基于UG的等高轮廓铣和曲面轮廓铣注意问题的探讨

等高轮廓铣和曲面轮廓铣是U G自动编程最常用的加工方法,对其相关参数设置和容易出现错误的问题进行了深度分析和探讨,以保证生成安全可靠的加工刀路。     

UG固定轴曲面区域轮廓铣在高精度翼片曲面加工中的应用

针对具有高精度曲面翼片类这一典型零件,讨论了固定轴曲面区域轮廓铣在数控程序设计及加工中的应用。以曲面的刀路轨迹设计、工艺方案的选用以及铝合金材料变形的控制等因素为研究重点设计了合理的工艺方案,粗加工采用压板固定,在三轴机床通过一定的工艺流程加工,精加工采用专用工装夹紧在四轴加工中心加工,并详细说明了工艺流程中辅助支承的支承力大小、一夹一顶工装夹具拉应力的转变等问题。重点针对在四轴加工中心应用固定轴曲面轮廓铣,研究了固定轴轮廓铣刀轨原理、固定轴曲面区域轮廓铣实施的流程步骤及固定轴曲面区域轮廓铣在流程步骤中各主要参数设置。固定轴曲面区域轮廓铣较其他驱动方法应用更广泛,灵活性更高,其刀轨下刀点、切削方向、投影矢量方向等更易控制、调整,为四轴加工中心加工翼片类零件曲面提供参考和借鉴。     

基于UG／CAM模块可变轴曲面轮廓数控铣的研究

提出了UGNX／CAM模块中可变轴曲面轮廓铣削的CAM及NC程序生成的思路、方法。通过一具体实例讨论了可变轴曲面轮廓铣数控加工中,工艺设计与规划的方法,研究了可变轴曲面轮廓铣数控加工中,参数的合理设置方法及其误差的有效控制手段。     

电话外壳凸模数控加工工艺分析与编程

通过采用Cimatron E软件对电话外壳凸模进行数控加工程序编制,探讨了运用Cimatron E CAM系统对复杂零件进行程序编制的新思路,分析了凸模的加工工艺特点,实现了其刀路的编制,采用了体积铣、流线铣、精铣所有、精铣水平区域、型腔铣削—环切、平行切削、封闭式轮廓铣以及开放式轮廓铣等加工方法;采取了岛屿缺口的曲面补成完整曲面以及对于局部轴线与底面不平行的外形或孔槽建立新的坐标系再进行编程等方法。结果表明,采用Cimatron E软件CAM系统,提高了产品的质量,降低了生产成本。     

侧铣表面点位轮廓误差预测方法

曲面加工工艺中需要对关键点位的轮廓度误差即点位轮廓误差进行预测,为了提高预测精度,提出了一种侧铣表面点位轮廓误差预测方法。首先利用刀触点和刀位点之间的几何关系,计算得到侧铣扫掠面上的轮廓点阵列;然后结合轮廓度误差的测量原理,利用NURBS曲面拟合方法构建了理想和实际加工表面模型,推导了预测点法线与实际加工表面交点的求解方法,实现了侧铣表面点位轮廓误差的预测;最后实验结果表明,预测值和测量值的差值都在0.006mm以内,且变化趋势相同,从而验证了该预测方法的有效性和准确性。     

四轴曲面铣削加工

总结归纳了可变轮廓铣曲面四轴加工的6种方式,并对功能参数"曲面百分比"、"前倾角"、"侧倾角"、"旋转角"进行了深入讲解和剖析,这些编程技巧、设置方法可广泛应用于四轴、五轴编程中,可变轮廓铣曲面加工策略能深度拓展四轴机床功能,提升设备加工能力。     

基于UG的孔及螺纹铣削加工技术

分析了平面铣、型腔铣/深度加工轮廓、固定轮廓铣曲面驱动、HOLE_MILLING四种操作在孔铣削方面的异同。剖析了THREAD_MILLING牙型和螺距四种类型(从模型、指定、从表、从刀具)在螺纹铣削加工方面的差异,并比较了THREAD_MILLING、HOLE_MILLING的异同点。     

