This project (PSM) is carried out with the purpose of studying the suitable cutting parameters when using machining process on workpiece. The scope of this study chose a CNC milling operation for machining process and spindle speed, and feed rate for cutting parameters. The workpiece were used in this project are aluminum, brass, and copper and High Speed Steel (HSS) as the cutting tools. When the process machining is finish, the surface roughness of the workpiece will be measured and analysis on it. The relationship surface roughness between spindle speed and feed rate is will be show by graph plotted, where surface roughness (Ra) versus spindle speed ~d feed rate (Rmax). From the experimental results, it can show that' s a particular spindle speed, and feed rate produced the different surface finish.