<p>In this study, an automatic process planning system for end-milling operation is proposed, in which CAM operator's intention for process planning is considered. In the previous process planning systems, the machining sequence is calculated geometrically, based on the Total Removal Volume (TRV) and the machining region split from TRV. However, it remains difficult to determine the best machining sequence from the large number of the calculated machining sequences. The previous process planning systems also do not consider CAM operator's intention in the determination of the appropriate machining sequence. First, our new process planning system stores the priority of machining feature and the geometrical properties of the selected machining region when a CAM operator decides the machining sequence. After storing the priority of machining feature and the geometrical properties, the appropriate machining sequence can be automatically determined by referring this information. CAM operator's intention, which is involved implicitly in the stored geometrical properties of the machining region, can be applied to decide machining sequence. A case study was conducted to show the effectiveness of our new proposed process planning system. In the case study, user-specific machining sequences were automatically determined based on the implicit relation among the geometrical properties of the machining region and the individual CAM operator's intention.</p>