Development and Research of the Optimal Control System of Electroplated Processes in Multi-Anode Baths

Abstract

The relevance of increasing the distribution uniformity of the electroplated coating thickness on the surface of details is considered in the article. The analysis of control actions that affect the uniformity of the electroplated coating thickness was carried out, during which preference was given to the use of multi-anode baths. The existing modes of the electroplated process in multi-anode baths aren’t widely used due to the constructive implementation complexity arising from the need to ensure the uniformity of the resulting coating thickness for multi-assortment industries. The authors propose an electroplated process mode, during which the optimal number and anodes size are found, as well as the current and duration of its flow through them, which ensure the alignment of the electric field lines distribution in the electrolyte between the anodes and the coated detail surface. The control system structure (mathematical model, search algorithm, control and actuator) with feedback on the current through the detail surface is designed to implement considered mode optimal control and an algorithm for its operation (based on the PID law and relay control) is proposed. The practical implementation was carried out using the industrial automation software package CoDeSys V2.3 in the programming language FBD. The proposed mode optimal control was found on the example of applying a zinc coating to a Z-shaped detail. As a result of simulation modeling, the control loop was tuned to the squared deviation integral minimum of the setpoint and the correctness of the control system operation algorithm was demonstrated by a relative average coating thickness deviation up to 5 %, which is comparable to the error of modern thickness gauges.