金刚石涂层钻头钻削碳纤维增强复合材料钻削力和撕裂预测

通过全面实验进行了金刚石涂层钻头钻削T300和T800碳纤维增强复合材料的研究,并用测力仪系统和超景深显微镜对钻削力和出口撕裂进行了测试与观察。运用指数公式模型对钻削力实验结果进行了回归分析,得到了T300和T800钻削力与转速以及进给量的之间关系式,并对该方程进行了检验,验证误差值均小于6%;建立了出口撕裂因子与钻削力的关系;T800碳纤维增强复合材料的轴向力与撕裂因子呈负线性关系,T300的轴向力与撕裂因子呈正线性关系。     

金刚石涂层钻头钻削碳纤维增强复合材料的工艺

采用金刚石涂层854钻头进行了钻削碳纤维增强树脂基复合材料T300和T800的试验,使用测力仪与超景深三维显微系统对钻削过程中的钻削力以及孔出、入口缺陷进行了测试与观察。分析了钻削力随时间的变化规律,切削用量对切削力和钻孔质量的影响。实验结果表明:在相同进给速度下,随转速增加,轴向力呈减小的趋势;在同一转速下,轴向力随着进给速度增加呈逐渐增大的趋势,已加工孔的入口质量比出口质量好。在相同参数下,T300比T800的轴向力要小,T300的平均力约为T800的2/3左右。T800的撕裂长度约为T300的1/3左右。     

PCD钻头钻削碳纤维增强复合材料的切削力研究

利用PCD钻头对碳纤维复合材料钻削力进行试验研究。通过单因素试验的方法得到切削参数对切削力的影响规律;通过多元线性回归得到钻削轴向力的经验公式,应用SPSS软件对经验公式进行方差分析;对经验公式进行显著性检验,回归方程非常显著,回归模型可以为钻削轴向力提供预测。     

高速钻削碳纤维复合材料轴向力的非线性回归分析

针对高速钻削碳纤维复合材料的轴向力问题,采用φ5.0 mm的硬质合金麻花钻钻头进行了试验研究。得到转速n和进给速度vf在9 000 r/min≤n≤19 000 r/min和40 mm/min≤vf≤130mm/min范围内成立的二元非线性回归公式的2种形式Fz=Fz(vf,n)和Fz=Fz(f,n)。还给出固定其中任何1个自变量,约化出的一系列一元函数公式的曲线,并从中总结出4点唯象规律。     

采用BP神经网络预测碳纤维增强树脂基复合材料的钻削力

采用双锋角钻头对碳纤维复合材料进行钻削试验,基于反向传播算法的人工神经网络建立钻削轴向力与主轴转速、进给速度之间的非线性关系模型,对比分析三种不同第二主切削刃与第一主切削刃之比的双锋角钻头在试验加工参数下钻削轴向力变化规律。结果表明:与多元线性回归预测模型对比,在相同试验数据为基础的预测计算下,BP神经网络预测值相对误差明显减小,网络预测值误差均在3%之内,而多元线性回归模型最大误差值达到了12.46%,BP神经网络能建立更精准轴向力预测模型。从降低钻削轴向力的角度分析,应采用第二主切削刃与第一主切削刃之比为1的双锋角钻头进行钻削加工。     

碳纤维复合材料高速钻削实验研究

研究了硬质合金钎焊金刚石钻头高速钻削碳纤维复合材料时钻削力、扭矩的变化规律,得到了进给量、切削速度对钻削力和扭矩的影响规律。对钻削力和扭矩实验结果进行了回归分析得到了钻削力和扭矩的指数公式。     

钻头几何参数对低频振动钻削CFRP/钛合金叠层材料钻削轴向力及温度的影响

通过开展低频振动钻削叠层材料单因素试验,研究了刀具的顶角、螺旋角和后角对钻削轴向力及温度的影响。结果表明:钻头顶角越大,轴向力越大,螺旋角的变化对钻削CFRP层轴向力影响较小;在钻削钛合金层时,轴向力随着螺旋角的增大呈先下降后上升的趋势,钻头后角越小,轴向力越大;钻头几何参数对钻削温度的影响可以忽略,得出较为适合CFRP/钛合金叠层材料振动制孔的钻头几何参数为顶角120°、螺旋角25°、后角20°。     

医疗钻头钻削力和钻削温度的试验研究

在高速钻削猪胫骨过程中,钻削力和钻削温度对改进医疗钻头的设计是非常重要的.研究结果表明:在钻削骨头的过程中,钻削力和钻削温度受进给速度和钻削速度的影响.相比不锈钢麻花钻,带三个切削刃的新型医疗钻头能够取得更小的钻削力和低于47℃的钻削温度.     

