Hybrid modelling of machine tool axis drives

The x-axis dynamics of a milling machine where the workpiece and saddle are mounted on supporting slides is considered. A permanent magnet motor, lead screw, ball nut and bearings are employed as the machine, traverse actuator mechanism. Hybrid, distributed–lumped parameter methods are used to model the machine tool x-axis drive system. Inclusion of the spatial configuration of the drive generates the incident, travelling and reflected vibration signature of the system. Lead screw interactive torsion and tension loading, which is excited by cutting and input disturbance conditions, is incorporated in the modelling process. Measured and results from simulation exercises are presented in comparative studies enabling the dynamic characteristics of the machine to be identified under, no load and with the application of cyclic, cutting force disturbances. The effect of the lead screw length, cutting speed and hence the load disturbance frequency are examined and the resulting performance accuracy is commented upon.     

高速切削加工的计算机数控

根据对高速切削加工计算机数控控制精度和控制速度的影响，分析了直线插补与样条插补方法的优缺点，介绍了高速数控系统的速度预控制，通过多轴变换和坐标变换实现刀具补偿，误差补偿，劳动安全保护等其它功能。     

Developments for High Performance Machine Tool Spindles

One important demand on spindle systems in modern machine tools is to realise higher rotational speeds in order to increase the machining efficiency. Additionally, for a given speed range a better robustness is demanded so that the spindle system is desensitised against improper operating conditions.The paper presents research results in various fields which contribute to the improvement of spindle-bearing systems. At first, new results for alternative spindle bearing kinematics with four contact points are presented.Secondly, a new solution for floating bearing arrangements is discussed. A modified cylindrical roller bearing is presented which can be operated at higher speeds. Finally, the potential of coated bearing components is discussed in the context of improved fail-safe properties. In this paper both analytic studies and experimental tests are presented.     

高速立式加工中心

本文对具有高速，高精度和高刚性特点的高速立式加工中心作了介绍。     

Machining prediction of spindle–self-vibratory drilling head

The drilling of deep holes with small diameters remains an unsatisfactory technology, since its productivity is rather limited. The main limit to an increase in productivity is directly related to the poor chip evacuation, which induces frequent tool breakage and poor surface quality. Retreat cycles and lubrication are common industrial solutions, but they induce productivity and environmental drawbacks. An alternative response to the chip evacuation problem is the use of a vibratory drilling head, which enables the chips to be fragmented thanks to the axial self-excited vibration. Contrary to conventional machining processes, axial drilling instability is sought, thanks to an adjustment of head design parameters and appropriate conditions of use. A dynamic high-speed spindle/drilling head/tool system model is elaborated on the basis of rotor dynamics predictions. In this paper, self-vibratory cutting conditions are established through a specific stability lobes diagram. Investigations are focused on the drill's torsional–axial coupling role on instability predictions. A generic accurate drilling force model is developed by taking into account the drill geometry, cutting parameters and effect of torsion on the thrust force. The model-based tool tip FRF is coupled to the proposed drilling force model into an analytical stability approach. The stability lobes are compared to experimentally determined stability boundaries for validation purposes.     

机床沿曲线高速进给加工的最大安全恒定进给速度的确定

分析了曲线、曲面轮廓数控加工中,刀具路径曲线的几何特性与机床运动学特性的关系,建立了机床沿曲线恒速进给的运动学方程;基于虚功原理推导出刀具路径几何特性、机床特性及电机特性等之间关系的动力学方程.并用解析法,计算了在各坐标轴加速度、伺服电机额定转矩及额定转速约束条件下,机床沿曲线进给时的最大安全恒定进给速度.在最大安全恒定进给速度范围内,选择合适的进给速度,既能使加工表面粗糙度均匀,保证加工表面质量,同时又能获得较高的高速加工效率.     

Selection of design and operational parameters in spindle–holder–tool assemblies for maximum chatter stability by using a new analytical model

In this paper, using the analytical model developed by the authors, the effects of certain system design and operational parameters on the tool point FRF, thus on the chatter stability are studied. Important conclusions are derived regarding the selection of the system parameters at the stage of machine tool design and during a practical application in order to increase chatter stability. It is demonstrated that the stability diagram for an application can be modified in a predictable manner in order to maximize the chatter-free material removal rate by selecting favorable system parameters using the analytical model developed. The predictions of the model, which are based on the methodology proposed in this study, are also experimentally verified.     

