基于稳健设计方法的五轴微小型铣床结构设计参数分析

采用田口稳健设计方法对五轴微小型铣床的结构设计参数进行分析.首先,建立了基于刚体运动学的五轴微小型铣床的空间误差模型;然后,将机床的结构设计参数作为控制因素,将机床的局部几何误差作为噪声因素,以机床的空间误差作为稳健设计的目标函数,以正交试验为工具安排了多组仿真试验;最后,通过对试验结果的统计分析评价了机床各设计参数对空间误差的影响及其稳健性.     

数控机床五轴变换系统设计与研究

为实现数控机床五轴联动加工,基于国内蓝天系列数控系统提出了控制系统结构的改进方法。数控系统分为任务层和运动层,五轴变换单元集成在运动层。在对五轴机床进行分类并分析其几何信息的基础上,设计了机床的五轴运动库。以CA摆头机床为例,推导了其正向和反向运动变换。基于改进系统及五轴运动库,设计并分析了机床旋转刀具中心控制和三维半径补偿端铣。改进系统具有较好的可移植性,可在数控加工中直接执行刀具位置和方向指令。     

《组合机床与自动化加工技术》2006年总目次

专题述评先进制造系统信息集成技术综述……郭于明,孙延明,郑时雄(04-001)基于Fieldbus和PLC的分布式控制系统综述……………………………………………………………………………虚拟轴并联机床研究的发展、关键技术及趋势李强,闫洪波,杨建鸣(08-001)……………………………………………………………………设计与研究协同集成反求工程系统关键技术研究…………………………………………………………………………崔焕勇,高琦,姜兆亮,等(01-001)五轴铣床运动链构形方案分析………刘建慧,邹慧君,颜鸿森(01-004)空间三角形网格优化算法的研究……     

五轴数控旋风铣削机床加工螺纹的误差补偿研究

基于小误差运动假设,分析了五轴旋风铣削机床误差运动和补偿运动间的相互关系,建立了考虑工件热胀冷缩时进行其空间5个误差量计算的数学模型,为五轴旋风铣床用于螺纹精加工时的误差实时插补提供了理论基础,也是建立考虑工件热变时通用五轴旋风铣床误差实时插补数学模型及以旋风铣削精加工质量为目标函数、约束于多变量的数学模型的第一步.     

五轴龙门机床转动轴误差检测方法研究

在五轴龙门机床中,针对线性轴检测方法已基本完善,而转动轴误差检测方法还存在不足,因此对转动轴检测方法研究很有必要。文章首先分析了转动轴误差产生的原因及其对机床的影响;其次对机床误差,尤其是转动轴误差进行了分析和建模,最后基于五轴龙门机床补偿,提出了一种简便的、有效的五轴龙门机床转动轴检测方法,效果良好。     

大型复杂构件数控焊接机床的设计与分析

针对大型复杂构件焊接及其加工技术要求,介绍了一款双摆轴五轴联动数控焊接机床的设计与分析,包括机床总体设计,各进给轴设计以及机床结构有限元分析,为大行程空间复杂构件数控焊接机床研制提供了可靠的技术支持.     

基于PowerMILL的五轴数控机床仿真与应用

通过虚拟仿真技术,基于PowerMILL软件自带的机床仿真功能,以双转头五轴数控加工中心为例,介绍五轴机床仿真模型的建立和仿真机床参数设置,并以轴流风叶片进行数控刀路仿真、优化和试切加工,验证仿真系统的有效性,确保五轴数控机床的加工效率和可靠性。     

数控机床虚拟样机的虚拟加工实现

虚拟加工是对数控机床虚拟样机进行性能测试的内容之一。本文在UG IS＆V环境下建立了一台三轴数控铣床的仿真模型。在该模型的基础上分别对零件加工过程中的刀具路径和铣床运动进行仿真，在虚拟样机上实现了虚拟加工。通过虚拟加工分析，可对设计的机床进行性能预测和评价，进一步完善初步设计。     

