切削用量对切削振动影响的实验研究

针对钛合金进行干式车削实验,通过单因素实验法,研究了切削用量中切削速度、进给量和切削深度单独变化对切削振动的影响.研究结果表明:随着切削速度的上升,切削振动加速度先上升后下降再上升;随着进给量变大,切削振动加速度也变大;切削振动加速度随着切削深度的增大而增大,当切削深度达到某个限度时,切削振动加速度开始减小.     

超声椭圆振动切削钛合金切削力特性研究

利用超声椭圆振动切削(UEVC)对TC4钛合金切削力特性进行了研究。基于ABAQUS力-热耦合模型分析了超声椭圆振动切削钛合金的瞬态切削过程,模拟在不同切深和切削速度下的瞬态切削情况,提取和对比普通切削(CC)和超声椭圆振动切削的主切削力,进而进行数据处理,分析两者主切削力对比情况和平均主切削力之差的变化。研究分析表明:在椭圆振动切削下,切削力减小比率随着切深的增加而减小,随着切削速度的增大而增大。最后进行试验验证,实验结论与仿真结果一致。对超声振动切削难加工材料钛合金时切削用量的选择提供了参考。     

淬硬钢旋削时的刀具特性对切削温度的影响

为了研究淬硬钢旋削时的刀具特性对切削温度的影响,在数控加工中心上对热传导率不同的刀具进行旋削加工实验。后刀面的切削温度用传统的温度测量方法无法准确测量,使用独创的光纤维耦合器型的2色温度计进行了测量。实验结果表明,切削速度和刀具的热传导率对刀具后刀面的温度有相当大的影响,切削温度随着切削速度的增加而上升,切削刀具热传导率越高,则切削温度越低。     

复合材料切削温度影响因素的实验研究

从切削温度的影响因素出发,研究尼龙、45号钢以及碳纤维3种材料在车削加工过程中切削温度的变化规律。通过实验,改变切削参数,进行切削温度的测量并测得切削后的加工表面质量,研究了切削参数对切削温度的影响。实验结果表明,随着切削速度、进给量和背吃刀量的增加,切削温度升高,加工表面的粗糙度增大。为了研究刀具磨损对切削温度的影响,测量了相同切削参数下刀具不同磨损程度的切削温度和切削后的加工表面质量。分析发现,刀具磨损会造成切削温度的升高和表面粗糙度的增大。     

微铣削切削力特性及表面质量的实验研究

为了研究微铣削加工过程中切削用量对切削力的影响规律及加工质量,采用直径150μm的硬质合金微铣刀进行了微铣削加工实验.一方面,采用单因素实验方法,研究了铣削微槽时主轴转速、轴向切削深度和每齿进给量对切削力的影响规律,实验发现主轴转速和轴向切削深度是影响切削力的重要因素,而每齿进给量的影响最小.以每齿进给量与切削刃刃口半径的比值fz/Re为变量,研究了切削比能的尺寸效应现象,发现随着fz/Re的减小,切削比能增大,当fz/Re1.0以后,切削比能急剧增大.另一方面,从毛刺宽度和表面粗糙度两个方面研究了fz/Re对微铣削加工质量的影响规律,其结果表现出明显的尺寸效应现象,随着每齿进给量的的减小,毛刺宽度和表面粗糙度均先减小后增大.当fz/Re=0.5时毛刺最小;当fz/Re=1.0时,表面粗糙度最小.本研究可以为实际加工中合理选择切削用量以及分析微铣削尺寸效应现象提供理论依据.     

300M超高强度钢车削加工性能仿真模拟分析研究

目的研究不同切削参数对300M超高强度钢切削性能的影响。方法通过单因素试验法,采用Advant Edge切削仿真软件,建立300M钢三维有限元模型,对不同切削参数下车削300M钢的切削力、刀片温度、刀片应力及切屑形状进行分析。结果在300M钢车削过程中,刀片温度随着切削速度增大而增大,但切削力和刀片应力反之;背吃刀量和进给量越小,切削力、刀片应力及刀片温度越小;切削刃半径越小,切削力越小,但小的切削刃半径使得刀片应力变大,容易导致刀片磨损。车削300M钢的切屑呈锯齿螺旋状,切屑温度为带状分布,切削速度越高,进给量、背吃刀量越大,切削刃半径越小,切屑温度越高。结论在300M钢车削加工中,应选用较高的切削速度,适中的切削刃半径,较小的进给量和背吃刀量。     

