超细颗粒增强铝基复合材料钻削性能研究

文中通过超细颗粒增强铝基复合材料钻孔试验,找出了钻削用量等因素对钻削力的影响规律,并用轴向力与扭矩的比值来表示铝基复合材料的钻削特性;基于钻削力考虑,高速钢钻头完全可以满足超细颗粒(≤0.5μm)增强铝基复合材料的钻孔要求。     

钎焊套料钻钻削碳纤维增强复合材料层合板出口撕裂缺陷的成因分析

针对碳纤维增强复合材料钻孔时钻头寿命短、易产生加工缺陷等问题,将钎焊金刚石套料钻应用于碳纤维增强复合材料的钻削加工中。为更好地说明钎焊金刚石套料钻的加工性能,选取了复合材料钻削中常用的金刚石涂层麻花钻进行比较,并选择了实际加工中严重影响加工质量的出口撕裂缺陷进行成因分析。通过检测与分析出口处加工质量,得到以下结论：对于不同结构形式的钻头,仅依靠轴向力及扭矩并不能判断是否产生撕裂缺陷;在相同工艺参数下,钎焊金刚石套料钻的轴向力及扭矩均小于金刚石涂层麻花钻的轴向力及扭矩,使用钎焊金刚石套料钻更有利于减少撕裂缺陷,提高加工效率。     

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。     

微小孔振动钻削力的实验研究

介绍了高灵敏度的微小孔钻削测力仪的结构设计及微小孔钻削力测量系统的工作原理。通过多元正交多项式回归实验 ,得到了微小孔振动钻削力关于振动频率、振幅和进给量的非线性回归方程 ,进而分析了振动参数和切削参数对钻削力的影响 ,为深入研究微小孔振动钻削机理提供了必要的实验手段和有价值的研究方法     

多元变参数振动钻削复合材料的研究

根据复合材料力学和线弹性断裂力学，假设钻削轴向力为一集中作用载荷，从而构造了正交纤维束增强复合材料的钻削分层临界力的数学模型，仿真结果表明，随着待钻削深度的减小，分层临界力急剧降低。基于这一特点，提出了多元变参数振动钻削纤维增强复合材料的新思路，并进行了实验验证。     

基于ABAQUS/Explicit的SiC_p/Al复合材料三维微孔钻削有限元仿真

应用ABAQUS中Explicit显式求解器,基于微观尺度下的Johnson-Cook本构方程,对高体积分数SiC_p/Al复合材料微孔钻削过程进行了三维有限元仿真。研究了钻孔过程中钻削轴向力和扭矩的变化特性以及不同主轴转速和进给速度下钻削轴向力和扭矩的变化规律。此外,对不同主轴转速下钻屑形态的变化特性进行了分析。研究结果为颗粒增强金属基复合材料的微孔钻削工艺参数制定提供了参考。     

涂层钻头钻削碳纤维复合材料的轴向力研究

不同刀具材料对碳纤维复合材料的加工有较大的影响。通过合理选择钻头的基体材料和涂层材料,基于正交试验综合分析不同涂层材料、主轴转速及进给速度对钻削轴向力的影响。试验结果表明,涂层材料对轴向力的影响最大,涂层钻头的钻削轴向力比无涂层YG6X钻头小很多,类金刚石涂层(DLC)钻头最小。TiAlN和TiCN涂层钻头都有不同程度的磨损,DLC钻头的耐磨性和加工质量都远远高于其他涂层。     

抛物线槽型钻钻削力的试验研究

通过钻削试验装置,采用抛物线槽型钻和普通麻花钻在不同参数下对低碳钢和球墨铸铁进行钻削试验,针对钻削过程中轴向钻削力和扭矩及其变化规律进行研究。试验结果表明,抛物线槽型钻钻削过程的轴向力和扭矩比普通麻花钻小,且轴向力和扭矩的变化过程也比普通麻花钻稳定。得出了进给量、主轴转速、钻头几何参数(钻尖顶角、钻头直径)以及工件材料等因素对抛物线槽型钻轴向力、扭矩的影响规律,为钻削过程中抛物线槽型钻几何参数和切削参数的选择提供依据。     

