一种复杂平面型腔加工区域自动识别的算法

根据平面型腔的造型数据,自动识别并提取出需要进行数控加工的区域,按照环与环的位置关系,采用两次判别的方法,第一次为粗判别,得到加工区域的初步信息;在此基础上进行精确判别,生成加工区域的树状数据结构,获得特加工区域,算法适用于多个不连通区域的识别,为一次生成多不不连通区域的加工刀具轨迹奠定了基础。     

数控加工自动编程中环方向的判断算法

对环的处理是二维数控加工刀具轨迹自动生成算法中的关键之一,在环的自交和互交处理过程中,环的中以确定一个环是否有效。在对以往环的方向判断算法进行分析的基础上,本文提出了一种运用环的面积来判断环方向的算法,该算法具有效率高、通用性强和无需进行各种特例判别的优点。     

CAXA制造工程师应用中的几个疑点探析

下面以CAXA制造工程师XP版为例，就筋板生成、草图环不封闭、导动加工轨迹生成时遇到的一些疑点，进行一些分析探讨。     

电火花仿铣加工轨迹环切特征单元生成算法研究

基于数控电火花仿铣特征单元和环切特征单元理论,运用平面区域加工方法,给出一种较为简便的数控电火花仿铣加工轨迹的生成方法,从而有效的对电极损耗和放电间隙进行补偿。     

基于图象数据的平面图形加工数控编程方法

提出了根据图象数据生成行切加工刀路的区域填充算法和用于环切加工方式的适应性包容盒 (AIB)方法 ,用这两种算法可将平面图形的图象数据转化为分段直线 ,生成行切和环切加工刀路。基于这两种算法开发的CAD/CAM实用系统ImageCAM可实现图象输入、图象处理、自动编程和加工仿真的一体化。     

均匀偏置型腔加工残留区域分析

模具型腔平面铣削加工过程中,第一次加工采用两倍刀具半径均匀偏置型腔轮廓得到粗加工刀轨,然后对加工后残留区域进行分析,在不换刀的情况下先对刀轨之间的残留区域进行补加工,再换半径较小的刀具对轮廓边界拐角和轮廓与岛屿之间残留区域进行加工,生成加工刀轨。该方法大大提高了加工效率。     

带任意多岛屿的型腔环切加工刀轨生成

对带任意多岛屿的型腔环切加工刀轨生成进行了研究 ,提出了一种等距环互交处理的快速简便算法 ,设计了多个岛屿之间、岛屿与型腔之间的干涉处理方法 ,算法在超人CAD/CAM软件中实现 ,实践表明 ,该功能模块运行速度快 ,稳定性好 ,具有工程应用价值。     

基于MATLAB的镜片NC加工程序生成研究

为了解决非球面镜片数控加工程序难以编写的问题,探讨了基于慢刀伺服加工技术的镜片数控加工程序的自动生成。建立球面和环曲面镜片的数学模型,对数学模型进行笛卡尔坐标向柱坐标的转换。利用镜片数学模型进行等角度离散和法向半径补偿生成刀位点,通过MATLAB软件对得到的刀位点进行轨迹仿真,同时后置处理刀位点生成数控加工程序。加工实例表明,所探讨的基于MATLAB的镜片数控加工程序自动生成过程可以满足加工需要。     

复杂形状区域行切加工刀具轨迹生成

讨论了由任意多段直线、圆弧、自由曲线及其组合构成边界轮廓，且边界内包含多个岛屿的复杂区域加工刀具轨迹计算问题。详细介绍了岛屿分解、边界轮廓刀具干涉处理、加工路线规划及刀具轨迹生成原理与算法。     

型腔铣削单纯区及其判别方法

型腔类零件的几何形状通常比较复杂,在加工中心或数控铣床上加工时往往需要通过合理拆分加工域来实现刀具序列的优选,进而提高加工效益,从而需要判别加工域是否可分这一基础问题.为此,提出一种用于判别加工域是否可分的概念及方法--型腔铣削单纯区及其判别方法.提出铣削单纯区的概念,给出其定义,指出铣削单纯区是一类当且仅当使用一种刀具就可实现最优加工的特殊区域,该区域具有不可再分性、完全覆盖性和效益最优性等三大特点.给出并论证铣削单纯区的判别条件,从加工成本的角度建立铣削单纯区的判别模型,并在此基础上设计铣削单纯区的判别算法.对某文献中的算例型腔进行铣削单纯区判别,从而证明提出的概念及方法的理论价值和实用价值.     

高速铣削加工技术在汽车模具制造中的应用

五轴联动铣削可以优化切削过程，参数，有利于降低刀具磨损，减少后加工，是汽车模具加工技术发展的潮流。它适合于使用球头铣刀加工小曲率的凸表面和较浅的凹表面，也可用于使用铣刀侧面加工自由表面。采用3 2轴加工方式下可以最大限度加快走刀。数控铣削比仿型铣削精度高，后加工少。实现五轴高速铣削加工需要不断加强机床计算机数控系统的功能，使之能够直接接收全部设计数据并加以利用，能够有前瞻处理多个程序块，能够方便用户介入计算机辅助制造过程修正设计数据。     

General tool correction for five-axis milling

In this paper a method is presented by which cutter location data can be determined for any type of milling tools defined according to DIN 66215 whereby any point of the tool can be defined as the contact point. In addition, the cutter location point for 5-axis milling can be determined using a single formula for any type of milling tool.     

