圆柱插补功能在数控车铣加工中心的应用

随着社会生产和科学技术的发展,机械产品日趋精密复杂,这推动了数控加工技术的高速发展,数控车铣加工中心应运而生,它能通过一次装夹零件完成多种加工工序,大大提高生产效率,而掌握车铣加工中心编程方法就成为使用车铣加工中心的关键技术。本文介绍数控车铣加工中心的功能、特点和使用圆柱插补功能加工圆柱凸轮槽零件的编程方法。     

车铣加工硬铝合金微细轴技术

车铣加工能实现以铣代车加工回转体零件的外圆表面。它从切削原理上解决了微细轴类零件车削加工时切削速度低的问题。通过车铣加工微细轴试验,从切削速度和加工质量两个主要方面分析了车铣技术在解决微细轴加工中的特点。结果表明,车铣加工技术在实现微细轴的高速切削和保证零件加工质量方面都具有独特优势,是一种非常适合于微细轴类零件加工的技术。     

数控车铣加工中心C轴编程方法

车铣复合加工是利用铣刀旋转和工件旋转的合成运动来实现对工件的切削加工,使工件在形状精度、位置精度、已加工表面完整性等多方面达到使用要求的一种先进切削加工方法。车铣复合加工不是单纯的将车削和铣削两种加工手段合并到一台机床上,而是利用车铣合成运动来完成各类表面的加工,是在当今数控技术得到较大发展的条件下产生的一种新的切削理论和切削技术。掌握车铣复合加工中心手工编程技术成为关键,本文介绍数控车铣加工中心的功能、特点和使用C轴功能加工六边形零件及端面圆弧槽及钻孔加工方法。     

长征机床集团高端重型新产品研制成功

DMC1000重型铣车复合加工中心该产品采用了当今机床先进技术,具有大功率、高精度、高刚度的显著特点,能进行车铣钻等复合加工。具有X、Y、Z1、Z2、Z3、B、C1、C2 8个坐标轴,可实现八轴五联动。采用XY轴相垂直布局方式,有效增大Y轴行程,扩大加工范围;铣削、车削刀具均在同一工具主轴下装卡,可实现大型船舶曲轴等复杂零件一次装卡下铣车复合加工。     

封闭圆柱凸轮槽车铣加工与沿曲面曲率进刀方法研究

分析封闭圆柱凸轮槽结构,设计出专用夹具,实现零件在车铣复合机床上的快速装夹定位;使用UG NX4.0多轴加工功能编制出适合车铣复合加工机床的加工程序,提高了同类型凸轮零件的加工效率。提出沿曲面曲率进刀方法,解决了加工过程中因常规圆弧等进退刀方式引起的封闭圆柱凸轮槽内两侧面接刀痕的问题。经实际加工验证,采用该方法大大提高了零件的加工质量,降低了次品率。     

自由曲面五坐标数控加工中几个关键问题的研究

自由曲面用平头立铣刀五坐标数控加工可以明显地提高切削效率和零件表面质量,但无干涉刀位产生一直是个难以解决的问题,本文对其中的几个关键问题进行了研究,导出了平头立铣刀的有效切削半径的一种计算方法,给出了自适应走刀步长度算法和切削行距的计算公式,最后给出了无干涉刀位生成方法,并用实例验证了方法的可行性,为提高加工效率和精度提供了有效途径。     

车铣复合加工中心五轴加工仿真应用及研究

车铣复合加工中心具备七轴五联动加工功能,进行五轴联动加工时,NC程序编写困难且正确性难以检测。基于VERICUT仿真平台构建车铣复合加工中心的虚拟仿真加工系统,并以整体叶轮零件为样件进行五轴联动仿真加工。通过仿真加工,能够预知加工中可能出现的碰撞、干涉等危险状况,实现对NC程序正确性检验,保障实际加工中机床安全;同时,通过对仿真结果进行检测,分析加工结果中存在的过切、欠切等情况,便于对工艺路径进行改进、优化,进而实现NC程序的最优化,提高实际加工质量。应用虚拟仿真系统,能够实现在不占用实际物资的情况下,快速检测NC程序正确性、合理性,对保证实际应用中机床的安全性、高效性具有一定意义。     

B0326-II双主轴走心车铣中心小型复合轴零件加工技术研究

介绍B0326-Ⅱ双主轴走心车铣中心在加工小型化、大批量、高复合轴类零件方面的独特优势,对小型复合轴零件技术要求、加工工艺、产品调试过程、试加工问题分析等方面进行了深入的研究,为双主轴走心车铣中心的推广应用和同类零件加工提供参考。     

