hardened and ground to the highest degree of flatness  For the American market, Depth Gauges meeting the requirements of AGD standard available

Back Plunger Type Dial Gauges  A device which is highly accurate worm mechanism  It has gauging plunger at right angle to the dial that make it suitable for difficult inspection locations  Another characteristic is it has robust brass case and metallic bezel  For the American market, inch gauges conform to ASME B89.1.10M-2001

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Besides, in order to obtain Dial Gauge accuracy, we need a Dial Gauge Calibrator Tester. A Dial Gauge needs to be calibrated because calibration is important as it is a comparison between measurements. The periodic calibration is of vital importance for quality assurance as well as cost reduction. For this case, a Dial Gauge Calibrator Tester plays important role as it can be used to determine the deviation of readings of a Dial Gauge. The set of Dial Gauge Calibration Tester enables us to test four different kinds of precision measuring instruments and all the required accessories are included in the set. All tolerances and range have been standardised by Japanese Industrial Standards (JIS).

Dial Gauge Calibrator Tester

Labelling a Dial Gauge Calibrator Tester

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4.0 APPARATUS

Dial Gauge

Dial Gauge Calibration Tester

4.1 INDUSTRIAL APPARATUS

Computerised Dial Gauge Calibration Tester ( Optimar 100 )

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5.0 EXPERIMENTAL PROCEDURE Manual calibration 1. The dial gauge was set up for calibration manually. 2. The dial gauge was then set up on the calibration tester. 3. A series of Dial Gauge readings were taken in the 0-5 mm range. 4. The micrometer head of the Calibration Tester was set to zero. 5. Holders of Dial Gauge Calibration Tester adjusted so that there is light pressure on the spindle of the Dial Gauge. 6. The Dial Gauge was then set to zero. 7. For readings 1.0-2.0mm, an increment of 0.1mm was taken and then recorded. 8. For readings 2.1-4.0mm, an increment of 0.2mm was taken and then recorded. 9. For readings 4.1-5.0mm, an increment of 0.5mm was taken and then recorded. 10. All data have been recorded and is scheduled to perform the analysis.

Computerized calibration 1. Tests to calibrate the indicator dial is mounted to the lever type indicator test. 2. Dial indicator placed in a vertical guide to a height that can be adjusted easily and quickly. 3. Test automation is a process that uses only the spindle drive motor. 4. Computer-aided measurement system error compensation using a device to measure the test without loss of accuracy. 5. The test is set for calibration by the operator.

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6.0 RESULT & DATA ANALYSIS

INCREMENT GO

LIMIT (

RETURN

LIMIT (

AVERAGE

0.0 0.1 0.2 0.3 0.4 0.5 0.6 0.7 0.8 0.9 1.0 1.1 1.2 1.3 1.4 1.5 1.6 1.7 1.8 1.9 2.0 2.2 2.4 2.6 2.8 3.0 3.2 3.4 3.6 3.8 4.0 4.5 5.0

0.0000 -0.0002 +0.0018 +0.0010 +0.0004 +0.0020 +0.0002 +0.0002 -0.0018 -0.0022 -0.0026 -0.0010 -0.0002 -0.0002 +0.0020 +0.0020 +0.0002 +0.0006 -0.0012 -0.0020 +0.0002 +0.0004 +0.0002 +0.0008 +0.0004 -0.0030 -0.0024 -0.0018 +0.0002 +0.0002 -0.0022 +0.0004 -0.0024

-0.0016 0.0996 0.2004 0.2994 0.3996 0.4982 0.5988 0.6960 0.7968 0.8976 0.9984 1.0990 1.1996 1.2986 1.3981 1.4996 1.5982 1.6974 1.7970 1.8972 2.0016 2.2026 2.3996 2.5996 2.7970 2.9996 3.2014 3.3994 3.5984 3.7964 4.0026 4.4996 5.0024

+0.0016 +0.0004 -0.0004 +0.0006 +0.0004 +0.0018 +0.0002 +0.0040 +0.0032 +0.0024 +0.0016 +0.0010 +0.0004 +0.0014 +0.0019 +0.0004 +0.0018 +0.0026 +0.0030 +0.0028 -0.0016 -0.0026 +0.0004 +0.0006 +0.0030 +0.0004 -0.0014 +0.0006 +0.0016 +0.0006 -0.0026 +0.0004 -0.0024

-0.0008 +0.0003 -0.0011 +0.0002 0.0000 -0.0001 +0.0005 +0.6979 +0.0005 +0.0023 +0.0021 +0.0001 +0.0003 +0.0008 -0.00005 +0.0008 +0.0008 +0.0010 +0.0021 +0.0024 -0.0013 -0.0015 +0.0001 -0.0002 +0.0013 +0.0017 +0.0005 +0.0012 +0.0007 +0.0017 -0.0002 0.0000 0.0000

0.0000 0.1002 0.1982 0.2990 0.3996 0.4980 0.5998 0.6998 0.8018 0.9022 1.0026 1.1010 1.2002 1.3002 1.3980 1.4980 1.5998 1.6994 1.8012 1.9020 1.9998 2.1996 2.3998 2.5992 2.7996 3.0030 3.2024 3.4018 3.5998 3.7998 4.0022 4.4996 5.0024

Table 1: Data of Go, Return, Limit and Average readings

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AVERAGE LIMIT ( ) +0.0008 +0.0001 +0.0007 +0.0002 0.0000 +0.0001 0.0000 -0.0019 -0.0025 -0.0023 -0.0138 0.0000 -0.0003 -0.0008 +0.00005 +0.0008 -0.0008 -0.0010 -0.0021 -0.0024 -0.0007 -0.0030 -0.0001 +0.0001 -0.0013 -0.0017 -0.0005 -0.0012 -0.0007 -0.0012 +0.0004 0.0000 0.0000

Indication Error Whole measuring range 1/2 revolution 1 revolution 2 revolution Narrow range adjacent error Retrace error Repeatability error

Results

Tolerances

Unit

-4.58 2.22 -3.82 -3.82 3.18 3.17 1.36

±15.00 ±9.00 ±10.00 ±15.00 8.00 5.00 5.00

μm μm μm μm μm μm

Table 2: Table of Indication Error, Results and Tolerances.

