Industrial Maintenance - Dimensional Metrology - Precision ...

Industrial Maintenance

Dimensional MetrologyPrecision Measurement

Course Sample 8130685

Order no.: 8130685 (Printed version) 8130686 (Electronic version) First Edition Revision level: 12/2020

By the staff of Festo Didactic

© Festo Didactic Ltée/Ltd, Quebec, Canada 2020 Internet: www.festo-didactic.com e-mail: [email protected]

Printed in Canada All rights reserved ISBN 978-2-89789-910-3 (Printed version) ISBN 978-2-89789-911-0 (Electronic version) Legal Deposit – Bibliothèque et Archives nationales du Québec, 2020 Legal Deposit – Library and Archives Canada, 2020

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The purchaser shall be entitled to use the work to train his/her staff at the purchaser’s site/location and shall also be entitled to use parts of the copyright material as the basis for the production of his/her own training documentation for the training of his/her staff at the purchaser’s site/location with acknowledgement of source and to make copies for this purpose. In the case of schools/technical colleges, training centers, and universities, the right of use shall also include use by school and college students and trainees at the purchaser’s site/location for teaching purposes.

The right of use shall in all cases exclude the right to publish the copyright material or to make this available for use on intranet, Internet, and LMS platforms and databases such as Moodle, which allow access by a wide variety of users, including those outside of the purchaser’s site/location.

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Information in this document is subject to change without notice and does not represent a commitment on the part of Festo Didactic. The Festo materials described in this document are furnished under a license agreement or a nondisclosure agreement.

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© Festo Didactic 1

Table of Contents

General Safety Symbols and Procedures.................................................................. 5

Preface..................................................................................................................... 9

About This Course.................................................................................................. 11

To the Instructor..................................................................................................... 13

Introduction - Precision Dimensional Measurement............................................... 15Precision dimensional measurement ......................................15Precision measuring instruments............................................16

Unit 1 - Calipers...................................................................................................... 17

Exercise 1-1 - Vernier Calipers ................................................................................ 19Principle of the vernier scale ...................................................19

Least count ...................................................................... 20Vernier caliper.........................................................................21

Types of vernier calipers .................................................. 23Reading the inch scales on a vernier caliper..................... 23Reading the metric scales on a vernier caliper ................. 26Abbe's principle ............................................................... 28Proper use of vernier calipers........................................... 29

Proper care and adjustment of vernier calipers .......................30Adjustment of the movable jaw on a caliper..................... 30Periodic inspection of calipers ......................................... 31Care of calipers ................................................................ 31

Dial caliper..............................................................................32Measurement with a vernier caliper ........................................33

Measurement skills with a vernier caliper ........................ 36Linear measurement using a vernier caliper..................... 38

Exercise 1-2 - Digital Caliper................................................................................... 49Digital caliper..........................................................................49

Reading a digital caliper................................................... 51Measurement with a digital caliper .........................................52

Measurement skills with a digital caliper ......................... 53Familiarization with the incremental measuringsystem of the digital caliper ............................................. 54Linear measurement with a digital caliper........................ 55Measuring inside diameters and center‑to‑centerdistances with a digital caliper......................................... 59Measuring steps and depths with a digitalcaliper.............................................................................. 62

Unit 2 - Micrometers............................................................................................... 77Micrometers............................................................................77Outside micrometers...............................................................78

Operating principle of micrometers.................................. 78Uses of outside micrometers............................................ 79Variations of the outside micrometer ............................... 81

Calibration of outside micrometers .........................................82

Exercise 2-1 - Digital Outside Micrometers............................................................. 85Digital micrometers.................................................................85

Reading inch outside micrometers ................................... 86Micrometer stand............................................................. 88

Table of Contents

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Usage, check and care of micrometers........................................89Spanner wrench for micrometers .........................................89

Measurement with micrometers..................................................90Checking and adjusting the zero on a digitalmicrometer ..........................................................................90Developing measurement skills with a digitalmicrometer ..........................................................................91Measurement of external diameters with a digital micrometer .............................................................93

Exercise 2-2 - Conventional Outside Micrometer................................................................................................................................101

Conventional outside micrometers............................................101Reading metric outside micrometers..................................102

