Analysis And Improvement Of Manufacturing Quality Problems Of Company A

With the rapid development of China’s economy and the increasing demand for urban travel convenience,subway construction has entered the fast lane of development.By the end of 2019,the domestic metro has covered 40 cities,with a total operating mileage of 5180.6km.The scale of subway construction is huge,and the demand for supporting facilities is increasing.How to improve the quality management level of supporting facilities manufacturing enterprises is of great significance to ensure the quality of subway construction and safe operation in the future.Based on the investigation and data collection of the quality management status and manufacturing quality of a company’s subway structural parts production line,this paper analyzes and improves the three outstanding quality problems,such as:wrong welding of welding process and missing plating of hot-dip galvanizing process of structural parts 1、thin zinc layer of hot-dip galvanizing process of structural parts2.The main research works of this paper are as follows:(1)Based on the introduction of company A and the technological process of its core products:subway structural parts,this paper analyzes the current situation and shortcomings of enterprise quality management,and uses seven QC techniques such as arrangement chart to analyze and determine three outstanding quality problems in the manufacturing process of the enterprise,and finally introduces the research methods of the paper.(2)Aiming at the problem of wrong welding in welding process of structure part 1,the welding process flow is analyzed based on the process method.Six root causes of wrong welding are analyzed and determined by using the brainstorming method and correlation diagram.Combined with the demand analysis,process card and QM analysis,the quality improvement measures are put forward.The implementation results show that the defect rate of welding process of structure part 1is reduced from 14.07% to 3.81%.(3)Aiming at the problem of missing plating in the hot-dip galvanizing process of structure part 1,the hot-dip galvanizing process is analyzed based on the process method;26 potential factors that cause missing plating are analyzed by the causal analysis table,and 10 key factors that cause missing plating are determined and classified by further data analysis;three improvement schemes are put forward and evaluated by the selection matrix to determine the final result,The results show that the defect rate of hot-dip galvanizing process of structure 1 is reduced from 15.02% to4.77%.(4)Aiming at the problem of thin zinc layer in hot-dip galvanizing process of structural part 2,the Six Sigma method is used to analyze and improve according to the DMAIC process,and the thickness of zinc layer is determined as the key quality characteristic CTQ,In the measurement stage,the process analysis,process capability analysis and measurement system analysis MSA are carried out,The four factor and two-level full factor test design method is used to analyze the data of the experimental results and determine the results The results show that the capability index of hot-dip galvanizing process is increased to 1.37,the thickness of zinc layer reaches the target,and the defect rate of hot-dip galvanizing process of structure 2 is reduced from10.02% to 2.15%.Finally,the process optimization scheme is made in the control stage.The research of this paper provides some reference value for manufacturing quality control of urban rail equipment manufacturing industry.