Engineering Design Processes, Problem Solving &Creativity

Don L. Dekker
Rose-Hulman Institute of Technology

Abstract:

There is confusion as to what the terms in the title mean. None of them are clearly defined. ``The engineering design processes'' are often confused with open-ended problems. ``Problem solving'' has many definitions. ``Creativity'' is much more than the prevalent ``free-thinking'' view. The lack of a common definition leads to confusion when people, faculty included, are discussing these topics..

There are many listings of the steps or phases which comprise the engineering design processes. There are also many listing of the steps or phases of problem solving. Although completing an engineering design is solving a problem, ``problem solving'' is not engineering design. Engineering design and problem solving can be distinguished by the activities that take place during the project.

Early in most descriptions of problem solving and the design processes, there is usually a step called ``search for alternatives'' or ``ideate.'' This implies that creativity is needed only in this step. The prevalent, ``free-thinking'' view of creativity also implies that creativity will happen if all constraints and negative attitudes are removed. There are positive techniques that can help everyone become more creative. These structured creative enhancement techniques provide a tool to quantify creative skills. This quantification also makes creative skills easier to teach.

These creative enhancement techniques are consistent with the structure of the engineering design processes and the phases of problem solving. In fact, these creative skills must be used throughout the engineering design processes to produce a ``better'' design in a shorter time!

The Importance of the Engineering Design Processes

Two quotes emphasize the importance of design in the product realization process:

``After all, 70%of a product's total cost is determined by its design, and that cost includes material, facilities, tooling, labor, and other support costs.''

A. Sandy Munro [1]

``Studies have shown that 50 to 80 percent of the life cycle cost of products are influenced in engineering design.''

Description of Session DFM 3 [2]

The first quote not only indicates the large impact that the engineering design processes have on product cost but also some of the other considerations that go into the product realization process, (PRP), such as tooling, facilities, and labor. These other considerations dictate that certain members of the engineering design team must be knowledgeable in these other areas.

Introduction

Many authors have developed a ``framework'' or ``structure'' to help describe engineering design. Most of these ``structures'' have been developed in the European design community. Studying the engineering design processes became necessary only after WWII when the products which were being developed became more complex. When the companies which had been involved in the war effort reverted to peacetime producers, the associated design processes and development techniques carried over into their peacetime products. Greater use of physical laws, mathematics, information theory, materials selection, and systematic design techniques was required.

Perhaps the ``king'' of these complicated peacetime projects was the landing of a man on the moon. This required a concept, a lot of calculations, preliminary layouts, much prototype testing, a great deal of detail designing and specifying the shape of the parts and recording this in a document (drawing), production, and finally the ``moon shot.''

Engineering Design Processes

Most engineering design follows the ``moon shot'' type of format. Pahl and Beitz [3] provide one of the better known design ``structures.'' One of the useful parts of this ``structure'' is the fact that it not only shows the steps, it shows what the output of each step should be. The structured design steps of Pahl and Beitz &Hubka and Eder [4] show, in addition to the steps in the process, conceptual design, embodiment design and detail design. These three activities take place in all industrial design projects. In educational design projects, students may only complete the conceptual design phase, or both the conceptual design and embodiment design phase. It is important that the students and their instructor recognize what type of design they are expected to complete.

Ambiguity

All design challenges are ambiguous. Unlike answers to mathematical expressions like the derivative of , there are always several ``right'' answers to any design challenge. The answer is always uncertain or ambiguous. Not all design solutions are equally good, however, and some are definitely wrong.

The ``best'' design solution is the one that most completely fulfills the client's requirements and can be delivered when it is needed and produced with the available resources.

A. T. Roper [5]

All designs could be improved if there was more time and resources. Most products improve as time passes and the product is refined. However, there are windows of opportunity. A product that is too late or costs too much often is unsuccessful even though it may be technically superior. In time, new technology often provides ways to expand performance, increase reliability, lower cost, broaden applications, and overcome other limitations. Therefore the engineering design processes require judgment, creativity and discipline as well as technical skill.

Conceptual Design

Conceptual design is just like it sounds-the generation of a concept. Some of the terms used by Pahl and Beitz to describe it are: identify essential problems, establish function structures, search for solution principles, combine and firm up concept variants. Using the ``House of Quality'' [6] may be very useful at this stage.

An excellent example of this is the ``lunar-orbit rendezvous'' (LOR) which enabled American astronauts to land on the moon. Other options were earth-orbit rendezvous (EOR) and the direct ascent, which was an updated Jules Verne version. John Houbolt had a difficult task to get his new idea accepted. The LOR concept was ridiculed and other NASA scientists said it wouldn't work. This has been described in Space [7] by James Michener and in LIFE in Space [8].

Embodiment Design

Embodiment design consists of preliminary layouts and configurations, selecting the most desirable preliminary layouts and refining and evaluating against technical and economic criteria.

After NASA selected the LOR concept to land a man on the moon, there was an incredible amount of design work to be done. The rough, conceptual sketches of the LOR do not provide any direction as to how to built these devices. Much work had to be done to refine the concept. Configurations, shapes, weights and interactions had to be determined before detail design could begin.

Detail Design

The detail design includes specifying the materials, the sizes, the type of motor, the size of the hydraulic pump and cylinders, where the attachment and assembly holes should be drilled, the size of the holes, etc, etc, etc. It requires a lot of skills to specify this myriad of items correctly if the design is to ``go together'' in a satisfactory manner. Many alternatives and options should be considered during this part of the engineering design processes.

Many of the skills required in detail design can be acquired early in the student's career. Students can acquire skills, such as dimensioning, tolerancing, surface finishes, welding, heat treating, and many others during the first two years of their studies.

Iterations

All of the steps or phases of the engineering design processes indicate feed-back arrows which indicate RE-DOING or iterating the steps.