Measurement with micrometers................................................104Checking and adjusting the zero on a conventionaloutside micrometer............................................................104Measurement of external diameters with aconventional outside micrometer.......................................107

Exercise 2-3 - Three-wire Method .............................................................................113Three‑wire method....................................................................113

Pitch diameter of a thread..................................................113Description of the three‑wire method ................................114Selection of the wire size ...................................................115

Measurement of pitch thread diameter usingthe three‑wire method ..............................................................117

Unit 3 - Standard Tolerances and Inside Measurementswith Micrometers .....................................................................................................129

Inside micrometers ...................................................................129Standard tolerances..................................................................130

Exercise 3-1 - Inside Measurements by Transfer.......................................................133Inside measurements by transfer ..............................................133

Small hole gages................................................................133Telescoping gages..............................................................134

Measurement skills with telescoping gages..............................136Development of measurement skills with telescopinggages .................................................................................136

Measurement skills with small hole gages ................................140

Exercise 3-2 - Limits and Fits ....................................................................................145Limits on linear sizes.................................................................145

Definitions related to limits and fits ...................................146Limit deviations in metric units ..........................................146Limit deviations in inches...................................................148

Fits ............................................................................................150Types of fits........................................................................150

Standard tolerances and measurement withtelescoping gages .....................................................................152Standard tolerances and measurement withsmall hole gages .......................................................................157

Exercise 3-3 - Project on Precision Measurement .....................................................167Project on precision measurement............................................167

Introduction to transversal skills ........................................167

Table of Contents

© Festo Didactic 3

Creating measurement instructions ...................................168

Appendix A - Equipment Utilization Chart ................................................................177

Appendix B - Augmented Reality Application ...........................................................181

Appendix C - Marker for Pump Shaft ........................................................................183

Appendix D - Marker for Conveyor Cover ..................................................................185

Appendix E - Marker for Brake Caliper H1.................................................................187

Appendix F - Marker for Brake Caliper H2.................................................................189

Appendix G - Marker for Locating Pin G1 ..................................................................191

Appendix H - Marker for Locating Pin G2 ..................................................................193

Appendix I - Drawings for Precision Measurement ...................................................195

Appendix J - Unit Conversion Table ...........................................................................211

© Festo Didactic 5

Symbol Description

DANGER indicates a hazard with a high level of risk, which, if not avoided, will result in death or serious injury.

WARNING indicates a hazard with a medium level of risk, which, if not avoided, could result in death or serious injury.

CAUTION indicates a hazard with a low level of risk, which, if not avoided, could result in minor or moderate injury.

CAUTION used without the "Caution, risk of danger" sign, indicates a hazard with a potentially hazardous situation, which, if not avoided, may result in property damage.

Caution, risk of danger. Consult the relevant user documentation.

Caution, risk of electric shock.

Caution, lifting hazard.

Caution, hot surface.

Caution, risk of fire.

General Safety Symbols and ProceduresThe following table lists the safety and common symbols that may be used in this course and on the equipment. Before performing manipulations with the equipment, you should read all sections regarding safety in the Safety Instructions and Commissioning manual accompanying the equipment.

If applicable, following subsections give general procedures related to the tasks you will be asked to perform in this course. Additional safety procedures are given before any task requiring specific safety precautions.

General Safety Symbols and Procedures

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Symbol Description

Caution, risk of explosion.

Caution, belt drive entanglement hazard.

Caution, chain drive entanglement hazard.

Caution, gear entanglement hazard.

Caution, hand crushing hazard.

Static sensitive contents. Observe precautions for handling electrostatic discharge sensitive devices.

Notice, non-ionizing radiation.

Consult the relevant user documentation.

Radio Equipment Directive (RED) geographical restrictions – consult the relevant user documentation.

Direct current.

Alternating current.

General Safety Symbols and Procedures

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Symbol Description

Both direct and alternating current.

Three-phase alternating current.

Earth (ground) terminal.

Protective conductor terminal.

Frame or chassis terminal.

Equipotentiality.

On (supply).

Off (supply).

Equipment protected throughout by double insulation or reinforced insulation.

In position of a bi-stable push control.

Out position of a bi-stable push control.

