METROLOGY LAB. I DEVICES BASED ON VERNIER SCALE

METROLOGY LAB. I DEVICES BASED ON VERNIER SCALE

Indirect Measurement; two balls 2 Lab6: Roundness Test 12/1/2017

Indirect Measurement; four balls 3 Lab6: Roundness Test 12/1/2017

Angle measurement using two balls 4 Lab6: Roundness Test 12/1/2017

Mechanical Devices Magnification Types: Vernier scale Screw & Nut Lever magnifications Gear magnification

Venier Princple 6 Lab6: Roundness Test 12/1/2017

7 Lab6: Roundness Test 12/1/2017

8 Vernier scale value Scale division of vernier (b) Length of vernier scale (1) Lab6: Roundness Test = a (1/n) = a (1-1/n) = a (n-1) 12/1/2017

Vernier magnification principle 9 Lab6: Roundness Test 12/1/2017

Usage of vernier caliper 10 Lab6: Roundness Test 12/1/2017

Vernier Measuring face 11 Lab6: Roundness Test 12/1/2017

12 Lab6: Roundness Test 12/1/2017

13 Lab6: Roundness Test 12/1/2017

14 Lab6: Roundness Test 12/1/2017

Vernier anvils 15 Lab6: Roundness Test 12/1/2017

16 Lab6: Roundness Test 12/1/2017

17 Lab6: Roundness Test 12/1/2017

Vernier construction 18 Lab6: Roundness Test 12/1/2017

19 Lab6: Roundness Test 12/1/2017

20 Lab6: Roundness Test 12/1/2017

21 Lab6: Roundness Test 12/1/2017

Measurement of tube thickness 22 Lab6: Roundness Test 12/1/2017

Screw and nut principle 23 Lab6: Roundness Test 12/1/2017

Micrometer principle 24 Lab6: Roundness Test 12/1/2017

25 Lab6: Roundness Test 12/1/2017

26 The principle of the micrometer is based on a very accurate made screw thread that rotates in a fixed nut anvil by rotating the thimble. A graduation is engraved in the sleeve with a division equal to the thread pitch. The beveled edge of the thimble is divided into a number of divisions each of them represents a fraction value of the spindle pitch. In case that, the thread pitch is 0.5 mm and the length of the threaded part is about 25 mm, a length of 25 mm on the sleeve is divided into 50 divisions Lab6: Roundness Test 12/1/2017

27 Lab6: Roundness Test 12/1/2017

Micrometer anvil 28 Lab6: Roundness Test 12/1/2017

Measuring external Surfaces 29 Lab6: Roundness Test 12/1/2017

Measuring Internal Surfaces 30 Lab6: Roundness Test 12/1/2017

Parallelism & flatness 31 Measure the diameter of an accurate ball at different points across the anvils. The correct flatness and parallelism is that the readings do not vary from point to point. Lab6: Roundness Test 12/1/2017

Squareness of anvils 32 Measure the diameter of two balls, the diameter of one being smaller than the other by any odd multiple of half the micrometer pitch (usually 0.25 or 0.5 mm). Repeat the measurement at different points across the anvil. The anvils are square if the difference in the reading corresponds to the true difference in the diameters of the balls. Lab6: Roundness Test 12/1/2017

Differential Micrometer 33 Lab6: Roundness Test 12/1/2017

34 Lab6: Roundness Test 12/1/2017

35 Lab6: Roundness Test 12/1/2017

36 As shown in Fig., a very high degree of accuracy can be obtained in the micrometer screw gauges utilizing the principle of differential screw on the operating spindle. In such a micrometer, the screw has two types of pitches, one smaller and one larger, instead of one uniform pitch as in conventional micrometer. Lab6: Roundness Test 12/1/2017

37 Both the screws are right-handed and the screws are so arranged that the rotation of the thimble member moves one forward and the other backward. If the larger screw has a pitch of 1.25 mm and smaller screw of 1.00 mm pitch, then the net result would be a total forward movement of 1.25-1.00=0.25 mm per revolution Lab6: Roundness Test 12/1/2017

