Design for serviceability

Unfortunately, a sensor failure in the field caused the circuit to "float" and make the equipment behave unpredictably. The small up-front savings were more than offset by manifold increases in downtime and maintenance costs.

This example underscores a truism of engineering design: Decisions made early in product development strongly influence life-cycle costs. Studies show that conceptual design accounts for only 4% of product cost and results in 70% of the total life-cycle costs. In the entire product-development phase, conceptual design accounts for 15% of initial product cost (including manufacturing equipment and production tools) and results in 95% of the total life-cycle costs. Other studies suggest that an additional 5% invested in improving part design can lower lifetime maintenance costs by 25%.

Products that are easier to service help boost profitability and lower both maintenance and total cost of ownership. Higher customer satisfaction and loyalty lets companies build a strong brand, be more competitive, and grow market share.

Given this background, making the case for design for serviceability (DFS) should be easy, right? So why is DFS not widely practiced? One reason: The value of DFS is not well understood, and its direct impact on product serviceability and service delivery can be difficult to measure.

Even more challenging is quantifying the link between serviceability and customer satisfaction. Saturn cars, for example, have color-coded handles on certain underthe-hood items to make oil changes and other routine maintenance straightforward. But what's the real value of this design practice? Can we measure it so as to justify the added costs of design, part sourcing, or manufacturing of color-coded handles? Given the shrinking number of do-it-yourself car owners, is this investment worthwhile?

Most design engineers focus on meeting operational goals and cost targets to the neglect of long-term, life-cycle costs. A product's design and serviceability qualities are locked in before the service organization gets it. Organizational structure and culture carry much of the blame.

Manufacturers that haven't built a strong service culture generally put cost savings ahead of maintainability. Design teams typically move on to the next project once the current one is complete and handed over to service. This practice reduces personal involvement and accountability for product quality and serviceability. Organizations that don't consider service an equally important product attribute are less likely to apply lessons learned in future designs. Conversely, manufacturers that understand the importance of life-cycle quality and serviceability and the role they play in customer loyalty, tend to foster design-service communications. Toyota, for instance, sets car-warranty goals during the design phase and wraps them into operational goals. The project's lead engineer is responsible for meeting these goals even after cars begin rolling off the assembly line.

In our view, manufacturers should focus on creating a culture that promotes DFS. This culture should elucidate the impact of design decisions on downstream processes. Up-front cost cutting may reduce availability and raise maintenance costs, while a small up-front investment can significantly boost long-term customer loyalty. It's clearly a case of pay now or pay later. Only the option to pay later often involves customers who may be much less forgiving.

Manufacturing Insights, an IDC Co. (www.manufacturing-insights.com), is a provider of research and analysis services.