金刚石刀具刃磨装夹系统的振动特性分析

在金刚石刀具的刃磨过程中,机床本身及其刃磨装夹系统的振动干扰会直接影响到刀具的锋锐度和表面粗糙度.通过对刃磨过程特征振动信号的分析,结合模态实验,对刃磨装夹系统结构的振动特性进行了分析和评价.     

金刚石刀具刃磨装夹系统的振动特性分析

在金刚石刀具的刃磨过程中,机床本身及其刃磨装夹系统的振动干扰会直接影响到刀具的锋锐度和表面粗糙度。本文通过对刃磨过程特征振动信号的分析,结合模态实验,对刃磨装夹系统结构的振动特性进行了分析和评价。     

单晶金刚石刀具机械刃磨技术进展

介绍了单晶金刚石刀具机械刃磨原理和刃磨机理,分析了刀具刃磨面、刃磨方向、刃磨参数和刃磨机床振动等对单晶金刚石刀具刃磨质量和刃磨效率的影响,综述了单晶金刚石刀具机械刃磨技术的发展趋势。     

基于杠杆模式施载的圆弧刃光栅刻画刀具刃磨机床研制

采用圆弧刃光栅刻画刀具,实现在线换刃技术是解决光栅刻画刀具使用寿命问题的一种有效的途径。在线换刃圆弧光栅刻画刀具对刃口质量及精度要求高,刃磨制作工艺难度大,且国内外市场几无此类刃磨设备,需要自行设计制作圆弧刃光栅刻画刀具刃磨机床。在圆弧刃光栅刻画刀具刃磨试验设备设计制作及圆弧刃光栅刻画刀具刃磨制作工艺研究基础上,针对圆弧刃光栅刻画刀具的刃磨特点,设计新型的基于杠杆模式施载的圆弧刃光栅刻画刀具刃磨机床;根据传统机床的设计程序,对刃磨机床的功能、总体设计及详细结构设计展开研究,并对施载与微进给机构进行了振动分析,排除了出现共振的可能性。最后完成了该机床的机械装调,并刃磨制作一把圆弧刃光栅刻画刀具,其定向角∠D=63°,刀尖角∠J=90°,刃圆半径R=8.56mm,在460倍体视显微镜下观察无崩口等缺陷,刃口弧线清晰可见。刀具检测及观测结果表明,所设计的圆弧刃刀具刃磨机床适用于圆弧刃光栅刻画刀具的刃磨制作,所采用的分析及设计方法对圆弧刃刀具刃磨机床及其他机床的设计和研制具有实际指导意义。     

PCD刀具刃磨技术

聚晶金刚石(PCD)刀具的刃磨极为困难,本文从磨床、砂轮、刃磨工艺参数等方面叙述了PCD刀具的刃磨技术。     

PCD的磨削特点与PCD刀具的刃磨技术

介绍了PCD切削刀具的制造工艺,分析了PCD材料的磨削加工特点及PCD刀具刃磨对工装的要求,重点阐述了PCD切削刀具的刃磨工艺及其要点。     

聚晶金刚石刀具在超硬刀具磨削机上的刃磨工艺

介绍了聚晶金刚石（PCD)刀具在EWAG RS09超硬刀具磨削机上的刃磨工艺及刃磨特点，为超硬刀具的刃磨提供了参考。     

一种刃磨硬质合金刀具的新方法

介绍了材料的可切削性的判定方法,通过被加工材料的可切削性分析编码,确定切削用量和刀具角度,为刃磨硬质合金刀具的前期工艺准备提供理论指导。提出一种硬质合金刀片刃磨新方法,即综合运用负刃刃磨法、低应力磨削技术和间断磨削方法;镗削实践证明新刃磨方法可显著延长刀具的工作寿命。     

关于聚晶金刚石刀具粗磨和精磨的机理分析与研究

研究了PCD刀具刃磨工艺和刃磨机理,建立了PCD刀具刃磨机理及相应的刃磨模型.实验结果表明在粗磨过程中,占主导作用的去除机理,是砂轮中金刚石磨粒对PCD刀具金刚石层的机械切除(磨除);在精磨过程中,占主导作用的去除机理,是砂轮中金刚石磨拉对PCD刀具金刚石层的摩擦作用去除.     