五轴联动BC型木工雕刻机床结构与数控系统设计

针对现阶段木工雕刻机床结构单一的问题,设计一种经济型五轴联动BC型木工雕刻机床及其数控系统。通过建立机床的运动学模型,研究五轴BC型机床的正逆解;根据运动学求解的结果,采用NC系统嵌入PC机的开放式数控系统模式,设计了数控系统的硬件。采用Visual C++6.0对数控系统软件进行编制,运用线程对运动控制进行监管,并对刀轨文件进行仿真加工。通过对维纳斯石蜡模型的加工与测量,验证数控系统加工精度符合加工要求。     

五轴数控机床后置处理开发及奇异点规避

机床后处理开发是数控加工技术的关键问题之一,五轴机床运动过程中可能出现的奇异点及其对加工造成的影响在后处理开发过程中极易被忽略。对此,文章基于刚体变换原理,推导了B-C轴式双转台五轴数控机床的运动转换关系,对五轴机床运动可能出现的奇异点现象进行了分析及规避,开发了实验室德玛吉DMU50五轴数控机床专用后置处理文件,经过加工仿真及实验验证,该后置处理对坐标转换计算正确,可以在机床上实际应用,有效的提高了机床的利用效率。     

A New 3-DOF Spatial Parallel Mechanism for Milling Machines with Long X Travel

It is well known that the shape and volume of the workspace are one of the greatest weaknesses of parallel kinematic machine tools (PKM). Hexaglide and Triaglide mechanisms are examples where workspace extension is achieved by elongating one axis as a principal motion axis that is a common feature of all Cartesian machines. With the idea of principal axis of motion in mind, a new 3-DOF spatial parallel mechanism for horizontal and vertical milling machines has been developed. In comparison with similar developed mechanisms it has several advantages such as: rather regular shape of the workspace (slightly modified block) similar to serial machines; greater stiffness by nature of the struts arrangement; good force and speed ratio through the entire mechanism's workspace. The paper describes the structure of the mechanism, modelling approach and simulation on a developed vertical milling machine prototype.     

Relationships between straightness and angular kinematic errors in machines

The software compensation approach for the improvement of machine tool and coordinate measuring machine accuracy depend to some extent on machine error modelling and measurement methodologies. The currently established methodology is based on the derivation of tool position error (for machine tools) or stylus tip position error (for coordinate measuring machines) by the combination of individual axis joint kinematic error parameters. The purpose of this paper is to propose a machine error analysis based on error classification. This taxonomic approach forms a conceptual basis for an analysis of machine errors with a deeper understanding of error mechanisms at more fundamental levels. The relevance of this approach is investigated through the case study of the coupling mechanism between joint kinematic angular and straightness errors of machine linear axes. The limitations of the joint kinematic straightness and angular error modelling based on purely abstract mathematical dependence principles are explored through simulations and experiments.     

提高大型高精立式机床精度保持性的新型转台技术研究

针对国内生产的高速、高精大型立式机床以及车铣复合机床等高档数控机床迫切需要提高精度保持性的重大需求,开发一种能提高大型高精立式机床精度保持性的数控回转工作台。该回转工作台采用一套精密推力向心组合圆锥滚子轴承,取消了传统结构中的主轴及其复杂的轴承支承系统。推力向心组合圆锥滚子轴承的底圈和上圈都安装在同一个轴台上,实现了上圈、底圈与轴台无间隙的紧配合,消除了轴承所有套圈和它们配合件之间的间隙,并能实现过盈配合,很大程度上提高了机床的精度保持性。     

Active vibration control in palletised workholding system for milling

This paper presents the development implementation and testing of an active controlled palletised workholding system for milling operations. The traditional approach to controlling vibration in a machining system is to develop control systems for cutting tools or machine spindles as in the case of milling machines. This work is a deviation from the traditional approach and targets a workholding system for the control of unwanted vibration. Palletised workholding systems, due to their compact design, offer an opportunity to design active control systems that are economical and easier to implement in the case of milling machines. The active control system developed here is based on an adaptive filtering algorithm, the filtered X-LMS, and employs piezo-actuators for dynamic control force. The system has been tested experimentally to demonstrate the reduction in dynamic force due to vibration. Extensive testing has been carried out to validate the performance of the system in terms of parameters of practical importance such as improvement in surface finish and increase in tool life.     