38 Lab6: Roundness Test 12/1/2017

39 Lab6: Roundness Test 12/1/2017

Lever magnification 40 Lab6: Roundness Test 12/1/2017

41 Lab6: Roundness Test 12/1/2017

42 Lab6: Roundness Test 12/1/2017

43 why a simple magnifying lever is limited to tilt small angle that not exceed 60. Lab6: Roundness Test 12/1/2017

44 Lab6: Roundness Test 12/1/2017

Gear magnification 45 c Z2 R Zp 0 Z1 0 Z3 Z5 x Z4 Lab6: Roundness Test 12/1/2017

Vernier caliper main parts

Digital caliper main parts

Dial caliper

Vernier principle Main scale: 1- Scale Value =? 2- Scale Division =? Vernier scale: 1- Scale Value =? 2- Scale Division =?

What is the difference? Types of Vernier Scale

Vernier Reading

Zero Reading 0 1 0 5 10

Special Purpose Caliper Applications

Special Purpose Caliper Applications (cont.)

Special Purpose Caliper Applications (cont.) The main parts of a vernier height gauge. 1.base 2. beam 3.vernier slide 4. clamp screw 5. scriber

Special Purpose Caliper Applications (cont.) Gear tooth vernier caliper

Bevel Vernier Protractor Body Scale Lock Turret Scal e Blade Lock Blade Working Edge

How to read?

METROLOGY LAB. I DEVICES BASED ON SCREW & NUT

Micrometer Working Principle Frame Fixe Spindle d Anvi l Screw

77 Lab6: Roundness Test 12/1/2017

78 Lab6: Roundness Test 12/1/2017

79 Lab6: Roundness Test 12/1/2017

80 Lab6: Roundness Test 12/1/2017

81 Lab6: Roundness Test 12/1/2017

82 Lab6: Roundness Test 12/1/2017

External Micrometer Main Parts

External Micrometer Construction

External Micrometer Construction (cont.) 1-Lock nut. 2-Ratchet. (slipping clutch measuring pressure). 3-Frame. 4-Anvils faces. (Lapped, 63 HRc, tipped (tungsten carbide)). 5-Spindle nut. (fitted into the sleeve). 6-Thimble. (permanently secured with the screw). 7-Spindle. (hard thread, accurate pitch, measuring face).

Micrometer Types External Micrometers

External Micrometers (cont.)

Micrometer Types (cont.) Sheet metal micrometer

Internal Micrometers Cantilever Type Rod Type

Micrometer Types (cont.) Depth Micrometer

Special Types (cont.) Thread Micrometer Spline Micrometer

Micrometer Types (cont.) V-anvil Micrometer Blade Micrometer

Micrometer Resolution Micrometer Pitch: Pitch of Micrometer = distance on linear scale / one rotation Typically = 0.5 or 1 mm. 1/40 in. Micrometer resolution: Resolution = S.V. Main Scale (Screw pitch) / no. of thimble divisions Commercial Micrometers: Resolution = 0.01 mm, 0.001 mm (With vernier scale), 0.001 inch, 0.0001 inch (With vernier scale)

Micrometer Reading

Micrometer Reading (Cont.)

Micrometer Reading (With Vernier)

Micrometer Anvils Check 1- Parallelism Check. 2- Perpendicularity Check. (Two Block Gauges diff. = 0.25 mm) 3- Flatness Check.

Example: 107 An external Micrometer was designed and manufactured to have a pitch equals 0.5 mm. The pitch of the micrometer threaded screw was checked and found that it has an error of sin pattern. If the reading of the micrometer over a 20 mm slip gauge was 20.02 mm, find the phase shift of the sin pattern. If the reading of the micrometer over a workpiece is 15.33, find the actual length of the workpiece. Lab6: Roundness Test 12/1/2017

METROLOGY LAB.I DEVICES BASED ON GEAR MAGNIFICATION

Construction of Dial Indicator Function? Function?

