外文翻译--高速切削加工的发展及需求

1 High-speed machining and demand for the development High-speed machining is contemporary advanced manufacturing technology an important component of the high-efficiency, High-precision and high surface quality, and other features. This article presents the technical definition of the current state of development of Chinas application fields and the demand situation. High-speed machining is oriented to the 21st century a new high-tech, high-efficiency, High-precision and high surface quality as a basic feature, in the automobile industry, aerospace, Die Manufacturing and instrumentation industries gained increasingly widespread application, and has made significant technical and economic benefits. contemporary advanced manufacturing technology an important component part. HSC is to achieve high efficiency of the core technology manufacturers, intensive processes and equipment packaged so that it has a high production efficiency. It can be said that the high-speed machining is an increase in the quantity of equipment significantly improve processing efficiency essential to the technology. High-speed machining is the major advantages : improve production efficiency, improve accuracy and reduce the processing of cutting resistance. The high-speed machining of meaning, at present there is no uniform understanding, there are generally several points as follows : high cutting speed. usually faster than that of their normal cutting 5 -10 times； machine tool spindle speed high, generally spindle speed in -20000r/min above 10,000 for high-speed cutting； Feed at high velocity, usually 15 -50m/min up to 90m/min； For different cutting materials and the wiring used the tool material, high-speed cutting the meaning is not necessarily the same； Cutting process, bladed through frequency (Tooth Passing Frequency) closer to the machine-tool - Workpiece system the dominant natural frequency (Dominant Natural Frequency), can be considered to be high-speed cutting. Visibility high-speed machining is a comprehensive concept.1992. Germany, the Darmstadt University of Technology, Professor H. Schulz in the 52th on the increase of high-speed cutting for the concept and the scope, as shown in Figure 1. Think different cutting targets, shown in the figure of the transition area (Transition), to be what is 2 commonly called the high-speed cutting, This is also the time of metal cutting process related to the technical staff are looking forward to, or is expected to achieve the cutting speed. High-speed machining of machine tools, knives and cutting process, and other aspects specific requirements. Several were from the following aspects : high-speed machining technology development status and trends. At this stage, in order to achieve high-speed machining, general wiring with high flexibility of high-speed CNC machine tools, machining centers, By using a dedicated high-speed milling, drilling. These equipment in common is : We must also have h igh-speed and high-speed spindle system feeding system, Cutting can be achieved in high-speed process. High-speed cutting with the traditional cutting the biggest difference is that Machine-tool-workpiece the dynamic characteristics of cutting performance is stronger influence. In the system, the machine spindle stiffness, grip or form, a long knife set, spindle Broach, torque tool set, Performance high-speed impact are important factors. In the high-speed cutting, material removal rate (Metal Removal Rate, MRR), unit time that the material was removed volume, usually based on the machine-tool-workpiece whether Processing System chatter. Therefore, in order to satisfy the high-speed machining needs, we must