Bath and Deposit Monitoring System for Electroless Nickel Plating Process

Electroless nickel plating is a widely used plating method in many industries. The usability of the coating is, however, restricted by the control problems related to the electroless nickel plating process. To ensure deposit quality, the transcendent properties of electroless nickel deposit should be accurately controlled during plating, which is challenging because of the spontaneous, unstable reaction and lack of online measurements. To improve operator based control, a special monitoring system for electroless nickel plating is presented in this paper. The monitoring system is calibrated especially to the electroless nickel process used for Plated-Through-Hole (PTH) board manufacturing. In the paper it is shown, that, the system is capable to estimate the electrical, chemical and deposit parameters of the plating process from standard measurements of nickel plating industry. The proposed monitoring system enables also the replace of the individual parameter supervision by the supervision of the overall process dynamics, i.e. the electrochemical processes. Key-Words: Monitoring, state estimation, electroless plating.