Testing the corners

Nope, this blog isn’t about test-driving a sports car, although a guy can dream.  Rather it’s about testing products at the various corners, not just at nominal. Which we do a lot–part of our We Design, We Test, We Break Things mantra.

So what’s a corner?  It’s when two or more use or process parameters are at an extreme. For example, a sports car designed to operate from -40 °C to +60 °C and from 85 to 100 octane fuel(hey we don’t actually design sports cars so this is just an example) should be tested at the following corners:

  1. High temperature  / High octane
  2. High temperature  / Low octane
  3. Low temperature  / High octane
  4. Low temperature  / Low octane

If there are N parameters, there are N squared corners. Of course some corners may be unnecessary–say if we wanted to test High snow or Low snow, the High temperature / High snow corner could probably be neglected.

While we neither design nor test sports cars, we do work on a stupidly wide variety of products, from clean-tech widgets to baby products, electric bikes to scientific instruments. Beyond that,we are involved from everything from very early engineering verification tests (EVT)  to formal design validation testing (DVT)  and even(especially) factory floor production testing. Early testing may be quick and dirty–we recently did – 10 °C to + 40 °C EVT testing utilizing cold Colorado mornings at one extreme and an impromptu sauna thanks to two space heaters-to full on regulatory testing at a certified lab (not us, but we know who to call). Besides temperature, other corner parameters could include humidity, operating voltage, tension, as well as physical tolerances, torque settings and a zillion or three other parameters.  And of course a good dose of Design of Experiments is needed when the number of corners gets excessive.


PS: If anyone wants to loan me a Tesla, I’d be more than happy to test its corners.  As long as slow isn’t one of the parameters. No charge.

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