Parametric Design And Side-Edge Process Modeling Of End Mill

End mill has found wide use in aerospace, automobile, medical devices, mold and general machinery industries because of its good performance in processing difficult-to-machine materials. In practice, in order to get the better processing quality and tool life, the end mill structure should be optimal designed according to the material and structure of the processed object. Due to the constantly emerging new material and structure characteristics, this demand is becoming more and more prominent. However, a large number of dimensions and complex structures lead to a poor efficiency and accuracy of its 3D modeling and manufacturing. According to the space analytic geometry, the differential geometry and the envelope principle, the parametric design, the manufacturing process, and the software implementation method of the end mill were studied in this paper.To get a 3D model, the end mill mathematical model should be firstly established. On the basis of space analytic and differential geometry theory, the mathematical model of helical blade lines, groove section lines with equal and variable pitch, tiny blade with round radius, chamfering shape and vibration reduction flank were built as expressions. According to the actual machining process, the Gash model was established by an approximate pentahedron. The mathematical model built above was not only the basis of the parametric 3D design but also the basis of the manufacture-based design of the end mill.As a key structure, the end mill groove was emphatically discussed. The method to predict the groove geometry with the known grinding process was studied. Inversely, the way to calculate the right wheel positions or geometries with the known groove geometry was provided. The mathematical models of the wheel geometry used to manufacture the groove were firstly built. And the expression of the wheel contours at any position relative to the end mill blank was deduced. Then, the groove machining mechanism was analyzed and concluded as:there should be contact lines between the wheel and the groove surface at any time during the grinding process, and the groove surface normal at any contact point must intersect with the wheel axis, due to that the groove surface was enveloped by the surface family or the curve family. Accordingly, the groove prediction model for the wheel with simple generatrix was established by the enveloping theory. For the cases that there had discontinuity point or quadratic curve on the wheel profile, the enveloping theory was no longer applicable. So, a graphic algorithm, mainly based on the point cloud calculation, was proposed. Then the effect of the grinding process on the groove geometry was discussed. The iterative algorithm was applied to reversely calculate the wheel geometry, and the wheel geometry was reversely computed by the groove machining mechanism. Finally, the algorithms proposed above were encapsulated and verified by Matlab.To solve the process problems of the actual groove and clearance machining, the method to calculate and control the cutting edge of the end mill was proposed. The "undercut" phenomenon was analyzed and the conditions to manufacture an integrated groove or clearance were established. The process mathematical models for clearance with flat, eccentric or convex geometry were built. The machining mechanism for the eccentric clearance was emphasized, the "undercut" and "interference" problems were analyzed, and the process conditions to prevent these problems were deduced.According to the mathematical models and machining processes mentioned above, the parametric design and grinding simulation software of end mill was developed by the secondary development technology of UG. The 3D model of end mills with 2 to 10 teeth, equal or unequal pitch, and tiny flanks could be quickly established. The structural information could be exchanged between the UG software and the backend database. An accurate end mill model could be built based on the actual machining process. The established model could be converted to the 2D drawing. The groove and clearance machining process could be simulated and verified in UG. The independent and distributable groove model prediction software was developed by Matlab GUI. It could be used to predict the groove model with the known wheel geometry and positions. The result could be saved and exported in TXT format. Finally, five examples were taken to verify the research results. They were the parametric design examples, the groove and clearance machining simulation examples, the manufacture-based 3D design example, the groove machining process planning example and the groove model prediction examples.