Reliability

Reliability is the ability of a process, machine, or measurement system to perform as intended over time. There is an underlying assumption that at one point, the ability to provide good results existed.

The most common cause of a drop in reliability is the degradation of equipment. As machines wear out, they become less able to provide consistent results. The curve depicting the output in question either shifts or widens, resulting in an area under the curve extending past the specification limit.

Reliability is closely linked to the terms “repeatability” and “reproducibility”. Reliability centers on the process or machine’s ability to provide consistent results over time.

Repeatability is the ability of an individual operator to get the same results from cycle to cycle. It focuses more on the person than on the system.

Reproducibility is the ability of two different operators to get consistent results. It is an indicator of whether or not both people are following the same process. The underlying assumption here is that the same equipment and materials are used.

All three of these terms are important in determining whether you will be able to get consistent results from your operation.

The single best way to improve the reliability of the system is maintenance. Again, reliability implies that at one point, the system was, in fact, capable of delivering good results.

It is also important to make sure you have a strong process in place to maintain your equipment. Review our total productive maintenance term to learn more about integrating your maintenance work with your production operations.