Reliability dictates a product’s ability to perform a specified function within the required use environment over the desired lifetime. It is central to the success of the product, of course, but reliability also reflects on the brand – and not always favorably. Product failure could mean bad publicity, warranty claims and litigation.
The Advantages of Design for Reliability (DfR)
Design for Reliability (DfR) is a design analysis process for ensuring reliability of a product or system during the design stage – before the physical prototype is made. This simple but critical shift in the approach to reliability results in a range of DfR advantages, including:
- Reduced cost of quality by improving reliability upfront
- Faster time to market for larger market share
- Increased sales and profits
DfR Best Practices
There are four key steps in the proper implementation of DfR best practices:
Don’t paint yourself into a corner too early in the design process.
- Keep dimensions and fit loose. Arbitrarily placing size constraints at the outset of the design process leads to hardware mistakes like poor interconnect strategies and component selection. Random dimensional requirements can also push designers to use inappropriate technology for required reliability.
- Use the “Toyota approach.” Toyota’s development engineers invert the traditional “test and design” methodology to focus on learning as much as possible to first satisfy specs and then design the solution. Knowledge focused on the lowest design level translates to subsystem technology that’s developed and applied separate from testing, mitigating failure and rework.
- Be moderately conservative. Incorporating new, attractive component technology is tempting but it’s not always appropriate for high reliability embedded systems. Make choices that prevent technological stagnation during implementation without buying into the hype of the latest options.
Be aware of all requirements.
Your customers have specific expectations and product requirements. It is your responsibility to know and meet them in:
- Desired lifetime
- Use environment
- Product performance, including warranty/returns and survivability
- Dimensional constraints
Try to perform concurrent engineering.
Commit to have a reliability engineer learn a project’s electrical and mechanical details, and work closely with engineers in those areas throughout the process.
Use a design checklist.
Do not rely on tests to develop a design plan. Carefully scrutinize and monitor:
- Part selection
- Power stability
- Design for Manufacturability (DfM)/testability/environment
- Component wear-out