APPLICATION OF MECHATRONICS IN COORDINATE MEASURING MACHINE.USE OF MULTI-SENSOR TECHNOLOGY.CMM IS USED TO MEASURE COORDINATE OF A WORKPIECE WITH THE HELP OF PROBE.CMM CAN BE CONTROLLED WITH THE HELP OF NUMERICAL CONTROL. INTRODUCTION TO 5 AXIS TECHNOLOGY. ADVANTAGES OF CMM.TYPES OF CMM.

1. Shri Ramdeobaba College of Engineering & Management
(An Autonomous Institute under UGC Act)
Department of Electrical Engineering
Topic : Coordinate Measuring Machine(CMM)
Subject : Mechatronics
Assignment (PowerPoint Presentation)
Presented By-
Name : Sheikh Mohammad Sajid
Roll No. : 07
Specialization : Master of Technology
Branch : Power Electronics & Power Systems
Year / Semester : Ist / 2nd

2. Introduction
Why CMM?
 With the advent of numerically controlled machine tools, the
demand has grown for some means to support these equipment.
 There has been growing need to have an apparatus that can do
faster first piece inspection and many times, 100% dimensional
inspection.
 The Coordinate Measuring Machine (CMM) plays a vital role in
the mechanisation of the inspection process.
 Some of the CMMs can even be used as layout machines before
machining and for checking feature locations after machining.
 Coordinate measuring machines are relatively recent
developments in measurement technology.
 Basically, they consist of a platform on which the workpiece
being measured is placed and moved linearly or rotated.

3. A probe attached to a head capable of lateral and vertical
movements records all measurements.
 Coordinate measuring machines are also called measuring
machines.
 They are versatile in their capability to record measurement
of complex profiles with high sensitivity (0.25 µm) and speed.
Co-ordinate Measuring Machines are built rigidly and are very
precise.
 They are equipped with digital readout or can be linked to
computers for online inspection of parts.
 These machines can be placed close to machine tools for
efficient inspection and rapid feedback for correction of
processing parameter before the next part is made.
 They are also made more rugged to resist environmental
effects in manufacturing plants such as temperature variations,
vibration and dirt.

4. COMPARISON BETWEEN CONVENTIONAL AND
COORDINATE MEASURING TECHNOLOGY
CONVENTIONAL METROLOGY COORDINATE METROLOGY
• Manual, time consuming alignment of the
test piece.
• Alignment of the test piece not necessary.
• Single purpose and multi-point measuring
instruments making it hard to adapt to
changing measuring task.
• Simple adaptation to the measuring test
by software.
• Comparison of measurement with
material measures, i.e., gauge block.
• Comparison of measurement with
mathematical or numerical value.
• Separate determination of size, form,
location and orientation with different
machines.
• Determination of size, form, location and
orientation in one setup using one
reference system.

5. What are the Important features of the
CMM ?
(i) To give maximum rigidity to machines without excessive weight, all the
moving members, the bridge structure, Z-axis carriage, and Z-column are
made of hollow box construction.
(ii) A map of systematic errors in machine is built up and fed into the computer
system so that the error compensation is built up into the software. 98
Metrology and Instrumentation.
(iii) All machines are provided with their own computers with interactive
dialogue facility and friendly software.
(iv) Thermocouples are incorporated throughout the machine and interfaced
with the computer to be used for compensation of temperature gradients
and thus provide increased accuracy and repeatability.

6. The basic CMM has three perpendicular axis; x,y,z.
 The physical configuration of CMMs vary widely,
but they all provide a way to move a probe in three
axes with respect to workpiece.
 Five basic configurations that are used more
frequently :
1. Cantilever
2. Colume
3. Bridge
4. Gantry
5. Horizontal Arm
WHAT ARE THE DIFFERENT TYPES OF CMM?

7. 1) Cantilever Type-
• A vertical probe moves in the z-axis
• Carried by a cantilevered arm that moves in the y-axis.
• This arm also moves laterally through the x-axis.
• Advantage- A fixed table allows good accessibility to
the workpiece.
• Disadvantage- The bending caused by the cantilever
design.
• The cantilever design offers a long table with relatively
small measuring ranges in the other two axis.
• Suitable for measuring long, thin part.
2) Colume Type-
• Often referred to as universal measuring machine
instead of CMM.
• The column type CMM construction provides
exceptional rigidity and accuracy.
• These machines are usually considered gage room
instruments rather than production floor machine.
• The constructional difference in column type with the
cantilever type is with x and y-axes movements.
Fig. Cantilever type
Fig. Colume type

