We explained the geometric attributes that are generally used in manufacturing or quality control departments. So there must be some kind of tooling to measure these geometric attributes of produced products whether they are inside the defined geometric tolerances or not. In this article we will explain the two types of comparative measurement instruments called as ‘Gages’.
Comparative instruments are not give any direct measurement value, they only ‘compare’ the measured workpiece’s geometric feature with a standardized surface. And gives the direction of the comparative differences between them.
Dial Indicators: This is the most known comparative measurement device that the working principle depends on mechanical basis. In basic, there is a pointer that touches to the surface of the workpiece, and mechanism inside the dial indicator converts the linear movement of the pointer that originates from the surface roughness or other features, to a value on a analog screen by magnifying it. Magnification is made because it must be seeable by people. With dial indicators, straightness, flatness, parallelism, squareness, roundness, and runout can be measured or found on workpieces.
Electronic Gages: In general, electronic measurement devices give much more accurate results compared to the mechanical dial indicators. But these devices can be more expensive. In general manufacturing sites and quality control departments for same applications with dial indicators. If we state the working principle of electronic gages basically; There is a electronic transducer that converts the linear displacements into electric signals, and these electrical signals are amplified then converted to the data can be read from the user of electronic gages. In market, electronic measurement devices takes the places of mechanical instruments. So electronic gages also very common in manufacturing sites and quality control departments.
The most basic explanation of comparative gaging instruments can be made like this. Leave your comments and questions about ‘Comparative Measurement Instruments’ below!
Source Of Images: Fundamentals Of Modern Manufacturing Book