A sliding-disk method for decoupled planning of five-axis tool paths in flat and filleted end milling with uniform-scallop and uniform-strip-width constraints

Five-axis flat-end and filleted-end milling is crucial in high-efficiency machining of complex parts with curved surfaces. However, different from ball-end machining, there exists coupling influences between the scallop height, the strip width, the cutter-contact paths, and the tool-orientation paths in flat-end and filleted-end five-axis machining, which makes the toolpath planning so challenging that most existing methods cannot guarantee uniform scallop height and uniform strip width simultaneously. To deal with this problem, this paper presents a “sliding-disk” method for decoupled planning of five-axis toolpath in flat and filleted end milling, which transforms the problem of the toolpath planning into a problem of “a disk sliding on a rail”. First, the pose of the cutter is transformed into that of a “disk”. Then, the residual shape of the surface is transformed into a “rail”, where the scallop height and the strip width constraints are transformed into the constraint of the disk-rail contact status. Finally, the optimization process of the toolpath is transformed into the sliding process of the “disk” on the “rail”. By constructing the disk-rail contact constraints, the influence of cutter pose on the scallop height and the strip width can be decoupled, so that the tool-position and tool-orientation paths can be planned flexibly. By planning the “disk-sliding process”, the tool-position and tool-orientation can be optimized simultaneously towards a user-set performance index, without varying the uniform scallop height and the uniform strip width because of the decoupled property. Four groups of machining experiments are conducted to verify the effectiveness and advantages of the proposed method. It can be concluded from the experimental results that the presented method yields the most uniform scallop height and strip width, and the shortest toolpath length, when comparing with typical existing methods.