The Unintended Consequences of Design

Soon after boarding an early morning flight to attend the 2011 International DFMA Forum, the pilot announced there would be a slight delay. A few minutes later, he informed us the problem was due to a fuel leak. He explained that the plane's fuel tanks had been topped-off the previous night; apparently, there had been no indication one of the tanks had been overfilled.

After an hour of bleeding off excess fuel and attempting to clean up the mess, the airline decided to transfer us to another plane. Thirty minutes after the plane shuffle, we were in the air. Halfway through the flight, the crew began announcing missed connecting flights and the efforts being made to book passengers on later flights. The workers who fueled those tanks had done their jobs and gone home for the night, satisfied with their work. They likely had no idea they had set in motion a series of events that would cause trouble for their employer and hundreds of travelers.

As designers and engineers, have we ever been in the situation of those airline workers? Have we completed projects with requirements met and targets achieved, transferred the designs to production, and moved on to the next projects without eliciting or receiving any feedback about how our designs performed in production? During the production phase, efforts are often made to reduce cost and improve quality. Generally, these efforts achieve only small, incremental improvements, often because of constraints resulting from early design decisions. If these improvement efforts are insufficient, complete redesigns may be required. How can we avoid these unintended consequences of our design decisions?

Many papers presented at the DFMA Forum discussed tools and techniques designers have used to avoid the negative consequences of initial design decisions. Some papers focused on the benefits of early cost estimation and analysis of assembly efficiency to assess the cost consequences of design choices. Others discussed how collaboration between engineering, manufacturing, and sourcing had reduced costs and quality problems. Additional themes included cutting everything by 50 percent (parts, assembly time, and cost) and allowing sufficient time during early conceptualization to evaluate alternatives to achieve an optimized design. Presenters were excited to share examples of how these tools and techniques have allowed design engineers to peer into the future and see design consequences before the designs are implemented.

While we don't have crystal balls, there are tools available to help predict the future impact of today's design decisions. In addition to highlighting the DFMA software toolfrom Boothroyd Dewhurst, Inc., variations of the Lean and Value Engineering methodologies, along with the use of CAD and FEA modeling tools, had their benefits emphasized. Designers and engineers who utilize these tools, both early and often in the design process, can minimize the unintended consequences of their design decisions.