Is Testing Always Necessary?

Abstract

Chris and Fred discuss what happens when you have failure … but don’t know why. This is a challenging problem that most reliability engineers will face throughout their career. You will always need to use an objective, structured and strategic approach. And you will often find that a lot of information is at your fingertips – you may be able to create a very short list of candidate root causes without having to test. Effort without direction won’t solve problems. If you want to learn more about solving this really challenging problems, then listen to this podcast.

Key Points

Join Chris and Fred as they discuss their specific approaches to fixing problems or removing the root cause of failure when they don’t know why the failure occurred. When we have symptoms (and nothing else), we tend to go with what we know. Mechanical engineers will look for their favorite or pet failure mechanism. Chemical engineers will focus on what failed for them last time. Electrical engineers will look at a control system. And so on.

There are lots of excuses and dismissive statements that don’t help. We can’t just say that the machine failed was a ‘just’ a prototype – so it is expected to fail. What do we learn from this? Nothing. We also need to make sure that we don’t go with the person who has the loudest opinion. Emotion is the enemy of root cause analysis.

Topics include:

Define the problem – because sometimes it is more efficient to mitigate the root cause without eliminating it. We don’t need to eliminate the failure mechanism … we need to eliminate the effects of the failure mechanism.
Fred tends to use the ‘8D’ process which involves a strategic failure analysis approach with a heavy reliance on brainstorming.
Chris uses his own ‘illustrative strategy’ approach, where he summarizes the problem (and rectification strategy) with pictures. Sometimes, ‘Word’ document approaches don’t get the attention of the stakeholders.
Reliability engineers will never be as knowledgeable about the system as the people who designed it.
… which means that reliability engineers need to make sure there is a structured, strategic approach.
… and also means that designers may tend to focus on their ‘gut’ feeling.
… and there is always a desire to solve the problem ASAP – which motivates otherwise humans to jump to solutions without researching the issue.
The importance of measurement error and not assuming measurements are perfect (… the system may be perfect, but the measurement may not).
And perhaps most importantly, how organizational culture affects solving problems. If organizations punish people for speaking out, or stopping a production line when they spot something odd – then root causes will only become apparent once you have a catastrophic failure.

Enjoy an episode of Speaking of Reliability. Where you can join friends as they discuss reliability topics. Join us as we discuss topics ranging from design for reliability techniques, to field data analysis approaches.