Natural fiber is a hairy like raw material which comes from natural sources such as animal, plant, and mineral fibers. Kenaf fiber known with scientific name as Hibiscus Cannabinus is one natural fibers which becoming popular as a reinforced for plastic composites material in the industrial application such as automobile, aircraft, and marine engineering. However, milling these materials present a few problems, which are surface roughness and delamination factors are appear during the machining process, associated with the characteristics of the material and the cutting parameter. The objective of evaluating the cutting parameters (spindle speed, feed rate, and depth of cut), the influence of the fibers under surface roughness (Ra) and delamination factor (Fd). In this research study, Response Surface Methodology (RSM) was used to conduct the experiment. In addition, this method established considering milling with prefixed cutting parameters using HSS end mill. The experiment result was analyzed using Design Expert software. It was found that the optimum parameters for the minimum surface roughness and delamination were spindle speed at 2000 rpm, feed rate at 300 mm/min, and depth of cut at 2.0 mm. The spindle speed and feed rate are the main factors influence the effect of surface roughness and delamination in kenaf fiber reinforced plastic. High spindle speed and low feed rate resulted in minimum surface roughness and delamination.
