A contour line model for end milling simulation, which realizes high-speed arithmetic processing by reducing memory usage, is proposed. In this model, a 3-dimensional shape can be expressed by superimposing the contour lines of the cross-sections obtained by dividing the workpiece along any axial direction. Therefore, the memory usage is reduced compared to a Z-map model or a voxel model as the interior information of the object can be eliminated. The contour line model can also be applied to complicated shapes having overhangs. Furthermore, cutting volume can be calculated from the interference area enclosed by two contour lines of the workpiece and the tool cross-sections. The workpiece shape can be changed by eliminating the interference area. In the contour line model, cutting force can also be predicted with an instantaneous rigid force model using the uncut chip thickness for each cutting edge from the positional relationship between the interference area and the cutting edge. To validate the proposed model, cutting experiments were conducted, which confirmed that the predicted machining shape had good agreement with the actual machined shape. Furthermore, it was confirmed that the cutting force can be predicted accurately.

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