高速铣削下PCBN刀具的有限元分析

通过对PCBN铣刀高速铣削淬硬45钢试验所得的数据进行分析,得出在不同的主轴转速下的切削力。再通过Solid Edge建立铣刀模型,导入ANSYS,将不同主轴转速下的切削力施加于所建模型PCBN刀片的切削刃上并进行应力分析。选取不同应力分布图中的最大应力值进行分析、比较,可知其应力变化是随着主轴转速的增大而逐渐减小,与实际情况相符。因此,通过建立有限元模型并进行分析,对铣削加工时选择合理的主轴转速提供依据。     

浅谈数控机床主轴

1、概述 数控机床是现代加工设备的代表产品,机床的高速化是数控机床的发展主要趋势．．实现高速化的关键部件仍是机床主轴单元。主轴速度常用dn值（dn值是指主轴轴承的平均直径（mm）与主轴的极限转速（r／min）的乘积）来衡量,随着轴承技术、润滑技术的发展,机床主轴转速在逐年提高。     

防爆风机主轴单元静、动态特性分析

采用有限元分析方法,根据防爆风机工作情况及主轴单元结构建立了主轴单元的三维计算模型,运用ANSYS软件,对主轴单元结构和静、动态特性进行了计算,具体包括主轴在载荷作用下所受的应力、产生的变形、各阶固有频率和振型、临界转速等,为优化主轴结构和改善主轴的动静态特性提供理论依据.根据振动测试原理,建立了主轴单元的动态测试系统,对主轴单元进行试验模态分析.通过采集系统输入与输出信号,经参数识别而获得试验模态参数.将理论计算与试验结果相比较,结果表明,所建立的模型是有效的.文中对数据进行了分析,提出了改进主轴结构的建议.     

数控机床主轴无报警故障三例

数控机床无报警故障的修理，由于不容易找到故障点，修理方法不易掌握，在维修工作中难度较大。通过对FANUC系统数控机床主轴无报警３个典型故障修理过程的介绍，分析了故障产生的原因，检修的具体步聚以及分析问题的方法、解决手段和需要注意的事项。１维修实例一（１）设备简介设备名称：数控铣床；生产厂家：上海第四机床厂；型号：XK７１５F；数控系统：FANUC－７。（２）故障现象主轴自动或手动启动后，转速达不到指令转速，仅有１～２r／min，正、反转均如此。无任何报警。（３）检修方法MDI（手动数据输入）方式下，执行高、…     

机床主轴温升试验研究及控制措施

在静压轴承主轴的实验平台上开展了主轴温升试验,通过对主轴转速与温升试验数据的分析,得出了影响主轴温升的主要因素,并提出了控制主轴温升的一些措施.     

信息金桥

难题招标·97031高转速主轴目前国外主轴转速普遍达到8000～10000r／min，我国主轴转速已经达到6000r／min，制造技术趋向成熟。机床技术发展要求具备主轴高转速的铣床，现招标主轴转速达到10000r／min的高速主轴的全部技术（含主轴轴承、冷却结构等技术），主功率5．skw／3．7     

高体分SiC/Al复合材料微磨削表面粗糙度试验研究

SiC/Al复合材料是一种以铝为基体,碳化硅为增强颗粒的复合材料。由于材料的高硬度特性,导致已加工表面出现裂纹和磨损等现象,采用PCD刀具对SiC/Al2024进行微磨削试验,基于响应曲面法,设计实验数据,根据试验结果,建立主轴转速、进给速度和切削深度的回归方程。通过响应曲面图,分析主轴转速、进给速度和切削深度交互作用对表面粗糙度的影响程度,其从大到小依次为:主轴转速、切削深度和进给速度。主轴转速和进给速度交互影响显著,获得最小粗糙度为0.51μm。     

正交车铣SiCp/Al复合材料薄壁回转体振动信号的实验分析

运用MAZAK INTEGREX200Y机床上正交车铣SiCp/Al复合材料薄壁回转体试件,通过PCI-1712高速数据采集卡采集刀杆主轴的加速度振动信号,分析了不同刀具转速和工件转速对刀杆主轴振动的影响。结果表明切削力激振频率"i远小于薄壁件固有频率,且使用该参数不会引起颤振;刀具转速对切削振动有很大影响,正交车铣加工时应通过调整转速比,避开颤振敏感的刀具速度。分析结果对正交车铣加工薄壁件有指导意义。     

