Predictive Model for Machining Time in CNC Lathe Process

Estimating machining time is an important issue in the manufacturing industry, particularly for manufacturers producing small quantities of diverse products. Accurate estimation of machining time is advantageous for effective manufacturing scheduling and precise quoting. Computer-aided manufacturing (CAM) software often calculates the machining time using a fixed feed rate. However, CNC machining does not consistently employ a fixed feed rate throughout the process, leading to discrepancies between the software-estimated and actual machining time. The objective of this research was to develop a more accurate method for estimating the machining time of CNC lathes. Through experiments and regression analysis, this research determined the jerk of the CNC lathe at different feed rates. Subsequently, a model was developed to estimate the CNC lathe machining time based on kinematics and experiments. For two workpieces used in this study, the machining time obtained using the proposed model differed from the actual time by $1.7 \%$ to $2.7 \%$. In contrast, the prediction errors using commercial CAM software ranged from $16.4 \%$ to $20.0 \%$. The results demonstrate that the proposed predictive model of the lathing time is feasible and can provide more accurate results with simple procedures.