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。     

Taguchi method based optimisation of drilling parameters in drilling of AISI 316 steel with PVD monolayer and multilayer coated HSS drills

This paper focuses on the optimisation of drilling parameters using the Taguchi technique to obtain minimum surface roughness (Ra) and thrust force (Ff). A number of drilling experiments were conducted using the L16 orthogonal array on a CNC vertical machining centre. The experiments were performed on AISI 316 stainless steel blocks using uncoated and coated M35 HSS twist drills under dry cutting conditions. Analysis of variance (ANOVA) was employed to determine the most significant control factors affecting the surface roughness and thrust force. The cutting tool, cutting speed and feed rate were selected as control factors. After the sixteen experimental trials, it was found that the cutting tool was the most significant factor on the surface roughness and that the feed rate was the most significant factor on the thrust force. The results of the confirmation experiments showed that the Taguchi method was notably successful in the optimisation of drilling parameters for better surface roughness and thrust force.     

Machinability of Kevlar® 49 Composite Laminates While Using Standard TiN Coated HSS Drills

This article addresses the machinability of plain weave Kevlar® 49 prepeg composite laminates of different thickness while using 135° split-point TiN coated 6 mm diameter HSS drills. The effect of composite preparation parameters and the drilling conditions on the machinability of the laminates is assessed using the drilling thrust force, cutting torque, and specific cutting energy. The thickness and processing time of the laminates as well as the drilling process parameters were found to influence the maximum value of thrust force and torque as well as the quality of drilled holes. The wear features of the drills used in machining Kevlar composites have been found to be different from the conventional wear patterns that occur during drilling metals and alloys.     

Machinability of Kevlar® 49 Composite Laminates While Using Standard TiN Coated HSS Drills

Abstract

This article addresses the machinability of plain weave Kevlar® 49 prepeg composite laminates of different thickness while using 135° split-point TiN coated 6 mm diameter HSS drills. The effect of composite preparation parameters and the drilling conditions on the machinability of the laminates is assessed using the drilling thrust force, cutting torque, and specific cutting energy. The thickness and processing time of the laminates as well as the drilling process parameters were found to influence the maximum value of thrust force and torque as well as the quality of drilled holes. The wear features of the drills used in machining Kevlar composites have been found to be different from the conventional wear patterns that occur during drilling metals and alloys.     

Wear mechanism maps of uncoated HSS tools drilling die-cast aluminum alloy

A map describing the flank wear characteristics of uncoated high-speed steel (HSS) tools is constructed under the condition of drilling die-cast aluminum alloy. Several wear mechanisms are revealed which describe different wear modes observed by SEM in uncoated HSS tools, including adhesive wear, adhesive and abrasive wear, abrasive wear, severely plastic flow, and thermal wear. In the map, there exists a minor wear region, which is called “safety cutting zone” to the HSS tools. This map will be a good reference for choosing suitable drilling parameters of uncoated HSS cutting tools.     

Multi response optimization of machining parameters of drilling Al/SiC metal matrix composite using grey relational analysis in the Taguchi method

This paper presents a new approach for the optimization of drilling parameters on drilling Al/SiC metal matrix composite with multiple responses based on orthogonal array with grey relational analysis. Experiments are conducted on LM25-based aluminium alloy reinforced with green bonded silicon carbide of size 25 μm (10% volume fraction). Drilling tests are carried out using TiN coated HSS twist drills of 10 mm diameter under dry condition. In this study, drilling parameters namely cutting speed, feed and point angle are optimized with the considerations of multi responses such as surface roughness, cutting force and torque. A grey relational grade is obtained from the grey analysis. Based on the grey relational grade, optimum levels of parameters have been identified and significant contribution of parameters is determined by ANOVA. Confirmation test is conducted to validate the test result. Experimental results have shown that the responses in drilling process can be improved effectively through the new approach.     

电路板复合材料微小孔加工技术

介绍树脂基复合材料印刷电路板的机械钻削和激光钻削微小孔加工技术,分析了影响钻削质量的因素以及加工过程中易出现的各种缺陷和改进措施。机械钻削微小孔时,轴向力和切削扭矩是导致各种加工缺陷的主要因素,低进给量、高主轴转速可明显提高钻削质量。激光钻削时,选择合适的激光功率及减少激光照射时间可提高钻削质量。     

Performance of cryogenically treated M35 HSS drills in drilling of austenitic stainless steels

In this study, performance of cryogenically treated M35 high speed steel (HSS) twist drills in drilling of AISI 304 and 316 stainless steels was evaluated in terms of thrust force, surface roughness, tool wear, tool life, and chip formation. To present the differences in tool performance between untreated and treated drills, and machinability between AISI 304 SS and AISI 316 SS, a number of experiments were performed at different combinations of cutting speed, and feed rate. As the results of the conducted experiments, the treated drills showed better performance than untreated drills in terms of thrust force, surface roughness, and tool wear and tool life for both types of stainless steels. Tool lives of treated HSS drills in drilling of AISI 304 SS and AISI 316 SS improved 32% and 14%, respectively, when compared with untreated drills. Experimental results also showed that machinability of AISI 304 SS was harder than the machinability of AISI 316 SS.     

