A hybrid 5-axis CNC milling machine

5-Axis CNC milling machines are important in a number of industries ranging from aerospace to consumer-die-mold machining because they can deliver high machining accuracy with a spindle tilting capacity. Most of these machines have serial mechanisms so that modest static and dynamic stiffness become very critical design issues when high speed machining capability is required. Parallel mechanisms have recently received attention from machine tool designers because of their inherent potential for stiffness and because of their compactness. However, much of the promised advantages of parallel machines only occur within a very small region of their workspace. We discuss some of the kinematic and structural challenges to extract machining performance from serial and parallel machines. We compare a hybrid machine, which combines serial and parallel mechanisms, with typical serial and parallel machines such as Euler angle machines and a hexapod. In particular, we consider singularities, reversal characteristics, and manufacturability. We show that hybrid machines can benefit from the advantages of serial and parallel mechanisms while avoiding most potential pitfalls. However, hybrid structures can suffer from the manufacturing problem of over-constraint. We show that the degree of over-constraint depends on machine size. We have designed a small hybrid 5-axis motion platform, the MIT-SS-1, which can tolerate this over-constraint through a novel layout of axes. We show that this structure has potential as a small 5-axis CNC milling machine.     

五轴联动旋风铣削机床设计与仿真分析

应用虚拟制造技术拟订了五轴旋风机床的创新设计方案,建立了三维数字分析模型.首先在数字模型上进行了多体运动仿真,验证机构原理;其次在数字样机上进行了机构运动仿真,检查机构碰撞和干涉情况,验证机床运动功能;设计了电主轴,再进行了主轴的动态特性仿真,验证了主轴的刚度.通过仿真分析得知机床性能与设计质量能满足旋风加工要求,验证了方案的可行性.     

五轴数控加工叶轮轮毂曲面刀位轨迹的规划

对整体叶轮轮毂面的刀位轨迹排布进行了研究.首先运用分层的思想和旋转法得到均布于等长叶片叶轮轮毂面上的刀位轨迹;并在其基础上采用区域划分法对交错叶片叶轮轮毂曲面的刀位进行规划,得到C1连续的刀位轨迹.     

加工中心在线测量功能的实现

介绍加工中心在线测量的意义和基本方法,着重介绍测头的选用、系统的连接以及对测量数据的处理,对一般数控机床实现附加的测量功能具有指导性意义.     

数控电解车削装置及基础工艺试验

介绍数控电解车削加工原理及试验装置.利用直线刃阴极在试验装置上进行圆柱面和凸轮面的加工试验,并对试验结果进行分析.结果表明数控电解车削加工可用于回转件的加工.     

基于VDW-320五轴机床的后置处理与虚拟仿真研究

针对VDW-320五轴数控机床,研究了其后置处理技术,解决了VDW-320五轴机床与SurfCAM软件的接口问题.并结合单叶片曲面零件研究了采用五轴数控加工时的虚拟仿真技术.结果表明研制的后置处理文件是实用的,该技术可广泛应用来加工各种复杂模具或机械零件.     

Mapping and compensation of geometric errors of a machine tool at different constant ambient temperatures

Thermo-mechanical effects due to changes in the ambient temperature on the shop floor and internal heat sources caused by the manufacturing process significantly contribute to the geometric deviations of a machine tool and therefore, the geometric deviations of the manufactured workpiece. Minimizing these thermally induced geometric deviations is worthwhile since the requested tolerances of machined workpieces become continually smaller nowadays. To investigate the overall deformations of a machine tool structure due to variations in ambient temperature the geometric errors of a five-axis machine tool at different ambient temperatures by means of a portable climate simulation chamber are systematically mapped. While positioning and squareness errors of the linear axes are significantly influenced by the ambient temperature, straightness as well as rotational errors were less sensitive to temperature effects. For the investigated machine tool errors of the two rotational axes are negligible due to an active cooling of these axes. Through numerical error compensation of the linear axes, the geometric errors of the investigated machine tool can be reduced up to 80%. Finally, an outlook how a temperature-dependent compensation could be derived from previously measured compensation fields at discrete temperatures and afterwards applied on-the-fly during manufacturing is given.     

基于VERICUT非正交五轴机床加工仿真技术研究

针对非正交五轴联动加工机床结构复杂,加工准备周期长,程序验证复杂、干涉碰撞易发生等特点,对非正交五轴机床加工仿真技术进行了研究。利用VERICUT仿真软件,以DMU70evo机床为原型,构建与实际机床一致的虚拟仿真环境,主要包括仿真机床模型和仿真控制系统。利用建好的仿真环境,进行某异型法兰零件的数控加工仿真。结果表明:构建好的机床模型准确、可靠,验证了NC程序的正确性,提高了加工的准确性、安全性和生产效率。     

五轴联动数控工具磨床工作台运动方案与结构设计

数控工具磨床是硬质合金刀具加工的关键设备.结合五轴联动数控工具磨床的研制,根据刀具磨削加工的特点和技术要求,系统分析了常见五轴联动数控工具磨床的系统布局,讨论比较了不同工作台结构型式的特点,提出了数控工具磨床合理的工作台结构和进给系统设计方案,在此基础上完成了工作台零部件的结构设计.     