Graph of Limit against Increment Value of GO and RETURN GO

0.005

RETURN

0.004 0.003

Limit (mm)

0.002 0.001 0 0

1

2

3

4

-0.001 -0.002 -0.003 -0.004

Increment (mm)

Figure : Graph of Go and Return value of readings

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7.0 DISCUSSION

Calibration is a comparison between measurements. One of known magnitude or correctness made or set with one device and another measurement made in as similar a way as possible with second device. The device with the known or assigned correctness is called the standard. Based in table 1, the data show that the increment of Go and Return test of dial gauge. In this experiment, the increment was started at 0.0mm until 5.0mm than there was return from 5.0mm until 0.0mm.For Go in the half revolution at increment 0.5mm the limit Go is higher which is 0.0020 compare to the other than the increment at 0.0mm because the initial experiment at 0.0. Then, in the 1 revolution, the higher limit at 1.0 that is limit 0.0026mm compare to the other and the lowest limit at 0.1mm and 0.7mm that is limit 0.0002mm. The others in 2 revolution, the higher increment limit at 1.4mm,1.5mm and 2.0mm. The limit is 0.0020mm. Then the overall Go increment at 1.0mm that is 0.0026mm. After the Go increment had done at 5.0mm, the experiment were returned and in the 2 revolution, the higher limit at increment 1.8mm that is 0.0030mm limit compare to the other increment and the lowest increment limit at 1.2mm and 1.5mm, that is 0.0004mm. Then, in the 1 revolution, the higher increment limit at 1.8mm that is 0.0030mm and the lowest increment limit at 1.5mm and 1.2mm that is 0.0004mm compare to the others increment in the 1 revolution. After that, in the half revolution, the higher return increment at 0.5mm, the limit is 0.0018mm and the lowest increment at 0.1mm,0.2mm and 0.4mm, that is 0.0004mm compare to the others increment.

Based on table 2, the data tabulated of error occur and the limit. The whole measuring range obtained are 0.0030mm, tolerance ( . The indication error of half revolution is 0.0020mm, tolerance ( The indication error of one revolution is 0.0026mm, tolerance ( ). The indication error of two revolution is 0.0020mm, tolerance ( ). The narrow range of near error is 0.0024mm tolerance( ). The indication of retrace error is 0.0024mm tolerance( ).

From the graph, we can see the data of Go and Return slightly and can read the higher increment and the lowest increment. The graph of manual dial gauge test is little bit different than graph of automatically dial test. This happen, because of some error when doing the experiment. Some mistakes or error that we known is the thimble might be turned more which exceeded the reading at the dial gauge thus causing slight errors. At certain time, the spindle of the dial gauge did not retract to its original position which also causes some error in readings. Then, at the parallax error when reading the apparatus. That is the most error that student doing when construct the experiment.

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8.0 CONCLUSION

In conclusion, based on the results obtained and plotted graph, the dial gauge shows some errors in its readings which means is sligtly inaccurate. From the calibration graph, the greatest deviation is at the dial gauge reading of 3.0mm which shows GO value of -0.003mm. However, a Computerised Dial Gauge Calibration Tester is used in this experiment and the experiment is also assisted in a closed area under the supervision of qualified technicians. Hence, our objectives of this experiment have been achieved.

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9.0 RECOMMENDATION

1. Use magnifying glass in order to proper read the dial gauge and micrometer reading values. 2. Slowly and carefully rotate the dial gauge to make sure the readings is not wrongly taken because it is very high sensitive. 3. Try not to move or drastically colliding with the equipment or work table which will affect the dial gauge’s needle (readings of dial gauge). 4. Carefully clamp the dial gauge in suitable fixture under the contact point number of times of specimen. The test is repeated at two or three points along range of the gauge. 5. Take the average between five revolution of readings to reduce the percentage error by do the reading repeatability.

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10.0 REFERENCES 1. Mohan Sen, 2006, Basic Mechanical Engineering ,first edition, Laxmi Publications (P) LTD, pp 76-77 2. John Piotrowski, 1995, Shaft Alignment Handbook, second edition, Library of Congress Catalog-in-publication Data, pp 233-234 3. Anand K Bewoor,Vinay A Kulkarni,2009, Metrology & Measurement, Tata McGraw-Hill Education Private Limited, pp 40 4. “Dial Callipers” retrieved from http://www.longislandindicator.com/p112.html 5. “Dial Test Indicators” retrieved from http://www.docstoc.com/docs/80503355/DialIndicators-Dial-Test-Indicators 6. “Plunger Type Dial Gauge” retrieved from http://www.gaugesindia.co.in/plunger-typedial-gauges.html 7. “Lever Type Dial Gauge” retrieved from http://www.gaugesindia.co.in/lever-type-dialgauges.html 8. “Back Plunger Type Dial Gauge” retrieved from http://www.gaugesindia.co.in/backplunger-type-dial-gauges.html 9. “Depth Gauges” retrieved from http://www.gaugesindia.co.in/depth-gauges.html 10. “Bore Gauges” retrieved from http://www.gaugesindia.co.in/bore-gauges.html

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