纳米金刚石涂层刀具高速铣削7075铝合金的工艺参数优化

采用热丝CVD法制备纳米金刚石薄膜涂层刀具，利用场发射扫描电子显微镜表征薄膜的表面形貌，并用已制备的CVD金刚石涂层刀具，在无润滑干切条件下高速铣削7075铝合金工件，对其精铣工艺参数进行单因素及正交试验，探索精铣后工件的表面粗糙度变化规律并进行工艺参数优化。结果表明:随着主轴转速n从5000 r/min提高到8000 r/min， 工件平均表面粗糙度在逐级缓慢降低；当进给速度v_f在1000～7000 mm/min范围内，随着v_f提高工件平均表面粗糙度快速增大，在v_f为7000 mm/min时，其值达1.790 μm；当轴向切削深度a_p在0.1～0.4 mm范围内，随着a_p提高，工件平均表面粗糙度逐步增大，但a_p在0.2 mm之后其增大趋势变缓。对7075铝合金工件精铣表面粗糙度影响最大的是v_f，其次为n，a_p的影响最弱；其精铣的最优参数组合是a_p=0.2 mm、v_f=1 000 mm/min、n=8 000 r/min，精铣后的表面粗糙度平均值为0.516 μm。选用纳米金刚石薄膜涂层刀具精铣7075铝合金时，为得到较低的表面粗糙度，应选择高主轴转速、低进给速度、合适的轴向切削深度。 

Process parameters optimization of high-speed milling 7075 aluminum alloy with nano-diamond coated tool

The nano-diamond film coated tool was prepared by hot wire CVD method. The surface morphology of the film was characterized by field emission scanning electron microscopy. The prepared CVD diamond coated tool was used to mill 7075 aluminum alloy workpiece at high speed under the condition of dry cutting without lubrication. The single factor and the orthogonal experiments were carried out on the finish milling process parameters to explore the variation law of the surface roughness of the workpiece after finish milling and optimize the process parameters. The results show that with the increase of spindle speed n from 5 000 r/min to 8 000 r/min, the average surface roughness of the workpiece decreases gradually. When the feed rate v_f is in the range of 1 000～7 000 mm/min, the average surface roughness of the workpiece increases rapidly with the increase of v_f, and when v_f is 7 000 mm/min, its value reaches 1.790 μm. When the axial cutting depth a_p is in the range of 0.1～0.4 mm, the average surface roughness of the workpiece increases gradually with the increase of a_p, but the increasing trend slows down after a_p is 0.2 mm. The V_f has the greatest influence on the finish milling surface roughness of 7075 aluminum alloy workpiece, followed by n and a_p. The optimal parameter combination of finish milling 7075 is a_p = 0.2 mm, v_f = 1 000 mm/min, n = 8 000 r/min, and the average surface roughness after finish milling is 0.516 μm. When using nano-diamond film coated tools to finish milling 7075 aluminum alloy, the high spindle speed, the low feed rate and the appropriate axial cutting depth should be selected to obtain low surface roughness.