Multi-stage Inventory Control With Rework Process Under Fuzzy Demand And Defect Rate

Increasing competition among enterprises makes inventory cost control more and more important,and it occupies a large proportion of operations.The application of inventory control model enables the production manager to better determine the production or order lots so as to reduce the production cost.The product quality and demand of the traditional inventory model are perfect,and then the production and order quantities are calculated based on the known data.But in actual production,due to the steep fluctuations in market conditions,the network information increasingly developed,the enterprise is more and more difficult to grasp the product demand,and because the production system is not completely perfect state,so there will be incomplete,The demand and defect rate of the product is affected by the external environment,so it is uncertain.Therefore,Correctly handling the uncertainty caused by the external environment,balancing the costs and profits of the production system,and effectively controling and efficiently managing inventory are all challenges that need to be challenged..Therefore,compared with the classic inventory model,the inventory model under the fuzzy condition can solve the actual production problems more effectively.Firstly,building an inventory order model under certain conditions.Defect rate and allowable return conditions are added into the traditional ordering model.It is assumed that neither the retailer nor the customer will accept the defective product,so once the defective product is found through inspection,the supplier will accept the return unconditionally.Established the function of minimizing inventory cost when order quantity is variable.In traditional order based on the model,contrast the model and order containing defects and allow the return of the model,when the defect rate changes,changes in the number of returns,order batches,and expected profit per unit time with the defect rate,The results show that models that consider defects and returns have more practical value.Secondly,on the basis of the simple model,considering demand and defects in the practical production are unable to accurately determine,and general product is not completed by a simple phase but go through multiple production process,assuming that retailers and customers don't accept defective instruments,so through the inspection process found out takes heavy processing until a qualified products,construct a demand and defect rate as fuzzy variables,considering the multi-stage inventory cost model in the case of rework process,use symbols to blur distance method of fuzzy model,and design the double fuzzy simulation algorithm for the expected cost models,The conditions of optimal production volume and minimum expected cost are obtained.Finally,an example verification is carried out.The demand and defect rate are described with triangular fuzzy variables,and the fuzzy simulation algorithm is used to solve the minimum expected cost function model under 3 or 5 production stages,and the optimal production lot size and expected total cost of each stage are obtained,and the optimal production lot size is analyzed.With the changing law of demand and defect rate,it is proved that this model has more advantages in solving the problem of multi-stage production inventory.In order to propose a more effective method to reduce the total cost of production,the sensitivity analysis of the key parameters of the model is carried out,and the influence degree of each parameter change on the total cost of the production system is obtained.