Warranty is a contractual obligation incurred by a manufacturer (vendor or seller) in connection with the sale of a product. In board terms, the purpose of warranty is to establish liability in the event of a premature failure of an item or the liability of the item to perform its intended function. One of the commonly used warranty policies, especially for electronic and mechanical products is free replacement warranty (FRW). Under FRW, the warrantor agrees to repair or replace any failed item up to time W (the length of the warranty period), from the time of purchase, at no cost to the costumer. An effective warranty servicing strategy is essential in reducing manufacturer’s warranty servicing costs and increasing profits from product sales. Warranty claims are not always due to product failures. They can also be caused by human factors. A model is proposed to investigate the effect of human factors on warranty cost under sales delay conditions. The model is considered under two types of failures, namely fatal failures and intermittent failures and two types of human factors. Also the case of sales delay is considered in this model. Finally, the proposed model is evaluated by a numerical example.
