on Product Reliability

A helpful analogy  in communicating the concept of statistical reliability confidence is the “new airplane” example. Let’s say I am developing  an entirely new technology for airplanes. The airplane has an engine that has never been used before for air travel; a fusion engine. I tell the world that this new airplane with a fusion engine will have a reliability of 99.99999999%, the highest any airplane has ever had. It’s not possible to fully demonstrate this reliability until every single unit of this airplane has been produced, used to full life, and the full fleet is retired.  As long as one is still flying it can add or subtract from the reported reliability number.  So, how do we make decisions at product launch regarding the design’s reliability?  No products have yet to be produced or used by customers, so how can we trust the design?

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There is a lot to be said for having a plan. Now, I’m not saying I always operate with a plan.  In my personal life, I tend to shoot from the hip, so to speak, and those that know me would undoubtedly describe me as impulsive.  As evidence of my spontaneity, I can cite a few  ever-morphing construction projects that had to be half redone once the final was denied  as well as dinners that ended up tasting a little weird because the recipe was composed of whatever I could find. Neither of these scenarios have devastating consequences when they are over budget, late to delivery or  kind of suck as far as accomplishing the original goal. We can always fix the weird porch extension next year and if you really don’t like my chicken, rice, tartar, mustard and olive dish then just order a pizza.  [Read more…]

There is an issue up for vote this year in my home state of Massachusetts. It’s called “Right to Repair.” The proposed law states that automotive manufacturers can not lock owners and independent repair shops out of vehicles on-board diagnostic computers. These are the arguments on either side of the issue:

Auto manufacturers don’t want independent repair shops completing work on their vehicles with technicians who are not factory trained. They are also concerned about repairs being completed with non-factory parts that could potentially be sub-standard. These manufacturers believe they should have control regarding repairs because they are held responsible when issues occur under warranty. So why is this an issue now?

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Sometimes we can only test one use case before we ship our product. So what should it be? Should it be the hardest use case? The nominal use case? The 95th percentile use case?

No! It should be the “midlife crisis use case.” What is it? I’ll show you.

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Well, it’s time for another exploration in Use Case 7. Unfamiliar with UC7? It’s simply when customers do unexpected things to our products. We often ignore it, but in fact, it is one of our best ways to learn about our product’s reliability. [Read more…]

This is a direct followup to my post last week.

I usually don’t do two part posts but….

I got some great responses to my post last week.  I then got this image from my buddies at NASA (on the ground, not on the space station). One is actually my roommate from college. His hair is much shorter now.

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Sometimes I see images that speak strongly to how reliability engineering affects us everyday.  Think of how many items you own or use systems that you wouldn’t touch/interact with if  you couldn’t be absolutely sure they would work as expected. I wouldn’t use my microwave if I thought there was a 1/1000 chance it would catch fire.  The amount of faith I have in traffic lights working correctly is astounding.  If they malfunction it could be fatal.

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