Initial failure period

Bathtub curve (failure rate curve): In the period from equipment installation until entering the random failure period, the failure rate decreases sharply. This period is characterized by a high occurrence of failures called initial failures, which are caused by defects in the design and manufacturing stages of the equipment. As the causes of failures are identified, initial failures rapidly decrease, leading into the random failure period. In particular, when a model change results in the renewal of components, there tends to be a higher incidence of initial failures due to the lack of failure data.