共查询到20条相似文献,搜索用时 31 毫秒
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于栋梁 《机械制造与自动化》2022,51(1):56-60
为修正五轴数控机床加工误差,提高五轴数控机床加工质量,提出一种新的五轴数控机床加工误差动态修正方法.构建五轴数控机床加工误差计算模型,获取五轴数控机床加工的刀心方位、刀轴方位轮廓误差;锁定误差方位后,通过五轴数控机床误差的动态实时补偿方法,实现五轴数控机床加工误差动态修正.研究结果表明:所提方法可实现全方位、高效率的五... 相似文献
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MODELING AND COMPENSATION TECHNIQUE FOR THE GEOMETRIC ERRORS OF FIVE-AXIS CNC MACHINE TOOLS 总被引:7,自引:0,他引:7
Wang ShuxinYun JintianZhang ZhifeiLiu YouwuZhang QingSchool of Mechanical Engineering Tianjin University Tianjin China 《机械工程学报(英文版)》2003,16(2):197-201
One of the important trends in precision machining is the development of real-time error compensation technique. The error compensation for multi-axis CNC machine tools is very difficult and attractive. The modeling for the geometric error of five-axis CNC machine tools based on multi-body systems is proposed. And the key technique of the compensation-identifying geometric error parameters-is developed. The simulation of cutting workpiece to verify the modeling based on the multi-body systems is also considered. 相似文献
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Jianxiong Chen Shuwen Lin Bingwei He 《The International Journal of Advanced Manufacturing Technology》2014,71(1-4):635-642
As the geometric errors of motion axis can be equivalent to the differential movement, regarded as a differential operator based on its ideal position, a new modeling method for multi-axis CNC machines based on differential transform theory is proposed in this paper. First, the workpiece coordinates is selected to observe the errors of the tool pose. Then, a general geometric error model for multi-axis machines is established. Moreover, the Jacobian matrix is applied to describe the relationship between the tool pose error vector and the compensation error vector. All the elements of the matrix are obtained by computing the differential operators instead of computing the partial derivatives. The compensation errors vector is solved using the pseudo-inverse Jacobian matrix. Finally, an automatic modeling procedure is developed to construct the geometric errors for multi-axis machine tools. An experiment on a five-axis machine tool is conducted to test and verify the proposed method. The results show that the proposed method dramatically improves the overall position accuracy of the test tool path. 相似文献
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Hongbin Liang Xia Li 《The International Journal of Advanced Manufacturing Technology》2013,68(9-12):2791-2800
Five-axis machining is more widely used in manufacturing of freeform surfaces. However, in five-axis machining of freeform surfaces, incomplete information exchange between computer numerical control (CNC) and computer-aided design/computer-aided manufacturing (CAM) results in many limitations need to be rectified. In the paper, a new structure of CNC based on STEP-NC standard is proposed, where tool path planning, tool offset, and inverse kinematics are transferred from CAM to CNC. In order to guarantee good openness, open platform and standard interface are applied in the development. Technology of module collaboration and design of data flow are studied. A five-axis real-time interpolator for non-uniform rational B-spline surfaces machining is realized. Based on these technologies, a five-axis CNC is developed in the manner of software realization, which consists of interpreter, task coordinator, axis group, softPLC, etc. The software CNC system has been applied on a tilt-rotary type five-axis machine tool, where the milling experiment has been performed successfully. 相似文献