Influence of thermal mechanical coupling on surface integrity in disc milling grooving of titanium alloy

Disc milling strategy has been applied in grooving for decades for its capacity to provide huge milling force on the difficult-to-cut material. The processing efficiency of machined components thus can be tremendously improved with the application of disc milling. However, the fundamental research of the mechanisms of disc milling on cutting metal materials, especially on titanium alloys, is lacking in the literature. In this study, the milling force and temperature were inspected in disc milling grooving experiment, and the effect of thermal-mechanical coupling on surface integrity of titanium alloy, including surface roughness, surface topography, surface and subsurface residual stress, microstructure, and microhardness, was analyzed. The results showed that a better surface quality can be obtained at the center of the surfaces compared to the marginal regions on the same machined surface. Residual compressive stress was generated on the machined surface and subsurface and gradually reduced to zero with an increase in depth. The microstructure of lattice tensile deformation was emerged along feed direction, while the phase transition was not produced. A hardened layer was found on the machined surface and subsurface, mostly causing by the mechanical loads and oxidation reaction.     

Adaptive Gregory Patch Approximation to Z-Map Data

A method is proposed for Gregory surface approximation to 3D array data points. Surface approximation is the process of constructing a compact representation to model an object surface based on a fairly large number of measured 3D data points. Based on an adaptive subdivision technique, the proposed method begins with a rough initialisation of the surface and progressively refines it in successive steps in the regions where the data is poorly approximated. The method has been implemented using piecewise bicubic Gregory patches with G 1 continuity. An advantage of this approach is that the refinement is essentially local, reducing the computational requirements that permit the processing of a large number of data points This method, combined with the inverse offsetting method, can be used to obtain an offset surface without self-interference. The offset surface can be used to generate gouging-free CL tool paths for machining compound surfaces on milling machines.     

NEW APPROACH ON CUTTER PATH GENERATION FOR PLANE MILING

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An Operation Planning System for Multi-Axis Milling of Sculptured Surfaces

Multi-axis milling of sculptured surfaces with cylindrical or toroidal cutters has many advantages compared to the use of three-axis milling with ball nose cutters. Surfaces to be machined are often of complex shape and characterised by convex, concave and saddle areas. Today, CAM-systems do not support the user in the selection of the different operations in order to finish the workpiece. This paper describes an operation planning system, which facilitates process planning for the multi-axis machining of sculptured surfaces. The core of the system is surface analysis, which divides the surfaces into regions, each characterised by a preferred milling direction and tool diameter. Further, for each region or set of regions, a drive surface is constructed that is used as the basis for the tool-path calculation. The drive surface approximates to the original workpiece as closely as possible, and the isoparametric lines which will be the tool-path feed direction lie in the preferred milling direction.     

薄壁结构件铣削参数有限元正交优势分析及优化

大型整体薄壁结构件在航空、航天工业中得到了广泛应用。但由于其刚性差,在铣削加工过程中常常出现铣削力过大而引起较大的变形,严重影响工件的加工质量和精度。针对上述问题,提出一种有限元正交优势分析方法,用以优化铣削参数,减小铣削产生的零件变形。该方法采用正交试验设计规划指导有限元铣削加工变形分析的参数方案设计,通过不同方案的计算结果研究分析铣削速度、铣削深度、铣削宽度、每齿进给量对加工变形的影响,得到各铣削要素选择的较好水平;采用优势分析方法对正交试验结果进行处理,得到各铣削要素对加工变形的贡献率,从而确定优化的铣削加工方案。以某薄壁框类零件为例得到了铣削参数的优化组合,经过验证,优化后的试验方案减少了铣削产生的最大变形量,证明了该方法的可行性及有效性。     

Accessible regions of tool orientations in multi-axis milling of blisks with a ball-end mill

Noninterference tool orientations are hard to be determined in multi-axis milling of blisks, because the integrated structure of blisks introduces more geometrical constraints. To address this problem, an original approach without interference detection is proposed to solve accessible regions of tool orientations in milling of blisks. Based on the visibility of checking surfaces, only critical points on surface profiles are searched and processed to construct the accessible regions. In this approach, the start point of each profile is sought on boundaries of the main surface with a constant step length. From this point, a new critical point is first searched along a specified direction and then adjusted iteratively until it locates on a profile. When all critical points on profiles are searched like this, the searched points on each checking surface are reordered to form one or more than one closed curve to present the accessible region related to this checking surface. These curves are then mapped onto a unit sphere and divided into nonintersecting segments. After that, a concise approach is proposed to combine accessible regions of all checking surfaces into simply connected regions. This algorithm is finally verified with two kinds of blisks and compared with a referenced method. The results show that the proposed method can efficiently solve accessible regions in multi-axis milling of blisks with an expected accuracy.     

基于VB程序的指形齿轮铣刀齿形计算

论述了齿轮的渐开线齿形铣削原理,推导出指形齿轮铣刀齿形计算步骤,开发基于VB程序的指形齿轮铣刀齿形计算程序,使用该程序能迅速精确地运算出各种渐开线指形铣刀齿形数据,使计算过程由繁变简,提高了齿轮刀具的设计精度和效率。     

Spindle vibration suppression for advanced milling process by using self-tuning feedback control

The goal of this work is to concurrently counterbalance the dynamic cutting force and regulate the spindle position deviation under various milling conditions by integrating active magnetic bearing (AMB) technique, fuzzy logic algorithm, and an adaptive self-tuning feedback loop. The experimental data, either for idle or cutting, are utilized to establish the database of milling dynamics so that the system parameters can be on-line estimated by employing the proposed fuzzy logic algorithm as the cutting mission is engaged. Based on the estimated milling system model and preset operation conditions, i.e., spindle speed, cut depth, and feed rate, the current cutting force can be numerically estimated. Once the current cutting force can be real time estimated, the corresponding compensation force can be exerted by the equipped AMB to counterbalance the cutting force, in addition to the spindle position regulation by feedback of spindle position. At the end, the experimental simulations on realistic milling are presented to verify the efficacy of the fuzzy controller for spindle position regulation and the capability of the dynamic cutting force counterbalance.