© Festo Didactic 9

PrefaceMetrology is a scientific discipline concerned with the study of measurements. Although we may not notice it, measurements are present in many day-to-day activities, as well as in a variety of fields, such as in medical sciences, sports, military and industrial applications. Measuring consists of determining the value of a physical quantity. This makes it possible to evaluate the suitability of a product or system. For a measurement to be reliable, it is necessary to have the appropriate measuring instruments and to know how to correctly use them. It is also important to have standards to ensure that the instruments used are suitable for measurements.

Dimensional metrology is one specific field of metrology concerned with linear and angular measurement. Linear measurement is a critical task, especially in today's globalized world, where many complex subassemblies are manufactured in different parts all over the world and then assembled in a completely different place, which is usually very far from where the subassemblies have been manufactured. Results of linear measurements not only allow for quality control during all stages of the manufacturing process, but they also are a valuable source of information to evaluate the capability of a manufacturing process.

The Metrology Learning System is designed for students to learn important concepts related to dimensional metrology and to be able to use and read semi‑precision, precision, and advanced dimensional measurement instruments. Using a practical approach, the courses associated to the Metrology Learning System present the use of several dimensional measurement instruments used in today's manufacturing environments. The main goal is that students are able not only to use the instruments but also to develop competencies to select the appropriate instrument according to practical situations.

Tips, feedback, and suggestions

We invite readers to send us their tips, feedback, and suggestions for improving the course.

Please send these to:

[email protected]

The authors and Festo Didactic look forward to your comments.

mailto:[email protected]

© Festo Didactic 11

About This CourseCourse objectives

When you have completed this course, you will be able to select and use various precision measuring instruments for measuring dimensions in various types of components. You will also be able to combine the reading of technical drawings with the use of precision dimensional instruments to evaluate the conformity of workpieces.

Augmented reality content

The objects represented by some of the images in this course can be seen in augmented reality. To access this content, you need a smartphone or a tablet and the FESTO DIDACTIC AR application. Refer to Appendix B for information on how to download the FESTO DIDACTIC AR application.

When the icon shown below appears near an image, the associated object is available in augmented reality.

The images, or markers, of this course that are linked to an object in augmented reality are shown from Appendix C to Appendix H. To see the objects in full 3D, you must open the FESTO DIDACTIC AR application and point your device's camera at a printed or a digital version of the images. The printed version provides the best results. However, the results depend also on the ambient lighting, the quality of the print, and the type of camera.

System of units

Units are expressed using the International System of Units (SI) or the U.S. customary system of units. The use of one system or both systems depends on the topic studied.


To the InstructorYou will find in this instructor version of the course all the elements included in the student version together with the answers to all questions, results of measurements, graphs, explanations, suggestions, and, in some cases, instructions to help you guide the students through their learning process. All the information that applies to the instructor is placed between markers and appears in red.

Accuracy of measurements

The numerical results of the hands-on exercises may differ from one student to the next. For this reason, the results and answers given in this course should be considered as a guide. Students who correctly perform the exercises should expect to demonstrate the principles involved and to make observations and measurements similar to those given as answers.

Time requirements

At the beginning of each section in this course, you will find an indication of the time required by an average student to perform the section. This time indication is for reference purposes only. The actual time required by students may vary significantly from one class to another, and from one student to another.

To prevent inconsistencies in the times required to complete sections, it is recommended that the instructor perform the tasks in the section beforehand to obtain a general idea of the time required to complete the section. The instructor can then better estimate the time required for his or her class to perform the tasks.

Sample

Extracted from

Instructor Guide


Exercise 2-2

Conventional Outside Micrometer

Conventional outside micrometers

Learning outcomesAfter completing this section, you will be able to:

Conventional outside micrometers are widely used to measure external features in shops and manufacturing industries. Figure 90 shows the main components of a conventional outside micrometer.

Figure 90: Conventional outside micrometer.

The main components of a conventional outside micrometer are briefly described as follows:

76 min.

Identify and describe the main components of a conventional outside micrometer.

Read the metric scale on an outside micrometer.

Anvil: The fixed measuring face on the axis of the spindle. It performs the role of the datum on the instrument.

Spindle: The element that carries a movable measuring face at one end and an external thread at the other. The spindle's external thread engages with the internal thread of the inner sleeve. Measuring distance with a micrometer is performed by taking the reference of the linear displacement of the spindle to the anvil.

