Design for Excellence in Electronics Manufacturing

3Design for Reliability

3.1 Introduction

A long time ago, a wizened professor provided key insights into the beginning of the learning process. In a grand voice, and with a sweeping gesture, he stated, “If you cannot define it, you do not know it.” And thus, to honor his legacy, I try to always initiate any educational engagement with a definition of the topic to be discussed. So, to start a chapter on Design for Reliability, let us ask the question: what is Design for Reliability?

Design for Reliability (DfR) is defined as a process for ensuring the reliability of a product or system during the design stage before physical prototype, often as part of an overall Design for Excellence (DfX) strategy.

Each portion of this definition is highly relevant to the topic. A process is a series of actions or steps taken to achieve a specific goal. DfR is not a single activity, but a series of activities that build on each other with the purpose of meeting customer expectations of reliability. Reliability is the measure of a product's ability to:

• … perform the specified function
• … at the customer (with their use environment)
• … over the desired lifetime.

Therefore, the DfR process must take into consideration customer expectations about how and how often the product will operate, how the customer will use the product, and when the customer will no longer blame the manufacturer for the product's failure to operate.

The design stage before physical prototype is self‐explanatory. Some will ...