Pro／E在复杂曲面文字雕刻加工中的应用

为了有效地提高复杂曲面文字雕刻的质量,探讨了采用Pro/E软件在FANUC 5轴数控加工中心上实现复杂曲面文字雕刻的方法。利用建模模块进行零件模型设计,并根据加工零件特点进行数控加工工艺分析;接着使用NC模块实现复杂曲面文字雕刻的自动编程,并将软件生成的G代码传输至FANUC 5轴数控加工中心来实现曲面文字雕刻的实际加工。该方法实际应用效果很好,提高了曲面文字雕刻的精度和效率。     

我国五轴联动机床竞相推出

五轴联动数控是数控技术中难度最大，应用范围最广的技术。它集计算机控制，高性能伺服驱动和精密加工技术于一体，应用于复杂曲面的高效、精密、自动化加工。该技术为一个国家工业化水平的标志。适应多面体和曲面零件加工。从数控车床发展到铣削加工的车铣中心。加工效率相当于两台三轴车床。江苏多棱公司的五轴联动龙门加工中心。     

螺旋锥齿轮端铣加工刀位计算方法

针对螺旋锥齿轮在数控加工中心上加工效率低的问题,提出利用盘状铣刀对螺旋锥齿轮进行端铣的加工方法.由螺旋锥齿轮齿面及刀具的几何特征,调整铣刀与被加工齿面的相对位置,使齿面与刀具包络面的法截面相对法曲率最小,增大切削带宽,同时控制刀轴矢量调整切削深度避免加工干涉.最后将规划的加工刀位转化到数控机床轴上,利用VERICUT进行加工仿真验证该方法的可行性与正确性.     

基于CATIA平底铣刀五轴数控编程技术研究

在五轴联动数控加工中,通常采用球头铣刀进行曲面的加工,但是对于双曲面加工,球头铣刀的加工效果较平底铣刀有所不足,因此需要采用平底铣刀来替代球头刀具进行双曲面的加工。但是采用平底铣刀加工双曲面时,由于曲面各处曲率的变化导致刀路轨迹的规划复杂而且困难,而大大影响其在加工曲面中的应用。对此,研究利用平底铣刀的五轴数控联动机床加工双曲面时的刀路轨迹,通过计算得到刀路轨迹的刀位点,设计出利用平底铣刀的五轴数控联动机床加工曲面的刀位轨迹规划方法。结果表明:该方法改善了五轴数控加工中球头铣刀的不足之处,提高了曲面加工的加工质量、加工精度和加工效率。     

Cutting force prediction in ball end milling of sculptured surface with Z-level contouring tool path

This paper presents an approach to predict cutting force in 3-axis ball end milling of sculptured surface with Z-level contouring tool path. The variable feed turning angle is proposed to denote the angular position of feed direction within tool axis perpendicular plane. In order to precisely describe the variation of feed turning angle and cutter engagement, the whole process of sculptured surface milling is discretized at intervals of feed per tooth along tool path. Each segmented process is considered as a small steady-state cutting. For each segmented cutting, the feed turning angle is determined according to the position of its start/end points, and the cutter engagement is obtained using a new efficient Z-map method. Both the chip thickness model and cutting force model for steady-state machining are improved for involving the effect of varying feed turning angle and cutter engagement in sculptured surface machining. In validation experiment, a practical 3-axis ball end milling of sculptured surface with Z-level contouring tool path is operated. Comparisons of the predicted cutting forces and the measurements show the reliability of the proposed approach.     

螺旋曲面的四自由度加工方法

文章在研究螺旋曲面的加工原理的基础上,提出以工件旋转、刀具的坐标变化以及刀具的螺旋角度变化为基础,按空间包络法计算刀触点轨迹,由四轴插补形成了刀具沿螺旋线方向的进给运动,从而实现了前后两个加工截面之间的螺旋位置关系。该方法在国内首次提出四轴坐标系下应用无瞬心包络铣削理论实现螺旋曲面加工,为四轴联动数控机床加工复杂螺旋曲面提供了可靠的理论基础。     

Tool deflection compensation in peripheral milling of curved geometries

This paper presents compensation of surface error due to cutting force-induced tool deflections in a peripheral milling process. Previous research attempts on this topic deal with error compensation in machining of straight geometries only. This paper is concerned with peripheral milling of variable curvature geometries where the workpiece curvature changes continuously along the path of cut. In the case of curved geometries, both process geometry and the cutting forces have shown to have strong dependence on workpiece curvature and hence variation of surface error along the path of cut. This calls for a different error compensation strategy than the one which is normally used for machining straight geometries. The present work is an attempt to improve accuracy in machining of curved geometries by use of CNC tool path compensation. Mechanistic model for cutting force estimation and cantilever beam model for cutter deflection estimation are used. The results based on machining experiments performed on a variety of geometries show that the dimensional accuracy can be improved significantly in peripheral milling of curved geometries.     

