Research On The High-Speed Milling Of Pocket Corner

Different from traditional machining technology, High speed machining (HSM) is used to improve machine efficiency and quality in die and mold industry, based on its high spindle speed, fast feed, small cutting depth and little pace. During high speed machining, approaching and retracting processes, non-uniform of machining allowance, abrupt change of tool path will result in frequent change of cutting force, which influence the tool life and service efficiency of machine centre. Early failure of tools is one of the key problems in HSM. However, the problems of HSM have not been taken into account in most of CAM software, which results in many problems in machining and restricting extensive application of HSM.Therefore, smooth of tool path should be ensured in HSM NC program. Managing of Sharp corner technology is important project while high speed milling mould cavity.In this thesis, by means of series of experimental and theoretical analysis, the effects of corner angle and radius of transition arc on cutting force and vibration are researched, in which micro end-mill is used to HSM die steel (HRC30) by different cutting parameters. Cutting allowance and over-cutting are also studied. Accordingly, the fundamental of corner-cutting parameter optimization is presented, which will provide theoretical support and application guide for corner-cutting NC programming.By measure and analysis of cutting force and vibration, conclusions are drawn as the following,As the corner angle reduce, cutting allowance in the corner and contact angle will increase, showing the tendency of enhancement of cutting force. To depress the vibration, sharp-angle-like cutting 1. should be avoided if possible.2. As feed per tooth increase, cutting force enhances. But the enhancement is also based on the corner angle. However, increase of feed per tooth does not always result in aggravation of vibration.3. As cutting speed increase, the tendency of enhancement of cutting force and reduce of vibration presents. The variation range of vibration magnitude is the largest as the corner angle is 30°.4. As radial cutting depth increase, cutting force enhances, but the influence of the depth on vibration reduces. Under the same conditions, the cutting depth has more infection than the feed per tooth to the vibration.Finally, by the means of theoretical and' experimental analyses, the influence of corner angle, the minimum of transition arc and feed speed on over-cutting is studied, and the fundamental of corner-cutting parameter optimization is given. Then the conclusions come as the following,1. The effects of the minimum of transition arc to over-cutting are irregular.2. As corner angle reduces, in different radius of corners, the measurements of corner radius go down, which will lead to over-cutting.3. Over-cutting produces easily as the feed rate speeds up. The optimal values of feed rate for various minimums of transition arc are different under the conditions of diversified dimensional precision.