on Product Reliability

Over the past week, I received a couple of interesting questions. One concerned assuming a Weibull beta value for an accelerated life test plan. The second involved assuming expected life models for elements within a reliability block diagram.

In both cases, we faced incomplete data and uncertainties, yet felt the need to assume some values in order for the math to work out. We do make assumptions in order to solve problems. We also can make mistakes that lead to unwanted consequences. [Read more…]

One of the enjoyable parts of reliability engineering work is the consistent need to learn. We learn how new materials, designs, applications, and systems work, and fail. Sometimes we learn through proactive characterization studies, sometimes via unwanted field failures.

Failures will occur, it is what we learn from them that matters. The ability to gather and remember the lessons learned is a common and ongoing need for every organization. We are not very good at it, in general. [Read more…]

Uncertainty is another word for risk. Reliability uncertainty or risk is neither good nor bad, it just a bit unknown. Until we know the outcome, the eventual reliability performance, we will not know the impact.

So, how do we deal with reliability uncertainty? Will our product or system work as expected over time, or will it fail? Let’s examine a few of the common approaches in use and when and why the approach is effective. [Read more…]

How is it that some people continue to get better at managing meetings, designing complex test plans, making presentations, or solving problems? How in general do people improve their performance over time at something? [Read more…]

Some time ago when talking with someone I just met, the conversation turned to what we did for a living. I mentioned being a reliability engineer, and his response: “Oh, yes, we do reliability”. Curious, as I’m not sure that I ‘do reliability’, we then talked about what he meant.

The conversation revealed that they had a list of tasks that they accomplished for each product under development. They did tests and reviews of the results. A lot of testing. They did FMEA and HALT. He believed the engineers did derating or stress/strength calculation. He didn’t know about process stability with vendors or internal manufacturing lines.

They did stuff, which meant they did reliability.

[Read more…]

Some time ago, earlier in my career, I worked for a wonderful boss. She would stop by my office on occasion and ask ‘what’s new?’ or “how’s it going?’ Just a check-in. I often let her know about the current vexing problem I was struggling with at the moment.

The funny thing is she never directly solve the problem for me. She certainly could have. Instead, she would ask a couple of questions that always helped me to find the solution. This happened with problems concerning dealing with a difficult person, strange material properties, motivating change within a group, or finding someone that could design and run a computational fluid dynamic model for me.

It was her questions the helped. She did this in meetings, in presentations, and when she swung by my office for a chat. [Read more…]

In a recent blog post, Seth Goin discussed the need for ongoing investment to maintain infrastructure. Whether a road or building or even your own skills, it takes regular care to avoid system failures or obsolesce. [Read more…]

Statistical process control, SPC, is a set of tools to enable monitoring the stability of a process. SPC is also the first step to checking process capability with measures such as Cpk. Many consider SPC a quality or manufacturing tool. Yet, having and maintaining a stable process is also essential to creating a reliable product. Let me explain why. [Read more…]