Surface roughness improvement for passenger car hood die manufacturing process

Abstract

Surface roughness of a die is a crucial factor for making a high-quality car hood. This research thesis is made for improving die surface quality in die manufacturing process. If the performance of milling process is not enough, it consumes a lot of time for doing polishing and might result in poor die quality that does not meet customer’s need. Therefore, the purpose of this research is to improve the CNC milling process. Tools used for milling and all relate parameters are studied in order to figure out the most appropriate condition for the finish milling process. Nowadays, a 1-blade cutting tool is used with 5,500-rpm Cutting speed, 4,800-mm/min Feed, 0.1-mm Dept. of cut, and 0.5-mm Pitch for doing the finish milling process.

Parameters in each machining condition designed by the program are inputted into the CNC machine for doing the milling process with a die specimen that is the same as actual of the company. All experiments are designed by the Surface Response Methodology; all parameters are analyzed by the program in order to find out the best parameters for use.

The result from this improvement shows that using a 3-blades tool with 11,670-rpm Cutting speed, 3,563-mm/min Feed, 0.1-mm Dept. of cut, and 0.5-mm Pitch literally provides the best result. This new machining condition significant decreases the surface roughness which brings about the elimination of polishing process, total time reduction, and cost reduction.