Research On Quality Improvement Of Commercial Refrigerator In M Company Based On Lean Six Sigma

The National 14 th Five-Year Development Plan points out that the strategy of manufacturing power should be further implemented,and clearly mentions that the intelligent manufacturing project should be further implemented to promote manufacturing products to "increase variety,improve quality and create brand".Among them,product quality has long been an important source of gap between China and manufacturing powers.From design to production,to some extent,there is a lack of core competence to support the production of high-quality products.However,China’s small and medium-sized enterprises have begun to pay attention to the process optimization to reduce costs and increase efficiency so as to produce higher quality products.In this context,this thesis applies Lean Six Sigma related theories and methods to improve the quality of M Company’s refrigerator.On the basis of sorting out and referring to relevant literature at home and abroad,this thesis first elaborates the relevant theories and concepts of Lean Six Sigma.Using quality statistics and Pareto principle to analyze and find the M company’s refrigerators,especially the European model vertical two door refrigerator product of low through rate(87.37%),and then analyzes the causes of low through rate.Then,using Six Sigma DMAIC improvement method,combining with the principles and methods of lean production to improve the quality problems of refrigerator.In the problem definition stage,the key process output variable Y is identified by using 5W1 H and other methods,and the improvement scope is determined.In the data measurement and analysis stage,the variance method is used to analyze the reliability of Y measurement system,and the normal process capability analysis is carried out.In the stage of impact factor screening and analysis,causality graph and causality matrix are used to screen the impact factors of Y.In the improvement stage of the key impact factors,a single factor experiment design is carried out to determine the optimal refrigerant charging amount of 205 g.The error prevention method and the principle of motion economy is used to improve the leakage of refrigerant and the bending of the filling pipe.The height of the brazing table is improved by using the theory method of human factor engineering and the relevant standard data.After the improvement,the height of the brazing table is reduced from132 cm to 71.4cm,the height of the working face reaches 842 mm and the visibility and accessibility are improved.Then,the improved process and system are standardized by improving the standard operating instructions and other methods.Finally,in order to ensure the effective implementation of the improvement plan,this thesis evaluates its effectiveness and puts forward the guarantee measures for the continuous improvement of the refrigerator quality of M Company.The maximum membership degree of the effectiveness evaluation of the improvement scheme is 0.53 and the result is good.The results show that the management method of lean production and six sigma can effectively improve the quality of refrigerator.As the industrial cluster effect in the region where M Company is located becomes more and more significant,the scale effect also decreases,it will be an important growth point to use Lean Six Sigma to improve the process system so as to achieve the purpose of cost reduction and efficiency increase.In addition,the conclusion of this thesis will also have a strong reference significance to other similar enterprises.