基于FAHP及GRA的刀具优选方法研究

针对传统层次分析法(AHP)在构建刀具优选判断矩阵时没有考虑评价工程师主观判断的模糊性和指标属性的模糊性,导致刀具优选可信度和准确性降低的问题。分析了影响刀具选择的约束因素,建立了一种两级结构的多目标刀具优选模型,包括刀具的加工时间T、加工质量Q、加工成本C、资源消耗R、环境影响E五个优化目标;提出并设计了基于三角模糊数的模糊层次分析法(FAHP)及灰色关联分析(GRA)法进行求解刀具优选层次模型的算法,在三角模糊数互补判断矩阵传统计算权重方法的基础上,进行了算法优化。结合某航空制造企业叶片榫头铣削刀具优化选择的案例,证明了该方法用于刀具优选是可行且有效的。     

智能化CAPP系统中的刀具优选

本文针对刀具选择的特点,分析影响刀具选择的因素,利用模糊数学理论,建立刀具优选的理论模型,并开发了相应功能模块,集成运行于一个智能化ＣＡＰＰ系统环境中。两个典型非回转体零件验证了系统的可行性。     

数控刀具可靠度的分析与研究

针对数控加工的工艺特点,提出数控刀具的技术要求。建立数控刀具可靠度模型,提出数控刀具可靠度结构设计方法,并提出数控刀具可靠度的优选原则。     

基于刀具姿态控制的指令点插补算法

为克服五轴数控加工中忽略刀具姿态控制所带来的旋转轴速度和加速度不连续等问题,提出一种基于刀具姿态控制的五轴数控加工指令点插补算法。该算法根据给定的数控加工程序确定刀尖点位置集合和刀轴矢量集合,分别采用样条曲线对离散刀尖点和刀轴矢量进行拟合,得到刀尖点曲线和刀具姿态曲线,在此基础上进行指令点插补。实验结果表明,该算法能够将离散刀轴矢量拟合成位于单位球面的二阶连续曲线,保证旋转轴速度和加速度的连续性。     

非回转体零件数控铣刀的选择

数控加工中刀具的选择除需遵循传统加工的选择规则外,还应遵循一些特殊的原则。基于MasterCAM和Vericut软件,从数控用铣刀的分类、刀具材料、工艺参数等几个方面研究数控加工中刀具选择的问题,给出刀具选择一般规则。同时考虑到软件中提供的刀具不符合车间实际的情况,提出建立刀具库的策略,可提高数控加工的编程效率,对数控技术的运用起到积极的促进作用。     

智能化CAPP系统的中的刀具优选

本文针对刀具选择的特点，分析影响刀具选择的因素，利用模糊数学理论，建立具优选的理论模型，并发了相应的功能模块，集成运行于一个智能化ＣＡＰＰ系统环境中，两个典型非回转体零件验证了系统的可行性。     

0CR25NI20奥氏体不锈钢铣削加工研究

数控铣削加工中刀具参数选择是关键。介绍了不锈钢材料的加工特点,回顾了铣削加工0Cr25Ni20奥氏体不锈钢时存在的各种问题及其原因;通过选择不同的参数,得到不同的加工效果,从而分析铣削刀具参数对加工效果的影响,及所带来的各种问题和原因。研究结论为铣削刀具参数的选择提出了建议。     

Ti6Al4V车削加工时硬质合金刀具磨损的数值模拟

为研究硬质合金刀具车削加工钛合金过程中的刀具磨损,刀具选择刚性模型,工件选择塑性模型,利用有限元软件对切削过程的刀具磨损进行了模拟。运用正交试验分析了在不同刀具参数组合下刀具磨损量的变化情况。结果表明:在固定的工艺参数下,刀具的前角和后角的交互作用对刀具的磨损量影响较大;单一参数因素的变化对刀具磨损量的变化影响较小。分析结果对降低硬质合金车削加工钛合金时的刀具磨损提供了参考。     

基于PowerMill雕像的5轴加工应用

在5轴加工中对雕像的应用,对刀具的选择及切削参数尤为重要,雕像是由复杂的曲面组成,形状复杂且细节特征较多,所以在加工中选择采用5轴联动机床,制定工艺路线,基于PowerMill软件的5轴策略,设置加工区域,刀轴应用等参数,以雕像模型加工为实例,给出5轴加工曲面投影加工方法,编写刀具轨迹,运用PowerMill软件定向开粗和5轴联动加工生成刀具路径。     