This ``re-doing'' is necessary because we seldom know enough at any stage of the design process to produce a complete answer, let alone the best one. For instance, we must define the problem to begin, but the beginning is precisely when we know the least about the system we are designing. We learn about its characteristics, performance and limitations as we design. Thus, we must do and redo the design, that is, we must iterate.

Problem Solving

There are differences between the problem solving steps and the engineering design processes. Polya's [9] problem solving steps are probably the most well known. They are: (1) Define, (2) Think about it, (3) Plan, (4) Carry out the plan, and (5) Look back. The steps usually neglected are ``plan'' and ``look back.'' The looking back is essential if our thinking skills are to improve.

The author has used an eight step list for problem solving. These eight steps are: (1) Recognize a Need, (2) Accept the Challenge, (3) Define the Problem, (4) Collect Information, (5) Synthesize &Ideate, (6) Analyze &Optimize, (7) Evaluate, and (8) Implement. In either case the steps provide a ``roadmap'' or ``guide'' to follow. To improve our thinking skills, it is imperative that the processes used to solve problems are recognized. These processes are more important than the ``correct answer.'' We must think about our thinking processes.

Differences Between ``Problem Solving'' and ``Engineering Design Processes''

Conceptual design, embodiment design and detail design are the three activities that separate the engineering design processes from the problem solving processes. Problem solving is done by nearly everyone, nearly every day. A problem, like ``my car won't start'' or ``how can we increase our market share'' can be solved by following the problem solving steps. However, these examples are not problems in engineering design because there is no conceptual design, no embodiment design, and no detail design.

Creativity

Creativity is given a back seat in design education because it is poorly understood and difficult to teach. There are positive techniques that everyone can learn. Dr. Edward de Bono, in his book Serious Creativity [10], describes many different ways to produce creative ideas. A listing of de Bono's creative techniques is helpful here because the names of the techniques are very descriptive. The techniques are: ``The Creative Pause,'' ``Focus,'' ``Challenge,'' ``Alternatives,'' ``The Concept Fan,'' ``Concepts,'' ``Provocation,'' ``Movement,'' ``Setting Up Provocations,'' ``The Random Input,'' and ``Sensitizing Techniques.''

It is interesting to note that Dr. de Bono then discusses ``Harvesting,'' ``The Treatment of Ideas,'' ``Formal Output,'' and ``Group or Individual'' techniques. This means that once the creative ideas are generated, there are useful additional techniques for nurturing a young, tender idea so it will grow into a productive concept or solution.

Dr. de Bono concludes by mentioning several creative situations, many of which are applicable to design. The most applicable situations are: ``Design,'' ``Invention,'' ``Opportunity,'' ``Problems,'' ``Improvement,'' ``Planning,'' ``Futures,'' and ``Projects.'' Another one is ``Conflict,'' and there certainly needs to be conflict resolution when engineers work in teams. Creative conflict resolution would be useful in many, many situations. Of course, ``design'' and ``invention'' are two of these situations that are integral parts of the engineering design processes. A successful company will always be looking for ``opportunities'' and these ``opportunities'' will, by definition, occur in the ``future.'' Engineers are always working on ``projects.'' Certainly, all engineering design processes and projects must be ``planned.''

These creative skills must be practiced until the thought patterns in our minds become comfortable with these creative lateral thinking techniques. We can create these creative grooves in our mind so these techniques will be utilized. These creative lateral thinking techniques can be used to enhance all of these situations. These previously described situations are integral parts of the engineering design processes.

Conclusion

The engineering design processes include conceptual design, embodiment design and detail design. Engineering design is ambiguous and iterative. Open-ended problem solving may also be ambiguous and it may have several iterations. However, it does not include conceptual design, embodiment design, and detail design. The structured creative enhancement techniques provide a tool to quantify creative skills. The creative skills should be used in all phases of the engineering design processes. Upper level students have more and stronger analytical skills than first year students, but the lower level students can be learning and practicing the creative skills. The combination of creative skills and technical abilities will enable the students to be ready to ``hit-the-ground-running'' and produce in industry when they graduate. This also can help students produce better, more satisfying, and more creative designs. Ultimately this will produce better designs for society. Our students, the engineers of tomorrow, must have a command of the engineering design processes, and be ready to actively participate in the product realization process.

References

  1. Munroe, A. S., ``Is Your Design a Life Sentence?,'' Machine Design, 26 January 1995, pp. 156

  2. PREVIEW, National Manufacturing Week '95: National Design Engineering Conference Sessions 1995, Design for Manufacturability Track, Session DFM 3

  3. Pahl, G. and Beitz, W., Engineering Design: A Systematic Approach, Edited by Ken Wallace, Springer-Verlag, The Design Council, 1988

  4. Hubka, Vladimir and Eder, W. Ernst, ENGINEERING DESIGN: General Procedural Model of Engineering Design, Heurista, Zurich 1992

  5. Roper, A. T., Class Handouts, ME461, Aerospace Design, 1995, Rose-Hulman Institute of Technology

  6. Hauser, John R. and Clausing, Don, ``The House of Quality,'' Harvard Business Review, May-June 1988

  7. Michener, James, SPACE, Ballantine Books, New York, 1982

  8. LIFE IN SPACE, Mason, Robert Grant, Editor, Time-Life Books, Little, Brown and Company, Boston, 1983

  9. Polya, Gyorgy, How To Solve It, Princeton University Press, Princeton, N.J., 1971

  10. de Bono, E., SERIOUS CREATIVITY: Using the Power of Lateral Thinking to Create New Ideas, HarperCollins Publishers, Inc., New York, NY, 1992





mort@etp.com
Tue Oct 3 17:11:31 PDT 1995