Capstone Project in a Freshman Solid Modeling Course

This paper examines the use of rapid prototyping technology to introduce underclass mechanical engineering students to topics associated with their future studies. The course environment is an introductory modeling course where students study solid modeling and perform reverse engineering studies on several mechanical systems. The focus of this paper is a capstone project for the course where students design and build a blower for the purpose of inflating an air mattress. The project provides students with a tangible introduction to several topics that are important for their continuing studies. These topics include developing a better understanding of the relationship between computer models and physical models, the effect of manufacturing tolerances on design decisions, and an introduction to concepts in fluid flow. The project takes place during the final 3-4 weeks of the course with students working in teams of three. Each student in the team designs a separate component for a 3 piece blower. The components are then prototyped using a fused deposition modeling (FDM) process. The prototyped parts are assembled with a motor and tested to examine the performance of the models. The prototype and testing process provides an early experience in design, manufacturing, and fluid flow topics. From a design aspect, students get the opportunity to hold the models that were generated on the computer. This provides students with an initial exposure to how size and geometry relationships are perceived in a virtual environment compared to their actual physical size. A manufacturing aspect is revealed in the process by the need to consider design tolerances to mate the parts with one another as well as the need to be able to secure an off-the-shelf motor in the assembly. Early exposure to fluid dynamics concepts are introduced as finer design points such as a volute, diffuser, and Venturi are discussed through computational fluid dynamics analysis. Finally, the students are exposed to structured experimental procedures to determine the flow rate and maximum pressure capabilities of each blower. The end result of the project is the ability to provide freshman engineering students with an introduction to several important mechanical engineering topics in a relatively short time frame.