Presented in the paper is a methodology to remove burrs from parts produced by press machines. Burrs of press parts can cause various problems such as the dimensional quality of the part and even the safety of operators. This paper employs the six sigma methodology to accomplish the objective, burr free products. To find the source of the burr, we identify seven potential factors; clearance, material properties, punch wear, skill levels of operators, champer difference of C & R type, vibration of C-type press, and lubrication oil. Through an extensive experiments, we extract three key factors; clearance, punch wear and champer difference of C & R type. For the three key factors, we propose an optimization method and the result is very positive.