8. 3) Bridge Type-
• The bridge arrangement over the table carries the
quill (z-axis) along the x-axis and is sometimes
referred to as a travelling bridge.
• It is claimed that the bridge construction provides
better accuracy, although it may be offset by difficulty
in making two members track in perfect alignment.
• This is by far the most popular CMM construction.
• Disadvantage- With this design, the phenomenon of
yawing (sometimes called walking) can occur- affect
the accuracy.
• Advantage- Reduce bending effect.
4) Gantry Type-
• In a gantry type arrangement, arms are held by two
fixed supports.
• Other two arms are capable of sliding over the
supports.
• Movements of the x, y and z-axes.
• The gantry type construction is particularly suited for
very large components and allows the operator to
remain close to the area of inspection.
Fig. Bridge type
Fig. Gantry type

9. 5) Horizontal Arm Type-
• Unlike the previous machines, the basic horizontal arm-type
CMM.
• Also referred to as layout machine.
• Has a moving arm, and the probe is carried along the y-
axis.
• Advantage- Provides a large area, unobstructed work area.
• Ideal configuration for measurement of automobile parts.
Fig. Horizontal Arm Type

10. DIRECT COMPUTER CONTROLLED (DCC)
Fully programmable.
Use CAD data to determine whether the probe sensor contacts
the workpiece, collecting measurement data.
The fully automated CMM allows operator to place the
workpiece in a fixture/ worktable, run a stored program, collect
the data points and generate the output report.
Measurement reports can be saved in the computer to compile
a historical record for SPC.
A program of DCC machine has three components:
1. Movement commands – direct the probe to the data
collection points .
2. Measurement command – compare the distance traveled
with the standard built into the machine for that axis.
3. Formatting command- translate the data into a form for
display or print out.

11. Probing System
CMM probe is one of the most important systems of dimensional measuring
instruments and responsible for the coordinate measurement accuracy.
Fast response and accurate detection of the probe that can be computer
controlled, represents the current trend for the next generation of coordinate
metrology.
Varieties of probe designs are already available and compatible with most of
the CMMs.
The probing system in CMM machines includes stylus and stylus tip which
have their own dynamic characteristics during the measuring process .
The stylus tip contact with the detected surface is the source of signals that
will develop the pattern on the working objects.
So, the performance of the CMM overall system is very much dictated by the
motion precision of the probe tip and its actuator.
Therefore, the probe stylus tip is laterally at the center of the CMM operation
and a key element of coordinate measurements.
The detection probes branch into two main categories; there are contact
(tactile) probes and non-contact probes.

12. 1. Contact
a. Touch trigger probe
• As the sensor makes contact with the part, the difference in contact resistance
indicates that the probe has been deflected.
• The computer records this contact point coordinate space.
• An LED light and an audible signal usually indicate contact.
• Touch probe assemblies consist of three components; probe head, probe and stylus.
b. Analog scanning probe
• Use to measure contour surfaces, complex, irregular.
• Remains in contact with the surface of the part as it moves.
• Improve the speed and accuracy.
2. Non-Contact (Improvement is done)
a. Laser scanning probe
• Laser probes project a light beam onto the surface of a part.
• When the light beam is triggered, the position of beam is read by triangulation
through a lens in the probe receptor.
• Laser tool have a high degree of speed and accuracy.
b. Video probe
• The feature are measured by computer ‘count’ of the pixels of the electronic image.
• The camera is capable of generating multitude of measurements points within a
single video frame.

13. SENSORS FOR COORDINATE MEASURING MACHINES
The sensors of a
coordinate measuring
machine are used to pick
up the primary signal from
the workpiece. They are
designed using mechanical
and, in some cases, opto-
electronic and software
components of varying
complexity. The sensors
must be selected on the
basis of the conditions on
and near the workpiece,
the touch sensitivity of the
object, the size of the
features to be measured,
the requirements of the
measurement plan and the
number of measured
points. Thus, the selection
of the sensor basically
depends on the measuring
task at hand.

14. IMAGE PROCESSING SENSOR(VISUAL SENSOR)
Today, image processing sensors are
commonly used as visual sensors (Fig. 8).
The object is imaged onto a matrix
camera by the lens.
The camera electronics convert the
optical signal to a digital image, which is
then used to calculate the measured
points in an evaluation computer
equipped with the corresponding image
processing software.
The performance of such sensors is
heavily influenced by several individual
components including the illumination,
the lens system, the sensor chip, the
electronics and the computing
algorithms .
This design enables a 1 × to 10 ×
magnification and working distances
ranging from 30 mm to a maximum of
250 mm.

15. AUTOFOCUS(DISTANCE SENSOR)
The same hardware components are used for autofocus as for image processing.
When the sensor is moved along the optical axis, a sharply defined image results
only in a single position. If the sensor is defocused, blurred images are produced. The
contrast can be used as a parameter for the focus of an image. If the sensor is moved
along its optical axis within a range which contains the object plane, the contrast
reaches its maximum value at the point where the focal plane coincides with the
object plane. The location of the point on the surface can be determined from this
sensor position (Fig. 14a)

16. TOUCH TRIGGER TACTILE SENSORS(TACTILE SENSOR)
Basic touch trigger probing systems function according to the “three-leg
principle” (Fig. 19a).
If the stylus sphere contacts the workpiece, a trigger signal is generated for
read-out by the scale systems of the coordinate measuring machine.
The measured point results from the coordinates of the measuring machine
and is referenced to the center point of the stylus sphere. Via a rigid shaft, the
stylus sphere is attached to a three-point bearing equipped with a switch at
each of its three bearing points.
If the stylus is deflected from a given direction, at least one of these switches
will be opened.
This is then further processed as a trigger signal.
The major disadvantage of this system lies in the fact that the variation of
probing forces according to the probing direction results in a stylus deflection
of varying elasticity.
This in turn results in a directional probing behavior (three corner
characteristic) which is difficult to correct.

