ME 472 – Engineering Metrology and Quality Control

ME 472 – Engineering Metrology
and Quality Control
Chp 5 - Linear and Angular Measurements
Mechanical Engineering
University of Gaziantep
Dr. A
D
A. T
Tolga
l B
Bozdana
d
Assistant Professor
Measuring tools and instruments
Measuring tools and instruments
Direct (contact) measurement
(e g micrometer or caliper)
(e.g.
Graduated
(either linear or angular
graduations incorporated into
measuring system of the tool)
 Rules
 Vernier Calipers
 Vernier Ga(u)ges
 Micrometers
 Protractors
 Dial Indicators
Indirect (non-contact) measurement
(such as optical,
optical electronic and
pneumatic methods)
Non-graduated
(gauges or adjustable
tools which compare
the measurements)
NEXT WEEK!
 Calipers
p
 Gauges and Ga(u)ge Blocks
 Sine Bar
 Special-purpose tools
1
Graduated Linear Measurement - Rules
Imperial steel rules
(with graduations on each side)
Metric steel rules
(with graduations on each side)
 resolution?
How to read a rule:
 A = 22 mm (22nd graduation)
 B = 12 mm (12th graduation)
 C = 31.5
31 5 mm (between 31st and 32ndd)
 D = 40.5 mm (between 40th and 41st)
2
Graduated Linear Measurement - Vernier Calipers
More precise tools capable of measuring external
and internal dimensions as well as depths.
How to read a vernier caliper:
 First, read the graduation on main scale just
b f
before
vernier
i scale
l starts
t t (i.e.
(i 19th graduation
d ti
which gives 19 mm)
graduation on vernier scale
 Next,, read the g
where two graduation lines on main & vernier
scales perfectly match (i.e. 32nd graduation
which gives 32 * 1/50 = 0.64 mm)
 Finally, add fine reading into main reading
(i.e. 19 + 0.64 = 19.64 mm)
3
Graduated Linear Measurement - Vernier Calipers
Direct reading of an internal length
by d
g ta vernier
e e ca
pe
digital
caliper
Direct
Di t reading
di off an external
t
l length
l
th
by digital vernier caliper
Vernier caliper with a dial indicator
4
Graduated Linear Measurement - Vernier Height Gauges
Designed for use in toolrooms, workshops, inspection departments in order to measure
and/or mark off vertical and locating center distances.
Standard Height gauge
Dial Height Gauge
Digital Height Gauge
5
Graduated Linear Measurement - Vernier Depth Gauges
Designed for use in toolrooms, workshops, inspection departments in order to measure
depths of holes, slots, recesses, and so on.
Standard Depth Gauge
Dial Depth Gauge
Digital Depth Gauge
6
Graduated Linear Measurement - Outside Micrometers
VERNIER READING
THIMBLE READING
Metric Micrometer
SLEEVE (BARREL) READING
Vernier Metric Micrometer
B
How
H
tto read
d a vernier
i metric
t i micrometer:
i
t
Sleeve div. = 1 mm
Thimble div. = 1/50th of sleeve sub-div. = 1/100 mm
Vernier
Division
Thimble
Division
Vernier div. = 1/10th of thimble div. = 1/1000 mm
D
A. The highest figure: 5 * (sleeve div.) = 5 mm
C
B. The half-figures: 1 * (sleeve sub-div.) = 0.5 mm
C. The highest figure: 28 * (thimble div.) = 0.28 mm
D. The matching figure: 3 * (vernier div.) = 0.003 mm
Sleeve
Division
A
FINAL READING = A + B + C + D = 5.783 mm
7
Graduated Linear Measurement - Outside Micrometers
Dial-indicating Micrometers
Direct-reading
Micrometer
V-anvil Micrometers (measuring odd-fluted taps, milling
cutters, reamers as well as checking out of roundness)
Screw Thread Micrometer
(measuring pitch diameter
of screw threads)
8
Graduated Linear Measurement - Inside Micrometers
Standard Inside Micrometers
Digital
g
Inside Micrometers
9
Graduated Linear Measurement - Micrometer Bore and Depth Gauges
Micrometer Hole
and Bore Gauges
Inside Micrometer Set
Micrometer Depth
p Gauges
g
10
Graduated Angular Measurement - Protractors
(a)
Simple
Protractor
(measuring
angles from
0 to 180º)
((b))
Universal Bevel Protractor (main scale
consists of 4 portions of 90º)
Measuring acute (a) and
obtuse (b) angles
How to read an angle on a bevel protractor:
Main div. = 1º = 60′
Vernier div. = 1/12th of main div.  0.0833º = 5′
 The highest figure: 50 * (main div.) = 50º
 The matching figure: 4 * (vernier div.)  0.333º = 20′
 The final reading is:  50.333º or 50º 20′
11
Special Purpose Measurement Tools
Level (used for setting up and testing machinery)
Dial test indicator mounted on
a magnetic
ti stand
t d (used
(
d as an
apparatus with machine tools
for specific measurements)
Combination set (a square, a level, a depth/height gauge,
and a bevel protractor with centring head)
12
Non-Graduated Linear Measurement - Calipers
 Standard calipers have a fine adjustment screw and a quick-adjusting spring nut.
 Accuracy obtained with these tools depends mostly on the inherent skill of users.
 The measurements are carefully transferred to a graduated measuring tool.
Caliper for internal
measurements
Caliper for external
measurements
Caliper used
as a divider
13
Non-Graduated Linear Measurement - Gauges
Telescopic Gauges
(consist of a handle with
two plunger-contacts at
right angles to a handle
which both lock
simultaneously)
Small Hole Gauges (consist of
an expanding ball head adjusted to
size by a knurled knob to provide
an accurate “feel” for obtaining
measurements in a hole or slot)
Surface Gauge (consists of a ground
rectangular base with a round upright rod
and a fine adjustment feature on the base.
It can be used in a layout
y
work for scribing
g
lines on vertical/horizontal surfaces as well
as in inspection work as height/depth gauge)
14
Non-Graduated Linear Measurement - Special Purpose Gauges
Screw Pitch
S
Pit h Gauges
G
(
(consist
i t off a metal
t l case preserving
i many
separate leaves. Each leaf has teeth corresponding to a definite pitch.
By matching the teeth with the thread on work, the correct pitch can
be read directly from the leaf)
Tap and Drill Gauges (consist of
a flat rectangular
g
steel p
plate with
holes accurately drilled and
identified according to their size)
Radius Gauges (available as individual leaves and each leaf is
marked with its radius. Designed to check convex/concave radii)
15
Non-Graduated Linear Measurement - Rectangular Gauge Blocks
(a)
(b)
(c)
Linear Gauge Blocks: (a) rectangular, (b) square, (c) square with center hole
16
Non-Graduated Angular Measurement - Angle Gauge Blocks
parallel
+3º
+5
+5º
Target: 38º
+30º
Complete set of angle gauge blocks
True Square
Setting a revolving magnetic chuck
using angle gauge blocks
17
Non-Graduated Angular Measurement - Sine Bar
How to use Sine Bar:
 We want to set an angle of 14º 12′
using a 10 mm sine bar.
 This
Thi means: l = 10 mm and
d θ = 14.2º
14 2º
 So: h = l * sin θ = 2.453 mm
 Therefore,
Therefore the combination of blocks
providing this height must be used.
Limitations of Sine Bar:
 When using a sine bar, the height setting is limited by the available gauge block divisions.
This results in an error that mayy be negligible
g g
or in some cases q
quite significant.
g
 Due to the nature trigonometry; at larger angles, it is susceptible to errors in the length of
the sine bar as well as in the height of the gauge blocks.
18