The Pencil Has Changed: Integration Of Professional Level Cad Software Into The Undergraduate Me Curriculum

Abstract

The area of mechanical engineering design development and documentation was once the exclusive realm of the pencil and paper. As computer technology and its related software have improved this is no longer the case. In the last 8 years a new generation of dimensionally-driven, feature-based modeling packages have entered the marketplace. The tools of design have changed and we as educators must provide some level of instruction in their use. The challenge becomes to include such information in a format appropriate to a four year engineering program. This paper will discuss techniques for accomplishing this goal and provide suggestions for other institutions which plan to integrate such software into their curriculum. A relatively new course offering within the University of Wisconsin - Madison, Department of Mechanical Engineering will be used as a model.

Prior to the advancements made in computer technology (both hardware and software) over the past 20 years, most engineering design documentation began and ended with the pencil. Education in design documentation was referred to as engineering graphics or mechanical drawing. Students were instructed in the fundamentals of projections, dimensioning and the accepted standards. While some time was allocated to the use of drawing instruments, this typically represented only a small portion of total instructional time. After all, the principal tools of mechanical drawing were the pencil and the straightedge and students had been using those in some fashion since their education had begun. With appearance of PC-based 2D CAD packages, many instructors felt it necessary to integrate this technology into their engineering graphics courses. At many institutions, the debate ensued as to whether instruction in software use fit the mission statement of the four year university program. At many institutions, a misplaced de-emphasis on engineering graphics also placed serious constraints on the amount of material which could be included in these courses. As the software has evolved, its effect upon the professional community has increased to the point where today the areas of design, analysis, and manufacture are all significantly impacted. Professional level CAD packages are now becoming a standard part of the design engineer’s arsenal and the educational community must examine their inclusion in the engineering curriculum.

Relationship of CAD and Geometric Modeling to Engineering Design

The development of computer-aided part modeling software can be traced to the early 1960’s. These early CAD packages were two dimensional systems, designed to fulfill only the role of electronic drawing board. During this same period, efforts in the area of NC machining by companies in the aeronautical and automotive industries lead to the mathematical work in the area of computer- modeling of sculptured surfaces. Finally, computerization of engineering analysis began with the development of finite element analysis (FEA) software. This software relied upon geometric modeling techniques for both pre-processing (development of the model geometry) and post-processing (display of the results)5.

During the early 1970’s, efforts were directed toward the development of solid modeling systems. Two separate paradigms developed somewhat simultaneously. These are the Constructive Solid Geometry (CSG) technique which is based upon the use of set specific Boolean operators to combine volumetric sets defined by algebraic inequalities and Boundary Representation (B-Rep) system which defines a solid in terms of a set of finite orientable surface elements. From these research efforts followed commercial applications in the late 1970’s and early 1980’s. Industry began to use solid modeling systems for design development, creation of 2D graphical output,

1996 ASEE Annual Conference Proceedings