Capacity And Plan Of Smpes Operation System Adapting To Complex Demands

Under the environment of CHINA’s reform and opening up for thirty years, the Small and Medium Production Enterprises (SMPEs) have been seizing the opportunity to develop rapidly, so that the number, size and businesses of these enterprises are growing up. The SMPEs are playing important role in the national economic development and social stability, it displays as follows:promoting GDP growth, improving the market economy system, absorbing social employment,increasing in government revenue and promoting industrial restructuring.However, due to the economic slowdown and the complex domestic and international market demand, coupled with problems of fierce market competition, rising labor costs and resource prices, difficulty financing and so on. Many SMPEs are facing a severe difficult for the survival and development. Under the current environment, the complex market demands are recognized as follows:diverse performance, process complexity, the number of demands changing in trend, cyclical fluctuations, random fluctuations and uncertainty demanding time and so on. Within the enterprise, it exists problems of low management level, weak planning functions, difficulty recruitment and high rate of frontline staff turnover. For the SMPEs operation system that the staff are playing the dominant elements on the line, these problems seriously affect the stability of production capacity. Dynamically changeable market demands and unstable capacity will result in a mismatch between the demands and capacity, so that enterprises are facing issues of imbalances production schedule, high WIP inventories, serious deferred delivery, instability product quality pass rate and poor operational performance. In order to minimize the frequency of these problems,control production costs, improve operational efficiency and enhance the management level and corporate reputation, the problems of capacity and guaranteed delivery decisions about the SMPEs operation system must be urgently addressed from the aspect of theory and practice.For the SMPEs operation system that the staff are playing the dominant elements on the line, the practical problems under the environment of complex demands are refinied as theoretical issues which are decisions of capacity facing to medium- short-term needs and guaranteed delivery facing to short-term needs.They are researched and solved by using methods and tools of modeling, simulation, optimization. Details are as follows:The form of complex needs is sorted and descripted through literatures review, including: the sort based on demand interval and the degree of change, the classification based on stochastic demand process, probability distribution model and function of time and price about demands.For the medium- short-term demands changing by trend, cyclical fluctuations, and random fluctuations, in order to meet the demand as far as possible and achieve a balance between capacity and demands, the capacity decisions of SMPEs operation system are researched that the goal is minimizing the total production cost and the research basis is the workers multi-skill, speed stable and dynamic balance of the line load. Details are as follows:(a) Irrespective of the random staff turnover rate of the line, for the seasonal fluctuations of multi-product demands and random fluctuations of single product demands, considering staff salaries and training costs, inventory costs, overtime and outsourcing costs, the number decision-making of the line’s workers is studied through nonlinear optimal model, discussion, analysis and of solving, and the sensitivity analysis about staff salaries and training costs coefficient, inventory, overtime and outsourcing cost factors, the manufacturing time of single product, mean and standard deviation of demands is carried out and relevant conclusions are drawn. (b) Respective of the random staff turnover rate of the line, for the trend change and cyclical fluctuations of multi-product demands, the number decision-making of the line’s workers is studied through a re-integration optimal function modeling, analysis and solving that costs include staff salaries, training costs and mismatch costs between capacity and demand; For a single product random changes in multi-stage demand, the number decision-making of the line’s workers is studied through double integral function modeling, discussion and analysis in consideration of the associated costs, the sensitivity analysis about the mean and standard deviation of worker turnover, mean and standard deviation of demands various cost factors and time factors is carried out and relevant conclusions are drawn. (c) Respective of the workers turnover rate of the line, for the multi-product demands of seasonal and trend changes, the four levels of capacity which are built by formal workers and temporary workers working hours are proposed, it carries out various schemes after comparison with demand hours and each level of capacity. On the basis of cases analysis and various parameters (including all types of cost factor and the time factors, the rate of temporary workers, temporary mass failure rate and other parameters) sensitivity analysis, the relevant conclusions are drawn.For the time sensitivity and random of the short-term demands, the number of workers at the beginning of the plan is the capacity constraints(the minimal capacity is built by workers normal working hours, the max capacity is built by workers normal working hours and overtime.), the guaranteed delivery decision about SMPEs operation system is modeled based on determined makespan that the custom demands, price and guaranteed delivery is the linear function in some intervals. It is discussed, analyzed and solved based on the function about demands, price and guaranteed delivery, the numerical example is analyzed. The parameters sensitivity analysis about the number of the front-line workers, the processing time per unit of product, the procurement and management costs per unit of product, factors of normal working hours and overtime costs, factors of delivery and price, the initial demand is carried out and some optimization strategies about delivery and cost are proposed on the basis of the sensitivity analysis.The study of this subject is funded by the National Natural Science Foundation of China (Name:Research about organization and optimization of SMPEs operation system adapting to the complex demands, number:71271060).