Materials Planning in Engineering Change Situations
This overall objective of this thesis is to contribute to a better understanding of materials planning in engineering change situations. The analysis is both quantitative and qualitative, based on (1) theory and literature related to materials planning, engineering change and information quality, (2) empirical data collected from five in-depth case studies in the automotive industry. The studies are related to six research questions and presented in seven papers.
The first three research questions focus on materials planning in engineering change situations. A framework that gives a structural description of engineering change situations impact on materials planning is developed. The framework was derived from literature on materials planning environments and has been used and verified in three case studies. It is shown in a case study that the effects of an engineering change vary and can be improved, for example by the choice of materials planning strategy which has significant impact on the number of scrapped items. These findings verify earlier research on materials planning strategies in engineering change situations, but extend it to account for block change situations and for supply chains. A materials planning allocation model was developed in order to facilitate the allocation of resources in engineering change situations, meaning that the materials planning resources can be allocated to items which have a potentially high materials scrap cost.
The fourth and fifth research questions focus on information quality. The findings reveal the complexity of information flows in engineering change situations and show the importance of information handling for successful materials planning. They also show that considerable information is required in engineering change situations that does not have the same importance in a steady-state situation. Additionally, it is shown how insufficient information quality can be linked to many problems that occur for materials planning and often result in substantial time delays. The information quality model was developed to assess the information quality in materials planning processes. Here, ten information quality dimensions have been identified as relevant and give managers suggestions on how to deal with the problems of information quality deficiencies.
The sixth research question focuses on design of materials feeding and its implications for materials planning in engineering change situations. It is shown that the design of materials feeding (e.g. item racks and choice of packages) has a major impact on the possibility to manage engineering changes efficiently at a workstation. Item racks with small packages and large depth increase the new products and modification flexibility. For example, with free space the new and old items can be displayed and fed to the same station.