Simultaneous determination of economic production quantity and economic control chart design under truncated Weibull shock models

In this paper, a FORTRAN computer program for jointly determining economic production quantity, inspection schedule and control chart design is presented. The program is written based on the work of Rahim. A Weibull distributed shock model having increasing failure rate is considered and age-dependent salvage value of the equipment is utilized. The notion of a truncated production cycle is introduced which begins when a new component is installed and ends with a repair after the detection of a failure or after a specified number of inspection intervals, whichever occurs first. The product quality characteristic of the product is assumed to be normally distributed and monitored under the surveillance of a control chart. The optimal values of the economic production quantity and the economic design parameters are determined by minimizing the total expected cost (inventory and quality control cost) per unit time. Both uniform and non-uniform inspection schemes are presented. For a uniform scheme, the length of the inspection intervals is kept constant. However, for a non-uniform scheme, the length of the inspection intervals is regulated to maintain a constant integrated hazard rate over each inspection interval.