Outer sleeve: The fixed member that carries the scale of the axial displacements, as well as the reference marks for the circumferential graduations should a vernier scale be present on the micrometer. The

Exercise 2-2 – Conventional Outside Micrometer

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Reading metric outside micrometers

A metric outside micrometer that does not include a vernier scale can record measurements to 0.01 mm. When a vernier scale is present, the instrument can measure to 0.001 mm. Each of the 10 divisions on the vernier scale represents 0.001 mm because the vernier scale divides the 0.01‑mm graduations of the thimble into ten increments.

The spindle of a metric micrometer advances 0.5 mm for each complete rotation of the thimble, and 0.01 mm per division of the thimble. Numbers every tenth line on the sleeve represent increments of 5 mm. For example, 25 represents 25 mm, 30 represents 30 mm, and so forth. Each small vertical line on the thimble represents 0.5 mm. Figure 91 indicates the value of each division on a metric outside micrometer.

Figure 91: Readings represented by the divisions of a metric micrometer.

The following table describes the basic steps for reading the metric scale on an outside micrometer. Based on the steps indicated in the table, the measurement corresponding to Figure 91 is determined as follows:

micrometer also has an inner sleeve (not shown), which is fitted at one end of the spindle to ensure the linearity of the spindle motion in the axial direction.

Thimble: A hollow cylinder fixed to the spindle so that both elements turn together. The thimble is knurled for easy turning.

Ratchet stop: A mechanism that serves to ensure a uniform measuring force by applying a constant force to the piece being measured.

Spindle lock: A clamp fixed to the micrometer's frame that locks the spindle against the inner sleeve. It can be used to lock the spindle at a desired position to use the micrometer as a snap gage.

A snap gage is a C‑shaped go/no‑go gage that can be used to quickly check external dimensions.

The values indicated next to the dimension lines in Figure 91 refer to the readings represented by each division. These values are shown to ease the understanding of the reading process. They should not be interpreted as the actual measurement of the divisions. That is, if you measure the divisions with a ruler or a caliper, they will not measure the value indicated in the figure.



1.

2.

3.

4.

5.

Reading stepResult in the

exampleRecorded value

Record the reading corresponding to the first large number division on the sleeve that is at the left of the thimble edge.

First large number: 30

30 mm

On the sleeve, count how many small vertical lines are between the large number division identified before and the edge of the thimble. Multiply this number of lines by 0.5 mm and record the result.

Counting of small vertical lines: 0

0 x 0.5 mm= 0 mm

On the thimble, identify the 0.01 mm graduation that coincides exactly with the central horizontal line of the sleeve or that is just below that line. Record the corresponding reading.

Thimble graduation: 48

48 x 0.010 mm = 0.480 mm

When a vernier scale is present, count how many lines are between the central horizontal line on the sleeve and the line of the thimble that lines up perfectly with any line of the vernier scale. Multiply this number of lines by 0.001 mm and record the result. Notice that the value of the thimble scale division that coincides with the vernier scale does not matter here.

Counting of lines on the vernier scale: 2

2 x 0.001 mm = 0.002 mm

Add all the results to obtain the final measurement.

30.000 mm + 0.000 mm + 0.480 mm + 0.002 mm = 30.482 mm

30.482 mm (final reading)

Table 4: Guided reading of a metric micrometer.

Care should be taken not to identify in this step a 0.5 mm division that is overlapped by the edge of the thimble.



Measurement with micrometers

Learning outcomesAfter completing this section, you will be able to:

Checking and adjusting the zero on a conventional outside micrometer

In this part of the procedure, you will check and, if necessary, adjust the zero reading of a conventional outside micrometer of 25-50 mm.

Checking and adjusting the zero on a 25-50‑mm conventional outside micrometer

https://ip.festo-didactic.com/FDCAQRCodes/qrcode0230.html

Check and adjust the zero of a conventional outside micrometer.

Measure outside diameters using a conventional outside micrometer.

During this procedure, you can refer to the following video for more details on checking and adjusting the zero on a 25-50‑mm conventional outside micrometer.

Put on a pair of cotton gloves.1.

Locate the micrometer stand, the 25-50 mm micrometer, the 25‑mm setting master, and the spanner wrench of the micrometer provided with the learning system.

2.

Clamp the micrometer to the micrometer stand, as shown in Figure 93. Do not overtighten the micrometer on the stand.

