Research On Assembly Quality Of Automobile Car Door Based On Dimensional Engineering

With the profound reform of the industrial system and the rapid development of the national economy,automobile manufacturing,as a highly integrated product in the heavy industry,plays an increasingly important role in the global manufacturing development system,and the competition among major automobile enterprises is becoming increasingly fierce.As an important part of automobile manufacturing,car body assembly forms a multi-link production system from parts to sub-assembly,sub-assembly to assembly,assembly to whole car.The problem of dimension deviation accumulation is the key content of automobile manufacturing industry.At present,the dimensional engineering technology is often used in the main engine plants to ensure the rationality of the design link and scientific size deviation management in the production stage,so as to control the size of the system.On the premise of meeting the whole car dimension target,the correct development of dimension engineering can effectively avoid a large number of dimension defect risks and identify key dimension deviation sources,and provide reasonable solutions to enhance the robustness and reliability of design,and ultimately improve product quality.As an important outer covering part of automobile,car door module not only plays an important role in the aspects of car performance such as wind noise,water resistance,door closing force,etc.,but also attracts customers’ attention on the appearance perception quality of automobile.However,the assembly of car door and body involves stamping and welding forming of many different sheet metal parts,as well as the size matching of many parts,resulting in complex structure,poor technology and large size fluctuation.In the actual manufacturing process,due to the door assembly sagging or the matching gap is uneven,which leads to the poor sealing and flatness and other defects,the consistency control of assembly accuracy is poor.Therefore,in order to improve the assembly quality of automobile car door,this paper analyzes and studies the door assembly quality using dimension engineering.The main contents of this paper are as follows:(1)The development status,workflow and deviation analysis method of dimension engineering were described,and the dimension control objectives and difficulties in the process of door assembly were clarified.(2)The sources of door assembly errors were induced,the various assembly schemes and tolerance transfer of the door were analyzed,and the gap and flush dimension chain in each area were established.(3)According to the assembly characteristics of the car door assembly,the dimensional accuracy capability of each single part,sub-assembly part and assembly part under different reference strategies was studied.(4)According to the door assembly scheme,taking the dimensional engineering method as the main line,the assembly deviation simulation analysis was carried out with 3DCS software,meanwhile the simulation results were analyzed.(5)Based on the manufacturing cost-tolerance allocation model,the door assembly tolerance allocation was optimized by multi-island genetic algorithm to improve the car door assembly quality.