CrAlTiN梯度涂层高速钢刀具的切削性能研究

用闭合场非平衡磁控溅射离子镀PVD涂层工艺在高速钢麻花钻上沉积了CrA lTiN梯度涂层。在干式切削条件下,对45#号钢和30CrMnS iA钢进行了钻削试验。通过涂层与未涂层钻头的寿命、磨损和切削力等试验比较,表明CrA lTiN梯度涂层钻头的切削性能远优于未涂层钻头,是一种极有发展前途的刀具涂层。     

玻璃钢复合材料夹层结构钻削试验研究

玻璃钢复合材料夹层结构凭借其优越的性能在航空航天、国防等领域得到了广泛应用,但在钻孔的过程中经常因钻削轴向力过大而出现分层、撕裂等缺陷.为此,利用正交试验方法,选用不同材质的钻头、不同切削参数对玻璃钢复合材料夹层结构进行钻削试验,分析这些因素与钻削轴向力之间的关系,得出最适合的切削参数.然后通过方差分析,得出各因素对钻削轴向力的影响程度.最后从钻削工艺角度提出改进措施,进一步提高钻孔质量.     

The influence of the cutting tool microgeometry on the machinability of hardened AISI 4140 steel

The aim of this work is to define the cutting conditions that allow the dry drilling of carbon fiber reinforced epoxy (CFRE) composite materials taking into consideration the quality of the drilled holes (the exit delamination factor and the cylindricity error) and the optimum combination of drilling parameters. A further aim is to use grey relational analysis to improve the quality of the drilled holes. The machining parameters were measured according to 3³ full factorial parameter designs (27 experiments with independent process variables). The experiments were carried out under various cutting parameters with different spindle speeds and feed rates. Drilling tests were done using WC carbide, high-speed steel (HSS), and TiN-coated carbide drills. The experiment design was accomplished by application of the statistical analysis of variance (ANOVA). Results show that the thrust force is mainly influenced by the tool materials and the feed rate, which has a strong influence on the exit delamination factor. On the other hand, the spindle speed particularly affects the cylindricity error of the holes. Correlations were established between spindle speed/feed rate and the various machining parameters so as to optimize cutting conditions. These correlations were found by quadratic regression using response surface methodology (RSM). Finally, tests were carried out to check the concordance of experimental results.     

Effect of different features to drill-wear prediction with back propagation neural network

In this paper, a back propagation neural network (BPNN) has been applied to predict the corner wear of a high speed steel (HSS) drill bit for drilling on different workpiece materials. Specially defined static and dynamic features extracted by a wavelet packet transform (WPT) from the resultant force converted from thrust and torque together with the cutting conditions (workpiece material, spindle speed, drill diameter, feed rate) are used as inputs to train the network to obtain a better output, drill corner wear. Drilling experiments have been carried out over a wide range and, features newly defined and conventional ones, features extracted from different frequency bands are compared.     

Friction and wear behaviors of MoS2/Zr coated HSS in sliding wear and in drilling processes

MoS2 metal composite coatings have been successful used in dry turning, but its suitability for dry drilling has not been yet established. Therefore, it is necessary to study the friction and wear behaviors of MoS2/Zr coated HSS in sliding wear and in drilling processes. In the present study, MoS2/Zr composite coatings are deposited on the surface of W6Mo5Cr4V2 high speed steel(HSS). Microstructural and fundamental properties of these coatings are examined. Ball-on-disc sliding wear tests on the coated discs are carried out, and the drilling performance of the coated drills is tested. Test results show that the MoS2/Zr composite coatings exhibit decreases friction coefficient to that of the uncoated HSS in sliding wear tests. Energy dispersive X-ray(EDX) analysis on the wear surface indicates that there is a transfer layer formed on the counterpart ball during sliding wear processes, which contributes to the decreasing of the friction coefficient between the sliding couple. Drilling tests indicate that the MoS2/Zr coated drills show better cutting performance compared to the uncoated HSS drills, coating delamination and abrasive are found to be the main flank and rake wear mode of the coated drills. The proposed research founds the base of the application of MoS2 metal composite coatings on dry drilling.     