PCD刀具加工SiC颗粒增强铝基复合材料的合理切削速度

通过用扫描电镜等方式检测ＰＣＤ刀具的性能,并与天然金刚石的相关参数进行比较,阐明了ＰＣＤ的优异性能,通过ＰＣＤ刀具对碳化硅高比强颗粒增强铝基复合材料的试验,考察了切削速度对切削力、切削温度、刀具耐工和切削长度的影响,总结出高硅铝基复合材料切削中的合理切削速度。指出、在一定的切削条件下,当切削速度Ｖ＝３０－４０ｍ／ｍｉｎ时,可获得良好的综合效益。     

基于微量油膜附水滴技术的切削参数优化北大核心CSCD

为探索研究微量油膜附水滴(Oils on Water,OoW)技术在切削中对表面粗糙度的影响,选出较适宜的切削用量,通过进行浇注乳化液和OoW切削液的切削工件表面粗糙度对比试验,分析了两种切削液的冷却润滑性能,再利用响应曲面法(Response Surface Methodology,RSM),选择切削速度、进给量和背吃刀量作为优化变量,表面粗糙度(Ra)作为响应性能指标,设计中心复合实验,利用Design-Expert软件建立了相对应的响应分析模型,并对所建模型进行了可靠性验证,试验结果表明,使用OoW进行切削润滑,能够更明显地降低工件表面粗糙度,通过研究工艺参数间的交互作用,得到了各工艺参数间的最优组合为:切削速度为119.97 m/min,进给量为0.14 mm/r,背吃刀量为0.48 mm。     

SiCp/Al复合材料薄壁件钻削加工的有限元仿真

本文基于ABAQUS有限元仿真软件,对比研究了SiCp/Al复合材料薄壁件和厚壁工件的钻孔过程及切削力的变化特点,提出了薄壁钻孔的3个特征阶段;同时,通过改变切削参数,对薄壁件的钻削力及最大变形量的变化规律进行了研究。结果表明:在切削速度(或进给量)一定的条件下,随着刀具进给量(或切削速度)的增加,轴向力和钻削扭矩大体呈线性增加趋势;切削速度对薄壁钻孔变形影响不大,进给量对薄壁钻孔变形的影响较切削速度显著,薄壁件的最大变形量随进给量的增加而增大。     

基于CVD厚膜金刚石刀具的超声振动切削模具钢实验

采用化学气相沉积（chemicalvapordeposition,CVD）厚膜金刚石刀具进行模具钢超声振动切削实验．首先阐述刀具的材质特点,观测其刀尖微观形貌和切削刃截面轮廓．然后搭建了适应精密／超精密加工需求的超声振动切削实验装置,其中激振机构可稳定实现频率42．0kHz、振幅峰峰值8～9μm的振动输出．通过切削无氧铜实验证明该超声振动切削装置工作有效、稳定后,选用AISI420模具钢进行切削实验,研究切削工艺条件及切削用量对加工质量的影响,得到适用于CVD厚膜金刚石刀具的切削用量选取范围,对比研究发现超声振动切削在提升加工表面质量、减少金刚石刀具磨损方面均优于常规切削．本研究可使切削模具钢时的金刚石刀具磨损VBmax由500～600μm减少至40μm,模具铜表面粗糙度Ra由0．93μm改善至0．09μm．本研究为金刚石刀具超声振动切削模具钢的实用化积累工艺经验,并探索提供可行的技术实现途径．     

Werkstücktemperaturen bei der Zerspanung – Messung und Berechnung

Workpiece Temperatures in Machining - Measurement and Calculation Workpiece temperatures in machining of an austenitic steel, an aluminum alloy and copper have been both determined experimentally using infrared pyrometry and calculated numerically with a finite-difference-model. The influence of the cutting parameters such as cutting speed, cutting depth and rake angle on the workpiece temperature were investigated. Depending on the thermal diffusivity of the material an increase in cutting speed or cutting depth can either increase or decrease the maximum workpiece temperature. Increasing the rake angle always leads to decreasing workpiece temperatures.     