first improve the static and dynamic stiffness of machine spindle is particularly the stiffness characteristics. HSC reason at this stage to be successful, a very crucial factor is the dynamic characteristics of the master and processing capability. In order to better describe the machine spindle stiffness characteristics of the project presented new dimensionless parameter - DN value, used for the evaluation of the machine tool spindle structure on the high-speed machining of adaptability. DN value of the so-called axis diameter per minute speed with the product. The newly developed spindle machining center DN values have been great over one million. To reduce the weight bearing, but also with an array of steel products than to the much more light ceramic ball bearings； Bearing Lubrication most impressive manner mixed with oil lubrication methods. In the field of high-speed machining. have air bearings and the development of magnetic bearings and magnetic bearings and air bearings combined constitute the magnetic gas / air mixing spindle. Feed the machine sector, high-speed machining used in the feed drive is usually larger lead, 3 multiple high-speed ball screw and ball array of small-diameter silicon nitride (Si3N4) ceramic ball, to reduce its centrifugal and gyroscopic torque； By using hollow-cooling technology to reduce operating at high speed ball screw as temperature generated by the friction between the lead screw and thermal deformation. In recent years, the use of linear motor-driven high-speed system of up to Such feed system has removed the motor from workstations to Slide in the middle of all mechanical transmission links, Implementation of Machine Tool Feed System of zero transmission. Because no linear motor rotating components, from the role of centrifugal force, can greatly increase the feed rate. Linear Motor Another major advantage of the trip is unrestricted. The linear motor is a very time for a continuous machine shop in possession of the bed. Resurfacing of the very meeting where a very early stage movement can go, but the whole system of up to the stiffness without any influence. By using high-speed screw, or linear motor can greatly enhance machine system of up to the rapid response. The maximum a cceleration linear motors up to 2-10G (G for the acceleration of gravity), the largest feed rate of up to 60 -200m/min or higher. 2002 world-renowned Shanghai Pudong maglev train project of maglev track steel processing, Using the Shenyang Machine Tool Group Holdings Limited McNair friendship company production plants into extra-long high-speed system for large-scale processing centers achieve . The machine feeding system for the linear guide and rack gear drive, the largest table feed rate of 60 m / min, Quick trip of 100 m / min, 2 g acceleration, maximum speed spindle 20000 r / min, the main motor power 80 kW. X-axis distance of up to 30 m, 25 m cutting long maglev track steel error is less than 0.15 mm. Maglev trains for the smooth completion of the project provided a strong guarantee for technology In addition, the campaign machine performance will also directly affect the processing efficiency and accuracy of processing. Mold and the free surface of high-speed machining, the main wiring with small cut deep into methods for processing. Machine requirements in the feed rate conditions, should have high-precision positioning functions and high-precision interpolation function, especially high-precision arc interpolation. Arc processing is to adopt legislation or thread milling cutter mold or machining parts, the essential processing methods. Cutting Tools Tool Material development 4 high-speed cutting and technological