Design education focuses on teaching students how to do design, and these design courses could be offered from freshmen to senior year at universities depending on the curriculum requirements (Tomiyama et al, 2009). Adams et al (2003) pointed out educating effective engineering designers is an important goal. Exploring the extent to which this goal is met hinges on our ability to characterise what contributes to the effectiveness of learning design, and to map students' performance against such standards.
Among design theory and methodology, design-for-X (DFx) is an important term in engineering design, which can also be understood as design-for-excellence or design-for-e very thing, as it covers a wide range of purposes during the design process. Further, from the perspective of design, X can be Teganded as a variable or a variable vector with infinite number of feasible values according to our design requirements. DFx is primarily an engineering approach aiming to improve design and manufacturing of engineered products from cradle to grave. Engineering products hereby will be defined as something discrete, engineered and physical, which can be as simple as a screwdriver or as complex as an airplane. This excludes development of products such as services or software. For engineered products, competitiveness of the manufacturer in its marketplace is a crucial factor that must be met by increasing product quality while decreasing production (and post-production) costs. DFx aims to achieve this goal in the domain of X, by representing a body of knowledge, procedures, analyses, metrics and design recommendations. X is a characteristic of the product, its production or its Hfecycle management. The most important Xs are assembly (DFA), manufacturing (DFM), disassembly (DFD), recyclability (DFR), environment (DFE) and safety (DFS). The latter concept itself involves other techniques that aim to identify the results or effects of item failure on system operation and eliminate or reduce the severity of those effects. This is generally known as failure mode effect analysis (FMEA), which can be educated outside the generalised scope of DFx mentioned above. In essence, FMEA is a method to systematically identify and correct potential product or process deficiencies before they occur.
DFA has been widely known and taught in higher education since the mid-1980s after Geoffrey Boothroyd and Peter Dewhurst developed its underlying principles (Boothroyd & Dewhurst, 1984). The most important aspect of DFA, similar to other DFxs, is to provide a well-defined method to assist decision making process for engineering teams who usually face multiple, and often conflicting, goals. Their detailed design and manufacturing decisions can substantially impact product quality and cost, which is a key determinant of the economic success of the product. DFA provides metrics and measures to compare alternative designs and configurations and frees the engineer's mind towards more creative efforts early in the product development process.
Hands-on product dissection and disassembly has proven to be a useful method in DFA education (Smith, 1998). Smith (1998) presented an approach where an integrated set of lectures, laboratory exercises and examination were developed for DFA education of industrial engineering students. In his approach, students learn the theory of DFA in lectures and subsequently implement the theory in laboratory exercises by dissecting and analysing products that are carefully selected by the teacher. Smith's approach relies on using Ullman (1992) table, which involves a series of rating criteria to assess each component of the product. There are other simple methods such as Poli-Graves expert system spreadsheet that have been used for DFA education too (Wardeiner, 1996). However, most of these methods are quite basic compared to more rigorous methods such as that developed by Boothroyd & Dewhurst (1984). …