Research On Bearing Line Quality Improvement Based On Lean Six Sigma

Bearing manufacturing industry has developed more than one hundred years,with a wide variety of products.Bearing manufacturing process is complex and has many processes.How to control the quality of the manufacturing process has become the focus.At present,the most scientific and effective quality management method is Lean Six Sigma theory,which integrates the methods and tools of Lean Production and Six Sigma,and the implementation effect is significantly improved compared with the single theory.Therefore,it is of great research significance to carry out Lean Six Sigma project to improve the process stability and product quality of bearing manufacturing enterprises.The tapered roller bearings produced by A Company have been largely repaired and scrapped due to the lack of process capacity of the production line,resulting in an unstable quality and output,a waste of cost and an urgent need for improvement.This study aims to carry out Lean Six Sigma method application research,systematically combine lean and six sigma tools and methods under the theoretical framework,improve the production process of tapered roller bearing products of A company in research practice,improve product quality and reduce production costs.First of all,by sorting out and analy zing the product quality data of A company,the problem of high repair and scrap rate of taper roller bearing was put forward,and the Lean Six Sigma was introduced to improve the problem.Secondly,through the analysis of bearing production process and process capacity analysis,it was found that the scrap rate of inner hole grinding process accounts for the highest proportion,and the production process fluctuates greatly.Fishbone analysis and cause＆effect matrix analysis were carried out for inner hole grinding process,and the key process quality factors were selected as conicity,squareness and ovality.According to the result of failure mode and effect analysis and hypothesis test results further filter out the two key factors influencing the scrap rate for driving plate flatness and grinding wheel connecting rod stiffness,formulate the improvement measures to adjust the driving plate flatness standard and the change of grinding wheel connecting rod diameter,to improve the process capability is verified.Finally,the verified effective improvement measures were solidified,the driving plate dressing operation instructions were updated,the diameter selection formula of grinding wheel connecting rod based on taper was proposed,and the reference standard for selection of grinding wheel connecting rod was formulated based on the formula to ensure the continuity of the effect.The results show that the process capability index of tapered roller bearing production line is significantly improved,the scrap rate is significantly reduced,the quality cost is successfully reduced,and the improvement effect is obvious.The success of this project provides reference for other bearing manufacturing enterprises to apply Lean Six Sigma method to improve product quality.