基于啮合间隙的螺杆齿形设计与成形加工方法

针对螺杆泵关键部件螺杆转子设计过程复杂、加工难度高导致啮合间隙不均匀的问题,在分析螺杆啮合间隙形成机理基础上,运用空间解析几何基础理论,提出基于啮合间隙的螺杆齿形设计新方法,建立螺杆加工过程进刀轨迹-螺杆齿形-啮合间隙转换方程;结合微分几何等距曲面构型原理,得到预定加工间隙的螺杆端面齿形;研究螺杆与刀具在加工过程中的空间包络特性与几何特性,结合机床、螺杆、刀具协同运动所生成的接触线形状和空间位置参数,提出一种基于离散点齿形的螺杆加工成形刀具设计方法——形位几何法,该方法基于具有稳定接触的包络结构,将抽象的空间包络问题转化为平面解析几何问题,简化包络求解模型,克服传统啮合理论设计刀具时无法精确计算齿形曲线尖点的关键性技术难点,提高成形刀具齿形设计的精确性。     

异形螺杆数控加工技术

为了提高复杂螺杆的加工精度,从生产实际出发对包络法加工复杂螺杆的关键技术进行研究。为了提高截面曲线的计算精度,采用基于极坐标的样条曲线拟合算法对原始数据点进行密化,使密化点尽量均匀并光滑过渡;为了提高插补点的计算精度,采用二分法对盘铣刀刀触点进行计算。最后,采用专用机床对生成的加工程序进行加工验证,获得了良好效果,可以满足实际生产需求。     

螺杆的内旋包络铣削法及其数控加工的数学建模

常用的螺杆铣削成形法，刀具制造困难、生产成本较高.针对成形法存在的不足，进行包络式螺杆加工方法的探讨.即采用标准的圆形或三角形刀片，在自行改造的内旋风式三轴联动数控铣床上，根据所给的螺杆型线通过包络原理实现螺杆螺旋面的加工.主要介绍内旋包络式数控螺杆铣削加工的数学模型。     

复杂曲面几何仿真与误差分析

针对复杂曲面数控加工中加工误差进行了研究,分析了各种铣刀的几何特征,归纳出一种用参数表示的通用铣刀模型,并以通用铣刀模型为基础,结合复杂曲面的包络法数控加工原理,给出了一种基于啮合基本定理的点接触包络加工表面的几何仿真算法.利用几何仿真的计算结果,分析复杂曲面加工中的法向误差,该仿真算法把复杂的仿真问题转化成了非线性方程组的求解问题,从而使仿真过程得到简化,对于提高数控编程精度具有重要意义.还以截面包络法数控加工螺旋面为例,验证了该仿真算法,并分析了螺杆加工精度.     

最小有向距离算在螺杆加工中的应用

从空间啮合原理出发，研究刀具与工件表面的接触规律，将最小有向距离算法应用于螺杆加工的数控编程中。在给定工件端截面参数方程的条件下，可采用该方法生成刀具运动轨迹，实现经济、高效的螺杆加工。该算法适用于种种截面廓型为一阶连续可微曲线的圆柱螺旋面螺杆加工，并可通过分段处理技术实现对截面廓型由多段曲线组合而成的螺杆进行自动编程加工。     

内齿轮齿形系数

一、前言内齿轮齿形系数是内齿轮强度设计的关键,但现有的计算方法比较粗糙,且对内齿轮危险截面的位置究竟在何处也存在着两种观点,一种是根据材料力学的等强度理论,把抛物线与齿廓的切点作为危险点,另一种是用切线法来确定危险点。本文拟采用后者对内齿轮齿形系数公式进行推导。我们知道目前最常用的齿轮加工方法是切制法中的展成法,它是运用包络原理求共轭曲线的方法来加工齿廓的,内外齿轮的加工都是如此。ISO中外齿轮齿形系数公式便是通过包络原理来推导的,而现有     

供送异形截面容器的变螺距螺杆四轴数控加工

分析了异型截面供送变螺距螺杆的结构特点和工作原理,设计了其加工工艺,提出了一套加工该螺杆的独特的数控编程方法.该工艺方法经实践证明,生产效率和加工精度均令用户满意.     

采用包络法计算刀具刃口齿形

为了提高刀具的齿形精度,采用包络法计算刀具刃口齿形。根据二次包络环面蜗杆成型原理,提出了用包络法建立蜗轮齿面数学模型的方法,推导了蜗轮在中间平面齿形方程,即刀具刃口齿形方程,并利用MATLAB软件绘制出刀具刃口齿形。基于逆向工程的思想,用Pro/E软件建立了蜗杆三维模型。结果表明:蜗杆齿槽在轴向截面齿形与包络法计算得到的刀具刃口齿形一致。     

