An inspection model for a process with two types of inspections and repairs

This paper considers a problem often met in practice. A production process may be subject to two types of deteriorations. The first is a shift in product quality caused by minor process defects that may be identified and rectified by routine inspections and repairs. The second is a major defect caused by a major mechanical or electrical problem that can be observed only when the defect has led to a breakdown of the process or the defect is revealed by a major inspection followed by an appropriate major repair action at the time of the inspection. We formulated an inspection model for the above problem and aimed at optimising the inspection intervals for both types of inspections. A numerical example is given to demonstrate the applicability and solution procedure of the model.