Research On Processing Of Carbon Fiber Materials Based On The Short Pulse Laser

Carbon fiber composite material is a new type of material.It is an extremelyimportant multifunctional engineering material,both in military and civilianfields.Especially in the aerospace field,it has great value.But the research of it in Chinadevelops slowly and there’s no system work of the machining process and themechanism,which makes the research work significant. Because of carbon fibercomposite material’s ultra-hardness,traditional processing method can not satisfy therequirements of elaborate processing.This paper take the advantage of short pulse laserin special processing, research the carbon fiber composite material machining processbased on short pulse laser,including efficient processing conditions and interactionmechanism.This paper explores the effect of laser with different pulse width on super hardmaterials processing,including femtosecond pulse laser, nanosecond pulse laser andcontinuous laser. In the method of punching carbon fiber composite material which itsthick is3.5mm,compared the hold’ morphology and the processing efficiency.Resultsshows: the hold which the femtosecond pulse laser processed has little thermal effectand the relativity of diameter and depth is small.The hold which the nanosecond pulselaser processed has a large thermal effect area. The continuous laser has greater thermaleffect on processing.It is clearly that it removing material by melting it.By theoreticalanalysis,the continuous laser ablation threshold of carbon fiber composite material is1.0×104J/cm2,consistent with experimental results. At the same time,analysis of thenanosecond pulse laser and the femtosecond pulse laser threshold of carbon fibercomposite material.Mainly depend on the size of the ablation area under different singlepulse energy is different, according to the ablation area diameter the carbon fibermaterial threshold can be calculated.The femtosecond pulse laser threshold of carbonfiber is0.50±0.05J/cm2,which pulse width is40fs. The nanosecond pulse laser thresholdof carbon fiber is4.1±0.5J/cm2,which pulse width is40ns.The results show that shortpulse laser has high energy utilization rate and good morphology.Through contrast experiment, research the effects of the different parameters onthe carbon fiber ultra-hard materials processing, find the parameters which makeprocessing efficiently and in a good quality. Mainly depend on the result of drilling,groove, and processing microstructure, explore the aeffect of the laser frequency,scanning frequency, scanning speed, different light source and laser focus displacementquantity on carbon fiber composite materials processing.Concluded that:(a)Theinfluence of the repetition frequency: if the processing precision demand is higher, it isrecommended to use the laser of lower repetition frequency.If the processing precisiondemand is moderate,it is recommended to use the laser of higher repetition frequency, avoiding the waste of resources.(b) The influence of scanning frequency and scanningspeed: in the case of engraving line on material surface, it should increase thescanning speed and increase the number of scanning times, but it also should controlscan times. In this way, we can ensure depth of lines and better morphology.(c)Theinfluence of different light sources: femtosecond pulsed laser can engrave line in asmaller shape and a higher quality, nanosecond pulse laser can engrave line with a largerdepth.(d)The influence of focus displacement:In the case of the influence offemtosecond laser engraving lines of carbon fiber composite material, the laser focusshould be selected within the range of1/4-1/2which is the ratio of relative displacementand the depth in a single scan, to be able to get larger depth. And by using thefemtosecond pulse laser, reducing power and using short focal length lens, finermicrostructure can be got.According to the experimental results, the interaction mechanism of the short pulselaser and super hard materials can be concluded: in the process of the interactionbetween short pulse laser and material, femtosecond pulse laser take use of the plasmato remove material to the benefit of high precision processing; nanosecond pulse lasertakes use of the energy to remove material directly.