Laser-drilled PVC template for electrodeposition of multi-core orthogonal fluxgate sensing element

The sensing performance of the multi-core orthogonal fluxgate sensor has been found to be significantly enhanced as compared to single-core orthogonal fluxgate sensor, with the magnitude of the enhancement proportional to the number of core wires in sensing element. One of the methods of making the multi-core sensing element could be a template deposition approach, in which laser drilling of hole arrays in PVC templates and then electrodeposition of the soft magnetic pillars in the holes are involved. As such, the optimization of the Nd:YAG laser parameters on the quality of the holes on the PVC templates has been carried out in this study. The effect of laser processing parameters, including: (1) laser fluence; (2) laser irradiation time; (3) number of pulses; (4) laser focal point, was investigated in relation to the hole quality and tapering effect. In particular, the laser fluence was the major factor in determining hole diameter and depth. The laser irradiation time affects the heat affected zone the most severely, and the number of pulses used ensures a hole that is relatively clear of debris. In order to obtain holes of the best quality finish, high laser fluence and optimum values of laser irradiation time and number of pulses should be used. By setting the focal point above the surface of the PVC, the tapering effect was found to be minimum.