Study On Machining Quality And Tool Wear Of Milling Carbon Fiber Reinforced Plastics

Carbon fiber reinforced plastics(CFRP)has been widely used in various fields of aerospace,wind power,sports equipment,automobile and so on because of their excellent comprehensive performance.Due to its characteristics of laminated structure,non-uniform distribution,anisotropy and so on,which make it easy to cause serious machining defects such as burr,tear,delamination and so on,and machining quality is difficult to control.High strength,high hardness and low heat dissipation characteristics of CFRP easily lead to serious tool wear,short tool life,affect the machining quality and efficiency,causing high machining cost,and CFRP belongs to the typical materials which is difficult to machine.According to the difficulty of machining CFRP,the related experimental studies on milling force,machining quality and tool wear problem were carried out in the process of milling CFRP.Different tools were adopted for milling unidirectional and multidirectional T700 CFRP laminated,and analyzed the influence of milling parameters and tool materials on milling force,surface quality and tool wear.The research has a very important theoretical significance and practical reference value on the choice of tool materials and milling parameters of milling CFRP in this paper.The main works and achievements are as follows:(1)The influence law of fiber cutting angle on the component force F_y of the radial cutting depth direction is studied.Establishing the milling force F_y experience formulas of HTi10,VP15 TF,NX2525 and PCD tools,and also having a significant analysis on milling parameters,the results show that the spindle speed of the HTi10 tool has a higher impact on the milling force F_y than the feed speed,however the feed speed of the VP15 TF,NX2525 and PCD tools has a bigger influence degree on the milling force F_y than the spindle speed.In the milling process,the minimum milling force F_y is PCD tool,and the maximal value is NX2525 tool.The milling force F_y of VP15 TF is greater than HTi10 gradually when the number of cutting is more than 20(cutting distance 2.4m),but the difference is small.(2)Influence of milling parameters on surface roughness is studied with HTi10 tool,and the surface roughness is smaller when the higher spindle speed and the lower feed speed.The influence of tool materials on surface roughness is analyzed,and it's found that the surface quality is best when using PCD tool,but it's worst when using NX2525 tool.The machining surface microstructure characteristic is observed through the SEM pictures when the fiber cutting angle is different.Surface material has a deformation due to lacking of support in the milling process,and it's easy to produce burr and tear defects.(3)Wear mechanism of HTi10,VP15 TF,NX2525,PCD tool is analyzed by SEM,the result show that the main wear forms of tool are abrasive wear,chip adhesion,coat shedding,peeling and micro-chipping.The changing laws of tool flank wear and influence on milling force F_y are studied in the milling process.The wear resistance of PCD tool is best,but tool wear affect milling force F_y largely.The milling force F_y and tool wear of NX2525 is largest.The tool wear degree of VP15 TF tool is higher than HTi10 tool,but the milling force F_y is less than HTi10 tool when their tool wear is the same.The wear value of VP15 TF tool increases as the spindle speed increases,and decreases with the increasing of feed speed.