基于遗传算法的曲面加工优化双刀具选择算法

针对球头刀加工自由曲面时的局部干涉影响曲面加工效率问题,提出了优化双刀具选择算法。基于曲率模型求取无曲率干涉加工自由曲面的最小刀具尺寸,给出对应不同尺寸刀具划分自由曲面干涉区域和非干涉区域,等面积平面近似曲面计算刀具路径总长度计算方法,基于遗传算法求解由刀具尺寸与刀具路径长度建立的双刀具选择模型。验证实例表明该算法能够显著提高自由曲面加工效率。     

Wear Behavior of CVD-Diamond Tools

Diamond cutting tools are often the only choice for the machining of high-strength and highly abrasive non-ferrous alloys. During machining, a complex interaction of different wear mechanisms takes place on the tools. This interaction considerably hinders a purposeful detection of specific wear mechanisms. Therefore, the objective is to systematically analyze the wear processes that occur when machining a hypereutectic aluminum silicon alloy with CVD-diamond tools. The main wear mechanisms are identified and the limits for the use of various CVD-diamond tools are indicated. The findings gained will serve in the further development of these high-performance cutting materials.     

Multifunctional Application of a Synthetic Ester to Machine Tool Lubrication Based on MQL Machining Lubricants

Machine tools generally necessitate a variety of lubricants. Since some of those lubricants are often contaminated with cutting fluids and disposed without adequate separation treatments, it must certainly be convenient to prepare a multifunctional fluid applicable to both machining and other lubricating parts. In minimal quantity lubrication (MQL) machining, synthetic polyol esters are the successful cutting lubricant. This study therefore proposes a certain synthetic ester as a base candidate of environmentally friendly multifunctional fluids. Several cutting and lubrication tests have demonstrated the successful multifunctional lubrication performance of this ester with a very small quantity of a highly effective additive.     

Surface integrity when machining age hardened Inconel 718 with coated carbide cutting tools

Considerable attention has been given to the use of ceramic cutting tools for improving productivity in the machining of heat resistant super alloys (HRSA). However, because of their negative influence on the surface integrity, ceramic tools are generally avoided particularly for finishing applications. As a result the main high end manufacturers are more or less dependent on carbide cutting tools for finishing operations. Still the improper use of carbide cutting tools can also result in poor surface integrity. The objective of this investigation is to develop a set of guidelines, which will assist the selection of the appropriate cutting tools and conditions for generating favorable compressive residual stresses. This paper specifically deals with residual stresses and surface finish components of surface integrity when machining (facing) age hardened Inconel 718 using two grades of coated carbide cutting tools specifically developed for machining HRSAs. The cutting conditions were obtained from investigations based on optimum tool performance. The effect of insert shape, cutting edge preparation, type and nose radius on both residual stresses and surface finish was studied at this optimum cutting condition. This investigation, suggested that coated carbide cutting tool inserts of round shape, chamfered cutting edge preparation, negative type and small nose radius (0.8 mm) and coolant will generate primarily compressive residual stresses.     

深型腔加工中刀具碰撞和避空问题的研究

针对深型腔模具加工中刀具、夹持的碰撞及其避空问题,通过利用PowerMILL编程软件的刀杆、刀柄碰撞检查,可以避免刀具碰撞现象的发生,同时,设置合理刀具避空,可以充分利用刀具,提高模具的加工精度。     

Experimental investigation on the effect of the material microstructure on tool wear when machining hard titanium alloys: Ti–6Al–4V and Ti-555

An experimental investigation was conducted in this work to analyze the effect of the workpiece microstructure on tool wear behavior and stability of the cutting process during marching difficult to cut titanium alloys: Ti–6Al–4V and Ti-555. The analysis of tool–chip interface parameters such as friction, temperature rise, tool wear and workpiece microstructure evolution under different cutting conditions have been investigated. As the cutting speed increases, mean cutting forces and temperature show different progressions depending on the considered microstructure. Results show that wear modes of cutting tools used for machining the Ti-555 alloy exhibit contrast from those obtained for machining the Ti–6Al–4V alloy. Because of the fine-sized microstructure of the near-β titanium Ti-555, abrasion mode was often found to be the dominate wear mode for cemented cutting tools. However, adhesion and diffusion modes followed by coating delamination process were found as the main wear modes when machining the usual Ti–6Al–4V alloy by the same cutting tools. Moreover, a deformed layer was detected using SEM–EDS analysis from the sub-surface of the chip with β-grains orientation along the chip flow direction. The analysis of the microstructure confirms the intense deformation of the machined surface and shows a texture modification.     

