**5. Experiments**

Our main objective is to define a design process of mechatronic systems for Rapid 3D Wireframing techniques. We study two design processes executed by novice students and advanced students in mechanical engineering. The two design processes are freeform and a design process inspired in TRIZ principles.

Students groups were selected in such a way that we can observe differences between the cognitive, interpretative and creative processes. Novice students are from the first semester of mechanical engineering (sophomore). Advanced students are from the last semesters of mechanical engineering (senior). It is expected that both groups are very different in the cognitive, interpretative and creative processes.

The general statistics of the universe of students studied were the following. There were 95 students from 4 groups in total (2 novice and 2 advanced), 57 novice students and 38 advanced students. From the general information got from the students, 95% and 84% of the novice and advanced students respectively were man. 86% and 39% of novice and advanced students respectively were between 15 to 20 years old; 14% and 42% respectively were between 21 and 25 years old; 19% of the advanced students were more than 25 years old. 70% and 58% of novice and advanced students respectively do not have industrial experience.

## **5.1 First experiment**

178 Industrial Design – New Frontiers

main contradictions in the technological innovation. According to Altshuller, there are three categories of contradictions: technical, physical and human. The methodology proposed by Altshuller consists on a series of the following sequential steps: finding a problem, abstractize the original problem to find the general contradiction, use the general principles to solve the general problem, concretize the general solution to the original problem. In Table 1 we have included this general procedure as a general engineering design thinking methodology. The use of this methodology will be explained in the following section.

The contributions of this chapter are the following. First, a new rapid 3D physical modelling technique is proposed, this technique is based on formative manufacturing processes. We named this technique Rapid 3D Wireframing. The technique is expected to be used in early conceptual design phases of the new product development process. Therefore, it modifies the industrial design process but this is not evaluated in this chapter. Second, a TRIZ-based design process is proposed to reduce the complexity of the mechatronic design to print the object (Rapid 3D Wireframing). We have named MDSU this design process. Since the Rapid 3D Wireframing technique is new, so the MDSU design process and the application of TRIZ principles to the design of this kind of mechatronic systems. MDSU stands for Mesh, Unfolding (*Desdoblado*), Separation and Union (MUSU in English). The MDSU approach reduces the degree of freedom necessary in mechatronic systems to automate the process. These four sub-processes belong to TRIZ principles. It is expected that the Rapid 3D Wireframing technique will be automatic; therefore a first prototype will be explained briefly. In this chapter the following research questions are explored: the implementation of MDSU will ease the design process of the mechatronic system; the implementation of MDSU improves the design thinking process and reduce the development time of the mechatronic system; the implementation of the Rapid 3D Wireframing technique improves the work conditions of the designers; the implementation of the Rapid 3D Wireframing technique reduces the designers competencies related to the conceptual design phase; the implementation of Rapid 3D Wireframing improves the new product design process.

Through our experiments we will try to answer the previous research questions.

Our main objective is to define a design process of mechatronic systems for Rapid 3D Wireframing techniques. We study two design processes executed by novice students and advanced students in mechanical engineering. The two design processes are freeform and a

Students groups were selected in such a way that we can observe differences between the cognitive, interpretative and creative processes. Novice students are from the first semester of mechanical engineering (sophomore). Advanced students are from the last semesters of mechanical engineering (senior). It is expected that both groups are very different in the

The general statistics of the universe of students studied were the following. There were 95 students from 4 groups in total (2 novice and 2 advanced), 57 novice students and 38 advanced students. From the general information got from the students, 95% and 84% of the novice and advanced students respectively were man. 86% and 39% of novice and advanced students

**4. Research contributions and questions** 

**5. Experiments** 

design process inspired in TRIZ principles.

cognitive, interpretative and creative processes.

Work done by hand can achieve a high level of quality. There are a lot of examples from the art craft domain. Automate such manufacturing processes is a highly complex task since it demands mechatronics systems with many degrees of freedom. To propose a design process for wirebending we must evaluate first the work done by hand. The first experiment was entitled "freeform construction of 3D objects by means of wire bending". First, the students were asked to register general information. Then, a brief introduction to the rendering process was given; the main focus was to provide a background about the wire-frame version of objects. Wireframing is used as an intermediate step to obtain rendering. Wireframing is an implemented function of several CAD/CAE platforms. Wireframing form depends on the finite element chosen (e.g. circle, square, triangle, etc.). Wireframing can be also seen as a kind of mesh. Third, students were asked to make three sketches where they will present the mesh of a cup (divergent phase). The cup was chosen because it is a well known form and a common object found everywhere. They were asked to sketch the cups with three different meshes. For the convergent phase, students were asked to choose the mesh based on some criteria: originality, design, easy to build, etc. Fourth, students were provided by enough material of 16 AWG wires (same size that will be used in the expected machine). They were asked to build their prototype by hand. Figure 2 shows two pictures of this experiment. Finally a questionnaire was applied to the participant students. In the following section we will present the more important results of this experiment.

Fig. 2. Pictures from the first experiment.
