TC4钛合金深孔(钻削)套料加工系统及其刀具研究

针对大孔径深孔加工的难加工性和TC4材料的难切削性,优化确定加工系统类型和钻头的不同几何参数。根据选择的几何参数,对套料钻头进行三维建模,并用ANSYS有限元软件分析钻头的受力集中部位和钻杆的模态频率。结合有限元分析的结果进行深孔套料试验,试验结果表明:加工孔内壁精度高,排屑良好。为TC4钛合金的大直径深孔套料提供了切实有效的刀具几何参数和加工系统。     

深孔加工技术研究进展

深孔加工技术是机械加工中一项重要的技术,在石油化工、航空航天、造船工业、核电管板、电力设备等大部分制造部门有着广泛的应用。同时深孔加工具有排屑难、导热差、冷却润滑难等问题。本文从现代制造业对于深孔加工的需求出发,阐述了深孔加工系统发展与特点,重点对BTA系统、吸喷钻系统及DF系统进行分析;分析了不锈钢、钛合金、镍基合金等不同材料的深孔加工特点,及所用刀具材料的选择;对深孔加工状态监测的国内外研究现状进行概述。在此基础上,本文指出钻头结构的优化设计及高性能钻头材料的研发是深孔加工技术发展的主要方向。     

钛合金材料的数控加工方法

文章对钛合金的物理性能、化学性能以及切削性能进行了详细地分析.根据产品技术要求,文中介绍了一种新的钛合金电缆端子数控加工工艺方法,其中包括利用加工中心的可编程性合理编制数控加工程序,利用加工中心的操作人性化之特点优化切削参数.文章运用了对比的方法介绍了合理选择刀具几何形状以及采用普通高速钢钻头和立铣刀加工高精度大孔径比钛合金孔的加工工艺路线和措施.并通过实际样件的加工验证了改进刀具、优化切削参数及加工工艺方法的实用性.     

利用行星减速器实现深孔加工的过扭矩控制

在机械加工中,我们经常遇到深孔加工。例如,各种发动机机体、曲轴的润滑油孔、液压元件的某些油道孔等。深孔加工中采用普通钻头时冷却排屑困难,钻头易于折断。为了解决冷却排屑,防止钻头因切削扭矩过大而折断,生产中广泛采用刀具分级进给自动循环的加工方法。图1所示为加工发动机曲轴润滑油孔的分级进给自动循环示意图。     

PLC在深孔加工中的应用

在机械加工过程中,我们经常碰到钻径比大于10以上的深孔加工。由于深孔加工的加工工艺性差,这给刀具的自动进给带来一定的困难,因为在深孔加工时,钻头的散热条件不好,且排屑不方便,故钻头的纵向送给运动需要往复几次才能完成。如果采用液压动力滑台驱动刀具的纵向进给运动,往往通过行程开关和行程阔来控制液压缸的顺序动作,但是,钻头要实现数次纵向运动,且每次的进给深度都不一样,如采用上述控制方法,就不能达到预定的要求。如果采用PDe控制钻头的纵向进给运动,其控制线路就变得非常简单。根据深孔的加工工艺性,我们采用以下…     

用整体硬质合金钻头加工深孔

越来越多的加工车间正用整体硬质合金钻头取代枪钻加工深孔。 在过去枪钻占主导地位的深孔加工刀具市场中,能钻削深度达16—40倍孔径深孔的新一代整体硬质合金麻花钻正占有越来越大的份额。为了提高加工精度和排屑性能,这种整体硬质合金钻头采用了横刃和螺旋槽,并采用高密度硬质合金材料以提高硬度,从而使其能以比枪钻快5—10倍的速度进行钻削加工。     

自动化加工用刀具的现状与今后的开发课题

本文在简单介绍了目前刀具材料发展状况的基础上,以切槽车刀、用于铝材加工的车刀、超轻型铁刀、刀片切向排列的面铣刀和加工金属模具用的立铣刀,以及用于深孔加工的钻头和自动化、省力化刀具为重点,对自动化加工用的刀具现状和今后研究开发的课题做了较详细的介绍。图12幅。     

金和田青玉超声波振动深孔钻削试验研究

基于和田玉特殊的物理性能,采用金刚砂钻头和高速钢麻花钻在附加超声波振动和不附加超声波振动的条件下进行了和田青玉的钻削试验,在加工工件的刀具损坏、出口毛刺、孔表面微观质量3个方面进行对比分析,超声振动波钻削能获得更好的加工质量和效率,并能减少刀具的磨损和破坏,为和田玉精密加工提供了一种新的深孔加工工艺方法。     

