Optimization of magnetizing parameters for multi-pole magnetic scales by Taguchi method

Magnetic encoders comprise a magneto-resistive sensor and a multi-pole magnetic scale. They are applicable under a harsh environment. The purpose of this study is to design and fabricate high quality magnetic remanence, both field strength and waveform, out of a magnetic scale aiming to a great improvement in resolution. However, magnetization study of multi-pole magnetic scale is few. Some factors have been identified for rotary multi-pole magnetic encoder [1]. Yet a symmetrical magnetized field is difficult for parallel magnetization. Effective parameters on the operation of a magnetizer have been simulated [2], but residual magnetic flux density is difficult to estimate. Analyses of magnetization distribution using a capacitor-discharge impulse magnetizer have been developed [3, 4], but the resultant pole-by-pole magnetized flux density is difficult to obtain through such analyses. This research focuses on optimization of parameters for magnetizing patterned magnetic scale to match the application of precision control.