钻削GH4169高温合金薄壁件钻削力仿真研究

GH4169高温合金的薄壁钻孔与厚壁钻孔相比有特殊性,运用ABAQUS软件进行钻削GH4169高温合金薄壁件的仿真,研究钻削加工过程中钻削参数和工件厚度对钻削力的影响规律及变化特征,分析应力的分布规律。结果表明:钻削初期,横刃的挤压和主切削刃切削长度的增加使钻削力和扭矩增大;稳定钻削阶段,横刃切出后,主切削刃切削长度不变切削直径增加,钻削力和扭矩稳定增加;钻削后期,副切削刃参与切削,主切削刃切削长度减小,轴向钻削力和扭矩减小,但副刃与孔壁的挤压摩擦,曲线波动较大;钻削速度、进给量及工件厚度的增加都会导致轴向钻削力和扭矩的增加;钻削时的最大应力分布在横刃和主切削刃与工件的接触部位。     

Predicting drill wear using an artificial neural network

The present work deals with drill wear monitoring using an artificial neural network. A back propagation neural network (BPNN) has been used to predict the flank wear of high-speed steel (HSS) drill bits for drilling holes on copper work-piece. Experiments have been carried out over a wide range of cutting conditions and the effect of various process parameter like feedrate, spindle speed, and drill diameter on thrust force and torque has been studied. The data thus obtained from the experiments have been used to train a BPNN for wear prediction. The performance of the trained neural network has been tested with the experimental data, and has been found to be satisfactory.     

GH4169高温合金薄壁钻削加工钻削力的仿真研究

GH4169高温合金薄壁钻孔与常规的高温合金厚壁钻孔相比有其特殊性,应用有限元分析软件对硬质合金钻头钻削镍基高温合金平板薄壁件的动态过程进行建模,总结钻削过程中钻削力的变化特点以及进给量和钻削速度对钻削力的影响。研究结果表明:当钻尖高度大于薄壁件厚度时,根据钻头与薄壁件的相对位置,可将钻削过程分为三个阶段,在不同阶段钻削力变化特点不同;轴向力和扭矩随着钻削速度的增加而增加,但轴向力增加幅度不大;轴向力和扭矩均随着进给量的增大而明显增大;进给量对钻削力和扭矩的影响较钻削速度明显。     

凹槽微织构刀具皮质骨切削仿真研究

在骨钻削过程中,钻削力过大会对骨组织造成损伤,研究表明,微织构能够有效改善刀具的切削性能。将钻削简化为二维切削,研究凹槽微织构刀具对切削力的影响。基于切削理论建立了凹槽微织构刀具的切削力模型,利用ABAQUS软件进行皮质骨二维切削仿真。设计单因素试验确定微织构参数(宽度、间距和刃边距)对切削力的影响,对比分析微织构刀具和无微织构刀具的仿真结果。结果表明:微织构刀具能够有效减小切削力;微织构参数对切削力有不同影响。     

复合钻削刀具负载的建模与验证研究

针对复合钻削刀具钻孔过程负载计算误差较大,负载动特性预测精度较低的问题,对复合钻削的切削负载动态过程进行了研究。基于斜角切削理论,针对主切削刃负载和倒角刃单元负载受力分析,分别建立了主切削刃和倒角刃的等效切削模型。由于复合钻削过程的复杂性,采用数学分析和经验值相结合的方法,提出了钻削过程动态负载模型。同时考虑钻削过程中主轴径向跳动对切削性能的影响,进一步优化了复合钻削负载模型。通过对复合刀具不同刃不同切削工况的负载叠加融合,提出了复合钻削动态负载模型,并进行了仿真和实验。结果表明,考虑主轴径向跳动所建立模型相较于未考虑主轴径向跳动模型更能够准确地描述复合钻削刀具的动态负载特性,其负载误差比未考虑主轴跳动的情况减小了10%。     

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。     

Measurement and analysis of thrust force in drilling of particle board (PB) composite panels

Particleboard is a wood based composite extensively used in wood working. Drilling is the most commonly used machining process in furniture industries. The surface characteristics and the damage free drilling are significantly influenced by the machining parameters. The thrust force developed during drilling play a major role in gaining the surface quality and minimizing the delamination tendency. The objective of this study is to measure and analyze the cutting conditions which influences the thrust force in drilling of particle board panels. The parameters considered are spindle speed, feed rate and point angle. The drilling experiments are performed based on Taguchi’s design of experiments and a response surface methodology (RSM) based mathematical model is developed to predict the influence of cutting parameters on thrust force. The results showed that high spindle speed with low feed rate combination minimizes the thrust force in drilling of pre-laminated particle board (PB) panels.