An Integrated Economic Production Quantity Model Consedering Rework And Failure Recovery

The traditional economic production quantity models often considerthe production process is perfect. But it’s not true in a real productionprocess. Because the equipment will behave a continuing recessionphenomenon caused by failure, parts corrosion, fatigue, wear of machineryand other factors. Therefore, after a certain period of time, the productionprocess state will be changed to uncontrolled state from controlled state.Aiming at the imperfect production process, the quality loss will be addedand the rework of rejects is considered for a certain degree to reduce theloss of cost.In a real production process, we usually use an unreliable processsystem, the unavoidable failure can change the rate of qualified products,indirectly influence the total cost per unit time. Therefore inspection,preventive maintenance and repair work usually be done regularly. How toset the number of inspection and time between inspections reasonably, andmake preventive maintenance and repair work plans effectively whileavoiding the cost burden brought by over-maintenance and inspection isalso the key point in this article.Based on the balance of traditional holding cost and setup cost,adding quality loss cost, rework cost, repair cost, maintenance cost and soon. Then the asymmetric Taguchi loss function is used to show the qualityloss cost to fit the actual production process. In this article we consider twoconditions about the model, one is considering rework only the other one is considering fault recovery and rework together. In the foundation offunction, this model is to find the best economic production quantity aimedat the minimum total cost per unit time. Finally the example is given tovalidate the model by numerical analysis. Under different initial condition,we find the numerical solution of the best economic production quantity,best inspection numbers and interval, production cycle, preventivemaintenance level and so on. We also conclude the factors to influence thecost.