新型电弧离子镀AlTiN涂层的制备及其切削性能的研究

采用一种新的PVD电弧离子镀技术,在硬质合金立铣刀上沉积了新型AlTiN涂层。研究了新型电弧离子镀沉积的AlTiN涂层的硬度,表面形貌,结合强度及其高速铣削淬硬钢的切削性能,并与传统电弧离子镀制备的AlTiN涂层进行了对比。结果表明,新型电弧离子镀制备的AlTiN涂层不仅具有传统电弧离子镀的优良结合力,而且比传统电弧离子镀制备的AlTiN涂层具有硬度更大,表面更加光滑等优点,从而在高速铣削淬硬钢的切削试验中表现出更长的切削寿命。     

钛合金拉伸高速铣削试验研究

通过对钛合金TC4在拉伸状态下的铣削试验,重点研究了高速铣削对钛合金TC4(Ti6A14V)表面残余应力和表面粗糙度的影响,得到了在不同切削参数下钛合金TC4表面残余应力和表面粗糙度的实验数据.实验结果表明,拉伸装夹基本不影响表面粗糙度,但可以大大提高加工表面残余压应力并增大残余压应力层的厚度,为开展钛合金拉伸高速铣削加工提供了依据.     

TC4钛合金表面激光原位反应制备TiN涂层及性能研究

TC4钛合金因其具有质量轻、强度高、延展性强等特点,被广泛应用于医学、航空航天等各个领域。近年来,关于钛合金的研究日益深化。为进一步提升钛合金表面硬度,通常采用涂层制备的形式。研究表明使用激光原位反应原理制备的氮化钛涂层具备良好的抗腐蚀性、抗磨损性以及更强的表面硬度。由于钛合金本身硬度不高,在使用过程中极易产生严重的表面磨损,大大缩短钛合金产品的使用寿命,因此,对TC4钛合金进行涂层制备至关重要。良好的涂层性能有助于扩大钛合金材料的适用范围,提升钛合金的综合性能。     

钛合金高速铣削表面完整性研究

研究了钛合金TC4的高速铣削。着重讨论了高速铣削钛合金TC4已加工表面完整性的问题,重点研究了表面粗糙度、表面变质层等因素对表面完整性的影响。研究结果表明,切削速度在v=200～350m/min范围,钛合金TC4高速铣削获得的加工表面完整性较好。     

TC4钛合金深槽插铣加工

针对钛合金深槽开槽加工效率较低的问题,对TC4钛合金深槽进行插铣开槽试验研究,并对其已加工表面形貌、切屑形态、刀具磨损及切削效率进行了分析。结果表明:插铣加工表面粗糙度较大,铣刀的端面刃为主切削刃,刀具磨损主要发生在铣刀的端面刃。对于钛合金深槽的开槽加工,插铣加工切削过程平稳,具有比层铣更高的切削效率。     

PCBN刀具高速切削钛合金切削性能研究

采用PCBN刀具对钛合金TC4进行了高速车削试验,从切削力、工件表面粗糙度和刀具寿命等方面分析了PCBN刀具加工钛合金的切削性能,并与未涂层硬质合金刀具、涂层硬质合金刀具作了比较,证明了在高切削速度、低进给量和小背吃刀量的条件下,PCBN有着较长的刀具寿命。     

微喷砂处理对AlTiN涂层刀具表面性能的影响研究

涂层刀具以其自身的优势广泛应用于制造业中,而表面处理能够提高刀具表面性能;其中,微喷砂处理技术能够实现刀具性能的提升。选取Al_2O_3、ZrO_2两种喷料针对AlTiN涂层刀具进行微喷砂试验,探究微喷砂对AlTiN涂层刀具表面形貌、表面粗糙度以及残余压应力的影响;研究表明:喷砂时间过长或喷砂压强过大会冲蚀掉部分AlTiN涂层,影响刀具切削性能,增大表面粗糙度值;而合适的喷砂参数(喷料种类、喷砂时间和喷砂压强)能够减小表面粗糙度值并且增加表面残余压应力。该研究能够为微喷砂的参数设定提供指导性意见,有助于推动涂层刀具表面处理技术的发展。     

