What Is an Eccentricity Measuring Instrument?
An eccentricity measuring instrument is used to measure the eccentricity of rotating objects, such as rollers and motor shafts. Eccentricity refers to the distance between the center of rotation and the rigid center, which is the geometric center of the rotating object. In precision instruments with rotating parts, eccentricity is often designed to be zero, and any deviation can cause malfunctions. There are two typical types of eccentricity measurement methods: the transmission type, which measures using transmitted light, and the reflection type, which measures using reflected light.
Uses of Eccentricity Measuring Instruments
Eccentricity measuring instruments are crucial for the inspection and maintenance of equipment with rotating motors, such as machine tools, robot arms, and rollers. When selecting measuring instruments, factors like the measurement method, accuracy, and range must be considered.
Examples of eccentricity measurement applications include:
- Eccentricity measurement of the roller section in a rolling mill.
- Eccentricity measurement of the shaft in a lathe used in machine tools.
- Eccentricity measurement of a wafer rotating part in semiconductor manufacturing equipment.
Principles of Eccentricity Measuring Instruments
The principle of eccentricity measurement is divided into transmission and reflection types.
- Transmission Type
Transmission type instruments consist of a light-emitting part with an element and a light-receiving part with a sensor. The rotating body to be measured is placed between the emitter and receiver. The light emitted is partially intercepted and transmitted by the rotating object, then received by the sensor. By high-speed sampling of the received light, the degree of runout is observed, and eccentricity is calculated. Some devices can measure eccentricity at multiple points for greater accuracy. - Reflective Type
Reflective instruments consist of a light-receiving sensor and a light-emitting element. During measurement, a laser-like light is shone on the rotating object, and the reflected light is received to measure eccentricity based on the deviation of the light period. This type is smaller in size and can measure from one direction. However, it may have higher error margins with thin objects, requiring careful application.