In the process Industry, homogeneous products have to be packed For an unpacked product (mtlk. pamt), a variety of packaging materials (glass. tm) and packagmg sizes (4 lure, 1 kilo) are available. Generally, the packagmg lines are used for vartous products (milk, buttermilk) in one type of packaging maternal (glass) and various packaging stzes (i litre, 1 htre). These posslbihties make the scheduling of the packaging hnes rather complex.
In recent years, under market pressure. the number of products in the process Industry has been Increased, the order sizes have been reduced, and the delivery times have been shortened.
Thts has caused augmented schedulmg tasks and, usually. the scheduhng systems supporting these tasks have not followed these changes sufficiently. We have investtgated and compared the ortgms of the Increasing complexity of the scheduling problems of several companies m the process industry producmg datry products, pharmaceuttcal products, tobacco, paint, chocolate products, and foods. and we have analyzed the ways m which these compames deal wtth this mcreasmg complextty m drfferent situations. Schedulers have to deal with a wide range of mformatton such as due dates, availabihty of maternal, sequence-dependent set-up ttmes, and availability of packaging lines and employees. In most cases the scheduhng IS stall done by hand, which 1s very ttme-consuming. We show the need for a more adequate support system whtch will provtde necessary information, and speed up the development and evaluatton of production schedules. We also dtscuss future trends wtth regard to the packaging process. and their hkely effect on the scheduhng process.
' We use the term "scheduling" also at places where "planning and scheduling" or only "planning" is meant.