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