development of the history, tool material is continuous progress of history. The representation of high-speed cutting tool material is cubic boron nitride (CBN). Face Milling Cutter use of CBN, its cutting speed can be as high as 5000 m / min, mainly for the gray cast iron machining. Polycrystalline diamond (PCD) has been described as a tool of the 21st century tool, It is particularly applicable to the cutting aluminum alloy containing silica material, which is light weight metal materials, high strength, widely used in the automobile, motorcycle engine, electronic devices shell, the base, and so on. At present, the use of polycrystalline diamond cutter Face Milling alloy, 5000m/min the cutting speed has reached a practical level. In addition ceramic tool also applies to gray iron of high-speed machining； Tool Coating : CBN and diamond cutter, despite good high-speed performance, but the cost is relatively high. Using the coating technology to make cutting tool is the low price, with excellent mechanical properties, which can effectively reduce the cost. Now high-speed processing of milling cutter, with most of the wiring between the Ti-A1-N composite technology for the way of multi-processing, If present in the non-ferrous metal or alloy material dry cutting, DLC (Diamond Like Carbon) coating on the cutter was of great concern. It is expected that the market outlook is very significant； Tool clamping system : Tool clamping system to support high-speed cutting is an important technology, Currently the most w idely used is a two-faced tool clamping system. Has been formally invested as a commodity market at the same clamping tool system are : HSK, KM, Bigplus. NC5, AHO systems. In the high-speed machining, tool and fixture rotary performance of the balance not only affects the precision machining and tool life. it will also affect the life of machine tools. So, the choice of tool system, it should be a balanced selection of good products. Process ParametersCutting speed of high-speed processing of conventional shear velocity of about 10 times. For every tooth cutter feed rate remained basically unchanged, to guarantee parts machining precision, surface quality and durability of the tool, Feed volume will also be a corresponding increase about 10 times, reaching 60 m / min, Some even as high as 120 m / min. Therefore, high-speed machining is usually preclude the use of high-speed, feed and depth of cut small cutting parameters. Due to the high-speed machining cutting cushion tend 5 to be small, the formation of very thin chip light, Cutting put the heat away quickly； If the wiring using a new thermal stability better tool materials and coatings, Using the dry cutting process for high-speed machining is the ideal technology program.High-speed machining field of applicationFlexible efficient production line. To adapt to the needs of new models, auto body panel molds and resin-prevention block the forming die. must shorten the production cycle and reduce the cost of production a nd, therefore, we must make great efforts to promote the production of high-speed die in the process. SAIC affiliated with the company that : Compared to the past, finishing, further precision； the same time, the surface roughness must be met, the bending of precision, this should be subject to appropriate intensive manual processing. Due to the extremely high cutting speed, and the last finishing processes, the processing cycle should be greatly reduced. To play for machining centers and boring and milling machining center category represented by the high-speed machining technology and automatic tool change function of distinctions Potential to improve processing efficiency, the