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April 2007 Contents

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Design for Life Cycle

By Caroline Hayes

Caroline Hayes is a professor in the Department of Mechanical Engineering at the University of Minnesota in Minneapolis, MN, where she is the Director of Graduate Studies for the Human factors and Ergonomics graduate program. She served as the Papers, Program and Conference Chair for the Design for Manufacturing and Life Cycle conference in 2002, 2003, and 2004, respectively, and has participated in this conference from its inception in the mid 1990’s.

In Fred Sampson's article, “Old Dogs, New Tricks,” in the February, 2007 issue of the UPA Voice, he describes his frustration that software development teams view User Centered Design as “the person who pretties-up the interface” after the design is completed, rather than a design process which everyone should follow to create effective products. Additionally, he laments that usability testing is typically an afterthought to the design process, when it's already too late to make major changes. As a solution, Sampson suggests changes to education: university students intending to become new software developers should be required to take a few usability and English communication courses. Developers already in the workforce should be sent to a “re-education gulag” and must prove that they have become “enlightened” before they are allowed to return to society.

On reading this article, I was struck by the similarities in the challenges of getting software engineers to consider usability during design, and getting mechanical product designers to consider life cycle issues during design. It occurred to me designers may resist adopting these two design processes for very similar reasons, and that possible solutions may be almost identical. I will explore this idea by describing:

  • The Design for Life Cycle approach
  • Challenges shared with Design for Usability
  • Thoughts on what is needed to change practices and culture of designers

Design for Life Cycle Approach

Design for Life Cycle is an approach to product design which has emerged in the mechanical design community over the last 15 years. In this design approach, many facets of the product's life cycle must be considered concurrently. Facets of a product's life cycle may include everything from marketing, manufacturing, packaging and shipping, usability, servicing, and finally de-manufacturing and materials recovery (Figure 1). Note that usability is one of these facets. Each of these facets, also known as “perspectives” should be considered at each stage of the design process starting from the very earliest concept development. Ideally, stakeholders who understand each of these life cycle “perspectives” should participate in all phases of the design process. The practice of Design for Life Cycle is also known as life cycle engineering.

Design should be considered at all stages of the life cycle: marketing, engineering, manufacturing, supply chains, packaging, delivery, usability, servicing, and recycling

Figure 1: Design for Life Cycle

Like usability, if these perspectives are each to be addressed effectively, their consideration cannot be left until after the majority of the design has been completed. At that point in time it is too late to make changes that will have a major impact.

Challenges Shared with Design for Usability

For example, consider the “Recycling” perspective. In a typical mechanical design process, in contrast to a Design for Life Cycle process, designers focus primarily on creating a product that can meet the technical specifications provided by the customer. Recycling issues are considered only as an afterthought to the design process, if they are considered at all. This is a problem because it is very difficult to make a product recyclable if the designers do not consider it from the very beginning and use it to guide their choices.

Thus there are few improvements that a recycling engineer can make if the designers have already chosen non-recyclable materials, or they have failed to design the assembly so is easy to remove recyclable components at the end of the product's life. What is most unfortunate is that recyclable products do not necessarily have to cost more than non-recyclable products if recycling is considered throughout the design process. The same is true for most of the life cycle perspectives shown in Figure 1 (with the exceptions of marketing and engineering).

This story should sound identical to what typically happens with usability, where frequently, designers and developers do not consider it until the end of the design process. At that point there is little that can be done to make a design more usable when it never considered the user's needs in the first place. This is particularly unfortunate because it does not necessarily cost much more to consider usability early in the design process, but failure to consider it may cost much in loss of product appeal and sales.

There are many reasons why life cycle perspectives, including usability, may not be properly considered during design. First, design teams already have a difficult job simply developing products that include all appropriate functions in a reasonably integrated framework. Also asking them to consider usability, marketing, manufacturing, recycling, etc. adds many levels of complexity to an already challenging process. Second, they are not typically taught these design processes in their formal education, except perhaps as a brief mention in a senior project class. Third, good metrics and case studies which would allow designers and their managers to weigh costs and benefits of following these processes do not exist or are not widely accessible.

What's needed to Change the Designer's Practice and Culture

Design for Usability and Design for Life Cycle both require more up-front development time than traditional design processes. Without an easy way to assess downstream cost savings, designers tend to view these processes as “extra work.” If we realistically expect designers to embrace these processes, we need to drastically change education and assessment processes to effect a multi-discipline wide changes in design practice and culture.

Thus, while I agree with Fred Sampson, that introducing a few usability courses (or design for life cycle courses) in the education of new designers is a good step in the right direction, I feel that much more is needed. Students need to be introduced to these concepts early in their education, starting from the freshman year, not just as a lecture or two in a senior capstone design course. Furthermore, these concepts need to pervade the whole curriculum; they cannot just be presented in a few isolated courses as “add-ons” to the design process. Design for Life Cycle and Design for Usability require that students need to be taught a different way to think about design in a new way that is radically different from from what they have traditionally been taught.

How one might carry out such pervasive changes to design culture should perhaps be the topic of yet another article. In the meantime, I remind myself that even if I can only “enlighten” one student at a time, it is progress towards a broader cultural change.

 

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