UG可变轴轮廓铣曲面驱动在复杂曲面加工中的应用

需要采用五轴联动加工的部分基本上都是曲面,这些曲面如何编程是最关注的问题。以裸模为载体,利用UG NX9软件,构造驱动曲面,利用可变轴轮廓铣的曲面驱动完成零件的编程,利用DMU80 mono Block五轴镗铣加工中心来进行验证,来讲述这些需要五轴联动加工的复杂曲面的一个编程方法,给其他学习者以借鉴。     

NX软件在异形型面零件数控加工中的应用

针对某复杂异形型面零件,借助数字化设计与计算机辅助制造功能,应用NX软件进行数控加工工艺设计。研究了应用NX软件进行异形型面零件数控加工自动编程的一般方法,进行了型腔铣粗加工、固定轴轮廓铣半精加工、区域轮廓铣精加工、变轴曲面轮廓加工工艺设计,并进行了三维仿真验证,进而通过后处理生成机床可识别的数控加工程序。     

基于UG数控加工技术在模具加工中的应用

模具部件形状复杂,加工要求也多种多样。UG在数控加工方面提供了很多种加工操作,一个复杂工件的加工可能涉及到平面铣、型腔铣、面铣、曲面轮廓铣、等高轮廓铣和钻加工等多种操作,如果各种操作在粗加工、半精加工和精加工等加工阶段运用得当选择合理,便能使模具加工的质量和精度得到很大的提高。同时在模具加工中利用UG的数控加工技术,可以大大缩短模具的制造周期。     

Accuracy Optimisation for Mould Surface Profile Milling

In the profile milling process for mould surfaces, for any type of curve combination, when implementing the milling process on a CNC machine, the surface can be produced from straight lines or curves in a piecewise or continuous milling process. This work employs the features of a CNC machine: 1. To divide the various sizes of curve at different slopes. 2. To use with different milling spindle speeds. 3. To use cutting feeds for actual milling experimentation. The results of the profile dimension accuracy and profile surface roughness from these experiments are then used in a neural network to establish an experiment result and a model for the milling variables. The neural network is composed of a number of functional nodes. Once the milling parameters (spindle speed, feed speed and milling angle) are given, the milling processing performance (the surface roughness, the surface profile-error) can be accurately predicted by the net-work developed. The optimal milling processing parameters can be searched for by a simulation annealing (SA) optimis-ation algorithm with a performance index to obtain a satisfactory mould surface. The experiment is then used to show that improved conditions for mould profile processing can indeed be obtained.     

采油螺杆泵螺杆成形铣刀刀刃廓形设计与研究

基于对采油螺杆泵螺杆形状的分析建立了螺杆螺旋曲面方程;利用成形铣削原理和坐标变换理论,从成形铣刀与螺杆工件的相对运动关系出发,建立了基本的铣刀刀刃廓形方程。根据铣刀的实际使用情况,针对成形铣刀用钝重磨后产生的加工误差,进一步建立了具有合适前刀面和恒定后角的铣刀刀刃廓形方程。对廓形方程进行干涉检查,保证了铣刀廓形的正确性。该铣刀刀刃廓形方程为铣刀的设计制造奠定了理论基础,对实际生产具有重要意义。     

基于多体理论的数控双盘铣刀加工斜齿轮啮合分析

以多体系统理论为基础,根据数控铣齿机运动原理,建立了包含误差因素在内的数控双盘铣刀加工斜齿轮啮合模型,推导出被加工齿轮的螺旋面方程.分析结果表明,采用双盘铣刀加工的方法,可以减少齿廓余量,改善齿廓余量的不均匀性.     

