FLEXIBLE FIXTURES - A TREATISE ON FIXTURE DESIGN AND EFFICIENCY

Licentiate thesis, 2017

Even though a variety of efforts have been made in the area of flexible fixtures, the manufacturing industry still relies on dedicated fixtures with minor modular features. The main underlying reason, as these attempts have shown, is that the application of flexible fixtures has failed to yield the expected results, with the implemented technologies often leading to increased manufacturing costs when compared to dedicated fixtures. As this has a negative impact on industry’s return on investment, a grey and largely uncharted area has arisen around the efficiency of flexible fixtures. The research that forms the basis of this thesis is intended to explore, describe and increase the efficiency of flexible fixtures in manufacturing industry. In order to fulfil this aim, two research questions have been asked. The first question focuses on exploring and description of the efficiency, while the second question focuses on how methodically the concept of efficiency can be used in fixture design. The results presented in this thesis are based on four experimental studies carried out in the automotive and aerospace industries covering different aspects of modular and reconfigurable fixtures with manual, automated and active features. Based on these experimental studies, seven criteria regarding the efficiency of flexible fixtures have been identified. These criteria relate to physical flexibility, quality, interactivity, cost, time, modularity and maintenance. Furthermore, the thesis provides the expected states of criteria along with relevant metrics. Subsequently, a design procedure using these metrics is presented based on the characteristics of a manufacturing system, in order to identify the most efficient fixturing solution. Finally, the efficiency of flexible fixtures is found to be correlated to the individual and unique needs of a manufacturing system. Consequently, the ability of a fixture designer to understand and adapt to those needs is the key to increased efficiency; thus, the applicability of flexible fixtures.