THESIS FOR THE DEGREE OF DOCTOR OF PHILOSOPHY Use of Advanced Planning and Scheduling (APS) systems to support manufacturing planning and control processes

An Advanced Planning and Scheduling (APS) system is defined as any computer program that uses advanced mathematical algorithms or logic to perform optimization and/or simulation on finite capacity scheduling, sourcing, capacity planning, resource planning, forecasting, demand planning and others. Relative the massive interest, both from academia and industry in the subject area of manufacturing planning and control, there has not been much written about the use of APS systems in practice. For academia, this means a lost opportunity of understanding benefits and problems of implementing and using advanced planning and scheduling approaches. Seeing the many algorithms developed by academia during the years that never have been put into practice this should be valuable knowledge. For practitioners, the many failed implementations should make it important to understand what could be expected when implementing an APS system and what is required to effectively use it. This thesis studies how APS systems can support manufacturing planning and control (MPC) processes in adding value to the company by focusing on the consequences of using APS system and the variables influencing the consequences of using APS systems. It is different from previous studies concerned with APS systems as special focus is given to the use, i.e. when the APS system is operated in the MPC process instead of the implementation, the phase between the software selection and going live. Four case studies and one survey have been conducted to aid in fulfilling the overall aim. The thesis found that the use of an APS system can support MPC processes by improving the decision support, simplifying planning activities, and reducing planning time and by generating feasible plans and schedules that are possible to follow. Still, the use of an APS system might make the planning activities more difficult to conduct and result in plans and schedules that are difficult to retrace or which are incorrect. It was identified that not only the use or non use of APS functionalities, but also the way the functionalities are used and the extent to which the functionalities are used influences the MPC process. The planning environment complexity, identified as the number of/and dependencies between entities and uncertainties in demand, supply and the production system of a manufacturing company, was found to influence how the APS system 'should' be used. Variables connected to the implementation of the APS system and to the MPC process, on the other hand, influence how …