基于指数函数的机床主轴热误差补偿模型

在对机床主轴进行热特性分析的基础上,建立了基于指数函数的机床主轴轴向热误差补偿模型。该热误差补偿模型建模时间短、资金成本低,能够方便快捷地应用到工厂生产环境中。通过实验获得不同转速下的主轴轴向热变形数据。使用回归分析和最小二乘法建立了稳定状态下主轴轴向变形量和时间常数的估计方程,进而建立了基于指数函数的热误差补偿模型。该模型可以预测不同转速下主轴的轴向变形量。通过实验证明了该热补偿模型在机床主轴恒速运转和变速运转两种工况下均具有较高的精度。     

机床主轴动态评估技术研究

针对机床的主轴动态性能检验问题,对机床主轴动态评估技术进行了研究,介绍了振动、温度、转速综合分析办法;重点解决了非接触式参数采集问题,给出了红外线主轴温度检测方法,同时阐述了系统的构成、检测方法和数据采集、分析方法.     

Chatter prevention for milling process by acoustic signal feedback

This paper presents how real-time chatter prevention can be realized by feedback of acoustic cutting signal, and the efficacy of the proposed adaptive spindle speed tuning algorithm is verified as well. The conventional approach to avoid chatter is to select a few appropriate operating points according to the stability lobes by experiments and then always use these preset cutting conditions. For most cases, the tremble measurement, obtained by accelerometers or dynamometers, is merely to monitor spindle vibration or detect the cutting force, respectively. In fact, these on-line measures can be more useful, instead of always being passive. Furthermore, most of these old-fashioned methodologies are invasive, expensive, and cumbersome at the milling stations. On the contrary, the acoustic cutting signal, which is fed into the data acquisition interface, Module DS1104 by dSPACE, so that an active feedback loop for spindle speed compensation can be easily established in this research, is non-invasive, inexpensive, and convenient to facilitate. In this research, both the acoustic chatter signal index (ACSI) and spindle-speed compensation strategy (SSCS) are proposed to quantify the acoustic signal and compensate the spindle speed, respectively. By converting the acoustic feedback signal into ACSI, an appropriate spindle speed compensation rate (SSCR) can be determined by SSCS based on real-time chatter level. Accordingly, the compensation command, referred to as added-on voltage (AOV), is applied to actively tune the spindle motor speed. By employing commercial software MATLAB/Simulink and DS1104 interface module to implement the intelligent controller, the proposed chatter prevention algorithm is practically verified by intensive experiments. By inspection on the precision and quality of the workpiece surface after milling, the efficacy of the real-time chatter prevention strategy via acoustic signal feedback is further examined and definitely assured.     

Effect of Air and Helium on the Head–Disk Interface During Load–Unload

The tribological characteristics of the head–disk interface are investigated during load–unload for air and helium-filled drives as a function of the pitch static angle and the roll static angle between slider and disk. A custom-made experimental tester inside a sealed environmental chamber was used to determine the regions of “safe” pitch static angle and “safe” roll static angle in air and helium environment during the load–unload process. The presence of head–disk contacts during load–unload were evaluated by measuring the acoustic emission signal and the decrease in rotational speed of the spindle. Scanning electron microscopy and optical surface analysis were used to investigate wear of the slider and the redistribution of lubricant on the disk surface after 10,000 load–unload cycles. The results indicate that the tribological performance of the head–disk interface is improved in helium environment compared to air environment.     

电主轴温度场与热变形的仿真与实验研究

以Setco 231A240型高速电主轴为研究对象,考虑了内置电机的损耗生热和轴承的摩擦生热,计算了电主轴各部分之间的传热系数,利用有限元软件Workbench建立电主轴有限元模型,分析得到了电主轴在不同因素影响下的温度场分布,基于电主轴热-结构耦合关系分析得到了温度影响下电主轴的热变形。仿真结果显示,较低转速下电主轴转子温度最高,转速对电主轴温度影响较大;电主轴头尾部热变形较大,主要为轴向变形。最后,将温度场仿真数据与实验数据对比,验证了仿真分析的准确性。     

高速立式加工中心电主轴的温升测试及分析

针对高速立式加工中心电主轴内置电动机的特点,分析了电主轴产生温升的热源。通过设计与搭建电主轴试验平台,采用DH5922动态信号测试分析系统,选择热电阻适调器组成的检测系统,完成了电主轴的温升测试试验。通过对试验结果的分析,验证了电主轴温升产生的原因,并提出了相关对温升进行实时监控的措施。     