3.










Figure 92: Outside micrometer on the micrometer stand.

NOTICE

Never attempt to turn the thimble while the locking clamp is blocking the micrometer.

NOTICE

Don't turn the ratchet too fast as rapid rotation can give false readings.

Check the operation of the micrometer. The thimble should rotate evenly and smoothly. Check for play in the spindle.

4.

You can offset the zero reading of the micrometer previously to train students on how to adjust the zero reading.

Use a clean lint‑free paper or cloth to wipe the anvil and spindle of the micrometer, as well as the 25‑mm setting master.

5.

Inspect the measuring faces of the micrometer. The anvil and spindle faces must look like a mirror. No sign of pin holes or stains must be present.

6.

Unlock the locking clamp of the micrometer.7.

Insert the setting master between the anvil and the spindle, as shown in Figure 93. Rotate the ratchet stop until it clicks once. Next, lock the spindle by operating the spindle clamp of the micrometer.

8.



Figure 93: Checking the zero reading on a micrometer.

Figure 94: Adjustment of the sleeve in the CW direction.

Check that the zero line on the thimble is aligned with the vertical central line on the sleeve. In addition, check that the ninth division on the vernier scale coincides with the 0 of the outer sleeve.

9.

If the zero reading is correct, unlock the spindle by operating the spindle lock of the micrometer, and remove the setting master. You can skip the next steps of this procedure.

If the micrometer does not exactly read zero, insert the pin of the spanner wrench into the small hole at the back of the sleeve. Then, rotate the sleeve in the appropriate direction, until the zero reading is correct, as shown in Figure 94and Figure 95.

10.



Figure 95: Adjustment of the sleeve in the CCW direction.

Measurement of external diameters with a conventional outside micrometer

In this procedure, you will use a previously checked and adjusted conventional micrometer to measure an outside diameter on the pump shaft (piece E) included in the learning system.

Figure 96: Pump shaft (piece E).

Unlock the spindle by operating the spindle lock of the micrometer. Remove the setting master.

11.

Re‑insert the setting master and rotate the ratchet stop until it clicks.12.

Re‑check the zero reading of the micrometer and adjust it if needed. Keep the micrometer on the micrometer stand.

13.

Locate the pump shaft (piece E).14.

Clean the micrometer and its measuring faces.15.

Check the operation of the micrometer.16.

Review questions – Conventional Outside Micrometer


Figure 97: Measuring an outside diameter with a conventional micrometer.

Check the zero reading and adjust it if needed.17.

Make sure the micrometer is clamped to the micrometer stand.18.

Open the measuring faces of the micrometer to more than the measure of the largest outside diameter of the shaft to allow clearance between the shaft and the measuring faces.

19.

Use one hand to insert and hold the diameter of the pump shaft between the measuring faces of the micrometer.

20.

Rotate the thimble slowly with your other hand to bring the measuring faces into contact with diameter B.

21.

Once a good contact is established, slowly rotate the ratchet stop until it clicks once or twice, as shown in Figure 97. Lock the spindle by operating the spindle lock and take the reading.

22.

According to your reading, what is the measure of the outside diameter?

Outside diameter (mm) = mm

Outside diameter (mm) = [29.990 mm, 30.010 mm]

23.

Clean the micrometer and the pieces you have used.24.

Inspect the micrometer for wear and damage.25.

Lay the micrometer on its case. Do not clamp the spindle lock.26.

Return the pieces and tools back to their housings in the learning system.27.



1.

2.

Review questions

Which of the following measurements corresponds to the reading in millimeters shown in Figure 98?

b

Figure 98: Reading the metric scales on a conventional micrometer.


d

30.538 mma.

29.538 mmb.

29.530 mmc.

30.530 mmd.

31.000 mma.

30.490 mmb.

30.049 mmc.

30.500 mmd.



3.



a


25.977 mma.

26.477mmb.

26.977 mmc.

25.048 mmd.



4.

5.


c



a

25.224 mma.

26.506 mmb.

27.024 mmc.

26.042 mmd.

35.482 mma.

35.272 mmb.

35.982 mmc.

34.472 mmd.



6.



c


32.115 mma.

31.614 mmb.

32.113 mmc.

32.011 mmd.

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