Abstract:

A patented technology of micro hole laser engraving on the front bumper was adopted in the Geely Galaxy E8 car. In this technology， some elements such as sound， light， and electricity were added to obtain the world's first mass⁃produced integrated luminous front face， solving many problems such as inconsistent front bumper colors and multiple parts that require grille design for a car luminous front bumper. The feasibility of the integrated luminous front face was demonstrated from several aspects such as laser engraving sequence， laser engraving background color， laser engraving size， different post⁃processing methods， and different colors of paint. The results indicated that adopting front side laser engraving was superior to the back side laser engraving technology， which could avoid the problems of difficult shading and low qualification rate due to a requirement for spray painting on both sides. Adopting a substrate exposure scheme was more optimal to avoid adding primer even if primer was not used to directly laser engraving onto the substrate. Each of spraying and baking increased once， which increased the difficulty of construction， lowers the product qualification rate， and posed a higher cost risk. The micro hole laser engraving technology was superior to large hole laser engraving， which avoided the problem of large hole laser engraving. The laser engraving features were obvious， and there were black shadows on the boundary of the laser engraving features. Moreover， the exposed substrate was prone to yellowing after being light resistant. The 3⁃coating and 1⁃baking process cannot be used according to the requirement for design scheme of the front micro hole laser engraving. Wet paint can cause blurred laser engraving boundaries， and the 3⁃coating and 3⁃baking process consumes a lot of energy and is also complicated. Therefore， the 3⁃coating and 2⁃baking process is preferred， and all paint indicators can meet the requirements. Different colors of paints， differences in pigments and paint formulations， and demand to adapt to laser engraving parameters can also lead to differences in paint adhesion.

Key words: integrated luminescence, paint, laser engraving, adhesion