The background for this thesis was initially to create a model for takt-flow production. After a current-state analysis of issues surrounding the manufacturing function where complexity and difficulties in control were identified, the purpose was shifted. The authors argued that these issues could be seen as a result of several attempts in trying to adopt business improvement concepts where little emphasis had been taken to ensure that the fundamental components of the concepts were in place. The purpose of the study was now to develop a model which manufacturing companies can use in order to identify and attain the fundamental prerequisites needed in order to improve their business and therefore increase chance of success in today’s market situation. A model was developed, the CORE model. The model consists of a set of categories and criteria. The model was conceptualized from a theoretical framework, consisting of core components of several successful business improvement concepts. The model was tested as an assessment tool on a cross-section of PU Sandviken, a manufacturing unit within the Sandvik Mining and Construction supply chain. The result of the assessment indicates several major areas within the company where improvements are required, especially with regards to structure and control. Two suggestions for continued work were presented to the company. The first suggestion was for the company to start an improvement project, using the model as a whole. The second suggestion was an action plan involving the resolving of the major issues identified. The result showed that the model identifies areas within a business in need for change or improvement in order to attain the fundamental prerequisites of the study. The authors suggest that this model can be used for self-assessment in manufacturing companies, and that it should be a workable model for immediate use