Research On Quality Control Of Soil Covering Roller In Producing Process

As the soil covering component of film covering sower, the processing quality of film covering roller directly affects the motion stability of soil covering mechanism, film covering smoothness and uniformity of the soil tract, which is very important to field operating performance and the working life of the sower. Film covering roller is produced mainly by manual work and the quality is uneven and difficult to guarantee. Six Sigma management is a data-based decision-making approach, which can achieve goals of defect prevention and troubleshooting timeliness. In this paper, Six Sigma management is applicated to control the quality of film covering roller in the production process, which can provide a new idea and method for agricultural products processing enterprises on the quality control.First, based on historical data and field research, Pareto diagram was used to determine the coaxiality of left and right halfshaft of soil covering roller as the key quality characteristic. The process was judged in a steady state by building key quality characteristic measuring station, designing the measuring program, collecting the data and developing control charts judgment process in an unsteady state. After calculation, the process capability has meet the requirement.Secondly, Fishbone and brainstorming was used to identify primary impact factors of the key quality characteristics: welding deformation of the outer circle, bolt tightening deformation, roundness tolerance of flange circle, roundness tolerance of adjustment ring, roundness tolerance of intermediate fixed ring and coaxial tolerance of intermediate fixed ring assembly. At the same time, in order to identify scientifically and effectly the key influence factor of the key quality characteristic, a economic FMEA model was proposed considering quality risk and cost risk based on the traditional Failure Mode & Effect Analysis model. In the proposed model, econimy, as the 4th risk factor, is defined. The fuzzy belief structure and grey relational projection method were used to do with the information of occurrence, detectability and economy of primary impact factors. And ultimately welding deformation of the flange circle and halfshaft was determined the key primary impact factor.Next, welding speed and welding sequence were identified as the second level key factors through literature consulting and field survey. The orthogonal design and the welding simulation software, Sysweld, were used. Through the main effect analysis and range analysis, the result shows that when the welding speed is 3.35 mm·s-1 and the welding sequence is II discontinuous welding, the longitudinal deformation of left and right halfshaft and the flange is the minimum amount.Finally, the regression equation of welding speed, welding sequence and welding longitudinal deformation was obtained by Minitab. With test analysis, the regression was proved accurate and reasonable. The improved result was proved by designing control chart with field test. Coaxiality of left and right halfshaft can be controlled within the desired range. Research in this paper provides a specific management and control method to improve the manufacturing precision of agricultural products.