融合机床加工特性的主轴回转误差预测

针对机械制造装备主轴精度补偿问题,研究一种融合机床精度和加工参数的主轴回转精度预测方法。为获取主轴回转精度指标,研究基于多点测量的主轴实际回转位置测量方法,利用最小二乘法求解主轴端面跳动的最大圆、最小圆和最优圆,进一步得到端面圆度的极大误差和极小误差。建立BP神经网络模型,融合机床精度因素、加工精度因素获得输入指标,将极大误差、极小误差和其余实测指标作为输出指标,训练神经网络,获得网络权值。验证机床主轴回转预测精度,实验结果表明:已训练的网络预测偏差为0.5%。考虑机床本体精度和加工参数的误差预测结果可指导工程技术人员进行机床选型,根据不同加工要求选择最优加工方式,提高加工质量。     

多主轴卧式加工中心实现高效加工

文章介绍了当今国际金属切削加工领域里代表先进水平的多主轴卧式加工中心的结构特点、工艺先进性以及这种机床在生产实践中的应用。     

高速磨削加工工艺及应用

高速磨削加工属于先进制造方法。与普通磨削比,它有很多优点,且集粗精加工于一身,达到与车、铣、刨等切削加工相媲美的金属磨除率,能实现对难磨材料的高性能加工。本文阐述了高速磨削加工工艺的确定,高速磨削加工在工业中的具体应用,以及进一步提高磨削速度的设想。     

高速切削稳定性研究综述

介绍国内外学者在高速切削稳定性方面的研究成果,着重总结和分析以下几方面的研究工作:颤振的发生机理及数学模型、颤振的监测及预测以及抑制颤振提高切削稳定性的方法.     

自动换刀系统在数控加工中心中的应用及故障实例

文章分别从刀库的旋转驱动，选刀装置，机械手，系统确认等各自的功能情况来说明自动换刀系统的工作过程，并举实例解析自动换刀系统的故障。     

基于MasterCAM8.0建立开发PMC-10V20加工中心刀具库

在加工中心实际应用中，为了方便选用经过实践检验的刀具切削参数，提出在MasterCAM8.0中建立常用刀具库的设计思路，并加以应用开发。从而减轻工作劳动强度，延长了刀具使用寿命，提高工作效率。     

五轴高速加工技术应用分析

通过对不同五轴加工机床结构的分析,指出其各自的特点与适应场合,同时通过分析说明五轴联动与高速加工的内在关系及其优越性,提出了五轴高速加工技术的普及化发展趋势。     

高速切削加工CAM技术策略的研究

根据高速加工数控编程的要求,在CAM软件中,对高速加工的粗精加工选择不同的加工策略,满足了高速切削加工所需要的工艺条件,从而保证了加工质量.     

现代数控机床高速化发展的最新动向

在缩短加工时间、提高生产率的市场需求推动下,切削加工技术正经历着从低速重切削加工向高速轻切削加工方向演变的过程.高速切削加工技术的发展是机床高速化的直接动力.本文从切削技术高速化发展入手,依据机床发展统计数据以及产品研发情况,介绍了机床主轴单元及进给单元高速化发展的现状,并展望了其发展趋势.     

高速切削技术在薄壁零件加工中的应用研究

从薄壁箱体的加工效率、加工精度等角度出发,分析薄壁箱体零件高速切削加工的优势和可行性。针对其工艺特点及生产实际要求,分析高速加工中存在的工艺问题,给出具体的解决措施。实践表明:采用高速切削加工技术加工薄壁箱体,加工效率高,工件表面质量好。     

孔内环形槽加工装置

用本孔内环形槽加工装置加工小孔、深孔内的多条环形沟槽,克服了以往使用偏心刀杆存在的不足,加工后的环形沟槽完全能够达到图纸设计要求,并且生产效率高.     

织构刀具高速干式切削Al7075-T6的性能研究

表面微织构能够改善刀具的切削性能。为了研究织构刀具高速干切削Al7075-T6时织构参数对切削性能的影响,利用仿真软件建立正交二维切削仿真模型。对比了所选织构参数范围内的最优织构刀具与无织构刀具的主切削力、刀具温度、刀具应力,分析了织构参数对主切削力的影响程度。结果表明:合理的织构参数,可以减小刀具的主切削力,使刀具表现出更好的温度及应力分布梯度;所选织构参数范围内,织构宽度为60μm、织构间距为90μm、织构深度为30μm、织构刃边距为100μm的织构刀具切削性能最好;织构参数对主切削力影响程度从大到小依次为织构刃边距、织构宽度、织构间距、织构深度。     

基于模具的高速切削加工技术

叙述了在模具加工中为实现高速加工所必需的一些关键技术及高速加工技术在模具制造中应用的意义,并通过与电火花加工方式的对比,描述了高速加工的优越性和局限性,最后以加工实例说明高速加工能有效缩短加工时间,提高加工精度。