This study aims to optimize the manufacturing time when surface grinding carbon steel. To access effects of input parameters on replaced grinding wheel diameter for minimizing the manufacturing time, eight parameters consisting of the initial diameter of grinding wheel (Do), width of grinding wheel (Wgw), total depth of cut (z), ISO grade numbers of surface roughness (Ns), Rockwell hardness of work-piece (HRC), radial grinding wheel wear per dress (Wpd), total depth of dressing cut (aed) and wheel life (Tw) were investigated as input data. An experimental design with a 2-level factorial design with ½ fraction was set up, and 128 (2(8-1)) experiments were performed. Also, to access the effect degree of input parameters on output responses, the Pareto chart and Normal plot of the standardized effects were established and analyzed. Using linear regression method, a mathematical model, which shows the relationship between the optimal replaced grinding wheel diameter and the input parameters, was also proposed