三种涂层钻头钻削不锈钢的切削性能研究

以轴向力和扭矩为判据比较分析了三种涂层高速钢钻头钻削不锈钢时的切削性能。试验结果表明 :TiN表面多层涂层钻头钻削效果最好 ,TiCN表面多层涂层钻头次之 ,TiN单层涂层钻头钻削效果最差。同时发现 :不同涂层钻头钻削不锈钢时产生的轴向力和扭矩值随进给速度的增加而增大 ,但在固定进给速度 (0 .12mm/r)、改变转速时 ,三种涂层钻头的轴向力与扭矩值在转速为 1.4r/s时最小 ;转速增加至 2 .0r/s时轴向力和扭矩增至最大 ;转速继续增加至 2 .6r/s时轴向力与扭矩值开始下降     

轴向超声振动钻削的钻削力和切屑形态研究

建立了钻削加工仿真模型,并采用麻花钻对钛合金进行振动钻削试验。利用ABAQUS软件进行轴向超声振动钻削仿真,试验验证和对比分析了轴向超声振动钻削在不同加工参数下的切屑形态和钻削力。仿真与试验结果表明:随着进给量和振幅增加,钻削力增大,但进给量对钻削力的影响大于振幅;无论是进给量还是振幅的改变,对切屑形态均有影响。     

Delamination-free drilling of carbon fiber reinforced plastic with variable feed rate

A large number of drilling have been performed to assemble aircraft parts of carbon fiber reinforced plastic (CFRP). Although high quality is required in machining the holes with high productivity in terms of reliability of parts, delamination often occurs around the holes in drilling. This paper presents a novel drilling method with variable feed rate to machine the delamination-free holes at a high machining rate. In the drilling, the holes are machined at the standard feed rates when the chisel moves in material; and are finished with the negative thrust at higher feed rates after the chisel exits from the workpiece. Orthogonal cutting tests were conducted to measure the cutting forces and the friction angles for the uncut chip thicknesses and the rake angles. The negative thrusts were measured in large uncut chip thicknesses at large rake angles of the lips. Then, the drilling tests were conducted to verify the change in the cutting force in the variable feed rate drilling up to 100 holes. Negative thrust component appears consistently to raise the workpiece up in the exit process even though the tool wear progresses with repeating drillings. As a result, the variable feed rate drilling remarkably controls delamination compared to the constant feed rate drilling in the 100th drilling. The cutting process in the variable feed rate drilling is compared with the constant feed rate drilling in a cutting force model based on the minimum cutting energy. The negative thrust is verified when the friction angle becomes smaller than the effective rake angle with increasing the feed rate.     

碳纤维复合材料钻孔加工的缺陷分析

为了解决碳纤维复合材料(CFRP)钻孔加工过程中出现的撕裂、毛刺、分层等问题,以及将碳纤维复合材料更好地应用到机械制造行业中,进行了碳纤维复合材料的钻孔试验.通过实验研究了碳纤维复合材料的钻孔缺陷,分析了碳纤维复合材料钻孔加工的主要缺陷分类,以及钻削力、刀具的锋利性、钻削温度等因素对孔加工质量的影响,建立了钻削速度、进给速度与钻孔质量之间的关系;采用DM2500M金相显微镜以及KEYENCE VHX-1000三维显微系统进行了相关的试验.研究结果表明,钻孔加工缺陷出现部位呈现一定的区域性,钻孔毛刺、撕裂缺陷主要集中在出口部位,入口处几乎没有毛刺、撕裂等缺陷;随着进给速度的减小和主轴转速的增大,钻孔缺陷能够得到明显的改善;采用PCD钻头加工复合材料时宜在中、高转速下进行,高转速下钻头切削刃更易切断纤维,可以得到质量更高的钻孔.     