Residual Stress and Affected Layer in Disc Milling of Titanium Alloy

Disc milling is used in manufacturing, especially for difficult-to-machine material such as titanium alloy, because of its strong force and high machining efficiency. However, research on the cutting mechanism of the disc-milling technique is still lacking in the literature. In the present study, first, a disc-milling grooving experiment was designed and carried out to test the milling temperature correlated to the milling force for titanium alloy samples. After machining, residual stress, microstructure and microhardness were investigated. Residual compressive stress was found on the milling surface, which changes to tensile stress gradually with the increase of depth. The impact of cutting factors on residual stress was also analyzed numerically and the results showed that with the increase of speed of the mainshaft, the residual stress reduced gradually. For the factors of depth of cut and feed speed, increasing them had the opposite effects on residual stress. Next, the microstructures of lattice tensile deformation and lattice fracture were observed under different cutting conditions. The metallographic structure changed on increasing the milling temperature, progressing from an initial equiaxed microstructure to an α + β duplex microstructure, and then formed a lamellar microstructure later. The microhardness in the plastic deformation zone was also taken into account, which showed that the hardness increased under the combined effect of the milling temperature and force.     

前混合磨料水射流对HTPB推进剂的切割 工艺参数优化研究

利用前混合磨料水射流，对高、低两种燃速的HTPB推进剂开展切割试验，着重研究不同切割条件下工艺参数对切割效率的影响，进而为工艺参数优化提供理论依据。选取切割速度（v）、出口压力（p）、磨料浓度比（T）和靶距（L）4个工艺参数为主要影响因素，以最大切割深度（H）作为切割效率的衡量指标，分别通过单因素试验和正交试验进行分析，进而完成工艺参数的优化。试验结果表明，最大切割深度随切割速度的增加而减小，且单位时间内的切割面积存在最佳值；随着出口压力的增加，最大切割深度在特定范围内近似线性增加，并逐渐趋于平缓；磨料浓度比与靶距和最大切割深度均存在最佳对应关系。正交试验结果表明，切割速度对指标影响较为显著，靶距等3个工艺参数的影响相对较小。该研究可为前混合磨料水射流作为HTPB推进剂的工程化处废技术提供理论支持。     

Prediction and optimisation models for turning operations

Selection of process parameters has very significant impact on product quality, production costs and production times. The quality and cost are much related to tool life, surface roughness and cutting forces which they are functions of process parameters (cutting speed, feed rate, depth of cut and tool nose radius). In this paper, empirical models for tool life, surface roughness and cutting force are developed for turning operations. The process parameters (cutting speed, feed rate, depth of cut and tool nose radius) are used as inputs to the developed machineability models. Two data mining techniques are used; response surface methodology and neural networks. The data of 28 experiments have been used to generate, compare and evaluate the proposed models of tool life, cutting force and surface roughness for the selected tool/material combination. The resulting models are utilized to formulate an optimisation model and solved to find optimal process parameters, when the objective is minimising production cost per workpiece, taking into account the related boundaries and limitation of this multi-pass turning operations. Numerical examples are given to demonstrate the suggested optimisation models.     

难加工材料高速切削力非线性特征规律的最大熵谱分析与小波分析

在切削速度范围157～1 000 m/min内，综合应用析因试验与速度单因素试验，对航空用难加工材料2Cr13马氏体不锈钢进行了高速干式铣削试验。在分析其切削力显著性影响因素的基础上，对切削力随机信号进行了现代谱分析与小波分析。研究结果表明，高速切削马氏体不锈钢材料时，切削速度和每齿进给量之间的交互作用对切削力有显著影响；铣削深度和每齿进给量之间的交互作用在切削力响应信号中表现为低频周期信号；低频周期信号与高频信号叠加后，其波形的振幅将会增大。     

