Abstract
Magnetic linear encoder has been increasingly integrated in various position control application while demands for high precision machine tool to produce high precision products increase. Due to its advantage in withstanding unclean environment such as oil, grease, and dust over an optical encoder, a magnetic encoder has become a desirable choice for machine tools. During the manufacture of magnetic encoding medium, the medium is not expected to be flat due to packaging induced plastic deformation and residual stress. Medium deformation will result in damaging the performance of the medium such as the accuracy and magnetic flux density distribution. In this paper, the research efforts are devoted to develop a roller leveling system to flatten the curved magnetic medium. Variable roller leveling system is designed and manufactured to perform parameter studies such as number of leveling and the indentation, diameter, and spacing of leveling rollers. Parameter studies are carried out to investigate how roller leveling can be integrated into the manufacture of magnetic encoding medium to improve mechanical deflection and residual stress. Optimal performance of the roller leveling system under specific parameter has been determined. Furthermore, experimental results demonstrate that roller leveling can significantly improve mechanical deflection of pre-stressed curve magnetic medium up to almost 60%. Residual deflection and residual stress of the deformed medium are validated through analytical studies using theory of Euler-Bernoulli beam and Elastica.