侧铣加工空间刀具半径补偿技术实现

通过对侧铣加工空间刀具半径补偿算法的研究,建立刀具和工件模型,并对其进行了求解和公式推导。对任意侧铣加工曲面进行偏置计算,生成带有刀具半径补偿的侧铣偏置曲面,从而解决了侧铣加工中曲面偏置位置的问题,实现了侧铣加工空间刀具半径补偿,该方法的应用为数控系统研究侧铣空间刀具半径补偿提供了参考。     

Cutting process of glass with inclined ball end mill

Cutting processes with ball end mills are discussed for machining microgrooves on glasses. A surface is finished in undeformed chip thickness less than 1 μm at the beginning and at the end of the cut during the cutter rotation. The milling process is applied to glass machining. A crack-free surface can be finished in a large axial depth of cut more than 10 μm. Because glass undergoes almost no elastic deformation, roughness on a cutting edge in glass machining has a larger influence on surface finish than that of metal machining. The rotational axis of the tool is inclined to improve the surface finish. The cutting processes are modeled to show the effect of the tool inclination on the machined surface with considering the edge roughness. The tool inclination compensates for deterioration of the surface finish induced by the edge roughness in the presented model. The improvement of the surface finish is verified in the cutting experiments with the tool inclination. The orthogonal grooves 15–20 μm deep and 150–175 μm wide, then, are machined with the crack-free surfaces to prove efficiency and surface quality in the milling process.     

Process geometry modeling with cutter runout for milling of curved surfaces

Prediction of cutting forces and machined surface error in peripheral milling of curved geometries is non-trivial due to varying workpiece curvature along tool path. The complexity in this case, arises due to continuously changing process geometry as workpiece curvature varies along tool path. In the presence of cutter runout, the situation is further complicated owing to changing radii of cutting points. The present work attempts to model process geometry in machining of curved geometries and in the presence of cutter runout. A mathematical model computing process geometry parameters which include cutter/workpiece engagements and instantaneous uncut chip thickness in the presence of cutter runout is presented. The developed model is more realistic as it accounts for interaction of cutting tooth trajectory with that of preceding teeth trajectories in computing process geometry. Computer simulation studies carried for this purpose has shown that it is essential to account for teeth trajectory interactions for accurate prediction of process geometry parameters. This aspect is further confirmed with machining experiments, which were conducted to validate this aspect. From the outcomes of present work, it is clearly seen that the computation of process geometry during machining of curved geometries and in presence of cutter runout is not straightforward and requires a systematic approach as presented in this paper.     

模具自由曲面球头刀高速铣削点速度研究

球头铣刀高速铣削是加工模具自由曲面的重要工艺方法。在分析自由曲面铣削中球头刀铣削点和零件加工曲线几何位置关系的基础上,探讨球头刀铣削点的运动规律,得到加工模具自由曲面过程中球头刀铣削点的线速度和角速度方程。铣削点的速度方程将为研究球头刀的均匀磨损提供必要的理论依据,为曲面零件的超精密加工打下提供参考。     

五轴联动加工中进给速度的控制算法

目的研究刀具进给速度平稳性对五轴联动加工中复杂自由曲面表面粗糙度、轮廓精度的影响。方法首先对五轴联动机床运动过程中的空间线性插补原理进行了分析,推导出插补周期内各轴的分解速度数学模型。根据数控系统中不同的速度指令方式以及刀具在空间的实际运动距离,分端铣和侧铣两种情况,分别建立了刀具空间运动的实际速度计算模型,然后根据机床各轴的最高速度及加速度约束条件,对各轴分速度、分加速度进行校核处理,最终求得刀具实际的合成速度。最后,基于后置处理技术,用开发的专用后置处理软件进行刀位源代码后置处理,采用某叶轮试件进行了验证,并对实验结果进行了分析。结果在复杂曲面加工中,稳定的表面进给速度会获得较高的表面质量及轮廓精度,曲面曲率变化越大,速度变化对加工质量的影响越大。在同等条件下切削,刀具采用恒表面速度与采用恒进给速度相比,获得的叶片进出汽边轮廓误差值由0.1 mm减小为0.04 mm。结论在五轴联动加工中,越稳定的表面进给速度,越能获得较高的表面质量和轮廓精度,对于曲率变化较大的复杂曲面,需要严格控制刀具的进给速度,尽量获得稳定的表面速度以减少过切值,从而提高零件表面质量。