INTRODUCTION

The motivation of this study is to reduce production deficit in a semi-automated chrome plating production line. Since it’s semi-automated, we have human effort working in conjunction with a machine. The smooth functioning of this system requires that the manual processing activity is finished on time while the machine automates the immersion process. The machine is responsible for immersing the parts into a chrome plating bath, while the workers are responsible for loading, unloading and inspection of the parts. Hence, the manual processing goes hand in hand with the immersion process. When the manual processing of a batch is not done within a time window, a ‘load is missed’. When multiple loads are missed throughout the day, a production deficit problem occurs. The goal of this paper is to find a ‘satisfactory’ schedule that maximizes production and establishes good work-flow in the system.

The object of study is a chrome plating cyclogram that has only one immersion tank. The Dynamic Hoist Scheduling Problem (DHSP) and the Cyclic Hoist Scheduling Problem (CHSP) are problems where we program the chrome plating machine to carry out immersion of parts in a sequence of tanks. This problem is different in that, we are interested only in scheduling manual operations and not the machine. The process works in the following way: Parts to be plated are loaded onto a rack which is lifted up and immersed into a chrome plating bath for 24 minutes. Subsequently, the next rack in the system is immersed after the previous rack is removed from the bath. This gives us a time window constraint that we can work with. In the following pages, we study the similarity of this production line to a flow-shop