This document provides information about coordinate measuring machines (CMM). It discusses the history and development of CMMs, including that Russ Shelton is considered the father of CMMs. It describes the basic principles and types of CMMs, including cantilever, bridge, column, horizontal arm, and gantry types. The document also covers probe types, CMM software, advantages, disadvantages, and applications of CMMs in quality control and inspection.

2. COORDINATE MEASURING MACHINE
(CMM)
By
Vignesh Ramanathan

3.  Metrology And Measurements
 Introduction Of CMM
 History Of CMM
 Principle Of CMM
 Types Of CMM
 Types Of Probe
 Software of CMM
 Advantages Of CMM
 Disadvantages Of CMM
 Applications Of CMM
 Conclusion

4.  What is Metrology?
Derived From Two Greek Words
Metro - Measurement
Logy - Science
The Scientific study of Measurement.
Errors in Measurement
Changing Units in Form of Standards
Developing new methods in Measurement
Research the Causes of Measuring Errors
 Types Of Metrology
1. Scientific 2. Industrial 3. Legal 4. Fundamental 5.
Dynamic 6. Deterministic

5.  It is a universal dimensional measuring
device.
 It is more useful and advantageous than
vernier calipers, micrometer, screw
gauges etc.
 Thermal depends on CMM 18-20ºc (64 -
72ºF) of room standards.
 That has 3 axes (XYZ) coordinate points.
 It's controlled by an operator or computer
numerical control (CNC) machine.

6.  Russ Shelton is a Father of CMM
considered by many other.
 He had already manufactured several
CMM’s employing granite for
structural components and air
bearings for guidance
 His own innovative ideas and
machine architecture to found a new
company called Shelton Metrology in
1965.
 He was one of the first to build
scanning probes for CMMs.
 He introduces manual scanning
probes in the mid-70s and CNC
versions of the mid-80s.

7. Russ received a Design News
award for Veritas, deemed to be
one of the 100 most significant
inventions of 1971
Veritas into his CMMs he could
provide straightness-measurement
resolution and accuracy of ten
millionths over 56 inches.
Russ then designed the first
indexing touch trigger probe, that
probe remained in use from 1971
until 1995.
Shelton Metrology machines are
still in operation after 30 years

8.  The actual shape of a manufactured part is registered by points
based on coordinate system by measuring individual points on
the object surface with a probe system.
 From the registered coordinate points, a numerical model of the
part is generated. The numeric model of the part is a substitute of
the actual part shape consisting of basic geometric elements such
as circles, planes, cylinders, etc.
 The calculation of these geometric elements is based only on
touched points.
 When more points are taken, a better fitting element can be
calculated by a mathematical approximation method.
 The substitute shape is compared with the given nominal shape
and the results of this comparison are documented in a test
report.

9. 1. Cantilever Type of CMM
Measuring Probe attached to the
Z-axis it moves Vertical Direction.
The cantilever arm attached to Y-
axis.
A table attached to X-axis.
Easy access to work and it High
Workspace Volume.
It Suitable for measuring the
long and thin part.
Major Disadvantage Bending
caused by Cantilever design

10. 2. Bridge type of CMM
(a) Moving Bridge type
Measuring Probe moves
in the Z-axis direction and
its fitted with Y-axis arm.
Arm Moves in Y-axis
direction and its fitted in X-
axis.
The bridge moves in X-
axis and its Supported by
table.
Air Bearings are used in
their type.

11. 2. (b). Fixed bridge type
Measuring Probe moves in
the Z-axis direction and its
fitted with Y-axis arm.
Arm Moves in Y-axis
direction and its fitted bridge.
The table moves in X-axis.
This type of CMM
supported for Large and
Medium components.
It has better rigidity.
It has Higher Accuracy than
Horizontal arm CMM.
It has Limited work area.

12. 3. Column type CMM
Table Moves in X and Y
both axis directions.
The probe moves in the Z-
axis direction.
It has Good Rigidity and
High accuracy.
That commonly known as
a universal measuring
machine.
It is similar to drilling and
vertical milling machine

13. 4. Horizontal arm type CMM
Arm moves in the X-axis
direction.
Probe fitted with arm.
But it moves in Y and Z
axis.
The table moves in the
Z-axis direction.
That has large work
volume and free from
obstruction.
That CMM accessibility
for large objects like
dying, car bodies.

14. 5. Gantry type CMM
Crossbeam has a
carriage and it moves
in the X-axis direction
Carriage has probed
and it moves in Y-axis
Direction.
The probe moves in
the Z-axis direction.
It can measure a large
object.
It has more accuracy
than all other CMM.

15. A. Contact Probe
1. Hard Probe
It has a variety of probe tip shape and
size. But it is determined by
application.
Ball/Spherical shape probe used for
establishing surface locations.
Tapered or conical probe used for
locating holes.
The cylindrical probe used for
checking slots and holes in sheet metal.
That probe is used in small, manually
operated CMM.

16. A.2. Switching Probes
It is also called as
Trigger type probe
system.
The “Buckling
mechanism” is a three
point bearing it
arranged at 120º around
and circumference.
Switching probe
mostly used when an
object has to be
measured very fast by a
single point.

17. A.3. Measuring Probes
It used for the large
bridge type of CMM.
It's also a “Buckling
mechanism” this is system
have parallel gateways.
It is a three dimensional
probe.
Flexible parallelograms
Stylus able to deflect in
any direction
Measured either by
measuring system or
photoelectric sensor.
This also called mulling
probe.

18. B. Non-contact Probes
1. Laser Probe
The single-spot
laser triangulation
method.
This method uses
low-powered laser
beam for distance
measurement.
A light sensitive
detector at an angle
of approximately
25º.

19. B.2. Vision Probe
A charge-coupled
device (CCD) is
usually employed in
the camera.
It consists of
matrix arrays.
It measured by
computer ‘Count’ of
pixels.
The analog
voltage value of
each pixel converts
to a digital value.

20.  The measurement data with a computer-
aided drafting (CAD) model.
 Parameter programming to minimize CNC
programming.
 A program for the measurement of spur,
helical, bevel, and hypoid gears.
 The component is digitized using CNC-
CMM. Converted it into a computer model.
 The % of saving inspection time by using
CMM is 5 to 10 compared to manual
inspection methods.

21.  High precision and accuracy.
 Requires less labor.
 Accurate dimensions can be obtained just
by knowing the coordinates and distance
between the two reference points.
 Robustness against external force and
error accumulation.
 The rate of inspection is increased.
 Uniform inspection, quality is ensured

22.  The Coordinate measuring machines are
very costly.
 The CMMs are less portable.
 If the operating software cracks down it is
difficult to restart the entire system.
 It needs to construct some feature on its
own as some parts of the workpiece are
unreachable by the probe.
 The probe may have run out.
 There may be errors in the digital system.

23.  It is used in automobile, machine tool,
electronics, space and many other large
companies.
 For aircraft and space vehicle, 100% inspections
are carried out by CMM.
 It is ideally suited for development of new
products.
 It is ideal for determination of shape and
position, maximum metal condition, linkage of
results etc..

24.  Measurement is the most important thing for
any other components.
 If 0.1 also more important in a measuring unit
that mostly helped by CMM.
 Is that more efficiently than other measuring
elements.