17. TOUCH TRIGGER TACTILE SENSORS(TACTILE SENSOR)

18. MULTISENSOR TECHNOLOGY
Multisensor coordinate measuring
machines use a combination of
several of the sensors described
above. The properties of these
sensors usually depend on their
various primary applications (Fig.
27). Regarding applications, their
distinguishing characteristics
include the size of the object
features they can probe, the type
of object features they can probe
(edge, surface), and their
suitability for rapidly acquiring
large numbers of measured points
(scanning). In order to perform
complex measuring jobs, it is
usually necessary to use several
different sensors for a single
measuring run.

19. SOFTWARE FOR THREE-DIMENSIONAL GEOMETRY ANALYSIS
In a CMM, the computer and the software are an inseparable part.
They together represent one system. The efficiency and cost
effectiveness of a CMM depend to a large extent on the software.
The features that the CMM software should include :
• Measurement of diameter, center distances, lengths, geometrical
and form errors in prismatic components, etc.
Online statistics for statistical information in a batch.
• Parameter programming to minimize CNC programming time of
similar parts.
• Measurement of plane and spatial curves.
•Data communications.
•Digital input and output commands for process integration.
•Program for the measurement of spur, helical, bevel and hypoid
gears.
•Interface to CAD software.

20. ADVANTAGES OF CMM
1.Flexibility
CMMs are essentially universal measuring machines and need not be
dedicated to any particular task. They can measure almost any dimensional
characteristic of a part configuration, including cams, gears and warped
surfaces. No special fixtures or gages are required. Because probe contact is
light, most parts can be inspected without being clamped to the table.
2. Reduced Setup Time
Part alignment and establishing appropriate reference points are very time
consuming with conventional surface plate inspection techniques. Software
allows the operator to define the orientation of the part on the CMM, and all
subsequent data are corrected for misalignment between the parts-reference
system and the machine coordinates.
3.Single Setup
Most parts can be inspected in a single setup, thus eliminating the need to
reorient the parts for access to all features.
4.Improved Accuracy
All measurements in a CMM are taken from a common geometrically fixed
measuring system, eliminating the introduction and the accumulation of
errors that can result with hand-gage inspection methods and transfer
techniques.

21. 5. Reduced Operator Influence
The use of digital readouts eliminate the subjective interpretation of
readings common with dial or vernier type measuring devices. Operator
“feel” is virtually eliminated with modern touch-trigger probe systems, and
most CMMs have routine measuring procedures for typical part features,
such as bores or centre distances. In computer assisted systems; the
operator is under the control of a program that eliminates operator choice.
In addition, automatic data recording, available on most machines,
prevents errors in transcribing readings to the inspection report. This adds
upto the fact that less skilled operators can be easily instructed to perform
relatively complex inspection procedures.
6. Improved Productivity
The above-mentioned advantages help make CMMs more productive than
conventional inspection techniques. Furthermore, productivity is realized
through the computational and analytical capabilities of associated data-
handling systems, including calculators and all levels of computers.
Reference-
https://www.koordinatenmesstechnik.de/en/navigation/sensors-for-
coordinate-measuring-machines.html

22. ADVANCEMENT IN CMM TECHNOLOGY
Multi Sensor Measuring
◦ Incorporates touch, optical or laser sensors
◦ Operator can choose which sensor to use
◦ All work done in single setup
◦ Faster
◦ The co ordinates might not be correct owing to inputs from
many sensors
• 5 Axis CMM
◦ Revolutionary technology by Renishaw
◦ 2 axes controlled by servo
◦ Faster and quicker
◦ Not supported by OEM’s
•3 D Scanner
◦ Many technologies are used
◦ Color as well as contour information collected

23. 5 AXIS TECHNOLOGY
5-axis measurement technology breaks through that limit by using an
articulating head that moves in two rotary axes as it measures. This allows the
CMM to do what it is best designed to do - move at constant velocity in a
single vector while measuring. As the head is much lighter and more dynamic
than the CMM, with a significantly better bandwidth, it is able to quickly
follow changes in the part geometry without introducing harmful dynamic
errors, which results in much faster surface speeds and hence shorter
measurement cycles.

24. APPLICATION OF CMM
CAD based Inspection
Dimensional measurement
Profile measurement
Angularity or orientation measurement
Shaft measurement
Reverse Engineering

25. THANKING YOU