tailieunhanh - Kinematic Geometry of Surface Machinin Episode Episode 6

Tham khảo tài liệu 'kinematic geometry of surface machinin episode episode 6', kỹ thuật - công nghệ, cơ khí - chế tạo máy phục vụ nhu cầu học tập, nghiên cứu và làm việc hiệu quả | The Geometry of Contact of Two Smooth Regular Surfaces 147 Without going into detail mention will be made here that for the purposes of efficient surface generation in a machining operation it is desired to maintain that kind of contact of the surfaces P and T which features the highest possible rate of conformity of the generating surface T of the cutting tool to the part surface P. Actually while machining a part surface deviations in the cutting tool relative location and orientation with respect to the surface P are always observed. The deviations of the cutting tool configuration are unavoidable. Because of the deviations the desired local-extremal kind of contact is replaced with another kind of contact of the surfaces P and T. Such replacement can be achieved with the introduction of precalculated deviations of the cutting tool principal radii of curvature R1T and R . If the precalculated deviations are small then instead of the desired local-extremal kinds of contact of the surfaces the quasi- kind of contact of the surfaces P and T may occur. There are several kinds of quasi- contact including quasi-line contact of the surfaces P and T quasi-surface of the first kind and quasisurface of the second kind contact of the surfaces P and T. The required precomputed values of small deviations of the actual normal curvatures from their initially computed values can be determined on the premises of the following consideration. When the maximal deviations in the actual cutting tool configuration location and orientation of the cutting tool relative to the surface being machined occur the rate of conformity of the generating surface T with respect to the surface P must not exceed the rate of their conformity in one of the local-extremal kinds of surface contact. When the actual deviations of the cutting tool configuration do not exceed the corresponding tolerances then one of the feasible kinds of quasi-contact of the surfaces P and T is observed Evidently bigger