Research On The Enhance Of The Efficiency Of Assembly Line Based On Six Sigma Management

Recently, the government has increased the investment in infrastructure, such as the projects on roads, cities, airports etc, to stimulate domestic demands. As is mentioned in the "12th Five-Year" plan, by 2015, the macroeconomic environment of China's construction machinery industry is very good. And the industry sales are expected to reach 900 billion yuan. In addition, the international market demand for construction machinery will reach 2,000 billion dollars, while Chinese exports of construction machinery will reach 200 billion dollars. The market capacity and growth of graders occupies a relatively large share in the construction machinery industry, so graders will have a big increase in demand in recent years In Southeast Asia, Africa, North America and other developing countries, the increasing of road construction projects year by year has opened new markets for grader. China Grader has advantages in resources and cost-effective, and is increasingly welcomed and valued by users in these countries. Its exports are also increasing every year. Generally speaking, the grader products have good present market sales and future sales prospects. And the sales volume grows at an annual increase rate of 20% to 30%. With the rapid surge in production, the existing plant and assembly line of engineering machinery manufacturing enterprises can not meet the needs, while new plants are under construction. Meanwhile, in order to meet market demands, to ensure sales, we have to analyze the assembly process through the DMAIC methodology of the Six Sigma management system, and to improve the problem through the definition phase, measuring stage, the analysis phase, the improve stage and the control phase. Finally we can raise the productivity of the entire assembly line in existing plant, equipment, personnel unchanged or less variable situation. The enhance of assembly line efficiency has practical significance to the increasing of the overall business efficiency and decreasing of production costs. As a typical engineering machinery product, Grader has characteristics of universal product components of different series and short assembly cycle. Considering these characteristics are similar to other engineering machinery products, this theory has theoretical guidance and practical significance to other engineering machinery assembly line. I hope the case study in this article can be extended in construction machinery industry according to the enterprises'special situations.The research thinking of this paper is to analyse and improve the grader assembly line of enterprises using Six Sigma management system, and to optimize and control the process optimization problems on the assembly line. The paper aims at improving the assembly efficiency, reducing production costs and enhancing the competitiveness of enterprises. Its main contents are as follows:1. Describing the research background, significance, status, purpose, content, and the key problems and solutions of the issue. As the world's most advanced systems, Six Sigma are used by almost all the five hundred of the world's top manufacturing companies, such as Ford, Caterpillar, LG, Siemens, Samsung and so on. The Six Sigma gradually moves from an quality management approach into a highly effective business process design, transformation and optimization techniques, and then became the pursuit of management excellence in the world's most important strategic business initiatives. Through the application of the five stages of Six Sigma process analysis, assembly line efficiency of grader will be ehanced. This will have a profound influence on enterprises, and make the enterprises has a solid foundation in the fierce competition in the next few years.2. Introducing the basic theoretical knowledge of the assembly line and the Six Sigma Management involved in the topic. Basic elements of the assembly line include operating elements and takt time, and the slowest link is "bottleneck" which will restrict the whole assembly task time. Six Sigma, regarding customer as the center and being used to improve satisfaction and loyalty of customer, is becoming a scale which is used to determine the objectives of corporate strategy and product development and design. Its core is the pursuit of zero defect production, preventing risks, reducing costs, improving productivity and market share and continuous improvement of a quality management philosophy. Based on this quality management philosophy and the several multinational companies's experience of implementing Six Sigma management, the paper propose the DMAIC model of implementation of Six Sigma, which is thought of a more operational mode.3. Giving an outline of the existing structure of grader and the existing assembly line of enterprise. Grader, produced by xuzhou xugong road construction machinery co., ltd, is widely used in national defense projects, mine construction, urban and rural roads construction, water conservancy construction, farmland improving and other fields. At present, the total assembly line of the enterprise is a u-shaped production line of leveled bi-circulating form. According to the workshop size and the structure technology of grader, the assembly line is divided into two parts ---assembly line of components and total assembly line. The region of assembly line of components can be divided into eight workstations, while the region of total assembly line is divided into nine workstations.4. Considering the status of enterprise, this paper give a comprehensive analysis of the assembly line of grader by using Six Sigma management system, and make efficiency of assembly line improve. In the paper, the problem is solved by the five stages of definition phase, measuring stage, analysis phase, improving stage and controlling phase. In the definition phase, the average task time, obtained by statistical data, is 1.5 hour per units in recent years. After setting goals, enhancing the task time of 1.4 hour per units, and setting up the team to develop the project schedule. In the measuring stage, the paper make analysis of Y measurement system, export SIPOC macro-flow chart, determine the scope of the project and make micro-flow. The major potential failure mode, determined by C & E Matrix and FMEA analysis, is insufficient number of traffic and interference between the workstation. According to data analysis in analysis phase, the conclusion is obtained that the amount of grader in advance a day is decided by the total first workstation. In other words, the total first workstation, considered as a special workstation of, is the best driving line. The task time increase to 1.2 hour per units after final assembly line is improved. Assembly four and five work in different groups to shorten working hours and improve its line of balance. The improved line balancing LOB of assembly line will increase to 76.4% from 64.3%, and the tatk time will increase to 0.96 hour per units. It is obvious that the target has achieved. By controlling phase, developing of standards, the process will run constantly in a new level.This paper analyzes grader assembly process based on the characteristics of enterprises. It uses the DMAIC model of Six Sigma management methods to identify the key factors which affect the efficiency of the assembly in process of assembling. Some of the factors are immediately improved. Those factors which can not be immediately improved will be taken more in-depth analysis in the next stage. Through the analysis of key factors, various factors that affect assembly efficiency can be found. These factors will be confirmed and perfected, and then standardized through the program files. Finally the efficiency of grader assembly line will be improved, and it will create significant economic value for companies.