Quality through lean design

Dean Palmer looks at a technique that started life in the manufacturing environment but which could also help firms design and develop products better and faster "The reality is that many quality problems are design based, and primarily caused by a mismatch between product requirements and process capabilities," suggests Mike Campden, Design For Six Sigma (DFSS) programme leader at engineering training firm Smallpeice Enterprises. He continues: "Therefore, while applying Six Sigma principles within manufacturing offers considerable benefits, there are often even greater benefits to be gained by embracing these principles upstream during the product development process." It seems to make sense, but is it relevant to most manufacturers? In manufacturing environments, the reality is that as much as 60% of the cost of anything that is designed and placed into manufacturing is still driven by the design phase. And, the largest number of defects and defect opportunities are accounted for by quality problems that have been designed into products - some estimates suggest that 70 to 80% of all quality problems are design related and not caused by production. As Campden says: "There is a rapidly growing interest in Design For Six Sigma, as more manufacturers, in particular those that have started Six Sigma programmes, recognise that the higher levels of manufacturing improvement they are looking for cannot be achieved through production process optimisation alone... DFSS has been developed to help design teams achieve this." But there's another focus behind the DFSS approach. Campden says that product innovation is still typically hindered within many firms by ineffective new product development processes "that will just as often fail to deliver in terms of product performance, cost and time to market, as well as generating manufacturing quality issues." What DFSS offers companies is a customer-focussed approach to enhance their NPD process. Campden explains: "The techniques are developed around the IDOV [Identify, Design, Optimise and Validate] framework and has a comprehensive toolset. It forces development project teams to focus on gaining both a complete and clear understanding of the customer needs and priorities, and then establishing process capability and requirements. "From this knowledge, both design and process critical characteristics are identified and an understanding of how their variability impacts on the product specification is determined through measurement and data analysis. Finally, using real data rather than a judgement basis, teams can then concurrently optimise the final product characteristics in terms of customer, performance and manufacturing capability." In short, DFSS re-emphasises the importance of the customer and then provides clear quality targets for the NPD team to aim for. It also establishes within design the issue of measurement and analysis of data and the need to base decisions on data, not hunches. Then, according to Campden, comes a structured framework for integrating a wide range of design and process analysis tools. This includes functional analysis; quality function deployment (QFD); failure mode effect analysis (FMEA); design for manufacture and assembly (DFMA); value analysis and value engineering; statistical process control and capability analysis; reliability methods; and modelling and simulation tools. He concludes: "Design and development activities will have clear priorities and requirement sets, thereby reducing design iterations and clarifying verification approaches. Manufacturing issues are considered in every project, so maximising the re-use of facilities and equipment. And the product maintenance and repair strategy is developed right from the start, using reliability studies and product configuration work. As a result DFSS delivers potential cost reduction throughout the product lifecycle, with enhanced product utilisation and faster time to market."