基于在线测量工艺参数的数控加工程序后置处理算法的研究

本文研究以在线测量工艺参数进行数控车削的图形自动编程的加工程序后置处理的算法,以及在配有ＳＩＮＵＭＥＲＩＫ８１０Ｔ数控系统的数控车床上进行车削编程的技术。系统提出了利用高档数控系统的Ｒ参数来保存在线测量得到的加工余量,在加工时以此在线构造走刀轨迹的算法。     

基于在线测量工艺参数的数控加工程序后置处理算法的研究

本文研究以在线测量工艺参数进行数控车削的图形自动编程的加工程序后置处理的算法,以及在配有ＳＩＮＵＭＥＲＩＫ８１０Ｔ数控系统的数控车床上进行车削编程的技术。系统提出了利用高档数控系统的Ｒ参数来保存在线测量得到的加工余量,在加工时以此在线构造走刀轨迹的算法。     

NC数控车床辅助编程系统的开发

本文结合AutoCAD或CAXA电子图板等常用的计算机绘图软件用Visual Basic开发了NC数控车床辅助编程系统在绘图软件中绘制刀具的走刀路线代替手工编程的坐标点计算再用本系统接受绘图软件输出的DXF格式文件自动生成数控加工G代码和坐标值数据提高了编程效率一绘图阶段工作内容首先用AutoCAD或CAXA电子图板等绘图软件绘制零件设计图(如图1所示)再根据设计图绘制各刀具的起点和走刀路线(如图2所示)图1 示例加工零件设计图图2 示例加工零件走刀路线图为了使本系统能识别走刀路线并自动生成数控加工代码绘制图形时有以下基本要求(1)数控…     

壳体零件的数控编程基本实现过程

一、引言 数控编程技术包含了数控加工与编程、金属加工工艺、CAD/CAM软件操作等多方面知识与经验,其关键内容是数控加工走刀中的刀位点(简称CL点)的确定.     

球头铣刀铣削表面形貌建模与仿真

为了研究铣削加工的表面形貌,文章给出了考虑刀杆柔性的螺旋刃球头铣刀的动态铣削过程模型,并基于广义加工表面创成理论、球头铣刀丸线模型和铣削运动模型,对球头刀动态铣削表面形貌进行了建模和仿真。     

浅谈SIEMENS数控系统UG 后置处理常用TCL语句使用技巧

SIEMENS数控系统为满足数控加工中心高速、高效、高精度加工零件的要求,提供了一系列特有的指令功能, 其程序结构有独特的要求。使用UG软件的数控编程人员往往只需关心加工刀轨,把生成程序代码的任务交给后置处理来完 成。为满足数控编程人员的需求,就需要使用TCL语言制作后置处理。本文结合SIEMENS系统指令特点,简要介绍TCL语 言替换命令、流程控制命令在SIEMENS系统后置处理制作中的应用。     

一种专用数控系统中的软件实现技术

为了设计实现全自动专用数控系统中的软件,对该种类型软件的设计方法进行了研究。该系统是一个分布式的全自动专用数控系统,在汽车锁生产中实现大规模钥匙加工,采用工业PC为主控系统,利用PLC控制机械手系统、检测开关信号、通过DIO接口与主控PC进行通讯。采用面向对象及其软件构件方法,研制了系统控制软件、产品数据管理软件。研制专用数控系统大大提高了专业生产企业的自动化水平,软件构件也可在其他同类系统中应用。     

基于DG/K方法的成形铣刀设计模型

对广泛应用于曲面加工的成形铣刀设计困难的问题,基于DG?K方法,应用刀具展成面T和待加工曲面P在刀触点K的微小邻域内的一致率、曲面的包络和逆包络原理,以加工一个非共轴零件的特征曲面的成形铣刀设计为实例,建立了系统性的成形铣刀设计模型,包括待加工曲面P的数学模型、成形铣刀廓形的设计模型、螺旋刃口曲线数学模型以及实得沟槽曲面数学模型;并利用所建立的模型绘制铣刀螺旋刃口曲线和螺旋沟槽面的可视化图形,以验证该模型的正确性和可用性,为成形铣刀的设计提供一种理论方法和依据.     

