The Research On The Quality Improvement Of The Fuel Filter In SOFIMA (Changchun)

Sofima Automotive Filter (Chang Chun) Co., Ltd establishes in Aug. 2004, and in May 2005, begins to mass production, be as the independent proprietorship subsidiary company of Italy GGG group, it has two branding"SOFIMA"and"UFI". In the Filters trade, it is fifth in the world wide, Products cover high middle-and-low grade vehicles, be as single supplier for Ferrari.Sofima Chang Chun serves for FCC/FAW-VW/FAW Truck/Brilliance Group/Ha Fei Motor/ GreatWall Group for fuel filter, oil filter and air cleaner, and exports to Europe and America.This thesis introduces the difference of manufacturing engineering which producing aluminum fuel filter in domestic and overseas, at the same time, introduces the difference of quality management. Based on the quality principle and quality management procedure, we research its manufacturing process quality, especially the key process-Argon welding quality. For this, we establish a QM team to do this quality improvement, using the quality management software MINITAB.Quality management has two meanings: First, the quality characteristic has to be satisfied the request of the customers; second, the quality characteristic formation process should avoid defects.The quality characteristic have to been rightly defined quality to satisfy the request of the customer, with the accurate language to describe the product quality characteristic and full consider to the benefits and cost two aspects.For this thesis, the welding penetration is not defined by customer exactly, so we need to define the quality level according to the part service life and the quality level in similar trade. If it is too high, cost maybe improve, customer can not accept; otherwise, maybe can not meet the requirement. Finally, we define that the welding penetration is equal to the thickness of the part time 0.9. For this thesis, the welding penetration is defined≥1.08mm.The core characteristic of modern quality management is the highest customer satisfaction with the lowest resources cost. To customer, it means that acquire a satisfied product in time by the most acceptable price; to business enterprise, it means that carry out possibly biggest profits by the possibly small cost and the possibly short period. In Sofima Chang Chun, we can use the advanced welding technology---laser welding to realize this improvement fully, considering the requirement of capacity, we need to use the import welding machine, the cost is higher and the lead time is longer, and it is difficulty that customer accept this higher cost, so we decide that we carry out this quality improvement based on argon welding.We do this quality improvement according to PDCA procedure, at the every phase, we describe the questions and it's source detailedly. The key process of PDCA is Plan phase; we only find the root cause to settle it. First, we statistics all of defects by Column diagram, then compare them by Pareto chart to find the welding penetration is the major defect, it is about 80%. The manifestation of welding penetration is various, for example no seaming. Third, we analyze its cause by Cause and Effect chart from 5M1E (man, machine, materials, method, measure and environment), in this process, we discuss all of influencing factors by Brain Storm. But in these factors, which is the root cause? So we use Causal analysis matrix to calculate the effect degree of every factor form the final customer position, finally, we find the key factors, so the welding current, the position of tungsten pole and the distance between the tungsten and base metal be as the improvement emphasis. But we find that it is not enough that only optimize these 3 parameters, the precision of frock determine the position of tungsten pole, and the precision of inspection machine determine the result of inspection, it influences decision-making of QM team, so we make a detailed improvement plan. Updating the tooling and the inspecting machine, then optimize the process parameters.First, improving Argon welding machine and inspecting machine, according to the technological characteristics of argon welding, combined with the enterprise's actual situation. We define the welding penetration is the key indicator, because it influences the welding strength and part's service life directly, and part's leakage. But the factors of affecting the welding quality is various, the consequence is different too, so it is very important how to control the argon welding parameters. So we optimize the parameters by DOE to reduce the quality cost and improve FTT(FIRST TIME THROUGH).Finally, the fact shows this quality improvement is effective through several rounds of experiments and small batch production verification. We follow this project for six months, find that the defect rate is reduced about 60%, PPM is reduced form 80000 to 25000, FTT(FIRST TIME THROUGH) is improved observably. And reduce the quality risk from bad welding penetration, improve customer satisfaction. Although it does not show the direct economic benefit, the input for this improvement can be taken back by the saving cost in six months.Now, our company have more than 30 kinds of argon welding parts, we apply this improvement to the others, the quality can be improved too.Quality improvement is a continue activity, we realize its importance of quality improvement by this action, this is a beginning, we decide to carry out more improvement activities in company. In the meantime, this improvement result is profound, it changes the management idea of SOFIMA, pushes improvements in SOFIMA group.Quality improvement must be carried out if enterprise wants to develop, it is the only road which the enterprise improves overall level.