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

Abstract

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 vf is in the range of 1 000～7 000 mm/min, the average surface roughness of the workpiece increases rapidly with the increase of vf, and when vf is 7 000 mm/min, its value reaches 1.790 μm. When the axial cutting depth ap is in the range of 0.1～0.4 mm, the average surface roughness of the workpiece increases gradually with the increase of ap, but the increasing trend slows down after ap is 0.2 mm. The Vf has the greatest influence on the finish milling surface roughness of 7075 aluminum alloy workpiece, followed by n and ap. The optimal parameter combination of finish milling 7075 is ap = 0.2 mm, vf = 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.

Keywords

• cutting process
• cvd nano-diamond film coated tool
• finish machining
• high-speed milling
• orthogonal test
• optimization grouping