Big Ideas in Engineering and Product Design

The big ideas in design are themes that connect the skills and knowledge we seek to develop in the Capstone course sequence. The big ideas are:

Some of the big ideas, like design requires creativity and design requires teamwork and planning, are superficially obvious. However, putting these ideas into practice requires skills and understanding that are not taught in many engineering courses. Experienced engineers know that non-technical skills and knowledge can be equally or even more important than engineering analysis when solving practical problems.

The big ideas are motivation for the learning activities in the Capstone course sequence. If you find yourself asking, "Why are we doing this?", check in on the list of big ideas. If the connection is not obvious, ask me.

What is Engineering Design?

The definition of engineering design offered by Dym et al. is a good starting point.

Engineering design is a systematic, intelligent process in which designers generate, evaluate, and specify concepts for devices, systems, or processes whose form and function achieve clients' objectives or users' needs while satisfying a specified set of constraints.

– Clive L. Dym, Alice M. Agogino, Ozgur Eris, Daniel Fry, and Larry J. Leifer, Engineering Design Thinking, Teaching, and Learning, Journal of Engineering Education, 2005, vo1. 94, issue 1, pp. 103–120, DOI: 10.1002/j.2168-9830.2005.tb00832.x

What is the Design Process?

We will explore the design process throughout ME 491, 492 and 493. Although there is no one design process, there are common activities practiced by most people who use design to solve problems or create new processes or devices.

Generally speaking, the design process begins with efforts to understand the problem being faced, and ends with deployment of the solution developed. The path from the beginning to the end is usually iterative, meaning that ideas and prototypes are developed and tested to gain information, which causes the designer to rethink both the definition of the problem and the means to solving it.

Note that in this section we are concerned with the general activities involved in design, not just engineering design. The design process is described in more detail on a separate page. Also refer to Basic Design Process in the textbook Mattson and Sorenson, 4th ed. pp. 194-195.

Basic Design Process

The design process, as described by Mattson and Sorenson (pp. 194-195) can be described as a sequence of activities.

  1. Understand the problem
  2. Explore concepts – diverge to generate ideas; converge by using analysis to eliminate ideas
  3. Define the design – use modeling and experimentation to explore solutions
  4. Test – prototype and evaluate
  5. Refine the design – iterate steps 1-4 and within steps 1-4

You should not take the numbering of steps as a rigid procedure. There is logic in progressing through the steps in the order given. However, there is also a benefit to anticipating later steps, or revisiting prior steps. In practice, design is iterative and messy.

The Stage-Gate® or Phase Gate Model of Product Design

Note "Stage Gate®" is a registered trademark of Stage-Gate Inc.

The term "Stage Gate®" is applied to a design processes characterized by a sequence of activities (stages) with boundaries associated with a go/no-go decisions (gates) to determine when and whether to move to the next stage. We will use the term "phase gate" instead of the registered trademark term to describe a sequential design process segmented by decision points. This process is also called "waterfall design". Refer to the Wikipedia pages for phase gate and waterfall design process models.

Mattson and Sorenson advocate a model of product design with six stages:

  1. Opportunity development
  2. Concept development (a.k.a. conceptual design or architecture development)
  3. Subsystem engineering
  4. System refinement
  5. Producibility refinement
  6. Post-release refinement

Iterations happen within each of the stages. Thus, the Basic Design Process (or parts of it) described above can occur within each of the stages. The key difference between the six-stage process and the basic design process is that the six-stage process has well-defined starting and ending points, or gates, for each stage. In contrast the basic design process describes a more generic sequence, without an explicit acknowledgement of the transition from one stage to the next.

A phase gate process is commonly used to design physical products (as opposed to processes or software, for example). The physical products could be items purchased by consumers, industrial devices used in manufacturing, machines and parts used in commercial activities (think jet engines, farm equipment, forklifts, ships, etc.), infrastructure (buildings and building components, bridges, stop lights), and a large number of other categories. Physical products require manufacturing and the manufacturing process itself is an outcome of a design process.

Engineering Design is only one aspect or one part of design

Design is a common human activity, and ultimately serves humans. Design is familiar for some tasks (planning a trip or a party, organizing your closet, making dinner), yet applying design to unfamiliar problems is often challenging. There are also many ways that design is important outside of engineering and technology such as fashion design, graphics design, curriculum design, health-care, finance, etc.

In business, manufacturing and product development, different types of design activities are necessary, and these activities span disciplines beyond mechanical engineering related design. For example, the work needed to bring a new product to market involves facets of design in the following list.