PCD刀具在汽车零件加工中的应用

通过对汽车发动机铝合金零件切削工艺的研究,分析了零件加工超差的原因,提出选用聚晶金刚石(PCD)刀具替代硬质合金刀具。以加工孔为例详细介绍了PCD刀具的设计制造工艺,并改造了PCD刀具机械刃磨设备,既能满足加工要求,又能降低刀具刃磨成本。     

凸轮切点跟踪磨削过程振动分析

切点跟踪磨削是提高汽车凸轮制造精度的一种重要加工手段。某型号凸轮磨削时发现砂轮架切点跟踪时机床振动噪声较大,并且对凸轮磨削质量有很大的影响。本文针对该磨床工作过程中出现的砂轮架振动过大、噪声较大等问题通过对砂轮架模态测试、响应测试、砂轮架各工况下振动测试等原型试验方法,探明砂轮架非正常工作的根本原因与解决方案。     

Statistical quality control through overall vibration analysis

The present study introduces the concept of statistical quality control in automotive wheel bearings manufacturing processes. Defects on products under analysis can have a direct influence on passengers’ safety and comfort. At present, the use of vibration analysis on machine tools for quality control purposes is not very extensive in manufacturing facilities.Noise and vibration are common quality problems in bearings. These failure modes likely occur under certain operating conditions and do not require high vibration amplitudes but relate to certain vibration frequencies. The vibration frequencies are affected by the type of surface problems (chattering) of ball races that are generated through grinding processes.The purpose of this paper is to identify grinding process variables that affect the quality of bearings by using statistical principles in the field of machine tools. In addition, an evaluation of the quality results of the finished parts under different combinations of process variables is assessed. This paper intends to establish the foundations to predict the quality of the products through the analysis of self-induced vibrations during the contact between the grinding wheel and the parts. To achieve this goal, the overall self-induced vibration readings under different combinations of process variables are analysed using statistical tools. The analysis of data and design of experiments follows a classical approach, considering all potential interactions between variables. The analysis of data is conducted through analysis of variance (ANOVA) for data sets that meet normality and homoscedasticity criteria. This paper utilizes different statistical tools to support the conclusions such as chi squared, Shapiro–Wilks, symmetry, Kurtosis, Cochran, Hartlett, and Hartley and Krushal–Wallis.The analysis presented is the starting point to extend the use of predictive techniques (vibration analysis) for quality control. This paper demonstrates the existence of predictive variables (high-frequency vibration displacements) that are sensible to the processes setup and the quality of the products obtained. Based on the result of this overall vibration analysis, a second paper will analyse self-induced vibration spectrums in order to define limit vibration bands, controllable every cycle or connected to permanent vibration-monitoring systems able to adjust sensible process variables identified by ANOVA, once the vibration readings exceed established quality limits.     

旋转超声磨削加工中刀具结合剂类型与加工性能的关系

实验分析了硬脆材料旋转超声磨削过程中刀具结合剂类型对加工性能的影响以便提高加工精度和加工表面的完整性.首先,采用能谱分析研究了铁基、陶瓷基和青铜基3种超声振动刀具中结合剂与金刚石颗粒的把持形式,并根据相同加工工艺条件下刀具磨损形式确定了把持力大小.然后,结合超声振动刀具特性,通过旋转超声磨削加工实验研究刀具结合剂类型与切削力、刀具磨损量、加工表面完整性的关系,并对实验结果进行了分析.实验结果表明:相对于陶瓷基和青铜基结合剂超声振动刀具,铁基结合剂超声振动刀具把持力最大,Z轴切削力平均值最小(为46.8 N);加工18 000 mm3材料后,刀具轴向磨损量最小(为0.1 mm);而陶瓷基结合剂超声振动刀具加工表面质量最好,表面粗糙度最大值为21.79 μm.结果证实铁基超声振动刀具适用于粗加工,陶瓷基超声振动刀具则适用于精加工.     

