Hierarchical Optimization of Cleaning & Rinsing Operations in Barrel Plating

摘要

Cleaning and rinsing are two key unit operations in achieving high plating quality in an electroplating process. These two operational steps, however, are identified as major sources of waste, such as waste-water, spent solutions and sludge. In practice, the operations in plants are far below optimal, consuming excessive chemical solvents, water and energy. In order to improve environmental quality significantly and to maintain economical competitiveness for electroplating, the cleaning and rinsing operations must be optimized. In this paper, a practical optimization methodology is introduced to optimize the operations in the cleaning and rinsing steps. With this methodology, both optimal production and pollution prevention are realized in a cleaning and rinsing system. Since hierarchical dynamic optimization is difficult to implement, a statistical function approach is proposed to transform the bilevel programming problem into a single level optimization problem. Case studies are shown that demonstrate the desirability of adopting the method in plating lines.