comparators ppt 1.pptx [ mechanical engineering]

Comparators

1. Comparators PRESENT BY HARISH.S

2. INTRODUCTION A comparator is a precision measuring instrument used in metrology (the science of measurement) to compare the dimensions of a manufactured part with a standard value , such as a master gauge or reference. It does not measure the exact dimension, but it shows the difference (deviation) between the actual size of the part and the standard size.

3. Purpose of Comparators   To detect deviation from standard size   They help in identifying how much a part differs from a reference standard (like a master gauge).   To check components within tolerance   They are used to ensure the dimension of a part lies within the specified limits (upper and lower tolerance).  To improve quality control   Widely used in industries to inspect parts quickly and accurately during mass production.   To reduce human error   Since comparators give visual or amplified indications, they are less prone to operator errors.   For rapid inspection   They allow fast checking of parts in large quantities, saving time compared to using micrometers or vernier calipers .

4. Characteristics of Comparators  High Accuracy   - They can detect very small variations in dimensions (as small as 0.001 mm or less).  High Magnification   - Small displacements are amplified using mechanical, optical, or electronic systems for easy detection.  Sensitive to Minor Changes   - Even minute changes in dimension are sensed and displayed clearly .  No Scale or Graduation   - Most comparators don’t show actual measurements; they show deviations from a set value.  Quick and Easy Operation   - Once set with a master, they can be used repeatedly to check multiple parts quickly.

5. Needs of Comparators Comparator are essential in precision measurement systems for several reasons To Check Tolerance Limits In manufacturing, components must be produced within specific size limits (tolerances) Comparators help check if the part lies within these limits without measuring the exact dimension. To Improve Inspection Speed In mass production, using micrometers for every part is slow. Comparators speed up inspection without sacrificing accuracy. To Reduce Human Error Since comparators give visual or dial-based outputs, they are less prone to reading errors than manual instruments.

6. Types of Comparators Mechanical Comparators Electrical Comparators Electronic Comparators Pneumatic Comparators Optical Comparators Mechatronic Comparators Digital Comparators

7. Mechanical Comparators Introduction A mechanical comparator is a precision measuring instrument used to compare the dimensions of a component with a standard or master gauge. It operates purely on mechanical means , using components such as levers, gears, racks, pinions, and springs to amplify small linear displacements caused by dimensional variations in the workpiece. Types of Mechanical Comparators Dial Indicator Comparator Lever Type Comparator Rack and Pinion Comparator Sigma Comparator Solex Comparator

8. Dial Indicator Definition A Dial Indicator is a type of mechanical comparator used to measure small linear displacements of a surface. It converts the linear movement of a plunger into rotational movement and displays the deviation on a graduated dial with a pointer. Working Principle The plunger touches the surface of the workpiece. Any dimensional variation moves the plunger up or down. This movement is transmitted to a gear and rack mechanism inside the dial indicator. The mechanism magnifies the movement and turns the pointer on the dial. The pointer position indicates how much the part deviates from the standard.

9. Dial Indicator

10. Advantages Easy to read and operate. High sensitivity to small variations. Portable and suitable for on-site inspection. Limitations Sensitive to shock or rough handling . Friction and backlash may affect accuracy. Horizontal and vertical types must be used properly based on the application. Applications Checking roundness , flatness , and parallelism . Measuring runout (eccentricity). Aligning machine tools and fixtures.

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