Dr. Ramkumar gave an exceptionally informative webinar, we believe, our readers would benefit from. In this 4-part series, we will discuss the following topics: Quality vs. Reliability, Failure Modes and Mechanisms, Failures and Root Causes, and Reliability Testing over the next couple weeks.
In order to provide some context, let us discuss how failure, reliability, and quality are defined within the context of the presentation. Failure is the inability for a product to perform its function—a reliable product will have a failure rate close to zero, providing good quality over time. Quality is a measure of the conformance to product specifications at any given instant in time (does the product do what it was intended to do?), where reliability is a measure of the product’s ability to perform the desired function, without failure, under-stated conditions, for a stated period of time.
According to Dr. Ramkumar, even though quality and reliability have differing definitions, they are synonymous with one another—you cannot have reliability without quality and vice versa.
“A quality product will fetch you customers, but high reliability of the product will keep customers coming back to buy more product,” Dr.Ramkumar said. This was one of the main themes echoed throughout the presentation. Simply put, reliability is considered to be quality over a period of time.
Quality is at time “zero” (when the product is being made) and reliability is when you have created a quality product, sent it to your customer, and they are using it in the field. It’s at this point you are looking for the ability of the product to function, without failure, for a given period of time.
Most of the quality concerns, and the root cause for quality and therefore reliability issues, will occur at the manufacturing stage. It is at this point any found issues are corrected and in-circuit and functional testing should be done—it is crucial for both your budget and to-market timeline this testing is done accurately and quickly as possible. It is after this stage the concept of reliability is now focused upon.
At every stage of the product development cycle, you are going to start on quality and improve upon it in order to get to a higher reliability. With electronics, this is even more significant. Consider this, electronics are made of multiple components, and all of these components have their own standards of reliability which then define the reliability of the electronic product/system. The products you use to create any of these components or product pieces are integral to achieving your quality and/or reliability standards.