博士信箱

长沙读者 安红兵 问：在CIMATRON软件中，模拟切屑能否转动？ 答：在CIMATRON V10.6以后的版本就可以。方法是在SIMULATOR界面内，将毛坯渲染为实体，然后按下ROTATE SOLID按钮，右键控制旋转。温州读者 张鄞问：我不小心将CIMATRON的中文字体文件删掉了，可以用其他字体文件替换吗？另外，有一个从前视图看上去是C型的曲面，需用T型刀加工，我只能编端铣刀。因为刀具路径的计算是以刀具的底部为准，所以实际用T型刀加工C型曲面的上半部时产生了过切。我想打开曲面的自身检测干涉功能，哪知凹进去的曲面没有被加工。可…     

基于四点偏置法的非可展直纹面侧铣刀位计算

针对非可展直纹面五轴侧铣加工的问题,分析了非可展直纹面几何特点,根据等距 映射下的极差不变性,提出了一种计算非可展直纹面叶片五轴侧铣刀位数据的新方法。以刀具包 络面与设计曲面之间的整体误差为优化目标,建立了圆柱铣刀侧铣非可展直纹面的刀位计算方 法,运用四点偏置法确定初始刀位,采用最小二乘法对初始刀位进行优化,建立刀轴矢量偏转模 型进一步修正刀位以减小过切误差。通过实例计算分析,表明该方法可以在一定程度上减小加工 误差。     

An innovative approach to NC programming for accurate five-axis flank milling of spiral bevel or hypoid gears

To transfer power, a pair of spiral bevel or hypoid gears engages. From beginning to end of two tooth surfaces engaging with each other: for their rigid property, they contact at different points; and for their plastic property, they contact at small ellipses around the points. On each surface, the contact line (or called as contact path) by connecting these points and the contact area by joining these ellipses are critical to driving performance. Therefore, to machine these surfaces, it is important to machine the contact line and area with higher accuracy than other areas. Five-axis flank milling is efficient and is widely used in industry. However, tool paths for flank milling the gears, which are generated with the existing methods, can cause overcuts on the contact area with large machining errors. To overcome this problem, an innovative approach to NC programming for accurate and efficient five-axis flank milling of spiral bevel or hypoid gears is proposed. First, the necessary conditions of the cutter envelope surface tangent with the designed surface along a designed line are derived to address the overcut problem of five-axis milling. Second, the tooth surface including the contact line and area are represented using their machining and meshing models. Third, according to the tooth surface model, an optimization method based on the necessary conditions is proposed to plan the cutter location and orientation for flank milling the tooth surface. By using these planned tool paths, the overcut problem is eliminated and the machining errors of contact area are reduced. The proposed approach can significantly promote flank milling in the gear manufacturing industry.     

数字制造环境下的加工过程仿真验证技术研究

生产线数字制造环境是数字化工厂的核心，而加工过程的仿真与验证技术构成生产线数字系统的底层结构与制造过程数字化分析的主要内容。分析了目前加工过程在几何仿真与物理仿真方面的研究情况、研究方法与存在问题，就该项技术向生产线数字制造环境融合的关键技术，即综合设备数字样机的完整数字加工环境的建立及加工过程仿真与上层制造环境的信息集成等进行分析与研究。     

A decision support system for design of mass production machining lines composed of stations with rotary or mobile table

This paper describes a decision support system (DSS) developed in order to offer to machining line designers a cognitive aid for early design stages. The aim of DSS is to assist the decision makers in finding the configuration of a new line that will meet quality and productivity requirements and minimize the investment costs. The current version of DSS is oriented to design of mass production machining lines composed of machines with rotary or mobile tables. This decision support system is based on mathematical models and methods which were devised to provide the designers with the optimal parameters of new line configuration including the required number of working stations of different types, the number of working positions at each station and spindle heads at each working position. The system is implemented under Autodesk Inventor and includes the modules for part modeling, process planning and machining system configuration. Its modular character and open architecture make upgrading with new mathematical tools suitable for other machining systems easy and fast. Moreover, it can be employed either as a separate software or integrated in a Product Life-cycle Management (PLM) tool.     