钛合金TC4的钻削力试验研究

钛合金TCA属于较难加工材料,其小孔钻削尤为困难。为得到钻头直径、钻削参数（进给量、切削速度）和刀具材料对钻削力的影响规律,采用标准高速钢钻头对TCA与45钢进行了钻削对比试验,并用多元线性回归分析模型分别建立了扭矩和轴向力的经验公式。结果表明,TC4的钻削力比45钢大,钻削参数对钻削力的影响规律与45钢基本相同,即钻头直径对扭矩和轴向力影响最大,进给量次之,切削速度的影响最小。     

钻削监控传感及诊断

对有关钻削加工中的刀具磨损和失效的监控试验和报告作了综述.对监控中用到的间接测量方法有所涉及,如轴向切削力和扭矩、刀具振动、电机电流和功率以及加工中的声发射等.对所用的传感器和信号分析技术,包括统计方法和参数、快速傅里叶和小波变换以及倒谱技术均有所提及.对结果的诊断多数采用人工神经网络技术.     

颗粒增强铝基复合材料铣削加工实验研究

使用K10硬质合金铣刀,在不使用冷却液的条件下,对A12024/SiCp复合材料进行铣削加工实验,研究切削参数和颗粒尺寸对表面质量、切削力、刀具磨损的影响.研究表明,随着增强颗粒尺寸的增大,表面变粗糙、切削力增大和刀具磨损加重;在不同的切削条件下,法向力均大于切向力.随着切削用量的增大,铣削力呈增大趋势,其中,吃刀量对铣削力的影响最大,切削速度的影响最小;加工表面上存在凹坑、颗粒突起和基体材料涂敷等缺陷,表面粗糙度随着颗粒尺寸增大而增大,随着切削速度的提高而减小.     

钛合金与铝合金叠层材料制孔研究

通过对钛合金TA15与铝合金7075-T6组成的叠层结构进行干式钻削试验,分析了钻削参数对轴向力和扭矩的影响.结果表明,钛合金层的钻削力比铝合金层大,钻削参数对钻削力的影响基本相同.再通过不同刀具材料的对比试验,分析刀具磨损情况,证明硬质合金刀具具有较好的切削加工性.     

Drilling of hybrid aluminium matrix composites

This paper presents the influence of cutting parameters on thrust force, surface finish, and burr formation in drilling Al2219/15SiCp and Al2219/15SiCp-3Gr composites. The composites were fabricated using the liquid metallurgy method. The tools used were commercially available carbide and coated carbide drills. The results revealed that feed rate had a major influence on thrust force, surface roughness, and exit burr formation. Graphitic composites exhibit lesser thrust force, burr height, and higher surface roughness when compared to the other material. The reduced thrust force and burr height is attributed to the solid lubricating property of the graphite particles. The higher surface roughness value for Al2219/15SiCp-3Gr composite is due to the pullout of graphite from the surface. The chips formed when machining graphitic composites are more discontinuous when compared to SiCp reinforced composites and hence advantageous.     

Experimental investigations into rotary mode electrochemical discharge drilling (RM-ECDD) of metal matrix composites

Abstract

In the present work, rotary mode electrochemical discharge drilling (RM-ECDD) was employed to machine the Al-6063 SiC_p metal matrix composites (MMC’s). The effect of various process parameters such as applied voltage, pulse on time, tool rotation rate, electrolyte concentration and current on quality characteristics (hole over cut and depth of penetration) of the drilled holes was investigated. The underlying material removal mechanism during the machining of MMC’s with RM-ECDD is also proposed by considering the scanning electron micrographs (SEM) and simulation results as an evidences. A comparative analysis between RM-ECDD and ECDD was performed during the machining of MMC’s. The experimental results reveal that the integration of tool rotations in ECDD successfully evacuates the sludge/debris from the machining zone, and it also replenishes the electrolyte effectively. Therefore the use of RM-ECDD improves the aspect ratio (L/D), and it exhibits 23.07 times higher L/D ratio than the ECDD process. In ECDM, the discharge characteristics are very important outcome that explores the significant details of the involved mechanisms and phenomena of the process. In the present research, a DSO recorded voltage signals were used to understand the discharge behavior and their characteristics at different parameter combinations. This paper also presents a second-order mathematical models to determine the relation between input process parameters and quality characteristics. Desirability based multi objective optimization approach was employed to optimize the process parameters.     