航空发动机液压弯管振动特性影响因素试验研究

针对航空发动机液压弯管振动情况的特殊性及其复杂的工作环境,利用试验测试及仿真的方法研究航空弯管结构参数对其流固耦合振动特性的影响。研究结果表明:对于不锈钢液压弯管随着内表面粗糙度降低,管路振动幅度和噪声明显降低,而铝合金弯管利用磁力研磨加工后其振幅和噪声变化不显著,同时验证了不锈钢硬质材料的航空液压弯管内表面在经磁力研磨加工前后其固有频率均高于铝合金弯管的固有频率,并且液压弯管的角度、长度等因素在软硬质材料中均对弯管振动特性产生明显的影响。     

Investigation on the bonding strength patterns of ultrasonic vibration tools and influence on working performance during rotary ultrasonic grinding

During rotary ultrasonic grinding process, working performance of ultrasonic vibration tools varies according to the bonding patterns between diamond grit and bond. In order to understand the influence of ultrasonic vibration tools on working performance, bonding patterns and bonding strength of ceramic-bonded, iron-bonded, and bronze-bonded tools were investigated. Influence of bonding strength on cutting force, tool wear, surface quality, and edge breakout were studied, coupled with the characteristics of ultrasonic vibration tools. The results show that cutting force in Z axis and tool wear reduce with the increase of bonding strength while the surface quality and edge breakout become worse.     

Silicon Carbide Surface Quality Prediction Based on Artificial Intelligence Methods on Multi-sensor Fusion Detection Test Platform

On the basis of the grinding process experiments for SiC ceramic workpiece, grinding process parameters are measured on the multi-sensor fusion detection test platform and experimental results are analyzed. Lempel–Ziv complexity (LZC) is introduced to reflect the integrated grinding process stability due to kinds of factors such as vibration from grinding machine parts and noise from experimental platform. The greater the LZC is, the fewer period factors are in the grinding process, which reflect the nonlinear correlations in the grinding process impacting on grinding process. A method is given based on LZC for analyzing grinding process stability. Under consideration of experimental results, a predictive model for surface quality is given by the Kernel Principle Component Analysis and Modified Extreme learning machine method (KPCA-MELM), and grinding process parameters can be optimized too. KPCA-MELM predictive model overcomes disadvantages of MELM predictive model of the randomness of weight ω and threshold value b by introducing improved genetic algorithm, which makes the roughness predictive error more accurate with the maximum error of 4.803%.     

Al2O3工程陶瓷超声振动钻磨表面质量的试验研究

通过超声振动钻磨与普通钻磨的对比试验,研究了缓进给超声振动钻磨对工件表面微观形貌和表面粗糙度的影响。结果表明,超声振动钻磨可明显地提高A l2O3工程陶瓷表面的质量,是陶瓷精密加工的一种新方法。     

用谐波分布理论诊断滚动轴承磨削工艺过程

滚动表面的谐波分布对轴承的振动和噪声有重要影响，而谐波是在制造过程中经过不断突变和遗传形成的。结合6202轴承的磨削过程，研究用谐波分布参数诊断工艺过程的合理性问题。试验表明，使用该方法可以有效地控制工艺过程中轴承表面的谐波分布，并使工序的安排更加合理。     

Modeling and simulation of grinding surface topography considering wheel vibration

Grinding is an important means of realizing precision and ultra-precision machining. Vibration caused by an unbalanced grinding wheel in grinding process has a significant impact on the quality of workpiece surface. However, the effect of wheel surface topography and/or the relative vibration between grinding wheel and workpiece are not considered in most researches. Taking the relative vibration between grinding wheel and workpiece into account, alongside the abrasive grain trajectory equation, a new analysis and simulation model for surface topography of the grinding process is established. The model for the topography of the grinding wheel surface is first studied, and subsequently, a new simulation model for surface topography of the grinding process is proposed. Case studies are performed at the end, and the influence of grinding wheel vibration amplitude, wheel grit number, as well as grinding parameters on the surface waviness and roughness is discussed. The simulation results could be used to optimize the actual grinding process to improve the ground surface quality or predict the surface topography by given grinding parameters.