Rotors or shafts used in steam and gas turbines, turbo generators and compressors, or any large motor, have to work within set standards for runout to ensure efficient and safe operation.
Mechanical runout can be measured using a Dial Test Indicator (DTI) to establish the dimensional error as the shaft is rotated through 360º. Factors affecting this include the quality of the turning machine, the tooling being used, the grinding process, and material handling.
If excessive runout is not eliminated during the manufacturing process, the motor would have to be disassembled and the shaft reworked. This can be a time consuming and costly process and one the motor manufacturer would want to avoid.
So how does the use of a diamond burnishing tool help reduce the Glitch or electrical runout of the shaft?
The induced change realigns the surface structure of the material matrix resulting in a reduction in the electrical runout of the shaft, which in turn will lead to reduced vibration and noise when the shaft is in use.
This API (American Petroleum Institute) recommended method has a high success rate of reducing “glitch” to within acceptable limits as it produces a uniform work-hardened surface requiring no further treatment.
The technique can also be applied when repairing worn shafts as the burnishing process can help to eliminate the effects of surface damage due to mishandling and wear.
Elliott Tool Technologies has been a supplier of Diamond Burnishing tools for this process for many decades, with tools being used across the globe. The premium quality of the diamond knib ensures repeatable results for the end user.