This is an important area for mechanical engineering as the knowledge about measuring devices in Industrial engineering. ENGINEERING METROLOGY AND QUALITY CONTROL.

1. OPTICAL AND
PNEUMATIC
COMPARATORS
ABINESH T V
16BME059

2. COMPARATORS:
• In Metrology, The comparator is a Precision
Instrument, which is used to compare the
dimensions of the given component with the
actual working standard.

3. Types of Comparators:
• Mechanical
• Optical
• Electrical and Electronic
• Pneumatic
• Fluid displacement
• Projection
• Multi-check
• Automatic gauging machine

4. OPTICAL COMPARATORS:
• An optical comparator (often called just a comparator in context) or
profile projector is a device that applies the principles of optics to the
inspection of manufactured parts. In a comparator, the magnified
silhouette of a part is projected upon the screen, and the dimensions
and geometry of the part are measured against prescribed limits. It is
a useful item in a small parts machine shop or production line for the
quality control inspection team.

5. • Optical comparator:
Dorsey, 16H Horizontal Beam Optical Comparator

6. Principle:
• An optical comparator is a device that applies
the principles of optics for the inspection of
manufactured parts. In a comparator, the
magnified silhouette of a part is projected on a
screen, and the dimensions and geometry of
the part are measured against the prescribed
limits.

7. Advantage:
High accuracy will be achieved since it is
having very less moving parts.
Parallax error will be avoided.
Less weight compared to other
comparators due to fewer parts.
Very Suitable for precession
measurements due to high magnification
can be achieved.

8. Disadvantage:
• Need a separate electrical source.
• Optical means are expensive.
• Not suitable for continuous use due to the scale to be view thru
eyepiece.
• Suitable to use in Darkroom only.

9. Application:
• An optical comparator is a device that applies the principles of optics
for the inspection of manufactured parts. ... An optical comparator is
used for a wide range of dimensional inspection applications. Optical
Comparator horizontal models work well with parts that need to be
fixed, held in a vise, or on centers.

10. PNEUMATIC COMPARATORS:
• Pneumatic Comparators or Pressure Comparators |Metrology|
A comparator is a precision instrument used to compare the
Dimensions of a given working component with the actual working
standard. There are different types of comparators are available.

11. • Pneumatic Comparator:
P5513 Pneumatic Pressure Comparator
Pressure range 0 to 3,000 psi (210 bar)
This pneumatic comparison pressure comparator is designed
for testing pressure measuring instruments against master test
instruments. This cost effective instrument provides precise
control for important calibration requirements and include
many features found in our popular line of pneumatic
deadweight testers.

12. Principle:
• The working principle of pneumatic comparator is, when the air
under constant pressure discharges by passing through two openings.
If one of the hole is kept uniform, the pressure will change according
to the size of the other.

13. Advantage:
• High degree of magnification is possible.
• No wear takes place in on the workpiece due to no contact of the
comparator to the workpiece.
• High accuracy can be achieved due to very few moving parts.
• Suitable to measure the diameter of holes.

14. Disadvantage:
• Low speed of response compared to other types of comparators like
optical comparators.
• an accurate pressure regulator is required. and the apparatus is not
portable.
• The scale is not uniform.

15. Application:
• No wear takes place in on the workpiece due to no contact of the
comparator to the workpiece. High accuracy can be achieved due to
very few moving parts. Suitable to measure the diameter of holes.
Best instrument to determine the ovality and taper of the circular
holes.

16. THANK YOU