If you are reviewing a drawing or set of specifications and all the tolerances are set at a blanket value, this should raise your suspicions, for it implies that every tolerance has the same importance as all others. This may be true, yet it is often not possible nor necessary for the design and resulting system to function correctly. Continue reading
In a previous posting (Creating a Reliability Plan – Starting Points), I introduced the two basic philosophies for creating a reliability plan for a new product or system: the build, test, fix, approach, and the analytical approach. Combining these two styles in a balanced approach leads to the best results. In this posting, I want to get more specific and outline the 7 basic steps to follow to create a sound reliability program. Continue reading
There are two basic philosophies for creating a reliability plan for a new product or system. One is to experiment with prototypes as quickly and often as possible: This is the so-called build, test, fix approach. Alternatively, you can research and model detailed aspects of the materials and structures to characterize the strength of a product or system: This is the analytical approach. Both methods have obvious applications and not so obvious limitations. Continue reading
Accelerated life testing (ALT) provides a means to estimate the failure rate over time of a product without resorting to normal use conditions and the associated duration. In ALT, one uses a variety of methods to compress time. Continue reading
Reliability testing to determine what will fail or when the failures will occur can be expensive. Organizations invest in the development of a product and attempt through the design process to create a product that is reliable. The design process has many unknowns though. This includes uncertainties about materials, design margins, use environments, loads, and aging effects. Using the best practices of design for reliability will minimize this list of risks to product reliability, yet it will not resolve all the uncertainty. Continue reading