Study On The Improvement Of Production Key Process Quality Based On Lean Continuous Improvement Theory

With the advance of lean theory in FAW Jiefang Automotive Company, more and more lean theory and its methods are being applied in solving key issues of job site. One of the successful cases is the precision improvement of longeron assembly hole.Through the study of lean concept and continuous improvement theory, this paper puts forward originally the lean-continuous improvement theory as well as its 6 basic principles. After that this paper raises 7 kinds technology theory of improvement and summarizes systematically the 8 steps of improvement. Based on the relative theory and the comprehensive application of its methods, this paper studies the precision improvement of assembly hole of longeron, thus providing successful experience for quality improvement of finished automobile in the formation of improvement methods and quality control system.After the analyzing current situation of drilling technology of longeron, this paper sums up the diverse problems, then by using the methods such as 5w1h and so on, finds out the root causes affecting the accuracy of drilling deviation. Pointed to the root reasons we put forward three main tasks of improvement, they are improving manufacture techniques of drill plate to upgrade the precision of drill plate, improving the way of bit grinding to upgrade the precision of bit grinding, improving the means of processing to upgrade the processing precision. In order to realize the improvement target, we implement many kinds of measurement such as the design improvement of datum hole on drill plate, improvement of connection way between drill bush and drill plate, improvement of manufacturing technology of drill plate, applying the way of pickup and delivery by following activity in drill intensively grinding, improvement of stability between longeron and raceway. After improvement, hole place precision on the longeron (2801021/22-560) of tractor truck J5P 6*2 is upgraded from 84.8% to 90%,the longeron RTY and operation rate are upgraded from 90.9% and 89.7%, to 91.8% and 93.7% respectively. Meanwhile we draw up the instruction of standard operation of drilling procedure, set up the quality assurance system of key procedures in longeron production thus solidifying and upgrading the achievement of improvement.