Research On Modeling And Optimization Of Make-to-Order Enterprise’s Operation System

Most of enterprise adopts Make-to-Order (MTO) in China. MTO enterprise can better meet the diverse and individual demand, but it has to face the impact of market demand, casing product quality is unstable, lead time frequently delays and capacity is inefficient. So this dissertation researches on modeling and optimizing the enterprise, including modeling the operation system, optimizing the lot sizing, the capacity, and the lead time guarantee and capacity.(1)Researching on modeling the MTO system. Considering the MTO system is Discrete Event System.①Building up the model of MTO system by Generalized Stochastic Petri-Net, and then constructing a simplified and equivalent Markov chain to analyze the average of productivity and lead time by the retire mark method. ②Building up the model of MTO system by Colored Petri-Net, and then constructing the monitor functions to analyze the performance of current status and the sensitivity of indexes.(2)Researching on optimizing the MTO lot sizing.①Building up the model of quantity of putting into production as the product pass rate is uniformly distribution or normal distribution. We obtain the optimal quantity of putting into production by solving the model. ②Building up the model of quantity of putting into production for the producer-vendor supply chain. The optimal quantity of putting into production which can make the vendor’s expected loss of sales minimize, and also can make producer’s expected loss of putting into production minimize. ③Building up the model of lot sizing with random demand and random yield. We prove that the objective function is a concave function, and getting an equation which the optimal lot sizing must meet.④ Building up the model of lot sizing in view of outsourcing collaboration, and obtaining the suboptimal lot sizing by Genetic Algorithm.(3)Researching on optimizing the MTO capacity. First, Building up the model of single-stage capacity of single-product. The optimal capacity is the inverse function of demand distribution function with the variable of out of stock unit cost, capacity maintained unit cost, capacity purchased unit cost, and capacity time discount rate.Second,Building up the model of single-stage capacity of multi-products, and getting an equation which the optimal capacity must meet.Last,Building up the model of multi-stages capacity of product life cycle, and proving that the optimal capacity has three stages:capacity expansion, capacity maintenance, and capacity shrinkage.(4)Researching on optimizing the lead time guarantee and capacity. ①Building up the models of M/M/1 and M/D/1 by considering the demand is sensitive to lead time and the process of production.The optimal solutions show that promised lead time and capacity expansion have the relationship of Nike, and the values of them are restricted by the lead time reliability.②Analyzing the relationship between capacity, demand and lead time guarantee by Activity-Based Costing to build up the model of lead time guarantee and capacity,and then we obtain the optimal solution of model.