on Product Reliability

A common tool for comparing if two populations are the same is the “student t-test.”  This is often used in reliability, and science, if we want to investigate if a factor has caused a change in a respnse.

A population was assembled in location “A”.  Another population was assembled in location “B”.  Population “A” has an average defect rate of 4%.  Population “B” has an average defect rate of 5.5%. Does the location of assembly affect defect rate?  That’s just a big argument unless we can project the statistical likelihood that what we have measured is not just an overlap of noise. [Read more…]

The bane of our existence is one thing, generating enough data to demonstrate statistical confidence.  Every reliability engineer, every project manager, every Director and VP all have the same moment of panic in a new product development program.  In synchronicity they put their head in their hand.  It’s when the required number of test units and calendar time to demonstrate a required confidence in the reliability goal is calculated.  It’s usually about ten times more units than can be acquired and about two times longer than the entire product development program timeline.

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I was teaching a class on Reliability 101 a few years ago and it turned out to be one of those great classes where debate and discussion would just pop up all over the place.  I frequently start my classes with “If I end up being the only one speaking today I am going to take that as an indication of complete failure in having engaged you in this material.”  So I was loving that this group were starting to debate each other on the material we were covering.  I wasn’t even in some of the conversations.  This rich environment is where I just spurted out one of my more memorable reliability quotes. [Read more…]

We, as developers, create designs that we call “our own.”  Rarely are the materials for our in-house manufacturing process raw steel, rubber, and glass, like Henry Ford had feed into the Ford factory in 1930. Our manufacturing process receives a mix of materials and fully functional sub assemblies from other technology companies. It’s unlikely the PCB electronic components, bearings, motors, gears, drivetrains, sensors, power supplies, harnesses are ours. Why would you design any of these with so many options available made by specialists?  This results in us having little input or control in the development and demonstrated reliability of our entire product. [Read more…]

The Pioneers rarely reap the rewards of new discoveries.  It’s usually the settlers that really profit from the new expansion.  Many companies, especially small ones striving to get into a market, bet on a big technology breakthrough to get their foot in the door.  As consumers, we do eventually become aware of “the others” once the market for that technology is in motion.   “The others” were quietly watching and diligently developing the improved version based on the experiences of the pioneer’s first take. [Read more…]

The Vasa is a Swedish ship that was constructed between 1626 and 1628.  It is a great story of an engineering disaster,  well that’s how it is labeled. It doesn’t take too much investigation to see it is really a leadership disaster.

I saw the Vasa in beautifully restored condition at it’s museum in Stockholm Sweden.  It was retrieved from the ocean floor in 1961.   Amazingly after almost 300 years it was intact and well preserved in the freezing waters off Sweden.  This is it’s story… and warning! [Read more…]

The importance of reliability education in a product development program cannot be understated.  A design initiative with mechanical content can be created solely by the mechanical team, same for electrical, and software.  These other disciplines will create a better product if they collaborate from the start, but this is not necessary. A successful product can still be created if they intersect later.  Reliability doesn’t have this flexibility.  Reliability tools don’t have a deliverable like a function or a feature.  They are an assist for the function or feature during the process of creation.  As an assist discipline, it only works if implemented while the other processes are in motion.  Attempting to add it after the design has been completed requires a deconstruction of the previous work if improvements are needed. [Read more…]

I just returned from the IEEE ASQ Accelerated Stress Test and Reliability Conference, held this year in Austin, Texas.  It’s always been a great conference. There is such a good comradery and sharing of knowledge when a large group comes together on such a specific topic. I meet a lot of great people from many different industries, all with great experience to share. [Read more…]

Confidence is used in reliability to give a probabilistic value to the likelihood that a taken measurement will represent a full population.  It is determined by measuring a sample size and then using a selected statistical distribution table to translate to a likelihood. Emotional confidence is how one feels about making a decision based on known information at a specific point in time.   Similar but different. But it is important to connect them.  This is why. [Read more…]