Quality Improvement Study Of Medium Wheel Loader Axle Based DMAIC

Six Sigma is a method for analyzing and solving quality problems and controlling process variation using a systematic approach or statistical means,and has become one of the most important management tools for identifying improvement opportunities and driving system improvements.The axle is the core component of the loader,playing the role of support,steering and braking.Once the axle has a major or batch quality problem,it will bring a lot of rework and huge economic loss to the complete plant customer or end user.The paper investigates how to systematically improve the quality of loader axles by applying the DMAIC method of Six Sigma management in the context of the manufacturing process at the Company C Wuxi transmission plant.The paper uses the Six Sigma Management DMAIC method to systematically analyze and improve the manufacturing quality of loader axles.Through customer requirements collection and analysis of historical quality data,three key factors affecting axle product quality were identified: duo-cone seal oil leakage,parking brake rattling,and assembly manufacturing defects.To solve this problem,a project team was formed,improvement goals were set and an improvement plan was developed.For the duo-cone seal leakage problem,the potential influencing factors were analyzed by fishbone diagram,and then the key influencing factor was the height difference of the assembled duo-cone seal through hypothesis testing,correlation analysis and exploratory data analysis.For the parking brake noise problem,a one-way ANOVA was conducted to confirm that the height difference of the assembled combination seal could be improved by controlling it below 0.15 mm.For the parking brake noise problem,the key influencing factor is the parking brake clearance value through PFMEA analysis.After the confirmation of one-way ANOVA,it is concluded that the brake clearance control between 0.4mm～0.45 mm can meet the improvement requirements.For the assembly and manufacturing problem,the thesis improves the management’s attention to quality and agrees on quality objectives within the organization through the total quality management approach,while encouraging employees to actively propose and participate in quality improvement through quality activities and quality recognition,and continuously enhancing the quality awareness of employees through quality culture enhancement.Through this study,the manufacturing quality of the axle was significantly improved,while at the same time,Six Sigma management was more closely integrated with the daily operation of Company C.The team was able to better recognize the positive role of Six Sigma management in process improvement and further promote and deepen the Six Sigma management culture.