新型涂层刀具干式铣削加工SKD11切削性能研究

具有高硬度、耐高温、高耐磨性能和良好韧性的涂层刀具在干式切削加工中的应用越来越多,不同涂层刀具的应用场合及先进涂层的开发已成为目前涂层刀具技术研究的重点。本文基于TiAlN、AlTiN和TiAlN+WC/C三种涂层刀具在干式铣削加工SKD11时的切削力、切削温度和刀具磨损等物理量,对其切削性能作了详细分析。研究结果表明:在干铣加工SKD11时TiAlN+WC/C涂层刀具和AlTiN涂层刀具优于TiAlN涂层刀具,其中AlTiN涂层刀具的涂层材料硬度最高,而且在切削高温影响下生成Al2O3的薄膜层能延长该涂层刀具的寿命;TiAlN+WC/C涂层刀具的切削力小、刀具耐用度高,是干式铣削加工模具钢SKD11的理想刀具。     

TC4圆弧形槽铣削刀具的研发设计及试验研究

针对TC4钛合金圆弧形槽的加工设计一种专用铣削刀具。在钛合金切削加工过程中,刀具参数角度是影响工件表面粗糙度和加工精度稳定性的重要因素,在采用高速钢刀具对TC4钛合金进行高精高效加工时,利用刀具几何角度减小断面与圆弧面圆角半径,达到圆弧半径清根作用。在TC4钛合金圆弧形槽铣削加工中,设计了一种以W18CR4V高速钢为基体的切削刀具,并进行了铣削加工试验,利用SuperView W1光学3D表面轮廓仪测量其粗糙度和轮廓度,工件表面精度可达Ra1.6μm,且具有较强清根作用,经过试验对比验证,本设计可达到高效率铣削钛合金效果。     

TC4钛合金高速铣削加工刀具失效机理研究

以TC4钛合金为试验材料,采用超细硬质合金PVD涂层刀具进行高速铣削加工,研究刀具在铣削TC4材料时的失效机理。试验通过采用扫描电子显微镜(SEM)和元素能谱检测(EDS),分别对失效刀具的刃口区域、前刀面区域、后刀面区域的磨损进行失效形貌检测和合金元素成分的分析测试。研究表明:超细晶粒硬质合金PVD涂层刀具进行TC4钛合金高速铣削加工时,刀具的失效形式在不同加工区域各有不同,刃口以黏结磨损失效和热—机械疲劳磨损失效为主,前刀面和后刀面以黏结磨损失效为主,刃口的热—机械疲劳裂纹扩展到前刀面和后刀面,并加剧了刀具的崩缺失效。     

基于响应曲面法的钛合金TC21铣削参数优化

针对新型损伤容限型钛合金TC21的难加工性,通过基于响应曲面法的中心复合设计铣削试验研究工艺参数对切削力的影响规律,建立二阶响应曲面模型,以最小切削力为目标优化工艺参数。研究结果表明:轴向切深和每齿进给对切削力影响显著,径向切深和切削速度对切削力影响较小,最优加工参数为v_c=119.71m/min,f_z=0.06mm/z,a_e=0.87mm,a_p=16.01mm。将最优加工参数应用到工程实践中,可提高整体硬质合金刀具寿命和各类型零件的加工效率。     

Combined rough and finish machining of Ti–6Al–4V alloy by electrochemical mill-grinding

Abstract

This study proposes a combined method for the electrochemical mill-grinding of Ti–6Al–4V alloy to achieve a high material removal rate, high machining accuracy and good surface quality based on rough and finish machining. In the rough machining stage, a maximum feed rate of 2.7?mm min^?1 and a material removal rate of 248.3?mm³ min^?1 were achieved experimentally at a 10?mm cut depth using an abrasive tool with five rows of tool-sidewall outlet holes. In the finish machining stage, there were almost no overcuts or stray corrosions produced. The sidewall surface roughness and sidewall flatness were Ra = 1.06 and 76.8?μm after the finishing stage, which represent a 68% and 79.2% improvement compared with the rough machining stage, respectively. Finally, we fabricated a 1-mm-thick thin-walled structure using the combined machining operations, in which approximately 96% of the total material removal volume was performed at the rough machining stage.     