processing of complex parts used to be concentrated as much as possible the wiring process, that is a fixture in achieving multiple processes centralized processing and dilute the traditional cars, milling, boring, Thread processing different cutting the limits of technology, equipment and give full play to the high-speed cutting tool function, NC is currently raising machine efficiency and speed up product development in an effective way. Therefore, the proposed multi-purpose tool of the new requirements call for a tool to complete different parts of the machining processes, ATC reduce the number of ATC to save time, to reduce the quantity and tool inventory, and management to reduce production costs. More commonly used in a multifunctional Tool, milling, boring and milling, drill ing milling, drilling-milling thread-range tool. At the same time, mass production line, against the use of technology requires the development of special tools, tool or a smart composite tool, improve processing efficiency and accuracy and reduced investment. In the high-speed cutting conditions, and some special tools can be part of the processing time to the original 1 / 10 below, results are quite remarkable. HSC has a lot of advantages such as : a large number of materials required resection of the workpiece with ultrafine, thin structure of the workpiece, Traditionally, the need to spend 6 very long hours for processing mobile workpiece and the design of rapid change, short product life cycle of the workpiece, able to demonstrate high-speed cutting brought advantages. 高速切削加工的发展及需求 高速切削加工是当代先进制造技术的重要组成部分，拥有高效率、高精度及高表面质量等特征。本文介绍此技术的定义、发展现状、适用领域以及中国的需求情况。 高速切削加工是面向 21 世纪的一项高新技术，它以高效率、高精度和高表面质量为基本特征，在汽车工业、航空航天、模具制造和仪器仪表等行业中获得了愈来愈广泛的应用，并已取得了重大的技术经济效益，是当代先进制造技术的重要组成部分。 高速切削是实现高效率制造的核心技术，工序的集约化和设备的通用化使之具有很高的生产效率。可以说 ，高速切削加工是一种不增加设备数量而大幅度提高加工效率所必不可少的技术。高速切削加工的优点主要在于：提高生产效率、提高加工精度及降低切削阻力。 有关高速切削加工的含义，目前尚无统一的认识，通常有如下几种观点：切削速度很高，通常认为其速度超过普通切削的 5-10 倍；机床主轴转速很高，一般将主轴转速在 10000-20000r/min 以上定为高速切削；进给速度很高，通常达 15-50m/min，最高可达 90m/min；对于不同的切削材料和所釆用的刀具材料，高速切削的含义也不尽相同；切削过程中，刀刃的通过频率 (Tooth Passing Frequency)接近于“机床刀具工件”系统的主导自然频率 (Dominant Natural Frequency)时，可认为是高速切削。可见高速切削加工是一个综合的概念。 1992 年，德国 Darmstadt 工业大学的 H. Schulz 教授在 CIRP 上提出了高速切削加工的概念及其涵盖的范围，如图 1 所示。认为对于不同的切削对象，图中所示的过渡区(Transition)即为通常所谓的高速切削範围，这也是当时金属切削工艺相关的技术人员所期待或者可望实现的切削速度。 高速切削加工对机床、刀具和切削工艺等方面都有一些具体的要求。下面分别从这几个方面阐述高速切削加工技术的发展现状和趋势。 现阶段，为了实现高速切削加工，一般釆用高柔性的高速数控机床、加工中心，也有釆用专用的高速铣、钻床。这些设备的共同之处是：必须同时具有高速主轴系统和高速进给系统，才能实现材料切削过程的高速化。高速切削与传统切削最大的区别是，“机床刀具工件”系统的动态特性对切削性能有更强的影响力。在该系统中，机床主轴的刚度、刀柄形式、刀长设定、主轴拉刀力、刀具扭力设定等，都是影响高速切削性能的重 要因素。 7 在高速切削中，材料去除率 (Metal Removal Rate， MRR)，即单位时间内材料被切除的体积，通常受限于“机床 -刀具 -工件”工艺系统是否出现“颤振”。因此，为了满足高速切削加工的需求，首先要提高机床动静刚度尤其是主轴的刚度特性。现阶段高速切削之所以能够成功，一个很关键的因素在于对系统动态特性问题的掌握和处理能力。 为了更好地描述机床主轴的刚度特性，工程上提出新的无量纲参数 DN 值，用以评价机床的主轴结构对高速切削加工的适应性。所谓 DN 值即“主轴直径与每分钟转速之积”。新 近开发的加工中心主轴 DN 值大都已超过 100 万。为了减轻轴承的重量，还釆用了比钢制品要轻得多的陶瓷球轴承；轴承润滑方式大都釆用油气混合润滑方式。在高速切削加工领域，目前已开发空气轴承和磁轴承以及由磁轴承和空气轴承合并构成的磁气/空气混合主轴。 在机床进给机构方面，高速切削加工所用的进给驱动机构通常都为大导程、多头高速滚珠丝槓，滚珠釆用小直径氮化硅（ Si3N4）陶瓷球，以减少其离心力和陀螺力矩；釆用空心强冷技术来减少高速滚珠丝槓运转时由于摩擦产生温升而造成的丝槓热变形。 近几年来，用直线电机驱 动的高速进给系统问世，这种进给方式取消了从电动机到工作台溜板之间的一切中间机械传动环节，实现了机床进给系统的零传动。由于直线电机没有任何旋转元件，不受离心力的作用，可以大大提高进给速度。直线电机的另一大优点是行程不受限制。直线电机的次极是一段一段连续铺在机床的床身上。次极铺到哪里，初极工作台就可运动到哪里，而且对整个进给系统的刚度没有任何影响。釆用高速丝槓或直线电机，能够大大提高机床进给系统的快速响应。直线电机最高加速度可达2-10G(G 为重力加速度 )，最大进给速度可达 60-200m/min 或更高。 2002 年举世瞩目的上海浦东磁悬浮列车工程中的磁浮轨道钢梁加工，釆用沈阳机床控股有限公司集团中捷友谊公司厂生产的超长进给系统高速大型加工中心实现。该机床的进给系统为直线导轨和齿轮齿条传动，工作台最大进给速度 60m/min，快速行程100m/min，加速度 2g，主轴最高转速 20000r/min，主电机功率 80kW。其 X 轴的行程长达 30m，切削 25m 长的磁浮轨道钢梁误差小于 0.15mm，为磁悬浮列车工程的顺利竣工提供了有力的技术保证。 此外，机床的运动性能也将直接影响加工效率和加工精度。在模具及自由曲面的高速切削加工中，主要釆用小切深大进给的加工方法。要求机床在大进给速度条件下，应具有高精度定位功能和高精度插补功能，特别是圆弧高精度插补。圆弧加工是釆用立铣 刀或螺纹刀具