Acceptance Speech for the ASME Machine Design Award, 10/1/02

by Robert L. Norton P.E., Worcester Polytechnic Institute

I would like to thank ASME and the Design Engineering Division for this award. I consider it a signal honor to be included among the list of distinguished past recipients of the Machine Design Award. I also would like to thank Professor Emeritus Donald Zwiep for his efforts in nominating me, and the members of the Awards committee for selecting me. I thank my former students for all they have taught me, the folks at the Gillette Company for letting me play with their machinery from which I have learned a great deal about machine design, and most of all I thank my patient wife, Nancy, who has put up with me for 42 years.

I was asked to speak briefly about the current state of machine design education as I see it. I note an unsettling trend in the last several years to eliminate or severely curtail the teaching of kinematics in the ME curriculum in many schools. In some schools the course no longer exists. In others it has been “folded into” the Design of Machine Elements course. Given the large amount of material that needs to be covered in an “elements” course, it is doubtful that additional topics as complicated as kinematics can be given sufficient coverage within the time available. There are about 250 accredited mechanical engineering programs in the U.S. Only about 170 of them offer a course in kinematics, and that number is dropping.

There is always pressure on the curriculum to introduce new topics or courses that deal with the latest technology in order to be “up-to-date.” Since we must let the students out after about 4 years and 128 credits, it becomes a zero-sum game. To add something requires that something else be eliminated. Unfortunately, in these contests, kinematics tends to be the “poor cousin” with too few defenders and sometimes ends up on the cutting room floor.

This is doubly unfortunate because, in reality, kinematics (and I’m talking here about linkage and cam design) is the foundation stone of machine design. In my industrial and consulting experience, I have seen many instances of machine designs with severe problems that resulted from the designer’s lack of understanding of basic kinematics. Much effort and expense then must be borne to fix these deficiencies, often with a sub-optimal result due to the constraints then existing within the completed machine. I can cite examples in which the redesign of poorly designed cam-follower systems using proper kinematic and dynamic techniques has resulted in significant speed increases of production machinery with simultaneous reduction of scrap rates and audible noise levels.

The majority of practicing machine design engineers in U.S. industry has very little knowledge about linkage synthesis techniques, good cam-follower design practices, and related topics. I know this because I give seminars in industry on these topics and the material is new to most attendees. This is not their fault; it is ours. With some notable exceptions, engineering schools have, in my opinion, done a relatively poor job of making students aware of the power and techniques of linkage and cam design.

We purport to teach machine design. However, in some U.S. mechanical engineering curricula, this reduces to one fundamental course, the Design of Machine Elements course, followed later by a capstone design experience. I submit to you that the typical elements course, if taught from any of the common texts on the subject (including mine), is in fact an applied stress analysis course in which the students are exposed to issues of fatigue loading on machine parts and the proper sizing of those parts to avoid failure. While this is important, and is within the broad spectrum of machine design, it deals with what I term “detailed design,” in which the type of mechanism or part is known and only the size and shape details remain to be determined of, for example, a spring, a gear, or a shaft. This is not unstructured machine design.

In practice, detailed design comes at the “end” of the design process spectrum and is quite structured. While an important component of the machine design process, it alone does not give broad enough coverage to the topic to prepare the students to face real design problems in practice. They will be expected to determine what type of mechanism is appropriate to the problem, to synthesize it, and to analyze its kinematics and dynamic forces. Only then will the lessons later learned in the elements course be applicable.

I believe that the kinematics course, which deals with the “front end” of the design process, namely determining what types of mechanisms are needed to solve an unstructured problem, synthesizing those mechanisms, and analyzing them to determine their feasibility provides a superior vehicle for teaching the principles of machine design. Moreover, we now have commercially available linkage synthesis software that takes all the pain out of linkage design. Unfortunately, these packages have had little penetration into industry or academia despite their purveyor’s efforts. We could take more advantage of them.

Compounding this problem is the fact that in many schools, the machine elements course and the kinematics course (if it exists) are frequently taught by part time adjunct faculty, often people retired from an industrial career in machine design. This is a double-edged sword. Such faculty brings valuable experience and understanding of the subject matter to the classroom. They also have a deep reservoir of practical examples to draw from which benefits the students. But these people are inherently transient to the university making it difficult to build continuity of curriculum from year to year. When only part-time faculty support a course or topic, it has no voting defenders when discussions about what courses to cut take place.

The more important question is “Why do we need to use part-time people to teach these courses?” Sometimes the reason is that no one on the permanent faculty has the interest, experience, or expertise to do so. ABET is making increasing demands to integrate design in the engineering curriculum. To really do so requires that permanent faculty with interest and experience in design be trained, developed, and nurtured. I think it is difficult to teach something well if one has never practiced it.

So, what can we do to remedy this problem? The solution rests largely in our hands as machine design educators and practitioners. As educators, we need to give proper emphasis to this important subject of kinematics and defeat attempts to eliminate it from our engineering curricula. We need to replace it where it has been eliminated. As practitioners in industry we need to make our needs in machine design known to academia and to support the development of stronger curricula in that area. One way this can be done is to increase the interaction between machine design faculty and machine design practitioners through industry supported student projects, research activities, summer internships for faculty in industry, and industrial sabbaticals for faculty. Our academic administrators could give more support to this part of the curriculum by recruiting and developing faculty with the necessary interest and desire, and by inviting representatives from industry with an interest in machine design to be members of department advisory boards.

I urge you all as conscientious engineering educators to give kinematics its due and keep it in the curriculum. Giving our students a good foundation in mechanism design will have a salutary effect on the efficiency and effectiveness and profitability of our manufacturing industries. Please don’t throw this “baby” out with the bath water. Thank you.