Provided by Research Papers in Economics
A PRODUCTION AND MAINTENANCE PLANNING MODEL FOR THE
PROCESS INDUSTRY
J. Ashayeri and A. Teelen
Department of Econometrics
Tilburg University
Tilburg, The Netherlands
W. Selen
Vesalius College
Vrije Universiteit Brussel
Brussels, Belgium
_______________________________________Abstract______________________________________
In this paper a model is developed to simultaneously plan preventive maintenance and
production in a process industry environment, where maintenance planning is extremely
important. The model schedules production jobs and preventive maintenance jobs, while
minimizing costs associated with production, backorders, corrective maintenance and preventive
maintenance. The formulation of the model is flexible, so that it can be adapted to several
production situations. The performance of the model is discussed and alternate solution
procedures are suggested.
1. Introduction
For most companies, maintenance represents a very significant function within the overall
production environment. The developments in automation, and the resulting complexity of the
systems involved, have made the reliability of the machines even more important. This is
especially true in the process industry, characterized by expensive specialized equipment and
stringent environmental considerations. Nowadays, with profit margins decreasing, the need for a
good maintenance planning and control system is obvious. However, often maintenance is a
secondary process in companies that have production as their core business. The result is that
maintenance does not receive enough management attention. This was confirmed by a pilot
survey (Ashayeri et al. (1994)) conducted at six chemical firms where maintenance was done in
an ad hoc manner. Another reason for the lack of management attention is the belief that
maintenance costs cannot be controlled. Management often looks at maintenance as a necessary
evil, not as a means to reduce costs ( see also Paz and Leigh (1994)).
The model developed in this paper will show that a good maintenance plan, one that is integrated
with the production plan, can result in considerable savings. This integration with production is
crucial because production and maintenance have a direct relationship. Any breakdown in
machine operation results in disruption of production and leads to additional costs due to
downtime, loss of production, decrease in productivity and quality, and inefficient use of
personnel, equipment and facilities.
In the next section, the special characteristics of the process industries are briefly reviewed.
Section 3 discusses the maintenance problem in general, and maintenance in process industries in
particular. Section 4 will then present a mathematical model for simultaneously planning
preventive maintenance and production. The validation of the model is discussed in section 5,
while its performance is reviewed in section 6. Section 7 presents the overall conclusions.