عنوان مقاله [English]
In this paper, the influence of various factors on the quality of automotive coating appearance (NAP No., tension value, etc) such as coating layers, surface position, process conditions and film thickness were studied. Six-sigma method was employed to investigate and analyze the effect of the above mentioned factors. Via six-sigma methodology, the quality of factors was improved which in turn leads to improve the sigma level from 0.4 to 1.8 as well as increasing the quality of the product. Finally, the films thickness, flash off time, application temperature, grade of sanding and surface position were optimized .