Mechanical design
Though the field is quite broad, mechanical engineering design primarily deals with machinery that moves objects, moves fluids, or transfers heat or energy. The analytical tools of mechanical engineering are focused on inanimate objects. However, like most practicing engineers in other disciplines, the application of technical knowledge requires an integration of many additional factors (human, economic, environmental) that are necessary to satisfy all requirements of a problem.
Industrial design
Industrial designers specify the form and features of an object in order to make products effective, easy, appealing and safe to use. This usually involves the choice of shape, color, texture, user controls. The Wikipedia page and the web site for the Industrial Designers of the America has more information
Process design
Process design is focused on activities instead of objects. The activity could be the creation of a substance or material (chemical process design, metallurgical process design), a sequence of activities in a service-oriented company (business process design), the handling and flow of materials in a mass-production environment (manufacturing process design) or the specification of engineering procedures to create complex objects (engineering process design).
Systems Engineering
Systems engineering involves the application design principles to the integration and management of complex systems. For example, deploying, maintaining, and providing customer services for a car-sharing system would benefit from a systems engineering approach. Refer to the web site of International Council on Systems Engineering for more information.
User interface design
User interface design focuses on the way that people interact with technology. UI (or UX for user experience) design is an important part of software development. User interface design also applies to processes and physical products such as the type, number and placement of control buttons, levers, switches and the type, location and graphical design of indicators, gages and digital displays for operator information.
Human factors and ergonomics design
Human factors engineering solves design problems related to the way that humans interact with objects and systems. This is also known as ergonomics. As a complement to user interface design, human factor design focuses on comfort and safety of people using the product or process. It also applies to the optimization of workplaces to improve productivity. Human factors design uses information from biomechanics, physiology, psychology and industrial engineering. Refer to the Wikipedia page for more information.
Design for X
Design for X refers to the focus on, and optimization of, a particular trait, "X", during the design process. Design for X is a generalization of the concept of design for manufacturability, which focuses on optimizing a design so that it can be manufactured easily, and therefore more efficiently and cheaply. Other values of X are assembly (focusing on the ease, and hence cost, of assembling a device during manufacturing), dis-assembly (for ease of service, recycling and disposal), environment (design to reduce environmental impact), etc. The Design for X implies that the trait (X) is in addition to more basic requirements for performance and probably cost. Refer to the Wikipedia page on Design for X for more information.

The preceding list of design activities focus on the what – the thing being designed. In addition, we can also talk about the how – the criteria used in the design process and the process itself. Obviously, the design criteria affect the outcome. But even the attitude or decision-making processes used in design also affect the outcome.

Universal design
Universal design principles focus on maximizing accessibility in a way that benefits all potential users, regardless of age, size, ability or disability. Curb cuts in sidewalks and closed-captioning of videos are examples of universal design. A curb cut allows people in wheel chairs to cross city streets, and it also helps delivery people, parents pushing strollers and bicyclists. Closed-captioning allows people with hearing disabilities to watch video, and it also allows people to watch TV in a noisy bar, and people to watch movies that have narration and actors speaking in other languages. Therefore, although the universal design goal is to remove barriers to some populations of users, the goal is to benefits all users, and hence is universal.
Human-centered design
Human centered design is an approach to designing objects and systems in a way that focuses on the benefits to humans. A human-centered design may lead to a solution that uses as little technology as possible, if that yields the best outcome for the people using the product or process. Human centered design is often used when problems involve social and economic problems, and is a central principle in social innovation.
Social Innovation
Social innovation is a broad activity focused on solving problem faced by large groups of people, and not necessarily on making and selling products.

… we redefine social innovation to mean: A novel solution to a social problem that is more effective, efficient, sustainable, or just than existing solutions and for which the value created accrues primarily to society as a whole rather than private individuals.

James A. Phills Jr., Kriss Deiglmeier, and Dale T. Miller, "Rediscovering Social Innovation", Stanford Social Innovation Review, Fall 2008. URL.

Examples of social innovation are open-source software, fair-trade labeling, microfinance, crowdsourcing of community problems, and idea competitions.

Sustainable design
Incorporates sustainability – minimization of negative environmental impacts – in the design process while also seeking to improve benefits to human health and comfort. Sustainability more generally refers to the incorporation of long term environmental consequences in meeting human needs for food, shelter, safety, comfort and livability. Factors related to resource and energy consumption are considered in also stages of production, from material and water usage during resource extraction (mining, energy production), during manufacturing, product use, product maintenance, repair, recycling and ultimately disposal.

Mechanical engineering students often envision machine design when they think of design. While specifying mechanical components is an important design activity, machine design is only one aspect of mechanical engineering design. And as we have written above, engineering design is a very small part of product design, development and manufacturing.