加工复合地板耐磨层时PCD刀具切削参数的研究

切削参数是影响PCD刀具切削性能的主要因素。本文采用Element Six公司的SYNDITE CTH025型聚晶金刚石(PCD)复合片制成强化复合地板用切削刀具，进行了一系列加工强化复合地板耐磨层的切削实验。通过实验研究了切削参数对刀具切削力的影响，得出了切削力随切削参数的变化规律，指出随着切削深度的增加，PCD刀具切削力增加；进给速度的增加使切削力增加；切削速度的增加将会使切削力降低。同时，分析了切削参数对刀具磨损、工件加工质量以及加工效率的影响。最后，本文总结了采用PCD刀具加工强化复合地板时加工参数的选择原则，认为当n=6000r／min、f=10000mm／min能够实现较高的加工效率，并保证工件的加工质量。     

Tool setting on a B-axis rotary table of a precision lathe

A method has been developed for setting a single-point cutting tool on the axis of rotation of a B-axis rotary table on a precision lathe. The method requires that three grooves be machined in the face of a workpiece with the B-axis set at three different angles. The depths of each of the grooves are then measured, and the measured values are used to calculate the tool offset vector. Experiments on a four-axis diamond turning machine have verified the precision of this method. This method has a significant advantage over commercially available touch probe tool set stations, because touch probes are well known to damage the cutting edges of fragile tools, such as single-point diamond tools with a small nose radius and a large primary clearance angle. The method developed in this study does not subject the cutting edge of the tool to any stress beyond that of its intended purpose of machining workpiece material. Therefore, this method can be used to set extremely fragile single-point cutting tools without the risk of damaging the tools.     

Effect of micro-textured tools on machining of Ti–6Al–4V alloy: An experimental and numerical approach

In this work, an attempt is made to reduce the detrimental effects that occurred during machining of Ti–6Al–4V by employing surface textures on the rake faces of the cutting tools. Numerical simulation of machining of Ti–6Al–4V alloy with surface textured tools was employed, taking the work piece as elasto-plastic material and the tool as rigid body. Deform 3D software with updated Lagrangian formulation was used for numerical simulation of machining process. Coupled thermo-mechanical analysis was carried out using Johnson-cook material model to predict the temperature distribution, machining forces, tool wear and chip morphology during machining. Turning experiments on Ti–6Al–4V alloy were carried out using surface textured tungsten carbide tools with micro-scaled grooves in preferred orientation such as, parallel, perpendicular and cross pattern to that of chip flow. A mixture of molybdenum disulfide with SAE 40 oil (80:20) was used as semi-solid lubricant during machining process. Temperature distribution at tool–chip interface was measured using an infrared thermal imager camera. Feed, thrust and cutting forces were measured by a three component-dynamometer. Tool wear and chip morphology were captured and analyzed using optical microscopic images. Experimental results such as cutting temperature, machining forces and chip morphology were used for validating numerical simulation results. Cutting tools with surface textures produced in a direction perpendicular to that of chip flow exhibit a larger reduction in cutting force, temperature generation and reduced tool wear.     

高速铣削加工动静态监测技术的研究

从机床结构来说,电主轴和加工刀具是影响立式车铣复合加工中心精度的最直接因素。针对电主轴,开展基于电流法的车铣复合加工中心电主轴工作精度监测系统的研究;针对切削加工刀具,综合采用电机电流信号和声发射信号对刀具状态进行监测。     

新型陶瓷刀具的发展与应用

回顾了陶瓷刀具的发展简况及其意义,重点介绍了Si3N4基和TiCN基复合陶瓷刀具的研制、性能和应用.复合Si3N4陶瓷刀具有较高的耐磨性和抗冲击性,特别适合于各类铸铁件的粗精加工,也能进行铣削、刨削等冲击力很大的加工,其切削效率可提高3～10倍;复合TiCN金属陶瓷刀具具有很高的硬度和耐磨性,特别适合于各类高硬高强钢(如淬硬钢等)的加工,可对高硬材料实现"以车代磨"干切削,免除退火工艺和冷却液,大幅度提高生产效率.新型复合陶瓷刀具已经在我国冶金、水泵、矿山机械、轴承、滚珠丝杠、汽车、军工等十几个行业得到应用.