立装刀片机夹组合铣刀的设计工艺

提出了复杂型面的成型组合铣刀的设计思路,介绍了立装刀片机夹圆盘铣刀的设计方案、设计过程及三维设计软件在机夹铣刀设计中的应用。     

铣削钛合金加工表面形貌特征参数的预测

钛合金在铣削过程中受迫振动明显,刀—工接触关系不断变化,加工表面形貌特征参数难以预测,已成为制约加工表面质量进一步提高的瓶颈。针对铣削振动与加工表面形貌的非线性随机变化特性进行了切削钛合金试验,采用高斯过程回归法构建铣削振动作用下的加工表面形貌高斯过程模型。分析刀齿误差和铣削振动对加工表面形貌特征参数的影响规律,为以加工表面质量分布一致性为前提的铣削钛合金工艺设计提供参考依据。     

Modeling of interferences during thread milling operation

Thread milling is becoming more and more employed as a technique for producing thread due to its advantages for industrial manufacturing sectors, such as the aeronautics, aerospace, and energy industries. The thread milling operation is atypical and several aspects have to be taken into account to perform it in good conditions. As for milling or grinding worms, grooves, thread, or other sculptured surfaces, in thread milling, there exists a geometrical interference between the tool and the nominal surface which would be obtained. Thread mills have quite complex geometry and their profile has an effect on the machined thread. The present study details geometrical aspects of the thread milling process. This article deals with the link between thread mill geometry and nominal thread profile. An approach is proposed to analyze the thread profile generated by the thread mill envelope. It is deduced that thread milling produces interferences, i.e., the machined thread profile is affected by an overcut. A method is proposed to correct this geometrical error in order to produce accurate thread.     

Surface topography and roughness in hole-making by helical milling

Helical milling is used to generate holes with a cutting tool traveling on a helical path into the workpiece in which the diameter of the hole can be adjusted through that of the helical path. Based on an improved Z-map model, a 3D surface topography simulation model is established to simulate the surface finish profile generated after a helical milling operation using a cylindrical end mill. The surface topography simulation model incorporates the effects of the relative motion between the cutting tool and the workpiece, in which the effect of the insert runout error of the cutting tool is considered. Furthermore, the roughness parameters are deduced from simulations of the 3D surface topography. The experimental result shows that the proposed simulation algorithm can predict well the surface roughness in a helical milling operation. The surface topography simulation model is used to study the effects of cutting conditions such as the tangential feedrate, the diameter of the cutting tool and the hole, the insert runout error of the cutting tool, as well as the revolution of the cutting tool around the axis of the hole on the surface finish profile. It is found that the surface quality can be improved by optimization of the cutting conditions. As a result, the proposed model will be helpful in determining the cutting conditions to meet surface finish requirements in helical milling operation.     

Surface roughness modeling in Laser-assisted End Milling of Inconel 718

Inconel 718 is a difficult-to-machine material while products of this material require good surface finish. Therefore, it is essential for the evaluation and prediction of surface roughness of machined Inconel 718 workpiece to be developed. An analytical model for the prediction of surface roughness under laser-assisted end milling of Inconel 718 is proposed based on kinematics of tool movement and elastic response of workpiece. The actual tool trajectory is first predicted with the consideration of overall tool movement, elastic deformation of tool, and the tool tip profile. The tool movements include the translation in feed direction and the rotation along its axis. The elastic deformation is calculated based on the previously established milling force prediction model. The tool tip profile is predicted based on the tool tip radius and angle. The machined surface profile is simulated based on the tool trajectory with elastic recovery, which is considered through the comparison between the minimum thickness and actual cutting thickness. Experiments are conducted in both conventional and laser-assisted milling under seven different sets of cutting parameters. Through the comparison between the analytical predictions and experimental measurements, the proposed model has high accuracy with the maximum error less than 27%, which is more accurate for lower feed rate with error less than 3%. The proposed analytical model is valuable for providing a fast, credible, and physics-based method for the prediction of surface roughness in milling process.     

基于PLC控制的普通卧式铣床电气化改造

卧式铣床可用于平面、斜面和沟槽等加工,安装分度头后可铣切直齿轮、螺旋面,使用圆形工作台后可以铣切凸轮和弧形槽,是一种常用的通用机床。本文在传统机械加工的基础上,提出了一种基于PLC控制的普通铣床改造方案,该方案用PLC控制代替传统的继电器-接触器控制系统,提高了系统的灵活性。