TC9钛合金叶片的深孔加工

本文简要介绍某航空发动机第一级空心整流叶片细长深孔加工的一些经验,主要内容包括:1.TC9钛合金的加工特性;2.一级空心叶片通孔加工工艺方案的选择;3.TC9合金深孔加工试验;4.TC9合金的加工钻头和铰刀材料的选择与其几何参数的确定;5.切削用量的选择;6.加工中出现的问题及解决办法;7.深孔加工用冷却润滑剂的选择;8.对深孔加工中几个问题的探讨及改进意见。     

一种错齿双孔圆弧深孔钻头设计与应用研究

为了解决目前凿岩钎具尾孔加工过程中存在的工艺性差,加工效率低,加工出来的直孔与圆弧孔连接不好等缺陷;本文通过用一种新型的双孔内排屑圆弧钻头来代替传统BTA钻头在数控深孔钻床上对凿岩钎头尾孔加工过程的大量研究,探索出了一种用新型双孔内排屑圆弧钻头加工凿岩钎具尾孔的先进工艺,能在不更换刀具的情况下将凿岩钎具尾孔的直孔与圆弧孔部分一次加工成型,并使生产效率提升一倍以上,尾孔表面粗糙度可达到Ra0.8~3.2,极大地提高了凿岩钎具尾孔加工的质量和效率。     

Effect of MQL on the tool life of small twist drills in deep-hole drilling

Drilling of deep and small boreholes using twist drills has to be considered as one of the most difficult metal cutting operations. There are many reasons for this, one of them being that the cutting fluid has to be supplied externally. This research work investigates in how far the manner of supplying and the type of minimum quantity lubricant have an effect on the tool life of coated and uncoated high-speed steel twist drills of 1.5 mm diameter. Deep-hole drilling is performed as the holes, drilled into plain carbon steel, had a depth of 10 times the diameter. The feasibility of dry machining as an appropriate alternative to MQL in deep-hole drilling has also been investigated. This work shows that, compared to a continuous supply of the minimum quantity lubricant, a discontinuous supply brings about a significant reduction in tool life, especially in the case of heat-sensitive drills. With respect to the type of minimum quantity lubricant, a low-viscous type with a high cooling-capability gave rise to a notably prolonged tool life. It is also shown that dry drilling is associated with strongly accelerated tool wear for most of the twist drills tested, resulting in a significant reduction in tool life.     

On the design of ejectors for deep hole machining

A comprehensive study of ejectors used in deep-hole drills was conducted in order to understand the role of the ejectors with annular nozzles in the tool design. An analytical method was used to derive the equation for the operating energy characteristic of ejectors. The experimental investigations were carried out to explain the ejector's optimal design parameters necessary to achieve maximum hydraulic efficiency. The experiments also defined the principal criteria and compared different types of ejector nozzles suitable for deep-hole drills. Further investigation revealed the precise location of the ejector nozzle(s) in the deephole drill assembly and helped clarify the capabilities of the ejectors.     

基于二维超声振动辅助的钛合金切削加工分析与试验研究

针对普通切削时钛合金表面质量较差的问题,将二维超声辅助切削用于钛合金的加工过程。对钛合金的超声振动切削理论进行分析,找出影响刀具运动轨迹及切削力的因素;设计基于二维超声振动的钛合金表面切削试验,研究超声振动对切削力、工件表面形貌以及刀具寿命的影响。结果表明:与普通切削相比,二维超声振动辅助切削可以有效降低加工中的切削力,减轻加工过程对刀具的冲击,提高刀具的耐用度;且在相同加工条件下,二维超声振动加工时的切削力下降了47.7%,工件表面轮廓平均高度减小了40.9%,刀具的使用寿命提高了近1倍。      

基于切屑形态的42CrMo深孔钻削工艺参数优化

以难加工材料42CrMo高强度钢为研究对象,针对42CrMo高强度钢内排屑深孔钻削时存在断屑困难等问题,开展42CrMo高强度钢BTA深孔钻削试验研究。为了获得理想的切屑形态,分析BTA深孔钻削机床主轴转速与进给量对切屑形态的影响规律。试验结果表明：当转速为195 r/min、进给量为0.18 mm/r时,切屑呈现理想的C形屑、短卷屑,刀具磨损相对最小,有利于切屑顺畅排出,加工过程稳定。     