钛合金型腔圆角高速铣削特征研究

钛合金型腔圆角加工容易发生切削负载增大和颤振等现象,导致圆角表面质量较差,难以实现钛合金高效加工。通过钛合金型腔圆角铣削试验,基于铣削力和圆角表面质量检测,分析内圆角铣削特征和原理,并优化铣削参数。试验表明:采用小切削宽度的高速加工,可实现钛合金内圆角的高效加工;在Vc=90m/min,ft=0.06mm/t,ap=20mm,ae=1mm切削参数组合下,切削力相对较小,加工效率高,切削表面质量高。     

Influence of tool inclination on chip formation process and roughness response in ball-end milling of freeform surfaces on Ti-6Al-4V alloy

An experimental test part, which was made up of flat, concave, and convex surfaces of variable curvatures, was designed to be fabricated in a four-axis machining center. Aluminum alloy 7075 and titanium alloy Ti-6Al-4V were used for the fabrication. Within the finishing process, smeared/adhered material was found in some areas of the concave and convex surfaces of the titanium alloy. On the other hand, smeared/adhered material was not found in the aluminum alloy. To characterize the type of defects, the 3D roughness parameters of the surfaces were measured by confocal microscopy, and surface morphology was observed using optical microscopy and scanning electron microscopy. The kinematics of the ball-end milling process was modeled and it was found that the lead and tilt angles between the tool axis and surface normal vector vary continuously, producing transitions between oblique-plunge-push-up milling and oblique-reverse-push-up milling. This causes variation in the thickness behavior during the chip formation process. It was found that the lead angle has a moderate influence, while the tilt angle has a strong effect on the quality of the surfaces of the titanium alloy, with negative tilt angles producing the worst surfaces when there was the oblique-plunge-push-up milling process.     

Experimental investigation of top burr formation in high-speed micro-end milling of titanium alloy

ABSTRACT

Superalloys with burr-free parts are most preferably used in biomedical, aerospace, marine and automotive applications. In order to reduce the global pollution content, industries strive to execute stringent green manufacturing technologies. There is a need to investigate the different available tools in high-speed micro-milling process to achieve desired burr free with good surface finish on super alloys without using traditional coolants. In machining of titanium and its alloys, because of low thermal conductivity and reactivity with tool materials instigate the burr formation on work material and lowers the tool performance. The main objective of this article is to investigate the top burr formation in high-speed micro-end milling of alpha + beta-titanium alloy-grade 23 ELI (Ti-6Al-4V) under dry cutting conditions using Uncoated and physical vapor deposition coated AlTiN, TiAlN tungsten carbide end mills. Machining performance of the three cutting tools was compared. From the comparison of cutting tools for machining titanium alloy-grade 23, it is found that coated TiAlN tools produce less burr formation than coated AlTiN and uncoated tungsten carbide tools.     

钛合金精密铣削的表面粗糙度研究

进行了精密铣削钛合金粗糙度试验研究,采用正交分析方法,分析切削三要素铣削速度、进给量、铣削深度对表面粗糙度的影响规律,试验采用直径为2mm的3刃铣刀进行铣削。试验结果表明：表面粗糙度影响顺序依次是进给量、切削速度、切削深度。进给量选为0．01—0．05mm／min时,表面粗糙度随进给量的增大而增大。铣削深度在60—150μm、铣削速度在18．84-47．10m／min试验范围内,最优铣削速度为37．68m／min。而铣削深度对钛合金表面粗糙度影响不大。     

液氮冷却下大进给铣削TC4钛合金的试验研究

钛合金是现代飞行器的主要结构材料之一,是一种典型的难加工材料。针对切削加工钛合金时刀具磨损快、表面质量不易控制等难题,将TC4钛合金作为研究对象,以液氮作为冷却介质,进行了TC4钛合金的大进给铣削试验,测试了液氮冷却条件下大进给铣削TC4钛合金的铣削力、铣削温度以及刀具磨损等,并与乳化液和低温冷风条件下的测试结果进行了对比分析。结果表明:在以较大的切削速度和每齿进给量铣削TC4钛合金时,采用液氮冷却比使用乳化液能更有效地降低切削力和切削温度;比采用低温冷风冷却能更有效地延长刀具寿命。     

钛合金表面多磁极耦合旋转磁场光整加工特性

面向激光增材制造钛合金表面的光整加工需求,设计出一种多磁极耦合旋转磁场光整加工装置来研究光整加工特性。基于ANSYS Maxwell仿真软件分析了光整加工装置的磁场强度分布。搭建了实验光整平台,分析了主轴转速、C轴转速和加工间隙对表面质量的影响。结果表明,在主轴转速500 r/min、C轴转速160 r/min和加工间隙0.7 mm的加工条件下,表面粗糙度Ra由5.991 μm下降至0793 μm。扫描电子显微镜(SEM)观测表明,光整后的钛合金表面沉积层消失,表面质量得到显著改善。