Elements for Improving the Teaching of the Later Phases of the Mechanical Engineering Design Process

Introduction During the embodiment design and detail design phase, the designer has at his disposal a set of tools and techniques that him or her through the synthesis activity: basic rules, guidelines and principles (see [1]), but in the literature there are general design processes that help the designer to organize their work (e.g. [1]), but not at a very operational level. From a previous study [2], it has been observed that professional designer followed, though loosely, a determined process, while students had more difficulty at the operational level when dealing with the embodiment design and detail design activities. Thus, this year an embodiment design and detail design process method was introduced to the students.This study presents whether the introduction of this process led to an increase in students' effectiveness and efficiency, and thus whether this process has a place in the teaching of the later phases of the mechanical engineering design process. Methodology The analysis was made through the combined use of a design project reports review and a verbal protocol study. The verbal protocol study consisted of two sets of experiments: students performed a design task under experimental conditions before and after the course. A third set of experiments in which last years' students participated for an earlier study was also used. The analysis consisted of three phases. First we examined whether the students had assimilated the design process. From the analysis of the design project reports, the students' understanding level for each step of the process and the whole process was assessed. The assessment was further refined by means of the study of the verbal protocols. Increase in effectiveness was studied by means of comparing the students that did perform the experiments after the course with last years' students, who had not been taught any embodiment design and detail design process. Finally, increase in efficiency was measured by testing whether there was a correlation between the design process quality and the design result quality. Results and discussion By and large, the students understood the process. The elements of the process whose teaching needs to be first improved are, according to this study, the steps related to solution searching and solution evaluation. The introduction of a structured embodiment design and detail design process method to the students increased students' effectiveness for certain steps of the design process introduced: problem specification and decomposition; criteria specification. The students went faster and earlier to more concrete solutions and avoided useless feedback loops, which ensured a decreased design time. There is no correlation between the design process observed and the design results, but the heuristics "think in terms of standard components" seems to have an important impact on the results. The combined use of design project reports review and verbal protocol study was adapted to the objectives of this study. However, some steps should be investigated with deeper, specific experiments. An additional result of this study is that a structured process is actually requested by the students, who feel sometimes the need for clues and guidance during the design activity. As observed in [2], professional designers also sometimes needed guidance in their design activity that would have led to a faster process. This requires further investigation, but it seems that a design process that focuses on facilitating the design activity, on reported problems and weaknesses, could lead indirectly to the increase of efficiency and effectiveness. References [1] Pahl G., Beitz W., "Engineering Design – A systematic approach" (2nd Rev. Ed.), Springer, London, 1996. [2] Motte D., Andersson P.-E., Bjärnemo R., "A Study of the Mechanical Designer's Strategies and Tactics During the Later Phases of the Engineering Design Process", Proceedings of the DTM/ASME, Salt Lake City, 2004.