BURN-IN AND ITS APPLICATIONS

Burn-in is a widely used method to improve quality of products after t hey have been produced. Particularly, this method is useful when the f ailure rate of the product exhibits a bathtub shape. The choice of the burn-in time depends on the criterion chosen. Both the cases with and without consideration of cost are discussed. When the cost is our con cern, the expression for the cost incurred during the burn-in procedur e is obtained. Based on this and the cost and the gain in field operat ion, several cost structures are proposed. For some of them the mainte nance policies or warranty policies are also combined into the conside ration. For all these cost functions it has been established that the optimal burn-in time carl never exceed the first change point of the b athtub shaped failure rate. An example, however, is given to show that this conclusion is not always true for some other cost function(s).