Load/unload measurements using laser doppler vibrometry and acoustic emission

The dynamics of the load/unload process are studied using a so-called ‘periscope approach’ which allows us to follow the slider motion during load/unload (L/UL) with the beam of a Laser Doppler Vibrometer (LDV). LDV signals and acoustic emission signals are obtained for three different slider airbearing designs and for load/unload conditions with different vertical velocities and spindle speeds. The load process is investigated statistically using the acoustic emission signal in order to determine the effect of vertical load speed and spindle speed on the probability of contacts between slider and disk.The results indicate that small vertical load speeds decrease the number of head/disk contacts, and that slider designs with a cavity centered close to the trailing edge enable a smooth unloading process.     

砂轮接杆对陶瓷电主轴单元动态性能的影响

随着产品加工不断向高精度、高刚度、高速度方向发展,对机床主轴部件的动态特性要求也越来越高,因此对机床主轴部件动态特性分析也显得越来越重要。实验室采用陶瓷球轴承作支承的电主轴做高速精密磨削。在磨削过程中,陶瓷电主轴单元的性能直接关系到主轴能否实现平稳高速、精密加工。砂轮接杆虽然尺寸结构简单,但是对电主轴的动态性能影响很大。文中针对基于PMAC-PC控制下的精密磨床,通过不同转速下电主轴振动信号的傅立叶(FFT)谱,分析了砂轮接杆对陶瓷轴承电主轴单元动态性能的影响。     

主轴系统空运转模态分析

利用试验台模拟加工中心主轴系统安装状态下的空运转试验,结合DASP分析系统测得主轴系统的动态响应,基于随机子空间识别技术,用MATLAB软件编制相应的识别程序,剔除系统运转中的激励频率成分,选择合适的模型阶次,获得加工中心主轴系统的模态参数,识别结果与脉冲激励识别结果有一定的对应性,为主轴系统的结构改进设计提供依据.     

基于开放式控制器的铣削颤振在线抑制

为实现在线抑制铣削颤振,对颤振领域常用的传感器监控技术,尤其是三向切削力和振动加速度传感器的各向分量在颤振监控过程中的时域和频域敏感信号特征进行试验研究。针对监控的颤振敏感信号频域特性,研究快速傅里叶变换技术对信号有效信息的在线提取技术。对自激颤振的机理进行分析,建立颤振频率与主轴转速间的关系模型,为实现变主轴转速抑制自激颤振提供理论基础。对集成在线参数采集、反馈控制的全软件型模块化铣削控制器进行设计,将在线抑制颤振的相关变主轴转速算法嵌入开放式控制器中,并设计控制参数数据流在控制器模块间的实现流程。对连续变切削深度铝合金工件进行在线颤振抑制加工试验,试验验证开放式智能铣削控制器在线抑制颤振相关技术的正确性。     

Dynamic cutting force on-line estimation using a 4-electrode cylindrical capacitive displacement sensor mounted on a high speed milling spindle

In this paper, a 4-electrode cylindrical capacitance displacement sensor (CCDS) is presented as an indirect force sensor for a high speed milling spindle. A rotor-bar system for the magnetic exciter is designed to investigate the tool deflection with respect to the applied cutting force. To extract the deflection signal from the CCDS, the dynamic orbital motion at each rotating speed of spindle is predetermined and then subtracted from the CCDS signal. The CCDS signal is also used as a reference sync signal. The rotor-bar system is designed so that the rotor affects the tool-spindle dynamics only as an added mass but does not contribute to the bending property. The additional effect of the rotor mass in the exciter setup is compensated for by an experimental modeling. The cutting force can be estimated by using modified CCDS signals and FRF. Cutting experiments are conducted to show reliable performances of the proposed approach by high speed machining applications.     

加工中心关键部件的动态特性分析

可分度车削头是加工中心的关键部件,它的动态特性好坏直接影响到机床的加工精度和表面粗糙度.以车削头为研究对象,利用Solidworks实体建模,借助有限元分析软件ANSYS进行模态分析,并采用现有的高精度信号采集仪和测试分析软件进行模态试验.对比这两种不同的模态分析结果,找出了该关键部件的薄弱环节.结合对车削主轴动刚度的测试,为提高机床的动态性能和结构优化提供了有效依据.