钛合金可切削性的研究及加工刀具设计

分析了钛合金的相对可切削性 ,阐述了钛合金切削加工条件 ;以钛合金车加工和孔加工为例介绍了钛合金加工刀具的设计     

钛合金铣削刀具设计方法研究

钛合金属典型的难加工材料,文中从介绍钛合金的加工特点入手,提出一种新的钛合金铣刀设计方法,加工实践表明,该铣刀可提高切削效率及刀具寿命,改善钛合金切削加工困难状况。     

钛合金铣削加工技术研究现状及发展

钛合金比强度高、耐蚀性好、热强度高,是制造高温环境、易腐蚀环境下工作零件的理想高强轻质材料,被广泛应用于航空航天、生物医学、武器装备制造、石油化工及核电装备等各个领域。介绍了钛合金及其切削加工的特点,以钛合金切削机理和铣削性能的研究为主要内容,介绍了钛合金铣削加工性研究的现状,阐述了硬质合金、聚晶金刚石这2种适合切削钛合金的刀具材料的应用。介绍了高速切削技术、低温冷却技术、高效深腔加工技术在钛合金铣削中的应用特点和现状,讨论了目前钛合金铣削加工中存在的困难,并展望了钛合金铣削技术的发展趋势。     

切削加工钛合金的切削参数优化研究

钛合金材料因其具有强度高、耐腐蚀性好、耐热高等特点被广泛用于航空航天、舰船、民用工业等各个领域。而钛合金是典型的难加工材料,切削钛合金的加工效率和质量较低。本文选用了不同种牌号的硬质合金刀具,进行了切削加工TC4钛合金刀具磨损及耐用度试验。基于切削加工钛合金的刀具磨损及耐用度试验结果分析,确定了切削速度、切削深度和每齿进给量等切削参数作为设计变量,建立了以切削加工钛合金最大金属去除率为优化目标函数,依据实际加工条件设计了相应的约束条件,最终建立了切削参数优化数学模型。     

钛合金钻削加工及其新发展

从钛合金自身的切削加工性能出发,系统介绍了钛合金的切削加工基本原则。阐述了传统钛合金在钻削加工中常出现的几点问题:钻头材料、钻头几何参数分析和冷却介质的选择。根据钛合金的导热率低、弹性模量低、硬度较低和化学活性强等特点合理地调整钻头材料的选择,对原有钻头几何参数进行优化,正确选取冷却介质。并介绍了当前钛合金切削加工技术的新发展。     

在钛合金零件上实现高效钻削的方法

介绍了在钛合金零件上实现高效钻削的方法。以某航空零件为例,从刀具材料、刀具特点、切削参数、加工中应注意的问题等多个方面介绍了在钛合金材料上进行孔加工的经验,所介绍的孔加工刀具和方法对加工效率的提高和刀具寿命的延长都具有很大的优势,对于钛合金的高速切削技术有一定的参考意义。     

钛合金切削润滑研究现状与发展趋势*

钛合金在航空航天、生物医疗等领域具有广泛而重要的应用,但钛合金是典型的难加工金属,其切削润滑问题是制约钛合金加工效率与质量的关键所在,目前尚未得到较好的解决。从钛合金切削中的摩擦学问题、切削润滑问题、水基润滑问题三方面介绍钛合金切削润滑研究现状,以有望解决钛合金切削润滑问题的水基润滑为基础,从适合于钛合金切削润滑的微量润滑技术及纳米颗粒增效两方面探讨钛合金切削水基润滑研究的发展趋势,并总结以水基润滑剂为基础的高性能钛合金切削液体系设计是未来研发新型高效环保钛合金切削液的重要途径。     