三维工序模型切削载荷动态变化的工艺优化策略

综合零件的加工特征及约束条件并引入布尔差运算,可以分解出零件典型面组并 生成对应的工艺路线谱系,达到零件加工工艺快速优化设计的目的。通过分析三维工序模型典 型面组加工时的动态特性,采用B 样条曲线插值参数化的方法构建刀具-工件接触区域动态边界 的统一数学模型,预测切削载荷动态变化状况,并进行切削参数优化达到有效控制切削载荷的 目的。最后以某零件的车削加工为例进行分析,验证该工艺优化策略的可行性。     

Increasing CNC machine tool productivity by using tool-part touch control

In this paper a new system for increasing CNC machining productivity is described. The system is based on registering the moment when the cutting tool touches the workpiece during a machining operation. The cutting tool approaches the workpiece with rapid traverse and switches to work feed when it comes in contact with it. In this way, the time for ‘cutting air’ can significantly be reduced.     

高速电主轴瞬态温度场分析与测试

研究数控机床主轴温度优化控制问题,高速电主轴系统热变形影响机床加工精度。由于高速电主轴是一个复杂的非线性系统,对温度优化控制较困难。为精确了解高速电主轴系统瞬态温度场分布,采用MSC.Marc软件接触热阻,以多体接触的方式,对电主轴系统不同转速工况下进行有限元仿真分析,并通过现场验证仿真结果。结果表明,系统温度场分布不均,冷却水将系统分成高、低温区域;定子温度随转速非线性变化,转速3000rpm以上温度增长较快。以分析和测量结果为基础,利用冷却水降温。根据定子发热量随转速的变化规律,实时进行控制。测试结果证明,对高速机床温度测量精度效果好,为设计提供了依据。     

A multipoint method for 5-axis machining of triangulated surface models

In this paper, we present a multipoint machining method for the 5-axis machining of triangulated surfaces with radiused end mills. The main idea is to drop the tool onto the surface to find an initial point of contact, and then rotate the tool while maintaining tangency with this initial point of contact until a second point of contact is found. The proposed procedure ensures a gouge-free position with two points of contact, allowing for a larger side step than a single point of contact method. This proof of concept paper presents the mathematical equations that must be solved to position the tool with two points of contacts on an STL surface. The paper further verifies the concept with simulations and presents experimental results to confirm the simulations.     

弧面凸轮分度机构设计及建模方法研究

利用D-H坐标系建立弧面凸轮的轮廓方程和共轭接触线方程。充分利用球形滚子的几何特征,先绘制中心轨迹线,然后通过Pro/E软件建立弧面凸轮的三维实体模型,从而为实现弧面凸轮的数控加工、该机构的动力学分析和运动仿真等奠定了基础。     

G 2 blends of linear segments with cubics and Pythagorean-hodograph quintics

Fillets, also known as blend arcs, are used in CNC machining to round corners. Fillets are normally circular arcs, which have G ¹ contact with the straight line segments to which they are joined. Recent advances in machining technology allow NURBS, including Pythagorean-hodograph (PH) curve segments, to be incorporated in CNC tool paths. This article examines the use of cubic and PH quintic Bézier curve segments that have a single curvature extremum, and which have G ² contact with the straight line segments to which they are joined, as fillets. It is shown how the extreme circle of curvature can be determined. The point of curvature extremum and the corresponding value of the curvature can be changed by adjusting the joining points of the blending curve with the neighbouring straight lines. These blending curves can also be incorporated in computer-aided design packages for curve or surface design.     

A knowledge base model for complex forging die machining

Recent evolutions on forging process induce more complex shape on forging die. These evolutions, combined with High Speed Machining (HSM) process of forging die lead to important increase in time for machining preparation. In this context, an original approach for generating machining process based on machining knowledge is proposed in this paper. The core of this approach is to decompose a CAD model of complex forging die in geometrical features. Technological data and topological relations are aggregated to a geometrical feature in order to create machining features. Technological data, such as material, surface roughness and form tolerance are defined during forging process and dies design. These data are used to choose cutting tools and machining strategies. Topological relations define relative positions between the surfaces of the die CAD model. After machining features identification cutting tools and machining strategies currently used in HSM of forging die, are associated to them in order to generate machining sequences. A machining process model is proposed to formalize the links between information imbedded in the machining features and the parameters of cutting tools and machining strategies. At last machining sequences are grouped and ordered to generate the complete die machining process. In this paper the identification of geometrical features is detailed. Geometrical features identification is based on machining knowledge formalization which is translated in the generation of maps from STL models. A map based on the contact area between cutting tools and die shape gives basic geometrical features which are connected or not according to the continuity maps. The proposed approach is illustrated by an application on an industrial study case which was accomplished as part of collaboration.