Integrating Lean in a process has become increasingly popular over the last decades. Lean as a concept has spread through industry into other sectors such as service, healthcare, and administration. The overwhelming experience from this spread is that Lean is difficult to integrate successfully. It takes a long time and requires large resources in the integration, as it permeates all aspects of a process. Lean is a system depending on both tools and methods as well as human effort and behavior. There is therefore a need to understand the integration process itself. As many companies have worked with the integration of Lean, there should be a great deal of accumulated knowledge. The overall intent of this research is therefore to examine how a current state of a Lean integration can be established, that takes into account the dualism of Lean regarding the technical components of Lean, as well as the humanistic components of Lean. Both issues must be addressed if the integration process of Lean is to be efficient.  Through a literature review, eight views of Lean are established. Taking into consideration historical, foundational, and evolutionary tools and methods, systems, philosophical, cultural, and management views, a comprehensive model of Lean at a group level in a process is proposed. Through two multiple-case studies, the experiences of actual Lean integrations are compared with Lean theory to establish a current state of a Lean integration. There were large similarities in the experiences but also differences due to context and the complexity of Lean as a system. The current state is described in: 9 instances of strongly positive findings. They are often simple tools and methods. 11 instances of weakly positive findings. They are often of a system nature in the dependencies between the Lean methods. 3 instances with vague findings. Seems to be due to lack of focus on the intent of integrating Lean. 3 instances of mixed findings. Can often be connected to personal commitment and the creation of efficient islands. 3 instances of conflicting findings. Seem to be connected to contextual factors. 3 instances of insufficient data. The indications are too few to draw any conclusions.  Accurately establishing the current state of the Lean integration process is seen as a necessary first step of a Lean integration of Lean.

The purpose of this study was to find a method for exploring the potential of increasing the efficiency of a manual manufacturing process while simultaneously maintaining the flexibility and the ability to adjust to changes in demand. The study has been conducted in cooperation with Scania CV AB Engine Assembly in Södertälje, Sweden. This explorative study has been conducted using a framework mixing traditional Quality and Process Management literature, with theories of Innovation Management and ways of designing a production process. The framework was designed by focusing on perspectives to help explain and optimize the dynamics of a manual assembly process characterized by high variation. Increasing the efficiency has included the elimination of waste and disturbances while creating opportunities for continuous improvement. Improving the ability to adjust to changes in demand and volume has included reorganization of the information flow. Activities aimed at increasing the efficiency and improving flexibility requires a base of information which is sufficient and enables fact-based decision-making. An analysis of the current state was conducted using triangulation of data collection methods. Interviews, observations, focus groups, surveys, and numeric data was analyzed. Tools of Quality Management, Lean Management, and the Productivity Potential Assessment method were used to develop a framework for evaluating a manual production process and aim to collect, process, compile, weigh, prioritize, and visualize the processes and the identified challenges. Identification of improvement activities and the design of a future state was conducted through extensive interviews and focus groups and by interpreting relevant literature. Mapping of the current state generated five primary challenges which are complicating the daily work in different ways. The challenge estimated to have the highest overall impact on the studied process is Time Data Management. This challenge refers to the lack of valid and correct data on which to accurately plan and control the process.