Improvement Of Air Tightness Of Respirator Exhalation Valve Mask In Enterprise B Based On Six Sigma

As a personal protective device to protect human respiratory organs,eyes and face from injury,respirator is directly related to the health and life safety of users.With the development of social economy and the improvement of people’s safety awareness,the demand for gas masks is increasing.The front-line workers in some industries are in urgent need of qualified products to protect their own safety.The production and research of gas masks are widely concerned and valued.At present,the air tightness of gas mask exhalation valve produced by enterprise B is poor,which leads to the quantity of waste products and serious waste of product parts,and also affects the production efficiency.The problem of poor air tightness of the exhalation valve needs to be improved.At present,there are few studies on the air tightness of respirator expiratory valves.The causes and influencing factors of expiratory valves’ failure need to be further explored.Therefore,improving the air tightness level of respirator expiratory valves is of great significance to improve the overall performance and reliability of respirators.In this paper,Six Sigma method is introduced to solve the problem of bad air tightness of gas mask exhalation valve produced by B enterprise.According to DMAIC II process,MSA is analyzed by using measurement system to reduce the uncertainty of measurement process and ensure the reliability and stability of measurement data.The key variable factors influencing the airtightness of expiratory valves were found and screened by using the methods of Fishbone Diagram,C&E Matrix Analysis and FEMA.Then the easy-to-improve factors are improved quickly by lean method,and the flatness of valve seat seal is optimized by Moldflow flow flow analysis software through the combination of experimental design DOE and CAE,and the improved process scheme is verified by2-sample T-test.Through the implementation of Six Sigma Improvement Project,Enterprise B has finally achieved effective improvement of mask airtightness and reached the project goals,met the needs of customers,reduced the outflow of undesirable products in the production process,improved production efficiency and process capacity,and brought more economic benefits to the enterprise.The CAE method avoids the blindness of traditional injection process parameters test and shortens the development cycle of injection product process.The air tightness of the exhalation valve is characterized by the flatness of the seat seal,which provides a new way to improve the air tightness of the gas mask,and also provides a new way to improve and optimize the surface flatness of the injection parts.Finally,the comparison analysis and economic benefit evaluation of the improvement scheme are made,and the control plan is made to maintain the improvement results.The stability evaluation and monitoring of the improved air tightness level of respirator expiratory valves are made through the I-MR-R/S three-way control chart.