The Design For Six Sigma (DFSS) process consists of four phases, identification & definition of opportunity, concept development, design optimization, and design verification. In the phase of concept development, TRIZ (Russian acronym for Theory of Inventive Problem Solving) is useful for creating new ideas from the present ideas, which includes the trimming strategy, the antidote strategy, and the picket fence strategy.
In this paper, systems of a vehicle such as Variable Compression Ratio (VCR) engine, windshield wiper blade, and Continuously Variable Valve Actuation (CVVA) of engine, are selected and new concepts for each system are created by applying the previously mentioned three strategies.
FMEA (Failure Mode and Effects Analysis), the latter part in the phase of concept development in DFSS, is conducted for newly generated concepts of systems that are mentioned above. As a result of FMEA, it is found that the wind lift of the wiper blade can be a serious problem. Therefore, in attempt to fix the wind lift problem of the wiper blade, the optimization process is applied to it in the phase of design optimization. All the factors, including input, output, control factors, and noise factors, which influence the wind lift of the wiper blade, are identified. The activity of optimization process is conducted to obtain the optimized design of wiper blade. In the phase of design verification, the optimized design of the windshield wiper is tested in a real vehicle and it is proved to meet the target value of evaluation criteria for the wind lift. The conclusion is that TRIZ in the second phase of DFSS makes it possible to create new concepts from the present ones, which can be optimized and then later verified to meet the requirements with the follow-up phases of DFSS.
