The Flexible Product Line Design And Roubst Scheduling Optimization In N-SC Chain Considering Setup Time

Today,more and more enterprises adopt the production mode of multi variety and small batch in fierce market competition.The production mode has the characteristics of little differentiation,obvious demand fluctuation,uncertain processing environment and so on.These uncertainties make rigid production structure and production scheduling system fragile.Besides,the setup time will affect production and scheduling efficiency greatly.Therefore,it is significant to study the production line design and robust scheduling with uncertainties considering setup time.It is vital to improve the enterprises' production efficiency.This paper proposes a production line design model and a product robust scheduling model based on S enterprise.Firstly,this paper reviews the definition of manufacturing flexibility,the measurement of manufacturing flexibility,the decision making of flexibility investment,and the robust scheduling.The valuable methods and their shortages are concluded in previous researches.Besides,the production management problems existed in S company are analyzed.They are less flexibility investment in manufacturing systems and low robustness in production scheduling.Based on this,N-SC chains and robust scheduling theories with uncertainties are researched.They can solve the problem of less flexibility in manufacturing system.Secondly,the analytic method is applied to calculate production increment of N-SC chains with uncertain demand.Then,the flexible benefit increment model of 'N-SC chain is constructed after corresponding probabilities are calculated.Considering price factors,the N-SC chain investment mathematic model is proposed with equipment investment theory.The research result shows that the optimal N-SC chain freedom of S company is 4.The production increment of 4-SC chain is 457.4 thousand if demand increase by 30%.Besides,the influence of demand fluctuation and different setup time to production increment are analyzed.Thirdly,based on fuzzy mathematics theories,a robust Flow-shop scheduling model is constructed considering setup time.In this model,the uncertain process time is represented by fuzzy parameters.Then,percentiles method is used to change fuzzy scheduling model into deterministic scheduling model.A genetic algorithm is designed based on the data of S company.The algorithm,astringency is well,and the satisfactory solution can be calculated quickly.The results show that the robust scheduling for 4-SC chains can save 4 hours compared with initial scheduling strategy(initial scheduling time is 25.5 hours)when 156 batches of products are scheduled.The robust scheduling can reduce the delay percentage caused by uncertain processing time.Lastly,the influence of uncertain processing time parameters,different setup time,order fluctuation to robust scheduling are analyzed.The advantage of robust scheduling scheme is analyzed compared with initial scheduling scheme.The robust scheduling scheme can offer a reference for company.