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Related to Run-In: Run-in period
the first stage in the operation of a technical device, usually characterized by a level of reliability lower than that demonstrated during the period of normal operation. The lower level of reliability is seen in failures of the device caused by hidden defects, such as those resulting from errors in manufacture or assembly and installation.
During the run-in, devices that have failed and are not repairable are replaced; otherwise, defects are either eliminated by repair, or they may disappear by themselves as a result of changes in the dimensions and shapes of interacting parts. These changes are caused by mutual adaptation of the parts as they wear. Many devices are run in either totally or partially before they begin operation. The duration of the run-in depends on the physical properties of the parts and materials in the device.