螺杆数学模型及数控加工铣刀廓形求解

针对单头梯形螺杆转子设计过程复杂,加工难度高导致其表面精度难以控制的问题,在分析梯形螺杆成型原理的基础上,从梯形螺杆基本型线方程出发,避免齿间干涉,应用内凹齿面法,建立梯形螺杆数学模型。结合空间啮合原理,建立螺杆用成形铣刀加工过程中铣刀与工件之间的坐标转换方程。研究螺杆螺旋面几何特性及其与刀具在加工过程中的空间包络特性,提出基于空间啮合法的螺杆截面离散点成形铣刀设计方法,建立刀触点方程,求解铣刀轴向廓形。     

包络法实现数控螺杆铣床螺旋面加工的研究

采用包络法对数控螺杆铣床螺旋面进行加工,用螺旋面方程精确描述螺旋运动,进而来控制数控铣床刀具刃形空间运动轨迹,包络加工出所需的螺杆螺旋面,运用LabVIEW软件对包络法实现数控铣床螺旋面加工进行仿真。仿真结果表明,该方法可以简单、精确地控制数控铣床实现复杂螺旋面的加工。     

变螺距螺杆的通用机床加工

介绍了变螺距螺杆在通用机床上的加工原理,解决了通用机床无法加工变螺距螺杆的问题,大大降低了变螺距螺杆的加工成本,为变螺距螺杆的设计和应用铺平了道路。     

基于LabVIEW的双铣刀数控机床控制系统

为解决单铣刀螺杆铣床在加工塑料行业挤出机螺杆时存在效率低的问题,将采用工业计算机和运动控制卡设计开发开放式数控系统的技术应用于研制高效的双铣刀数控螺杆铣床中.开展了螺杆外形和现有螺杆加工过程的分析,建立了机床在螺杆加工时各个轴之间的关系,提出了采用虚拟仪器软件LabVIEW及其motion模块和NI公司的PCI-7390运动控制卡,设计双铣刀同时加工的专用铣床及其控制系统的方法;在理论上对双铣刀数控机床的可行性和加工效率进行了评价,并进行了两把铣刀同时加工螺杆的实验.研究结果表明,所研制的双铣刀数控机床不仅实现了两把铣刀的同时加工,使加工效率提高了10％以上,加工系统还具有工作界面简单、易懂,容易上岗操作的优点.     

五轴数控机床加工误差动态修正方法研究

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...     

四轴联动数控磨削锥度铣刀数学模型的建立

锥度铣刀的锥刃具有等前角、等后角、等螺旋角关系。需要四轴联动才能完成精确磨削加工。且需建立合理的各数控联动轴之间几何与运动的数学模型。基于进口的德国WALTER公司的Helleenter GC6六轴计算机数控工具磨床的结构。介绍了一套简明实用的建立复杂刀具的数控加工的数学模型方法。任何具有相同或相似的机床结构的系统，都可以采用类似方法建立工件的数控加工数学模型。完成复杂型面的精确加工。     

基于UG的维纳斯雕像五轴数控加工工艺设计

论述了应用五轴联动数控机床加工维纳斯雕像的工艺设计。首先,通过三坐标测量仪对石膏雕像进行点位测量并将测量数据导入UG软件,分析其基于UG软件的多轴编程刀路轨迹,选择曲面区域的刀路驱动方式并绘制出刀轴驱动曲面矢量图,根据刀路轨迹、刀具及设备制订出数控加工工艺;其次,计算刀具进给速度并校核、修正,根据UG软件前置处理的刀轨文件,设定相应的机床参数,并以FANUC系统五轴联动单摆头单转台加工中心为例,利用UGPOSTBUILD处理器完成后处理,生成可加工的程序代码;最后,设定坐标系及精确对刀后加工出实体雕像。     

基于PLC的挤出机进料段内螺纹加工控制系统研究

针对普通车床在塑料挤出机进料段内螺纹加工时存在效率低和内螺纹螺距超过500 mm时无法自行加工的问题,将采用触摸屏、PLC和其位置单元设计开放式控制系统的技术应用于研制高效数控专用铣床中。开展了内螺纹螺旋线理论方程和现有加工过程的分析,建立了专用铣床在内螺纹加工过程中各个轴之间的运动关系,提出了"采用威纶触摸屏MT8000和松下FP2可编程逻辑控制器及其插补型位置单元,设计内螺纹加工的专用铣床及其控制系统"的方法;在理论上对内螺纹加工铣床的可行性和加工效率进行了评价,并进行了控制系统的试验和生产实践。研究结果表明,所研制的数控铣床在进料段内螺纹加工时的效率提高了25%以上,达到了预期设计要求,同时加工系统还具备"操作界面简单、容易上岗"等特点。     

Simultaneous geometric error identification of rotary axis and tool setting in an ultra-precision 5-axis machine tool using on-machine measurement

