Why Test?
by Complete Test, INC.

     Before designing and creating a test system you may ask yourself, or more likely your management may ask you "Why are we doing this?  If  it works, ship it."  After all, testing can be expensive and time consuming.  You should have some reasons for doing it.  Testing provides the means to be able to judge the product.  It gives you the yes/no decision to ship.  If you can show that testing will save money in the long run, so much the better.

     There are benefits to testing products.  Marginal units may work while in the factory, but then fail immediately or shortly after the customer takes it home.  Not only does this cost you in warranty claims, but the perception of poor quality will cost you future sales to this customer and to the friends and relatives as well.  Ensuring the quality of all units shipped to customers will save you money and promotes good customer satisfaction.

     But testing can even go further than that - without further cost. You may be shipping products that will work satisfactorily for the warrantee period, but your process is headed for disaster.  By testing and keeping Statistical Quality Control Charts you can tell if your process is drifting or beginning to fluctuate wildly - even if the product is still working.  This early feedback on the manufacturing process will give you time to investigate and correct the problem before it gets to the point of having to shut the line down.  And on the positive side, Quality Control Charts may show that your process is better than you thought.  You may be able to improve your spec sheet and boast of this performance.

     When a Contract Manufacturer handles production, testing provides a way for the CM to prove the quality of their work. Compliance with ISO 9000, 9001, MIL spec, safety or other standards can also be shown by testing.  Indeed, these standards may require testing, making the question of "Why Test?" irrelevant.

     In addition to production testing, testing can also be done in the R&D or prototype phase of the project.  A burn-in test may show the weak areas of a design.  An accelerated test can give a statistical prediction of the failure or drift rate.  Is the failure rate acceptable?  Does the drift rate result in an undesirable calibration cycle?  Putting more work into these areas or buying the better part will improve the design and give the customers the quality products that they desire.

 

  Why Measure?
by Complete Test, INC.

     Measurement is a journey of discovery.  It shows you what is going on in a product or in any phenomena.  It gives you a basis to understand these things.  While a measurement may be used as part of a test, the measurement itself merely provides qualitative data - a gathering of information, whereas the test asks for a judgment call on whether or not that data is acceptable.

     A series of measurements may be used in the design phase of a product.  They show you what the design is capable of.  At this point you still have a choice.  You can either set the product specifications based on these measurements, or you may improve the product design to meet expectations.