钛合金切削性能的研究与应用

本文阐述了钛合金的相对可切削性及钛合金切削加工的切削条件；在此基础上以车加工和孔加工为例说明了钛合金加工的应用。     

基于快走刀层铣的TC4钛合金高效开槽加工

为提高钛合金深槽的开槽切削效率,对TC4钛合金深槽进行了快走刀层铣开槽试验。详细分析了其加工效率、切屑形态及刀具磨损情况。结果表明:在钛合金深槽开槽加工中快走刀层铣的切削效率较高,切削过程平稳,加工后槽腔表面的刀花均匀。快走刀层铣是一种高效的钛合金深槽加工方法。     

钛合金的深孔套料工艺试验研究

根据钛合金的材料特性和切削加工性能,设计和制造了适合于加工钛合金工件的套料钻并制定相应加工工艺,并对钛合金进行深孔套料加工试验.试验结果表明,切削过程稳定可靠,通过套料加工可显著提高钛合金的材料利用率,为钛合金套料提供了一套有效的加工工艺方法.     

超高速切削加工的刀具技术

超高速切削加工技术是一项综合性的高新切削加工技术,具有传统的切削加工技术不可替代的诸多优点,拥有光明的市场前景。文中根据国内外最新的研究资料,对超高速切削刀具的要求及应用范围,进行了较为详实的介绍和论述。     

高速切削机理的研究现状

对国内外高速切削机理的研究现状进行了概述,分析对比了高速切削切屑成形机理的两大理论体系——绝热剪切理论和周期脆性断裂理论,总结了高速切削刀具磨损方面的一些研究成果,指出了目前高速切削机理研究中存在的一些问题.     

A comparative study of the tool–chip contact length in turning of two engineering alloys for a wide range of cutting speeds

Tool chip contact length is an important parameter in machining, as it provides an indication of the size of area of interaction between the hot chip and the tool surface and hence the interface heat transfer zone. Heat transfer and thermally activated wear modes usually dominate tool wear in the high speed machining of steels and machining of titanium alloys at most cutting speeds. In this study, existing models for the prediction of tool–chip contact length are reviewed and examined for their suitability in high speed machining of two widely used engineering alloys. Orthogonal turning tests for AISI 1045 steel and Ti6Al4V titanium alloy are conducted for a range of cutting speeds from conventional to high speeds. New contact length models are presented for both materials covering a wide range of cutting speeds. More significantly, these contact length models are appropriate for high speed machining where thermal loads significantly influence process performance. Additionally, the work discusses how the machinability of engineering materials influences the ability to predict contact length.     

圆柱齿轮剐齿技术发展

剐齿技术是针对现有齿轮加工的局限而发展起来的新型圆柱齿轮加工技术,在小模数非贯通内齿轮的加工方面有明显优势。与传统的滚齿和插齿齿轮加工方法相比,剐齿技术采用干式、断续和微量切削,具有高速、高效、高精度及更环保等优点。本文详细介绍了剐齿概念、剐齿加工运动模型及国内外研究现状,指出了剐齿技术的发展方向。     

钛合金大进给铣削数控加工程序优化及应用

钛合金因其优越的比强度、机械性能和抗腐蚀性等优点而广泛应用于航空工业,但由于热导率低、弹性模量小、化学活性高等问题而导致其切削加工性差.介绍了大进给铣削技术这种高速高效的钛合金加工方法,分析了大进给数控加工程序编制带来的效率、品质和成本等方面的问题,提出了相应的加工程序优化方案,并在实际产品上进行了验证.     

SiC_p/Al复合材料高速切削的研究现状

介绍了SiCp/Al复合材料的特点、应用现状和加工难度,综合评述了SiCp/Al复合材料高速切削的国内外研究现状,分析了目前存在的主要问题及今后的研究方向。     

Problems and solutions in machining of titanium alloys

Titanium alloys are known as difficult-to-machine materials. The problems of machining titanium are many folds which depend on types of titanium alloys. This paper investigates the underlying mechanisms of basic challenges, such as variation of chip thickness, high heat stress, high pressure loads, springback, and residual stress based on the available literature. These are responsible for higher tool wear and worse machined surface integrity. In addition, many cutting tool materials are inapt for machining titanium alloys as those materials are chemically reactive to titanium alloys under machining conditions. To address these problems, latest techniques such as application of high pressure coolant, cryogenic cooling, tap testing, thermally enhanced machining, hybrid machining, and use of high conductive cutting tool and tool holder have also been discussed and correlated. It seems that all the solutions are not yet well accepted in the industrial domain; further advancement in those fields are required to reduce the machining cost of titanium alloys.     

