Modifying an Assembly Project to Improve Student Dimensioning Skills

摘要

Many first year graphics courses introduce students to solid modeling and technical graphics. At Michigan Technological University, all engineering students take a two to three semester sequence of introductory engineering courses. The last course in the sequence, ENG1102: Engineering Modeling and Design, focuses on solid modeling (3-D CAD), graphical communication, and computer programming. The solid modeling portion of the class exposes the students to sketch-based and feature-based solid modeling and creating engineering drawings and assemblies. The graphical communication portion of the course includes dimensioning, section views, and view selection. To give the students practice in creating CAD assemblies using parts they modeled themselves, student teams complete a project where they either model an object which consists of a few simple components or design an object using simple components such as PVC pipe. Students are given the components of the assembly and calipers to measure them during at least two class periods and are allowed to collect additional measurements at various times outside of class time. The students submit engineering drawings of the fully dimensioned components in the assembly and the part assembly. In the fall of 2012, the assembly project was modified in one section of ENG1102 in an effort to improve students' dimensioning skills. In this experimental section, the students were given a spring scale to dissect, measure, sketch, and dimension by hand in a single 75-minute class period. The students created solid models of the components from their sketches, and if necessary dimensions were missing from their initial sketches, they submitted a formal request to the instructor to obtain them. In the two control sections of the course, the students were given the same spring scales to model and measure in two 75-minute class periods. Additionally, if dimensions were needed outside of class, they had easy access to the scales. Individuals from each student team in both the control and experimental sections submitted fully dimensioned engineering drawings of two components of the spring scale. In order to assess if the change in the project did improve students' dimensioning skills, students were asked to complete a survey regarding the project. Responses to the survey and exam questions on dimensioning were compared. This paper will discuss the findings from these analyses.