‘Lean’ or ‘lean thinking’ refers to an improvement philosophy which focuses on the fulfilment of customer value and the reduction of waste. This philosophy is credited with the extraordinary rise of Toyota, one of the largest and most profitable automotive companies in the world. This thesis presents a pioneering study investigating how lean thinking should be applied to product development (PD). The aim of the research was to construct an innovative model which supports the implementation of lean thinking in PD. This was achieved through progressive collaboration with practitioners from European manufacturing companies. The model provides a process for the conceptual development of an engineering project, and is composed of phases and activities for which methodologies have been defined. The construction of the lean PD model was preceded by a systematic literature review and an industrial field study, wherein 36 semi-structured interviews were conducted in five manufacturing companies in Europe. The constructed model was later implemented on two real-life case studies via action research. The two conducted case studies involved the product architecture design for a car audio head unit and the development of a helicopter engine. It was concluded that the lean PD model addresses various industrial challenges including customer value, communication, and innovation. Furthermore, by focusing on conceptual design, the lean PD model is expected to reduce design rework. As a result of the positive effects of the model, one of the companies involved intends to implement the lean PD model further, and wishes to extend the model to the rest of the organisation. This research makes four main contributions: (1) a novel lean PD model; (2) a number of tools developed to support the model; (3) a framework for lean PD enablers; and (4) a categorisation of challenges faced by PD in industry used to verify the relevance of the lean PD model.

This thesis report presents the work of analysing current challenges in Multidisciplinary Analysis systems. Exemplary the system of an aerospace supplier, GKN Aerospace Sweden AB, is examined and several suggestions for improve- ment are implemented. The Multidisciplinary Analysis system, with company internal name Engineering Workbench, employs a set-based approach in exploring the design-space for jet engine components. A number of design cases with varied geometrical and environmental parameters is generated using Design of Experiment sampling methods. Each design case is then subjected to a set of analyses. Using the analyses results, a surrogate model of the parts behaviour in relation to the input parameters is created. This enables the product developer to get a general view of the model’s behaviour and also to react to changes in product requirements. Design research methodology is applied to further develop the Engineering Workbench into a versatile design support system and expand the functionality to include producibility assessment. In its original state, the execution of a study requires explicit domain knowledge and programming skills in several disciplines. The execution of a study is often halted by minor process errors. Several methods to improve this status are suggested and tested. Among those are the introduction of an interface to improve the usability and expand the range of possible users. Further the integration of a four level system architecture supporting a modular structure. Producibility assessment is enabled by developing an expert system where geometrical and simulation results can be caught, analysed and evaluated to produce producibility metrics. Evaluation of the implemented solutions indicate a step in the right direction. Further development towards Multidisciplinary Optimisation, involving experts in information technologies as well as case- based reasoning techniques is suggested and discussed.

Developing high-end aerospace components is a complex and highly competitive business. Hence methods for decreasing lead-time, while still providing the same quality and at a lower cost, has to be developed. This thesis is conducted at Research & Technology - GKN Aerospace in Trollhättan Sweden. A multidisciplinary analysis system known internally as Engineering Workbench, forms the base for implementation of the methods and tools developed in this thesis work. The system applies set-based engineering approach to develop new components. The evaluation of the design space is performed through parametric studies to find relations between the design parameters and performance metrics of the design. The engineering workbench allows GKN to define and evaluate a large design space within a limited timeframe. This thesis will look to improve the current producibility assessment system within the EWB by increasing the robustness and flexibility of the system. This is done by re-designing the producibility analysis part system and into a modular knowledge-based system that implements various techniques to increase the robustness and flexibility of the system. The re-designed system is automated, flexible and robust and is able to perform user defined weld assessments on a various designs and provides GKN with weld producibility data.

This thesis is a continuation of design automation studies within research projects financed by VINNOVA (the Swedish Governmental Agency for Innovation Systems) and Knowledge foundation that contributed to the development of producibility assessment system at a global aerospace products supplier, GKN Aerospace Sweden. A case study was carried at the company on Turbine Rear Structure (TRS) component design of a jet engine with the main objective to evaluate weld producibility assessment tools and to demonstrate system’s performance in multi-disciplinary design environment. The context of this thesis is a set-based product design development where several studies, i.e. thermal, structural, aerodynamic etc. are carried concurrently to gather knowledge between their parameter relations. The thesis contributes to the goal of fully integrated producibility assessment in multi-disciplinary studies to support product development process. The problems encountered during the thesis execution involved systematic analysis setup to extract and verify CAD geometry data, assessment of meaningfulness of producibility indicators, development of semi-automated data post-processing module and relating product design to its manufacturing aspects. Commercial and in-house developed software were used extensively to demonstrate the results of the system with the help of continuous company support to mitigate indispensable bottlenecks along the way. The work has led to systematic improvements, determined assessment limitations and most relevant weld producibility aspects. Collected feedback to evaluate prepared demonstrator showed promising results to support product design decisions considering both performance and producibility.