Drilling of X2CrNi 19 11 stainless steel with hiped NiTi coating

This study investigated suitability of TiN and TiCN-coated cemented carbide tools in the machining of conventionally produced stainless steel with HIPed (Hot Isostatic Pressed) NiTi coating. Near-equiatomic nickel–titanium alloy (NiTi) has many attractive material properties, such as pseudo-elasticity and shape memory effects, which result into beneficial engineering properties, e.g. as cavitation resistant coatings in addition to its well-known shape memory properties. Stainless steels are often considered to be poorly machinable materials; materials with high elasticity are also difficult to machine. In drilling stainless steel with a pseudo-elastic coating material, machinability difficulties are caused by the high strength and work hardening rate of steel and the pseudo-elastic properties of the coating material. The machinability was studied by analyzing cemented carbide drills and chips. The interface between stainless steel and NiTi coating was examined with SEM (scanning electron microscopy) and EDS (energy dispersive spectroscopy) analysis. The effect of feed rate on chip formation and tool wear was analyzed. The cutting tests indicated that cutting speeds of 50 m/min, a feed rate of 0.1–0.2 mm/rev, and solid carbide drills can be applied, from a machinability standpoint. A HIPed pseudo-elastic coating decreases machinability. When effective cutting speeds and feed rates were utilized, optimal tool life was achieved without a decrease in coating properties.     

Simulation of the BTA deep-hole drilling process

The dynamic disturbances of the deep-hole drilling process pose a great challenge. Especially spiralling, which causes holes with several lobes, can damage the workpiece irreparably. The causes for spiralling are not well explored yet, and it is important to analyze which conditions and process parameters can cause the spiralling. This article presents a simulation system for the idealized BTA (Boring and Trepanning Association) deep-hole drilling process. Methods of computer graphics allow the realistic modeling of the cutting edge and the workpiece. The simulation is able to calculate the sweep volume, cutting forces, and regenerative tool vibrations. It is also possible to generate the resulting geometry of the workpiece depending on the eigenfrequencies of the boring bar and on the process parameters. Thus, the pre-conditions for the spiralling can be analyzed.     

High-speed milling of titanium alloys using binderless CBN tools

The performance of conventional tools is poor when used to machine titanium alloys. In this paper, a new tool material, which is binderless cubic boron nitride (BCBN), is used for high-speed milling of a widely used titanium alloy Ti–6Al–4V. The performance and the wear mechanism of the BCBN tool have been investigated when slot milling the titanium alloy in terms of cutting forces, tool life and wear mechanism. This type of tool manifests longer tool life at high cutting speeds. Observations based on the SEM and EDX suggest that adhesion of workpiece and attrition are the main wear mechanisms of the BCBN tool when used in high-speed milling of Ti–6Al–4V.     

车-铣组合切削在钛合金加工中的应用研究

针对钛合金产品加工困难的问题,通过分析钛合金的切削加工性能,分别从刀具材料、刀具角度、切削用量及切削液等方面论述了钛合金产品车削加工工艺的优化策略,提出了采用楔形刀具和车-铣组合切削方式改善钛合金切削加工条件和提高加工效率的新思路,解决了传统切削加工钛合金产品的技术难题,对进一步研究钛合金的切削加工工艺具有一定的参考价值和生产指导意义。     

基于ABAQUS有限元仿真的硬质合金刀具磨损机制研究

钛合金在切削过程中会产生严重的加工硬化现象,导致切削性下降、刀具磨损加剧,直接影响工件的加工质量。为研究钛合金切削性能和刀具磨损机制,利用ABAQUS软件建立了钛合金的有限元模型,对其切削过程进行仿真分析,研究硬质合金刀具磨损机制;设计Ti6Al4V钛合金车削实验,研究不同加工参数对刀具磨损程度的影响规律。研究结果表明:在切削钛合金时,刀具的磨损主要发生在刀尖和后刀面位置,刀具的磨损长度随车削速度的增加而变大,随车削深度的增加而减小,随进给量的增加呈现出先减小后变大的情况,实验和仿真结果趋于一致,平均误差在6%以内。     

苯并三唑对碳钢/铜合金电偶腐蚀行为的影响

目的 研究NaCl溶液中苯并三唑(BTA)对碳钢/铜合金电偶腐蚀行为的影响.方法 使用丝束电极(WBE)技术和电化学阻抗谱(EIS)技术研究在未添加和添加BTA的NaCl溶液中,丝束电极表面的电位分布、电流密度分布和电化学阻抗谱演化,同时对比分析碳钢区域与铜合金区域的阻抗谱特征.结果 在未添加BTA的条件下浸泡72 h...