Optical and pneumatic comparators

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:

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.

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