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针对目前航空发动机叶片进排气边加工精度和表面质量较差的问题,提出了一种基于机床运动学约束球头刀多轴加工刀轴矢量优化方法。建立刀位优化变量与刀位数据之间的关系方程,同时建立刀位数据与机床回转轴角度之间的运动变换方程,从而推导出刀位优化变量与机床回转轴角度之间的关系方程。通过求解上述方程得到球头刀多轴加工复杂曲面的刀轴矢量计算公式。在此基础上,给出球头刀多轴加工刀轴矢量优化方法和刀轨生成方法。同时,以某航空发动机叶片为例,分析了本文算法和Sturz算法对机床回转轴角度的影响。分别利用本文算法和Sturz算法生成该叶片进气边加工的刀轨,并在五轴数控机床上进行加工试验。试验结果表明,该算法能够避免加工过程中机床回转轴的大幅波动,使机床轴运动更加平稳和光滑,从而提高曲面的加工质量和加工效率,具有一定的实际应用价值。 相似文献
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在五轴加工编程中,计算机辅助制造系统对曲面加工通常采用以折代曲,采用大量的微小G01直线段来加工曲面,在曲率半径较大的工件表面会出现明显折痕,严重影响工件表面的加工质量。为提高五轴数控加工工件的表面质量,提出一种五轴微段平滑插补算法。该算法考虑五轴加工中刀位数据的量纲差异,根据相邻数据点间的线性轴长度、线性轴的夹角和旋转轴角度变化量识别五轴数控加工程序中非连续微段和连续微段加工区域。对非连续微段加工区域按照原始直线段和旋转轴直接插补,从而保证加工精度。对连续微段加工区域,先通过五维变量获取节点参数,采用最小二乘法对指令点在允许的精度范围内进行修正;对修正后的指令点采用4点构造法计算二阶切矢,根据连续微段的指令点修正值,节点参数值和对应的二阶切矢值获取二阶连续的三次样条曲线;在二阶连续平滑的曲线上进行实时插补计算,控制机床进行五轴加工。试验结果表明:通过提出的五轴微段平滑压缩算法拟合后的路径要更加接近原始的曲面模型,平滑处理过的实际工件加工表面也要优于未进行处理的工件加工表面,提高了五轴自由曲面的表面质量。 相似文献
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In the machining of sculptured surfaces, five-axis CNC machine tools provide more flexibility to realize the cutter position as its axis orientation spatially changes. Conventional five-axis machining uses straight line segments to connect consecutive machining data points, and uses linear interpolation to generate command signals for positions between end points. Due to five-axis simultaneous and coupled rotary and linear movements, the actual machining motion trajectory is a non-linear path. The non-linear curve segments deviate from the linearly interpolated straight line segments, resulting in a non-linearity machining error in each machining step. These non-linearity errors, in addition to the linearity error, commonly create obstacles to the assurance of high machining precision. In this paper, a novel methodology for solving the non-linearity errors problem in five-axis CNC machining is presented. The proposed method is based on the machine type-specific kinematics and the machining motion trajectory. Non-linearity errors are reduced by modifying the cutter orientations without inserting additional machining data points. An off-line processing of a set of tool path data for machining a sculptured surface illustrates that the proposed method increases machining precision. 相似文献
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Automatic selection of cutter orientation for preventing the collision problem on a five-axis machining 总被引:1,自引:1,他引:0
Yao-Wen Hsueh Ming-Hsien Hsueh Hsin-Chung Lien 《The International Journal of Advanced Manufacturing Technology》2007,32(1-2):66-77
The rotation joints of a five-axis machine tool can offer freedom and appropriate rotation to prevent interference problem
between workpiece and the cutter. However, to a five-axis machine tool, it is quite difficult to determine the collision-free
cutter orientation. Over this problem, a two-stage cutting tool collision check method is proposed to prevent the collision
problem during the cutting process on a five-axis machine tool. The proposed method is capable of determining the collision
free ball-end cutter orientation automatically. The first stage is to obtain the tilting and collision-free angle range in
