Umudike Journal of Engineering and Technology

The process of taper-turning of pulley groove by adjusting the compound rest of a conventional lathe is consuming much energy and man-hours. The efficiency and trouble free operation of belt or rope drives largely depend on the groove design of the pulley. Elimination of rework and rejection caused by this bottleneck activity (Groove making operation) in the pulley production process requires a Six Sigma approach which was implemented in this study. The use of the define-measure-analyse-improve-control (DMAIC) methodology for the different phases of the project helped eliminate some causes of waste in the process. The result of iteration no. 1 gave a potential capability index (CP) value equal to 0.65 and performance capability index (CPK) equal to 0.5. The results primarily indicate the first status of the problem on hand before carrying out any improvement work. Iteration no. 2 matches the conciliator phase readings after performing moderate improvements with a marginal increase in CP to 1.74 and CPK to 1.6. Iteration no. 3 corresponds to the final phase readings taken after introducing the equivalent corrective actions known in the analysis stratum. Moreover, bringing in a noticeable improvement in the process performance with CP as 2.15 and CPK equal to 1.62. The data points of the control charts are also equally distributed across the mean line indicating that the process means as well as the process variation are stable, and the process is under control. The business impact of implementing the DMAIC methodology at Cp and Cpk values > 1.33 consistently indicates that by avoiding 99% component rejection and rework, sixty-one thousand, eight hundred and seventy-five naira (₦61875) can be saved per month. The method offers the benefit of lowering the machining cost using a reduction in machining time, steps, and energy savings.