钛合金超声扭振铣削强度优化设计仿真

钛合金具有比强度大、热传导率低等特点,对其进行强度优化设计仿真,可以提高其切削加工性能。运用Abaqus软件建立了二维超声扭振铣削模型,并采用John-cook分离准则、任意的拉格朗日-欧拉(ArbitraryLagrange-Euler,ALE)网格划分方法和施加相应边界等条件,根据刀-屑的周期分离原理,确立了接触率与角速度、振动频率和超声振幅之间的关系。此外,采用单因素法依次改变角速度、频率和振幅,以此进行强度优化设计仿真。结果表明,切削力和温度均随角速度的增加而增加;振幅的增大使得切削力有所降低,而温度却有所上升;频率的变化对两者影响不大。并得出结论:给定参数范围内,影响切削力的权重依次为振幅、角速度和频率;影响温度的权重依次为角速度、振幅和频率。     

Experimental investigation of cutting parameters influence on surface roughness and cutting forces in hard turning of X38CrMoV5-1 with CBN tool

This experimental investigation was conducted to determine the effects of cutting conditions on surface roughness and cutting forces in hard turning of X38CrMoV5-1. This steel was hardened at 50 HRC and machined with CBN tool. This is employed for the manufacture of helicopter rotor blades and forging dies. Combined effects of three cutting parameters, namely cutting speed, feed rate and depth of cut, on the six performance outputs-surface roughness parameters and cutting force components, are explored by analysis of variance (ANOVA). Optimal cutting conditions for each performance level are established. The relationship between the variables and the technological parameters is determined through the response surface methodology (RSM), using a quadratic regression model. Results show how much surface roughness is mainly influenced by feed rate and cutting speed. The depth of cut exhibits maximum influence on cutting force components as compared to the feed rate and cutting speed.     

Study on the influential process parameters in machining the austempered ductile iron

Since the machinability data on grade 3 austempered ductile iron is scarce, this experimental work mainly focuses on the impact of machining parameters on cutting force and surface roughness while turning the above work material with cubic boron nitride and tungsten carbide inserts. Parameters like depth of cut, cutting speed and feed were considered in this study when analyzing the machinability of austempered ductile iron. Austempered ductile iron was turned with CBN and coated WC inserts. The response surface methodology was utilized to design the experiments and optimize the cutting parameters for the work material by each of the above inserts. The cubic boron nitride insert performs well as compared to the coated tungsten carbide for turning the austempered ductile iron and it has been concluded by taking lower force and higher surface finish in to consideration. The optimum parameters for turning austempered ductile iron with the cubic boron nitride insert is as follows: 174 meter/minute cutting speed, 0.102 millimeter/revolution feed and depth of cut of 0.5 millimeter.     

Machinability study of silicon carbide and cenosphere reinforced Al7075 composite using three different tool materials

This research conducted a machinability study on Al7075 composite reinforced with nano-sized (100 nm) silicon carbide and cenosphere (industrial waste) particulates with 1.8 % weight. These composites were fabricated utilizing an ultrasonically assisted stir-casting setup and scanning electron microscope investigation was conducted to evaluate the dispersion properties of the reinforcement in the matrix phase. During the study, the effect of variation of feed rate, cutting speed and depth of cut on cutting forces and tool tip temperature has been studied. A total of 253 experiments were conducted using three different tool inserts polycrystalline diamond, cermet, and coated carbide under dry cutting conditions. Among the two components of the cutting force, it was noted that the primary cutting force was the largest. A full factorial response surface regression model has been developed and it is found that the regression model can predict cutting force and temperature with fair accuracy.     

An experimental analysis of effective high speed turning of superalloy Inconel 718

Superalloy, Inconel 718 is widely used in the sophisticated applications due to its unique properties. However, machining of such superior material is difficult and costly due its peculiar characteristics. The present article is an attempt to suggest Taguchi optimization technique to study the machinability of Inconel 718 with respect to cutting force, cutting temperature, and tool life in high speed turning of Inconel 718 using cemented tungsten carbide (K20) cutting tool. Therefore, the objective of this work is divided into two phases: (i) to demonstrate a correlation between cutting speed, feed, and depth of cut with respect to cutting force, cutting temperature, and tool life in a process control of high speed turning of Inconel 718 in order to identify the optimum combination of cutting parameters; (ii) to show the effect of high speed cutting parameters on the tool wear mechanism and chip analysis. These correlations were obtained by multiple linear regressions. The confirmation tests were carried out to make a comparison between the experimental results and mathematical models proposed. The proposed models agree well with the experimental results.