the plane that is normal to the tool path obtained. Next, a checking cone generated from this collision-free tool axis range
is used for the second collision check. The collision region is formed by the intersection of the neighboring surfaces. This
implies a collision-free yaw angle range. The final cutting tool orientation is determined automatically by referring the
original spindle axis and the least angular variation from the spindle axis. Finally, the implementation issue is discussed
with example. 相似文献
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五轴数控机床的几何误差和热误差是影响工件加工精度的两个重要因素,对这些误差因素进行分析可以有效提高薄壁件工件的加工精度。本文首先基于齐次坐标变换法,建立了双转台五轴数控机床的旋转轴几何误差模型;然后基于对标准球进行在机接触测量,辩识得出两旋转轴的12项几何误差,这些误差考虑了两旋转轴之间的相互影响和其热误差的影响;最后分析五轴数控机床加工空间的几何误差场,在该加工空间内几何误差从中心到外侧逐渐增加,当A轴旋转角度增加时,误差的最大值也随之增加。与其它位置误差辨识方法相比,本方法的测量精度符合加工要求,测量时间只需要30 min。 相似文献
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引入打印机的结构参数以表示两旋转轴与工件在机架坐标系中的位置,并采用指数积理论建立了双转台五轴3D打印机通用正向运动学模型。结合三角函数周期性、旋转轴行程、五轴结构特点等获得旋转轴角度双解的具体表达式,并提出基于旋转角度最短路径的选择原则以获得旋转轴角度的最佳组合。利用选择的旋转轴角度求出各平动轴位移量,获得的所有运动量都是基于各轴零位的绝对运动所得,进而生成能直接用于加工的数控打印代码,可在没有旋转刀具中心点跟随功能的帮助下完成加工。结合双转台、摆头转台、双摆头3种不同类型的五轴3D打印机研究了通用后置处理方法。将该方法用于五轴3D打印、五轴数控加工试验和多种结构类型的五轴加工仿真,验证了其正确性与通用性。 相似文献
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面向五轴联动数控机床的可靠性试验提出多维力随动加载方法,对五轴联动进给主轴施加多维力载荷,形成复杂进给抗力,部分模拟主轴复杂切削力环境。基于6-PUS并联机构研制多维力随动加载装置,采用模糊PID控制器建立显式力控制系统,比例和积分增益可随加载误差自适应调节。在五轴联动数控机床上开展多维力随动加载实验,结果表明,加载装置能够跟随机床主轴的单轴、三轴联动和五轴联动进给运动,根据期望值对主轴施加三维力,加载误差小于3.2%,在机床执行多种加工轨迹时形成有效进给抗力,为后续引入动态加载模拟复杂切削力提供理论和装备支撑。研究成果可为数控机床可靠性试验提供低成本、可循环的加载方式,有利于测试的规模化和标准化发展,也可为精度保持性、超载试验、跑合试验等机床性能测试提供新的负载模拟思路。 相似文献
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五轴数控机床的加工性能在制造行业一直是研究的热点,基于检验试件切削是常见的测评方法,然而试件和机床之间的映射关系难以确定,出现误差后如何调整精度成为难点。为了科学对其评价,通过仿真平台建立了机床控制系统参数与五轴机床检验试件——S试件加工误差之间的映射关系,引入机床各轴分类评价的隶属度,此基础上开发了误差溯源的综合评价体系,由三坐标测量机得到的S件轮廓误差数据反求出机床的加工性能等级和较差的轴类控制参数,并制订了基于S试件的机床加工精度测评规范,最后通过某五轴AB摆数控机床的切削试验,验证了方法的有效性。该成果有助于解决我国高端制造业长期缺乏机床性能测评的共性技术问题,具有重要的应用前景和经济价值。 相似文献
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A generalized cutting location expression and postprocessors for multi-axis machine centers with tool compensation 总被引:1,自引:1,他引:0
Chieh Tung Pei-Lum Tso 《The International Journal of Advanced Manufacturing Technology》2010,50(9-12):1113-1123
This research deals with tool compensation and postprocessor development for numerical control application. The content consists of three main activities. First, derives a cutting location expression of the tool for compensation and machining stability use. Second, establishes an analytical methodology to develop a kinematics transformation algorithm (KTA) for the specific type machine with a swivel spindle head and two rotary tables. And last, defines correspondent between workpiece and the cutter to attain the aim of three-dimensional tool compensation and presents postprocessors under KTA for two types of five-axis machine centers in examples. 相似文献
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由于非典型叶轮结构复杂,无法使用主流CAD/CAM软件提供的叶轮5轴模块,在粗加工阶段采用3轴定向加工时,残余毛坯留量体积大形状不规则,严重影响了5轴加工的效率和质量。为此,一方面对于叶轮开式区域采用双圆柱面投影法获得驱动曲面,从而实现4轴联动粗加工,切削刚性大效率高;对于非开式区域则通过构建驱动曲面获得5轴联动刀轨,刀轨连续且刀轴矢量无突变。另一方面,提出了一种基于NC程序的刀轴矢量评价方法,可快速直观地评价5轴编程质量。实际使用结果表明:基于驱动曲面的刀轴矢量优化法能够显著提高复杂工件5轴加工的效率和质量。 相似文献
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通过分析数控铣削加工中合理建立和灵活运用刀具半径补偿对零件进行编程与加工的过程,说明可以根据工件轮廓尺寸编制加工程序,以及预先存放在内存中的刀具中心偏移量,系统能自动计算刀具中心轨迹,并控制刀具进行加工;在加工过程中,只需根据工件坐标系的位置进行对刀,便可使用同一程序而对零件实现粗、精加工,以简化编程,并提高加工品质。 相似文献