This paper presents a method to identify the position independent geometric errors of rotary axis and tool setting simultaneously using on-machine measurement. Reducing geometric errors of an ultra-precision five-axis machine tool is a key to improve machining accuracy. Five-axis machines are more complicated and less rigid than three axis machine tools, which leads to inevitable geometric errors of the rotary axis. Position deviation in the process of installing a tool on the rotary axis magnifies the machining error. Moreover, an ultra-precision machine tool, which is capable of machining part within sub-micrometer accuracy, is relatively more sensitive to the errors than a conventional machine tool. To improve machining performance, the error components must be identified and compensated. While previous approaches have only measured and identified the geometric errors on the rotary axis without considering errors induced in tool setting, this study identifies the geometric errors of the rotary axis and tool setting. The error components are calculated from a geometric error model. The model presents the error components in a function of tool position and angle of the rotary axis. An approach using on-machine measurement is proposed to measure the tool position in the range of 10 s nm. Simulation is conducted to check the sensitivity of the method to noise. The model is validated through experiments. Uncertainty analysis is also presented to validate the confidence of the error identification.     

Design and accuracy analysis of a metamorphic CNC flame cutting machine for ship manufacturing

The current research of processing large size fabrication holes on complex spatial curved surface mainly focuses on the CNC flame cutting machines design for ship hull of ship manufacturing. However, the existing machines cannot meet the continuous cutting requirements with variable pass conditions through their fixed configuration, and cannot realize high-precision processing as the accuracy theory is not studied adequately. This paper deals with structure design and accuracy prediction technology of novel machine tools for solving the problem of continuous and high-precision cutting. The needed variable trajectory and variable pose kinematic characteristics of non-contact cutting tool are figured out and a metamorphic CNC flame cutting machine designed through metamorphic principle is presented. To analyze kinematic accuracy of the machine, models of joint clearances, manufacturing tolerances and errors in the input variables and error models considering the combined effects are derived based on screw theory after establishing ideal kinematic models. Numerical simulations, processing experiment and trajectory tracking experiment are conducted relative to an eccentric hole with bevels on cylindrical surface respectively. The results of cutting pass contour and kinematic error interval which the position error is from –0.975 mm to +0.628 mm and orientation error is from –0.01 rad to +0.01 rad indicate that the developed machine can complete cutting process continuously and effectively, and the established kinematic error models are effective although the interval is within a ‘large' range. It also shows the matching property between metamorphic principle and variable working tasks, and the mapping correlation between original designing parameters and kinematic errors of machines. This research develops a metamorphic CNC flame cutting machine and establishes kinematic error models for accuracy analysis of machine tools.     

A manufacturing model of helical groove on rotary burr and a universal post processing method

A systematic machining theory and precision method to determine cutter location in a grinding system is presented for rotary burr. First, the helical cutting edge on various kinds of revolving surfaces is built. Then, based on the geometry model of the helical cutting edge, the smooth spiral rake surface with constant normal rake angle and flank surface can been formed during the one-pass grinding process by this method. No interference between the grinding wheel and workpiece happens by the wheel special rotation. The method has the characteristic of detaching the grinding wheel path solution from specified machining conditions. The grinding wheel path is suitable for different NC machine tools through post processing. Meanwhile, a mechanism kinematic model of the NC machine tool is built, and a generalized algorithm for post-processing of multi-axis NC machine tools is presented. This model is applied to arbitrary configuration of NC machine tool, and the motion value for each axis will be generated by the inputting structure and motion parameters of the machine tool. The model, together with the machining method mentioned in this paper, make the calculation and generation of the grinding wheel path simpler and universal. At last, the validity of the method given in the paper is identified by an example of grinding.     

Postprocessor development for ultrasonic cutting of honeycomb core curved surface with a straight blade

When ultrasonically cutting honeycomb core curved parts, the tool face of the straight blade must be along the curved surface’s tangent direction at all times to ensure high-quality machining of the curved surface. However, given that the straight blade is a nonstandard tool, the existing computer-aided manufacturing technology cannot directly realize the above action requirement. To solve this problem, this paper proposed an algorithm for extracting a straight blade real-time tool face vector from a 5-axis milling automatically programmed tool location file, which can realize the tool location point and tool axis vector conversion from the flat end mill to the straight blade. At the same time, for the multi-solution problem of the rotation axis, the dependent axis rotation minimization algorithm was introduced, and the spindle rotation algorithm was proposed for the tool edge orientation problem when the straight blade is used to machine the curved part. Finally, on the basis of the MATLAB platform, the dependent axis rotation minimization algorithm and spindle rotation algorithm were integrated and compiled, and the straight blade ultrasonic cutting honeycomb core postprocessor was then developed. The model of the machine tool and the definition of the straight blade were conducted in the VERICUT simulation software, and the simulation machining of the equivalent entity of the honeycomb core can then be realized. The correctness of the numerical control program generated by the postprocessor was verified by machining and accuracy testing of the two designed features. Observation and analysis of the simulation and experiment indicate that the tool pose is the same under each working condition, and the workpieces obtained by machining also meet the corresponding accuracy requirements. Therefore, the postprocessor developed in this paper can be well adapted to the honeycomb core ultrasonic cutting machine tool and realize high-quality and high-efficient machining of honeycomb core composites.