Effect of microstructure and cutting speed on machining behavior of Ti6Al4V alloy

Machining of aerospace and biomedical grade titanium alloys has always been a challenge because of their low conductivity and elastic modulus. Different machining methods and parameters have been adopted for high precision machining of titanium alloys. Machining of titanium alloys can be improved by microstructure optimization. The present study focuses on the effect of microstructure on machinability of Ti6Al4V alloys at different cutting speeds. Samples were subjected to different annealing conditions resulting in different grain sizes and local micro-strains (misorientation). Cutting forces were significantly reduced after annealing; consequently, sub-surface residual stresses were reduced. Deformation twinning was also observed on samples annealed at a higher temperature due to larger grain size. Initial strain free grains and deformation twinning during machining reduces the cutting force at higher cutting speed.     

Machining of Titanium Alloy (Ti-6Al-4V)—Theory to Application

This article correlates laboratory-based understanding in machining of titanium alloys with the industry based outputs and finds possible solutions to improve machining efficiency of titanium alloy Ti-6Al-4V. The machining outputs are explained based on different aspects of chip formation mechanism and practical issues faced by industries during titanium machining. This study also analyzed and linked the methods that effectively improve the machinability of titanium alloys. It is found that the deformation mechanism during machining of titanium alloys is complex and causes basic challenges, such as sawtooth chips, high temperature, high stress on cutting tool, high tool wear and undercut parts. These challenges are correlated and affected by each other. Sawtooth chips cause variation in cutting forces which results in high cyclic stress on cutting tools. On the other hand, low thermal conductivity of titanium alloy causes high temperature. These cause a favorable environment for high tool wear. Thus, improvements in machining titanium alloy depend mainly on overcoming the complexities associated with the inherent properties of this alloy. Vibration analysis kit, high pressure coolant, cryogenic cooling, thermally enhanced machining, hybrid machining and, use of high conductive cutting tool and tool holders improve the machinability of titanium alloy.     

EFFECT OF COOLANT PRESSURE,NOZZLE DIAMETER,IMPINGEMENT ANGLE AND SPOT DISTANCE IN HIGH PRESSURE COOLING WITH NEAT OIL IN TURNING Ti-6AL-4V

Though titanium alloys are being increasingly sought in a wide variety of engineering and biomedical applications, their manufacturability, especially machining and grinding imposes lot of constraints. Titanium alloys are readily machinable provided the cutting velocity is in the range of 30–60 m/min. To achieve higher productivity, if the cutting velocity is enhanced to 60–120 m/min and beyond, rapid tool wear takes place diminishing the available tool life. Tool wear in machining of titanium alloys is mainly due to high cutting zone temperature localised in the vicinity of the cutting edge and enhanced chemical reactivity of titanium with the tool material. Rapid tool wear encountered in machining of titanium alloys is a challenge that needs to be overcome. High pressure cooling in machining is a very promising technology for enhancing tool life and productivity via appropriate cooling and lubrication. The present investigation is an attempt to study the effects of jet application parameters, i.e., coolant pressure, angle of impingement of the jet, spot distance and nozzle diameter on tool wear and chip morphology and to compare the effectiveness while turning Ti-6Al-4V bars under high pressure cooling with neat oil. Results indicated that at a cutting speed of 85 m/min and feed of 0.2 mm/rev, high pressure cooling provided a tool life of 24 min vis-à-vis 12 min under cryogenic cooling.