The incorrect slitting is the defect waste in slitting process which does not meet the single pack width and crease-to-edge width requirements. It is the highest contributor to the overall defect waste in slitting process at Company X Jurong (CXJ). To address this problem, the key input and output variables were identified. The inputs are the tension settings and knives' positioning, and the output is crease-to-edge width. The objectives are to optimize the tension settings and to achieve a centered process by a proper calibration of knives' positioning. The Design of Experiments (DoE) was conducted to study the significance of tension towards crease-to-edge width variance. For 200 mL pack size, it was found that the variance is constant within the allowable setting range. For 250 mL pack size, it was found that the overall average variance best represents the variance of the data within the allowable range. However, the process is currently off-centered. Therefore, a proper training for detecting any mean shift happening in the process to the operators utilizing the digital camera measurement system is recommended.