基于89C51/52单片机的数控机床面板智能处理单元

本文提出了基于８９Ｃ５１／５２单片机的数控机庆机板智能处理单元,介绍了基工作原理和系统软硬件,设计了一种新的软件消除键拌动算法。该处理单元通过标准串口与数控系统交换信息,已经用了三从九控铣床手动操作面板的控制,软硬件均可以可靠工作。     

基于NC程序的重型数控铣齿机床能耗预测

准确预测重型数控铣齿机床的能耗是制造过程节能降耗的理论基础。以重型数控高速铣齿机为研究对象，提出基于NC程序的能耗预测方法。分析数控机床耗能部件的能耗特征，并按能耗特征进行部件分类；建立各部件能耗模型，并提出齿轮成形铣齿的材料去除率计算方法；最后，开发重型齿轮铣削加工能耗预测程序。在2台不同型号重型数控铣齿机上的试验表明预测方法的预测精度在95%以上，方法可行；此外，分别提高10%进给速度在实验的2台高速铣齿机上，其分别节能7.52%和4.25%，结果表明重型机床规格越大，节能潜力越大。     

Accuracy enhancement of five-axis machine tool based on differential motion matrix: Geometric error modeling,identification and compensation

This paper presents the precision enhancement of five-axis machine tools according to differential motion matrix, including geometric error modeling, identification and compensation. Differential motion matrix describes the relationship between transforming differential changes of coordinate frames. Firstly, differential motion matrix of each axis relative to tool is established based on homogenous transformation matrix of tool relative to each axis. Secondly, the influences of errors of each axis on accuracy of tool are calculated with error vector of each axis. The sum of these influences is integration of error components of machine tool in coordinate system of tool. It endows the error modeling clear physical meaning. Moreover, integrated error components are transformed to coordinate frame of working table for integrated error transformation matrix of machine tools. Thirdly, constructed Jacobian is established using differential motion matrix of each axis without extra calculation to compensate the integrated error components of tool. It makes compensation easy and convenient with reuse of intermediate. Fourthly, six-circle method of ballbar is developed based on differential motion matrix to identify all ten error components of each rotary axis. Finally, the experiments are carried out on SmartCNC500 five-axis machine tool to testify the effectiveness of proposed accuracy enhancement with differential motion matrix.     

Dynamic calibration of the positioning accuracy of machine tools and coordinate measuring machines using a laser interferometer

This paper describes a method for evaluating the positioning accuracy of machine tools and coordinate measuring machines (CMM) under dynamic conditions. It is based on the Hewlett Packard 5519A laser interferometer which is capable of performing dynamic calibration. Such method uses the A-quad-B pulses from the machine encoder as the position trigger signals, thus enabling to make measurements “on-the-fly”. A software package has been developed so as to permit the data acquisition and presentation of the positional errors in accordance with ISO 230–2 standard. Thereby, the accuracy and repeatability of positioning of the machine axis on test are assessed considering the ISO parameters. This technique provides a more realistic and detailed picture of the errors of the machine. Such errors are measured in high resolution and dynamically. Application of this positional error calibrator on a moving bridge type CMM is undertaken. The results are presented and discussed.     

Five-axis milling machine tool kinematic chain design and analysis

Five-axis CNC machining centers have become quite common today. The kinematics of most of the machines are based on a rectangular Cartesian coordinate system. This paper classifies the possible conceptual designs and actual existing implementations based on the theoretically possible combinations of the degrees of freedom. Some useful quantitative parameters, such as the workspace utilization factor, machine tool space efficiency, orientation space index and orientation angle index are defined. The advantages and disadvantages of each concept are analyzed. Criteria for selection and design of a machine configuration are given. New concepts based on the Stewart platform have been introduced recently in industry and are also briefly discussed.     

五轴机床刀尖点频响特性及切削稳定域位置的演变

五轴机床在航空航天领域大型曲面零件加工中应用极其广泛,其高速、高精度和大材料去除率的加工特点对加工稳定性提出了很高要求,影响五轴机床铣削稳定性的主要问题是切削颤振。通过对一台转摆头五轴机床进行动力学性能测试,对比分析主轴系统在不同位置和转摆头在不同姿态下刀尖点的频响特性,得出刀尖点频响特性随位置的演变规律。以频域法构建切削稳定性叶瓣图,得到极限切深的位置演变规律。研究结果为五轴机床切削参数的优化提供了参考。