基于VERICUT的数控机床建模技术

数控机床建模是数控加工仿真的基础,通用化的建模方法是保证仿真高效的要求之一.本文简介了虚拟制造软件VERICUT的功能模块,基于VERICUT的建模技术,分析了不同类型数控机床的建模过程,总结了建模方法的共同特性,提出了面向不同类型、多种机床的通用建模过程.最后以五轴加工中心机床作为实例详细介绍了在VERICUT上的建模方法.     

工作台回转与刀轴摆动五轴联动数控加工编程技术研究

研究了工作台回转与刀轴摆动五轴联动数控加工编程中的刀轴矢量与转动角度之间的转换;刀位点在工件坐标系与工作坐标系之间的位置变换;刀轴摆动导致的基准点与刀位点之间的位置补偿等关键技术,为多轴联动数控加工编程技术提供参考.     

数控机床产生加工误差的原因及其改善措施

分析了数控机床产生加工误差原因,并指出了减少加工误差的相应措施.     

基于光栅测量的数控机床精度控制及故障处理

分析了闭环伺服系统的控制特性和控制要求。对采用光栅作为检测装置的数控机床,指出了影响数控机床控制精度和加工精度的主要因素。提出了对检测反馈信号进行倍频处理,从而提高闭环伺服系统检测精度及控制精度的措施。给出了倍频处理电路和EXE信号处理电路的设计方法。针对光栅使用中可能出现的故障,给出了故障诊断及处理方法。该方法不但可以提高数控机床的控制精度,改善闭环控制系统的特性,而且可以方便地进行测量系统故障的诊断与处理。     

数控机床定位精度的测量和评定

介绍如何使用激光多普勒位移测量仪测量数控机床的定位误差,并根据ISO 230—2（1997）标准确定数控机床的定位精度和重复定位精度,为进一步进行误差补偿提供基础。     

五轴数控加工奇异点问题研究

研究了五轴数控加工奇异点问题,分析了奇异现象及产生的原因。在对前人工作分析的基础上,提出了在刀轨规划时避免奇异现象的方法。该方法通过监测刀轴与旋转轴的夹角,找出产生奇异的刀位点,并以上一刀位点对当前刀位点进行优化。结果显示机床各运动轴能平缓通过奇异区域,证明该方法切实可行。     

快速检查机床电器故障的方法

了解机床的功能,掌握设备的原理,弄清元、器件的位置,熟悉它们的机、电关系是快速检修机床电气故障的关键。     

典型五轴零件的数控加工工艺分析与编程加工

文中在典型五轴零件的结构分析和工艺分析基础上,基于传统的三轴数控加工工艺,融合前沿的五轴加工策略,使用CAXA制造工程师设计了典型五轴零件的刀路,并完成了五轴零件的数控编程和加工,获得了满足要求的加工效果。     

论机床加工精度和精密机床的结构特点

从研究机械加工精度出发,针对机床本身的结构误差和运动误差,分析和叙述了机床误差对工件加工精度的影响程度,简要介绍了部分精密机床结构特点及其在提高精度方面所采取的方法和措施。     

Tool Positioning Algorithm Based on Smooth Tool Paths for 5-axis Machining of Sculptured Surfaces

The current research of the 5-axis tool positioning algorithm mainly focuses on searching the local optimal tool position without gouging and interference at a cutter contact(CC) point,while not considering the smoothness and continuity of a whole tool path.When the surface curvature varies significantly,a local abrupt change of tool paths will happen.The abrupt change has a great influence on surface machining quality.In order to keep generated tool paths smooth and continuous,a five-axis tool positioning algorithm based on smooth tool paths is presented.Firstly,the inclination angle,the tilt angle and offset distance of the tool at a CC point are used as design variables,and the machining strip width is used as an objective function,an optimization model of a local tool positioning algorithm is thus established.Then,a vector equation of tool path is derived by using the above optimization model.By analyzing the equation,the main factors affecting the tool path quality are obtained.Finally,a new tool position optimization model is established,and the detailed process of tool position optimization is also given.An experiment is conducted to machine an aircraft turbine blade by using the proposed algorithm on a 5-axis blade grinding machine,and the machined blade surface is measured with a coordinate measuring machine(CMM).Experimental and measured results show that the proposed algorithm can ensure tool paths are smooth and continuous,improve the tool path quality,avoid the local abrupt change of tool paths,and enhance machining quality and machining efficiency of sculptured surfaces.     

机床产品外观家族化设计方法研究

企业形象要求同一企业不同产品外观具有相似性,给消费者留下深刻印象,促进产品销量。由此引出产品外观家族化设计概念,按照流程对形态、色彩、质感与面饰工艺、装饰件四要素进行分析,从典型产品提取外观家族化特征,运用到全系列产品并作适当调整,将修正后的结果返用于典型产品,验证后再全面用于普通产品,形成产品家族化形象。该设计方法运用于企业实际案例时,达到了较好的不同产品系列家族化效果。