Working Principle

Using the Dial Indicator

Mechanical Comparator

Measurement using a Mechanical Comparator

Dial Indicator Magnetic Base

Use of Dial Indicator (Roundness test)

Use of Dial Indicator (Tolerance Micrometer)

Use of Dial Indicator (Micrometer Calibrator)

Use of Dial Indicator (Dial Vernier Caliper)

Use of Dial Indicator (Deflection test) Tested Beam Dial Indicator Weight

Use of Dial Indicator (Parallelism Test)

Types of Dial Indicators Conventional Dial Gauge

External Dial Caliper

Internal Dial Caliper

Depth Dial Gauge

Lever Type Dial Gauge

Back Plunger Dial Gauge

Resolution of Dial Indicator Commercial resolutions = 0.01 mm, 0.001 mm, 0.001 in, 0.0005 in. How can I know the scale value of the given dial indicator?

Reading of Dial Indicator Continuous dial (Few revolutions) Balanced dial (Part revolution)

130 An optical comparator is shown in the figure. The following dimensions are known, m1=10 mm, m2=40 mm, O1=15 mm and O2= 60 mm. Calculate the maximum acceptable angle of the scale. Calculate the minimum and maximum acceptable scale value. If it is required to decrease the minimum acceptable scale value to half of its calculated value, what dimensions you will change and what are their new values. Lab6: Roundness Test 12/1/2017

131 O2 O1 m1 m2 Lab6: Roundness Test 12/1/2017

132 Calculate the mechanical magnification and the working capacity of 0.01 mm dial indicator shown in figure. The drive goes from the rack to the compound gear wheels (ZP-Z1), then the compound gear wheels (Z2-Z3) then to the control pinion (Z4). The control pinion (Z4) is driven by gear (Z5), whose axis carries the backlash eliminating torsion spring and revolution counter. The divisions and revolutions counter pointers are 30 and 8 mm in radii, respectively. The module of all gears are 0.2 mm and the number oflab6:gear for the system Roundnessteeth Test 12/1/2017 are as follows

133 Gear ZP Z1 Z2 Z3 Z4 Z5 No. of teeth 35 125 20 80 25 125 Lab6: Roundness Test 12/1/2017

134 c Z2 R Zp 0 Z1 0 Z3 Z5 x Z4 Lab6: Roundness Test 12/1/2017

135 The diameter of the bore in a plain ring of height was H mm was measured using two balls. The ring was placed on a flat surface. One ball with a diameter (d1) was placed over another ball of diameter (d2). The distance from the top of the upper ball (d1 mm diameter ball) to the top of the ring was measured as (h1) mm while the distance from the top of the lower ball to the top of the ring was measured as (h2). Calculate the bore diameter then Prove that it is not affected by the ring height. If the two balls are equal, calculate the bore Lab6: Roundness Test 12/1/2017 diameter and the error expected in the diameter

136 A spirit level having a level constant of 0.02 mm/m is found that when one end of its base is raised 0.03 mm above the other, the bubble moves 1.5 mm along the vial. Calculate the radius of the vial and the number of divisions through which the bubble has been deflected, if the base of the level is 200 mm long. Lab6: Roundness Test 12/1/2017

137 The diameter of the bore in a plain ring of height was H mm was measured using two balls. The ring was placed on a flat surface. One ball with a diameter (d1) was placed over another ball of diameter (d2). The distance from the top of the upper ball (d1 mm diameter ball) to the top of the ring was measured as (h1) mm while the distance from the top of the lower ball to the top of the ring was measured as (h2). Calculate the bore diameter then Prove that it is not affected by the ring height. If the two balls are equal the diameter. Lab6:find Roundness Test bore 12/1/2017

138 Lab6: Roundness Test 12/1/2017

139 Lab6: Roundness Test 12/1/2017

140 Errors Combination

Example: Sine Bar error 141

142