Experimental investigation and optimisation in drilling of GFRP composites

Glass fibre-reinforced polymer (GFRP) composite materials are one of the important materials and are economic alternative to engineering materials because of their superior properties. This paper presents an effective approach for the optimisation of drilling parameters with multiple performance characteristics based on the Tagugch’s method with grey relational analysis. Taguchi’s L₁₆, 4-level orthogonal array has been used for the experimentation. The drilling parameters such as spindle speed and feed rate are optimised with consideration of multiple performance characteristics, such as thrust force, workpiece surface roughness and delamination factor. Response table and response graph are used for the analysis. The analysis of grey relational grade indicates that feed rate is the more influential parameter than spindle speed. The results indicate that the performance of drilling process can be improved effectively through this approach.     

Ion microprobe studies of reactions in squeeze-cast aluminium alloy matrix composites

An ion microprobe with high lateral resolution has been used to study the chemical reactions at the fibre/matrix interface of metal–matrix composites. During the squeeze-casting process, the Al–Si–Mg matrix reacts with the preform made of Saffil fibres (96% Al₂O₃, 4% SiO₂). The reaction occurs mainly between the silica binder and Mg from the matrix according to SiO₂ + 2Mg = 2MgO + Si. A continuous layer of MgO was formed around the fibres, even on surfaces that were not covered by the silica binder. Possible reasons are discussed for the formation of MgO in areas where binder coating was missing. In such areas, Mg reduces SiO₂ that is contained in the fibre. However, the fibres (A1₂O₃) are not attacked by Mg. In the isolated case of fibres that were completely uncoated, no reaction products were observed at the interface. The presence of silica binder seems to be an essential requirement for this reaction to occur. When squeeze-casting is performed with sufficiently high melt temperature, Al from the matrix also reduces silica.     

Active coatings for SiC particles to reduce the degradation by liquid aluminium during processing of aluminium matrix composites: study of interfacial reactions

The application of a surface coating on SiC particles is studied as an alternative means of solving problems of reactivity between SiC reinforcements and molten aluminium and problems of low wetting which limit the application of casting routes for fabrication of Al–SiC_p composites. The selected active barrier was a ceramic composed of SiO₂, which was generated by controlled oxidation of the SiC particles. The coating behaves as an active barrier, preventing a direct reaction between molten aluminium and SiC to form Al₄C₃ as the main degradation product. At the same time, the SiO₂ provokes other interfacial reactions, which are responsible for an improvement in wetting behaviour.
Composites were prepared by mixing and compacting SiC particles with Al powders followed by melting in a vacuum furnace, and varying the residence time. Transmission electron microscopy (TEM), high resolution electron microscopy (HREM) and field emission TEM were employed as the main characterization techniques to study the interfacial reactions occurring between the barrier and the molten aluminium. These studies showed that the SiO₂ coating behaves as an active barrier which reacts with the molten Al to form a glassy phase Al–Si–O. This compound underwent partial crystallization during the composite manufacture to form mullite. The formation of an outer crystalline layer, composed mainly of Al₂O₃, was also detected. Participation of other secondary interface reactions inside the active barrier was also identified by HREM techniques.     

Modeling and analysis of performances in drilling hybrid metal matrix composites using D-optimal design

The present paper deals with the modeling and analysis of machining responses such as the thrust force, surface roughness, burr height, and tool wear in the drilling of hybrid metal matrix composites using carbide, coated carbide, and polycrystalline diamond drills. Experiments are conducted on Al 356 aluminum alloy reinforced with silicon carbide of size 25 μm and mica of size 45 μm. Machining parameters such as spindle speed, feed rate, and weight percent of silicon carbide are chosen as the numerical factors; the drill material is considered as the categorical factor. An experimental plan of a four-factor (three numerical plus one categorical) D-optimal design based on the response surface methodology is employed to carry out the experimental study. The results indicated that the predicted values through the developed model are well in agreement with the experimental results. The results also indicated that the method used is effectively applied for the modeling and analysis of drilling parameters in drilling hybrid metal matrix composites.     

Experimental investigations of damage analysis in drilling of woven glass fiber-reinforced plastic composites

This paper presented a new comprehensive approach to select cutting parameters for damage factor in drilling of glass fiber-reinforced polymer (GFRP) composite material. The influence of drilling on surface quality of woven GFRP plastic composite material was investigated experimentally. Drilling tests were carried out using carbide drills of 8 mm in diameter at 50, 70, and 90 m/min cutting speeds and at 0.06, 0.12, and 0.18 mm/rev feed rates. Damage factor was investigated based on hole entrance and exit. Analysis of variance (ANOVA) test was applied to the experimental results. The compared values were employed by Duncan test to identify which groups were significantly different from other groups.