Operator-centric assembly station design

Productivity requirements in high volume manufacturing industry necessitate the widespread use of machine-based assembly stations. Although high production volumes can be achieved by a small number of workers (operators) the resulting fatigue on these operators is often overlooked in the design of the assembly station. Fatigue mitigation is then required via job rotation on the shop floor but this is both unsatisfactory and a partial solution only. The aims of this thesis are: ~ to develop an approach to the design of operator-centric assembly stations ~ to evaluate this approach in real life case study applications ~ to produce an evaluative tool which embodies "best practice" for use by designers enabling them to aim to avoid or mitigate musculoskeletal disorder problems for operators. The thesis reviews current approaches to the design of ergonomic- and process-driven assembly stations using literature available in the public domain which includes guidelines, regulations, and legislative requirements for health and safety. Also reported is work undertaken by the author, at H R Adcock Ltd, on two assembly stations which have been comprehensively re-designed in response to unacceptable health risks for the workforce, poor quality products and a low production rate. The original design and operation of the two stations will be analysed along with the techniques used for their improvement. The core of this thesis is to demonstrate a 'best practice' design approach to the re-design and to evaluate the outcome. It became clear during the compilation of this thesis that if it were possible to incorporate some simple checking procedures which would identify all potential hazards and evaluate risks early in the design process then this would eliminate or reduce the need for costly downstream design changes. The system developed is RIMAN - an acronym for Risk MANagement procedure. RIMAN incorporates the following: ~ Development of design criteria ~ Co-operation between disciplines to facilitate the development of the design criteria ~ Risk identification ~ Evaluation of identified risks and assessment of how to eliminate or reduce them to an achievable level ~ Utilisation of RIMAN as a recording/auditing tool and as a technical folder which would outline the regulations and standards used in the design criteria and specify the risk levels identified by risk evaluation. RIMAN was successfully evaluated, retrospectively, against the assembly station case study already mentioned. It demonstrated how particular risks were identified and dealt with early in the design process. It is proposed that further work is undertaken on a RIMAN version 2 and that the tool be actively incorporated into the working practices of H. R. Adcock Ltd., or any company, on a live design project.