In the Capstone course sequence, we will put a lot of emphasis on activities in the early stages of design and engineering design. That does not mean that engineering design (or machine design or thermal systems design to name two typical ME design activities) is not important. Rather, this class is about the bigger, more encompassing process, of which machine design and thermal system design are just parts. Furthermore, you have had a fair amount of practice in machine design (clearly even more practice is better), but you haven't had any practice with the larger, more encompassing part of the design process that we practice in Capstone.

Design requires creativity

The premise for design activity is that there is an unmet need or a problem, which implies that an obvious solution is not available. Therefore, creativity is required to develop a new system or device that does not yet exist and will satisfy the unmet need.

Creativity requires

  • An open mind
  • A willingness to consider ideas that have not been tried or have been tried and rejected
  • Confidence or at least a willingness to work with uncertainty (??)
  • An ability to work with people of different backgrounds and expertise (??)

Techniques to stimulate creativity in the process of generating ideas

The creative process involves divergent thinking as discussed below.

Design is iterative and messy

Ullman, in the The Mechanical Design Process, 1992, (p. 29) calls attention to the difference between an idealized and practical views of the design process. In the idealized view, the goals of the design are known in advance and the designer evaluates potential solutions against those goals. In most practical design problems (at least those that are not trivial), the goals are not clearly and completely known at the beginning.

Ullman writes

… for most design problems this view of design toward a known goal is too simplistic; because the problem is ill-defined, the goal cannot be completely know.

Design problems are said to be ill-defined and ill-structured, which makes it sound like the design problems have some inherent flaw. The "ill" in ill-defined and ill-structured refers to the lack of understanding that is typical at the start of challenging design problems. In fact, only trivial problems are well-defined and well structured at the outset.

Don't confuse the logic and order of the final product with the messy process of design work. Because design involves learning, your understanding of the problem and potential solutions later in the design process will (or at least should be) greater than it is at the outset. A constructive design process is a way to manage the initial uncertainty and lack of knowledge, while working to reduce uncertainty and increase knowledge.

Design Involves Learning

During the design process, you learn more about the problem you are trying to solve. Since this is inevitable and beneficial it makes sense to hold the perspective of a eager learner. Some attributes of an eager learner are

  • Curiosity: an eagerness to listen to, and seek to understand new ideas,
  • An ability to withhold judgement, especially when understanding is tentative or provisional,
  • A willingness to test your knowledge without a preconceived outcome (as opposed to only seeking information that confirms your beliefs),
  • A willingness to change your mind as new information becomes available.

The idea of witholding judgement should not be taken as a moral imperative or as an absolute. Witholding judgement is important when observing users or circumstances that demonstrate the design problem. Withholding judgement is also important when generating ideas to be used in the design. When decisions need to be made, analysis and judgement are essential. However, engineering students have years of training to learn the correct way to solve a problem, and that makes students predisposed to applying judgement during early phases of the design process.

Divergence and Convergence

Design alternates between generating ideas (expanding possibilities) and evaluating ideas (reducing possibilities). Almost all of your engineering education has involved evaluating ideas (engineering analysis), which has the goal of using standing methods to get "an answer", and even more importantly the correct answer. In design, there are often multiple "correct" answers.

In engineering analysis courses, we train you to use standard methods so that (1) you use methods that have been proven to work in the past, and (2) other engineers can quickly understand what you have done. Those skills and knowledge are very important. However, in engineering design (and design, in general) we must couple analysis – convergent thinking – with non-analytical divergent thinking. Figure 1 summarizes the traits of divergent and convergent thinking.

Divergent and convergent thinking

Figure 1: Comparison of divergent and convergent thinking processes.

The double-diamond model shows how the convergence and divergence processes apply to different stages in the overall design process.

Design requires balancing competing desires and outcomes

The goal of the design process is to solve a problem or satisfy an unmet need. That simple statement glosses over the reality that a solution involves many factors that may be (1) poorly understood or hard to quantify, (2) changing in time, and (3) in competition. The competition between desirable traits of a solution means that it is usually impossible to create a design that optimizes all individual factors, i.e. taking each factor in isolation. For example: it is generally not feasible to both minimize cost and maximize performance Because there is no perfect solution, the design process usually invovlves choosing between more than one feasible solution.

Design requires trial and error.

  • Since design involves learning, we are bound to make mistakes (have failures), especially in the early stages
  • Treat mistakes (failures) as learning opportunities
  • To reduce unknown, intentionally design experiments to gain more knowledge
  • Use prototypes – one way of experimenting

Design requires a clear understanding of your client's needs

The human component is essential. You, the designer, must focus on the client's needs, not your needs. While focusing on the client seems obvious, many designs fail because they a driven by forcing a business or technology idea onto a problem: the proverbial have-a-hammer and looking for a nail.

