基于MQL的碳纤维复合材料制孔表面质量及切削力试验

Experiment on Hole Making Surface Quality and Cutting Force of Carbon Fiber Reinforced Composite Based on MQL

目的 减少碳纤维增强复合材料(CFRP)制孔表面毛刺及边缘凸起等缺陷。方法 对比研究在干切削和微量润滑(MQL)2种加工条件下碳纤维增强复合材料(CFRP)的制孔,在切削速度一定时,探究切削方式、进给速度对制孔尺寸精度、表面质量、切削力的影响。采用方差分析对各影响因素及其权重进行分析。结果 得出了切削方式和工艺参数对制孔尺寸精度、切削力、表面质量的影响规律。试验结果表明,在微量润滑条件下,由于润滑和降温的影响,表面毛刺得到有效去除,纤维断面平整,剪切作用明显,抑制了由温升所引起的边缘隆起膨胀现象,试样的表面质量得到显著提高,切削力整体降低。在干切削和微量润滑条件下对制孔尺寸精度影响最大的是切削方式。对于切削力,在干切削时受到切削方式的影响最大,在微量润滑条件下受到进给速度的影响最大,随着进给速度的增大而增大。结论 在现有试验条件下,微量润滑的加工质量总体上优于干切削的加工质量,其制孔尺寸的精度整体更高,其切削力最大降低了84.26%。

The work aims to reduce the defects such as burrs and raised edges on the hole making surface of carbon fiber reinforced polymer(CFRP).A comparative study was conducted to investigate the effect of cutting method and feed speed on the dimensional accuracy,surface quality and cutting force of CFRP under both dry cutting and minimum quantity lubrication(MQL)machining conditions.Analysis of variance(ANOVA)was used to analyze each affecting factor and its factor weights.The effect of cutting method and process parameters on the dimensional accuracy,cutting force and surface quality of the hole was revealed.The experimental results indicated that under the minimum quantity lubrication condition,the surface burr was effectively suppressed due to the effect of lubrication and temperature reduction,the fiber section was flat,the shearing effect was obvious,the edge bulge expansion caused by temperature rise was suppressed,the maximum reduction of hole making dimensional deviation was 9.70%,and the minimum value was 1.162.Therefore,the hole making dimensional accuracy and surface quality were improved.Under the cutting force of drilling hole making and milling hole making methods,the cutting force was reduced overall,and the minimum value of cutting force was 3.36 N,and the cutting force fluctuation became smaller and more stable which was weakened by the impact and the tool wear resistance was enhanced.The great affecting factor on hole making dimensional accuracy under dry cutting and minimum quantity lubrication conditions was the cutting method.For cutting force,it was mostly affected by the cutting method under dry cutting and by the feed speed under minimum quantity lubrication conditions,and it increased with the increase of feed speed.According to the experimental results,the overall quality of minimum quantity lubrication processing under the existing conditions is better than that under dry cutting.Compared with that under dry cutting,the overall hole making dimensional accuracy is improved by 6.55%,the maximum cutting force is reduced by 84.26%,and the milling hole making is better than drilling.Carbon fiber reinforced polymer(CFRP)have excellent characteristics such as high specific stiffness and strength,high specific modulus,low density and high temperature resistance.Composites are characterized by high cutting force,high processing temperature,and some surface defects during processing.CFRP is very prone to burr,delamination,ablation and other defects in the process of hole making,resulting in rough surface and poor hole making accuracy.The improvement of CFRP reworking quality has been of great concern to scholars.In the study of the factors affecting the hole making surface quality of carbon fiber reinforced composite,the analysis indicates that:the surface quality is deeply affected by the cutting method,and milling hole making is generally better than drilling.Under dry cutting,the fiber is mainly tensile fracture,resulting in excessive burr,while the cutting edge extrusion is strong,and the edge protrusion is serious.Under the condition of minimum quantity lubrication,the cutting edge shearing effect is enhanced,and the burr is effectively suppressed.At the same time,the micro-lubrication processing plays the role of lubrication and friction reduction,the cutting edge extrusion is weakened,and the edge protrusion disappears.