The Reliability Engineering Glossary
Reliability engineering and related fields use a vocabulary unique to our field of endeavor. For example, the term ‘reliability’ has the meaning of ‘trustworthy’ in everyday English use. For us, ‘reliability’ has a precise engineering definition.
Glossary description and plans
This glossary is meant to help us learn the language of reliability engineering. The category of ‘Terms’ is like a dictionary, including terms and their definitions as used by engineers. The category of ‘Methods’ is a listing of the techniques, tools, approaches, or concepts that may be found within a reliability plan. In the near future, we expect to expand the ‘Methods’ pages to include guidelines on use or application, examples, and additional references.
We also plan to expand the glossary to include formulas and failure mechanisms. Please let us know if there is another list of terms that should be added if you do not find a term that should be included or if you would like to recommend a change to an existing entry.
Method Categories
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- Control chart, proportion or percent categorized unitsAn attribute control chart for number of units of a given classification per total number of units in the sample expressed either as a proportion or percent. Read More
- Control chart, quality scoreA multiple characteristic control chart using different weights to apportion event values depending on their perceived significance. Also known as a demerit control chart. Read More
- Control chart, rangeA variables control chart used to evaluate variation in subgroup ranges. Read More
- Control chart, standard deviationA variables control chart used to evaluate variation in subgroup standard deviations. Read More
- Control chart, trendA control chart used to evaluate the process level with respect to the deviation of the sub-group averages from an expected change in the process level. Read More
- Control chart, variablesA Shewhart control chart plotting continuous scale measures. Read More
- Control limitPart of a control chart, line(s) used to judge the stability of a process. On a Shewhart chart, and others, these line(s) represent control limits, or action limits. Other than on acceptance control charts, the control limits are not specification limits. The lines are statistically determined(...) Read More
- Control limit, action limitsLine(s) on a control chart between which the statistic under consideration lies with a very high probability if the process is in-control. Action limits are typically set ±3σ from the center line assuming the plotted data is normally distributed. Read More
- Control limit, Lower (LCL)The line on a control chart that defines the lower control boundary or action limit. Read More
- Control limit, probabilisticLines on a control chart together with the center line define the interval where the process statistic under consideration resides with a very high pre-set probability if the process in in-control. Read More
- Control limit, upper (UCL)The line on a control chart that defines the upper control boundary or action limit. Read More
- Control limit, warning limitsLine(s) on a control chart between which the statistic under consideration lies with a high probability if the process is in-control. Warning limits are typically set ±2σ from the center line assuming the plotted data is normally distributed. Read More
- Control limits, ShewhartUsing empirical evidence and economic considerations, the lines representing the limits are place a distance of ± z standard deviations from the center line. The lines provide a means to evaluate the stability of a process, i.e. an in-control or out-of-control process. Read More
- Control planA process document describing the system elements applied to control variation of process, product or service characteristics and to minimize deviations from target values. Read More
- Copper stress migrationA failure mechanism in semiconductor devices. Due to the combination of different materials and process temperatures used in chip fabrication, the Cu lines in advanced Cu technologies exist in a state of tensile stress. When geometric configurations produce local peaks in stress and when such(...) Read More
- CorrectionAn action taken to eliminate a detected nonconformity (Reference ISO 9000:2015 3.12.3) Read More
- Corrective actionA documented design, process, procedure, or materials change implemented and validated to correct the cause of failure or design deficiency. An action that eliminates a detected nonconformity cause or eliminates an undesirable situation. Read More
- Corrective and preventive action (CAPA)A process initiated by the identification of a nonconforming or other unwanted outcome that may include root cause analysis, short-term and long-term solutions, and follow up to check on the effectiveness of implemented solutions. CAPA affords a means to track, prioritize, and avoid future(...) Read More
- Corrective maintenance (CM)All actions performed as a result of failure to restore an item to a specified condition. These can include any or all of the following steps: localization, isolation, disassembly, interchange, reassembly, alignment, and checkout. Corrective maintenance provides a process to identify and(...) Read More
- Correlation coefficientA number between -1 and 1 that indicates the degree of linear relationship between two sets of numbers, where 0 indicates no linear relationship. Read More
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