Process and Tools for Understanding Client Needs

Refer to Chapter 3 in the textbook by Mattson and Sorensen. During the Opportunity Development phase of the design, the team seeks a clear definition of the client needs. Surveys, observational studies (watching users), market research (to establish benchmarks for existing products and estimate opportunties), patent searches (to discover applicable technologies and prior art) are tools for developing an understanding of client needs.

Human-centered design describes an approach that focuses the people using and affected by the product during all aspects of the design process. For more information on human centered design, follow these links:

  1. Wikipedia article
  2. Ideo's human-centered design process
  3. Design for America process for college teams

As information about the client needs are clarified, the design team develops engineering specifications that guide the design process. At this stage, tools such as Quality Function Deployment and Requirement-Measurement Matrices help the team identify the connections between client needs and engineering specifications.

Complications

A crucial part of engineering design is translating the client's needs into engineering specifications used to guide the design process. However,

  • The client may not have a clear understanding of their needs
  • The client's needs, or perception of needs, may change as the design evolves.

Refer to the quote from Ullman above

Design requires teamwork and planning

There is always too much work that could be done. The key is to identify the work that must be done, and to execute efficiently.

To be successful we need to manage our work

  • Manage competing requirements
  • Manage schedules
    • Coordinating with others
    • Choosing a good order of doing things
    • Dealing with delays caused by external actors
    • Allocating time for work tasks (being able to estimate and execute well)
  • Manage people: yourself, teammates, outside commitments (family, health, relaxation)
  • Manage budgets: what to spend on, how to ask for enough, keeping track

A successful team is composed of good team members. Do your best to be a good team member. Capstone projects, like design projects engineers work on aftergraduation, usually involve some degree of friction between team members. Refer to the teamwork page for more information.

Use planning tools

  • Gantt charts
  • Network diagrams (PERT, critical path)

Refer to the project management notes for more information.

The design process cannot be reduced to a foolproof recipe

There are many models of the design process. The design process is generally described as a series of step or phases, usually with some sort of iteration within the steps and between the steps. However, design cannot be reduced to a foolproof recipe.

Exceptions

There are many exceptions to an orderly progression of design steps. Design problems have their unique characteristics. Sometimes the conceptual design is obvious, for example when the design problem is to improve an existing product or process. Sometimes a final, mass-produced device is not desired.

In general, following a rigid set will lead to extra work (because some steps may not apply), loss of creativity (because you follow rigid rules instead of being open to inspiration and serendipity) and in general a less than optimal outcome.

Multiple Tools and Processes

There are many design process techniques and tools. Using too many (certainly not all) design process techniques and tools will waste time because not all techniques are beneficial in all situations and even beneficial techniques may not be necessary. Using too many techniques may distract from taking advantage of, and acting on, what you know (without further need to seek answers), and therefore slow progress.

Experience Helps

Given the many exceptions and many possible design tools and processes, experience helps. However, design experience is a boot-strapping problem: in order to gain design experience, you have to do design.

With or without design experience, it is helpful to have a metacognitive perspective to

  • recognize where your design problem is located on its evolutionary arc,
  • decide what kinds of process tools are useful or needed,
  • be mindful of the benefit of slowing down in order to finish a give process for maximum benefit,
  • accept when to move on, recognizing that you know enough to make the next important decision, or the risk of a bad decision now is outweighed by the risk of delaying the project futher.

Confusion is most prevalent (though not exclusively) in the early stages of the design process, when the problem is most poorly defined and most open to different directions. In the early stages, flexibility and openness to creative ideas is also important (at the risk of being confused) so that all constructive directions are sufficiently explored. Again, there is no foolproof recipe.

In the late stages of design, e.g. detailed design or design for manufacturing, creativity is very important. However, at late stages, the design process is less fluid for at least two reasons. First, in late stages of design the design problem is better understood, so the need to re-evaluate fundamental ideas about direction or design concept should be minimal. Second, changes in direction during late stages of design are very expensive because the team is larger, the concrete commitments are larger, and the cost of implementing an idea is larger.

Standards are very important

Although the design process is fluid and flexible, members of the design team should adhere to standards of behavior and practice

  • Safety is paramount
  • Contract format, timing with clients.
  • Internal budgets and financial processes
  • Ethical behavior within the team and in all external relations
  • Limiting work to areas of expertise
  • Documentation standards
  • Design review standards

The use of standards will impose some limits, but it also will likely increase team coherence (shared values and shared expectations) and improve efficiency (using same/similar methods creates benefits from practice)


Document updated 2016-09-13.