Abstract:

There is a historical way to teach and practice graphical dynamic analysis of machine elements in mechanical engineering. It includes the use of hand drafting tools such as triangles, scales, French curves, etc to draw linkage arrangements and dynamic polygons. Engineering students today no longer receive hand drafting training in high school or college as it is all done on computers using CAD (computer aided design) software. Thus, to require them to suddenly purchase the necessary tools and learn these now antiquated techniques for one course in their final year of study seems impractical. In addition, they will also never use these hand techniques in industry, which is wholly CAD based as well.
There are many advantages of using CAD over hand drawing including much improved accuracy, consistency, and precision. Designs are more readily imported into other design and computer controlled machining (CAM) programs commonly found in today’s college programs and industrial manufacturing facilities. These analyses and designs are also easy to share and dramatically improve efficiencies and shorten design cycles. This is also a critical issue in the academic environment. Those same sharing and efficiency issues can manifest into academic dishonesty events very easily and quickly. Certain actions and preventions are needed when using computers in today’s environment where information can be shared so easily over a variety of different mediums and technologies.
An example of this is if you demonstrate the technique using CAD, have students work homework problems using CAD, then they should also be tested using CAD. It is unfair to suddenly expect them to use drawing tools on an examination, which also defeats the purpose of using CAD throughout the course. Computer examination is more of an undertaking that it appears at first glance. Do students work take-home examination, can they all be trusted do only do their own work under those circumstances? Does every student have a computer with software that they can bring to class for the exam? How do you control communication between computers such as email or instant messaging while they are using the computers? At the end of the exam, how do they turn in their work? If you have disabled the internet in the room they cannot upload it to a learning management system or print to a network printer. USB or CD file transfers can be unwieldy and very time consuming and there is likely a class needing the room after yours.
In this paper I will discuss how I transformed this course from hand drawn solutions to a CAD based curriculum including working through the transition details such as software and computer access, lecture and presentation challenges, examinations on computers, controlling internet access during exams, printing exam solutions, and the need for computer test facilities with enough capacity for large classes on campus as this trend continues while not negatively impacting the pedagogical objectives and effectiveness of the course. In addition, the commonplace cardboard linkage models were replaced by a new kit that has an electric motor and plastic linkages that is much more realistic and legitimate in this day and age that asking students to cut out “paper dolls” of their machine elements.

Keywords:

Advanced classroom techniques, CAD instruction, technology in the classroom.