Painting System Design For Heavy Transmission And Enhance The Quality Of Painting

This paper is based on the actual situation of China National Heavy Duty TruckGroup Datong Gear Company. The company is specilized on the manufacturing ofmidium and heavy duty truck transmission and engine gear. Transmissions are thedorminant products of the company and also of important part of automobile driveline.Their functions are mainly reflected on the following respects: a.reduce speed andincrease torque to change ratio and help engine to drive under the most favorablecondition; b drive backwards while the engine speed remains unchanged; c cut offdriveline for shifting and power output at neutral. Therefore, the quality of transmissiondirectly affects the user’s evaluation for the vehicle. In particular, the customers are moredemanding on the appearance of transmission in recent years, the transmissionappearance will not only affect the ecnomic efficiency of the enterprise, but also has agreat influence on the enterprise goodwill and image.In2008, the succesful enter to China National Heavy Duty Truck Group as itssubsidiary helped the company to diverse product range from single countershafttransmission for medium and heavy duty truck to single and twin contershafttransmission and transmission of planetary mechanism with torque range of100N.M-2200N.M for light, medium and heavy duty truck. At the same time, we modifiedthe coating process from top coating only to the combination of prime coating and topcoating. With the change of OEM, the matched vehicle models have been switched fromroad vehicle oriented to engineering vehicle oriented. The worse working condition ofengineering vehicle put forward higher requirements on the coating quality. The mosttransmission housing are currently of aluminum die casting instead of previous cast iron.Due to the high surface finish of aluminum die casting, the adhesion of coating is of morestrict requirement. In this case, the original coating process no longer meet the OEM’srequirement for transmission appearance. Over2years after joining China NationalHeavy Duty Truck Group, the zero-kilo failure caused by appearance was on a risingtrend, such as downgrade of paint adhesion, decrease of paint hardness, occurance offlow mark and other defects.In order to meet the rapid development of the company, we moved to new plant in2010. The original old painting equipment and painting process are not up to thedevelopment of the company, it is necessary to introduce new equipment and technology and take this opportunity to redesign the painting system. The paint coating according tothe standard performance test, and the coating was not standard project to study therecipe by selecting the optimal combination of experiments to improve the overallperformance of the paint coating to reach the standard.Firstly, the paper is to analyze the working condition, corrosive environment, andprotective period of the transmission and to design the number of layers, the thicknessand other indicators of the coating system, Then paint formulations studied, so that thepaint to achieve the best performance.and design the process flow, process layout, andpainting process, finally give detailed explanation for the painting equipment design bestadapted to the needs of enterprise and market demand.