超声振动微孔钻削轴向力研究

超声振动微孔钻削技术可在硬脆材料上加工出大长径比的微孔,因而越来越受到工业重视。根据动态切削厚度建立轴向力计算模型,使用MATLAB软件模拟得到微细钻头切削轨迹和动态切削厚度,结合已建立的三维钻削模型计算钻削过程中刀具受到的轴向力和转矩,并使用有限元软件Advant Edge来进行切削模拟,得出微细钻头受轴向力情况。可以得出,计算结果和模拟结果中轴向力变化趋势相同。     

碳纤维复合材料-钛合金层板钻孔质量研究

对比钻削碳纤维复合材料(CFRP),碳纤维复合材料-钛合金层板(CFRP-Ti),得出钻削CFRP-Ti时的CFRP入口分层、孔径误差、形状误差以及孔的表面粗糙度均比单独钻削CFRP时的要差.其原因是CFRP在上层,当钻削钛合金层时,一方面轴向钻削力大,钻削过程不平稳;另一方面钛合金的钻屑为螺旋长条状,这些都会影响已形成的孔壁.尤其在高转速下,此影响更为严重.     

Thrust force and delamination of core-saw drill during drilling of carbon fiber reinforced plastics (CFRP)

Due to the inherent anisotropy and inhomogeneous nature of polymer-based composite materials, their cutting mechanism differs in many respects from conventional metallic materials. Amongst all machining operations, drilling using a twist drill is the most commonly applied method for generating holes for riveting and fastening structural assemblies. Most of the previous research correlates the drill geometry and feed rate to thrust force and delamination on the performance of a twist drill. The Taguchi method has been used to solve many engineering problems. In this investigation, drilling-induced thrust force and delamination by core-saw drill during drilling CFRP laminates were selected as quality character factors to optimize the drilling parameters to obtain the smaller-the-better characteristics. For thrust force and delamination quality character factors, the optimum conditions in drilling were also A₁B₁C₃, (i.e., diameter ratio = 0.55, feed rate = 8 mm/min and spindle speed = 1,200 rpm).     

Performance of plastic gear made of carbon fiber reinforced poly-ether-ether-ketone

A carbon fiber (CF) reinforced poly-ether-ether-ketone (PEEK) gear was prepared by injection molding, and its gear performance was evaluated. It was found that the wear process of the CF reinforced PEEK gear significantly varied depending on the test conditions, such as the kind of the partner gear combined and whether a lubricant exists on the engagement region or not. It was assumed that the existence of transfer film at the engagement region, the affinity between PEEK and CF, the compression modulus as well as surface hardness of the partner gear, and the characteristics of CF play a role of differentiation in the wear depth.     

基于非接触光声成像的碳纤维增强复合材料冲击损伤检测方法

为了探究碳纤维增强复合材料(CFRP)的损伤机制并对其制造过程进行质量监控,对 CFRP 的冲击损伤区域进行了高 分辨无损检测。 构建了全光式非接触光声显微(AONC-PAM)成像系统,利用自主开发的光学吸收结合背向散射的双对比度成 像模式,对 CFRP 在不同冲击能量下的损伤区域进行高分辨率无损检测。 实验结果显示,AONC-PAM 系统的空间分辨率为 2. 9±0. 5 μm;双对比度成像策略能以 2 s/ 帧的速率同时获得基于光学吸收和表面散射特性的图像及两者叠加的双对比度图 像;AONC-PAM 系统显示了比通用明场显微镜系统更多的成像细节,包括碳纤维分布和其他微观缺陷如纤维断裂、错位、缺束 和褶皱,可检测的微观缺陷尺寸达 10~ 20 μm,并实现了损伤区域的精准量化。     

Performance of plastic gear made of carbon fiber reinforced poly-ether-ether-ketone: Part 2

Five kinds of PEEK/CF composites, made by blending poly-ether-ether-ketone (PEEK) with three kinds of PAN type carbon fibers (CFs) and two kinds of pitch type CFs respectively, were injection-molded into gears. Their gear performance such as the load capability and the wear of tooth were evaluated. The wear properties of PEEK/CF gears extremely varied depending on the kinds of CFs, when the same type gears were combined and grease was initially applied. Also, the load capabilities were significantly influenced by the affinity between PEEK and CF. A composite gear reinforced with CF of the highest density indicated the highest load capability irrespective of the test conditions, due to the lowest abrasive property of the CF as well as the excellent affinity between PEEK and CF. Its load capability under a high temperature running condition was found to be superior to that of polyamideimide (PAI) composite gear or polyphenylenesulphide (PPS) composite gear.