1、毕业设计(论文)外文资料翻译学院 (系)： 机械工程学院 专 业： 机械工程及自动化 姓 名： 学 号： (用外文写)外文出处：Manufacturing Engineering 附 件： 1.外文资料翻译译文；2.外文原文。 指导教师评语：本文简单介绍了切削加工的概念，详细阐述了各种类型的钢的切削性能及其特点，并简单介绍了各种材料的切削特点及其机械加工性。翻译用词比较准确，文笔也较为通顺，为在以后工作中接触英文资料打下了基础。 签名： 年 月 日注：请将该封面与附件装订成册。附件1：外文资料翻译译文加工中心加工标准1 概述(1) 加工中心分粗加工和精加工。 (2) 大件加工流程： 开粗热处理
2、时效处理半精加工成型面精加工抛光分型面精加工。 (3) 模具表面不得有咬刀、切削瘤、锋线不得有倒圆、倒卷毛刺，如出现以上问题，作为不合格处理。 (4) 成型面、分配面和配合面，手感光顺、菱角清晰，表面粗糙度0.8，非成型面和配合面不能出现锋口和锐角，需圆滑过渡。 (5) 分型面加工流程： 粗加工半精加工成型面抛光精加工 (6) 避空部分有得有影响美观的刀痕。 (7) 芯子点孔要采用国心钻头，有允许用球刀。 (8) 零件上接刀误差不得超过0.02。 (9) 每个零件必须有符合图纸的加工基准，基准加工要光滑，无明显刀痕，粗糙度要求在0.8以上。提高数控加工中心切削效率的途径 数控加工作为现代制造业
3、先进生产力的代表，在机械、航空航天和模具等行业发挥着极为重要的作用。90年代以来，欧、美、日各国竞相开发和应用新一代高速数控机床，加快了机床高速化发展步伐。高速主轴单元中电机主轴转速15000100000r/min，高速且高加/减速度的进给运动部件的快移速度60120m/min，切削进给速度高达60m/min，高速加工中心进给速度可达80m/min，空运行速度可达100m/min左右。美国CINCINNATI公司的HyperMach机床进给速度最大达60m/min，快速为100m/min，主轴转速已达60000r/min。在加工精度方面，近10年来，普通级数控机床的加工精度已由10m提高到5m
4、精密级加工中心则从35m提高到11.5m，并且超精密加工精度已开始进入纳米级(0.01m)。而新一代高速数控机床特别是高速加工中心的开发应用与超高速切削紧密相关。1.国内外加工中心切削水平的差异目前先进国家的车削和铣削的切削速度已达到50008000m/min以上；机床主轴转数在30000r/min(有的高达10万r/min)以上。例如：在铣削平面时，国外的切削速度一般大于10002000m/min，而国内只相当于国外的1/121/15，即国内干1215个小时的活相当于国外干1个小时。据调查，许多加工中心的实际切削时间不到工作时间的55%。因此，如何提高加工效率，降低废品率成了众多企业共同探
5、讨的问题。对国内数控加工中心切削效率部分调查发现，普遍存在如刀具精度低、刀片跳动量大、加工光洁度低、工艺设备不配套等诸多问题。2.提高切削效率的途径（1）合理选择切削用量当前以高速切削为代表的干切削、硬切削等新的切削工艺已经显示出很多的优点和强大的生命力，成为制造技术提高加工效率和质量、降低成本的主要途径。实践证明，当切削速度提高10倍，进给速度提高20倍，远远超越传统的切削“禁区”后，切削机理发生了根本的变化。其结果是：单位功率的金属切除率提高了30%40%，切削力降低了30%，刀具的切削寿命提高了70%，大幅度降低了留在工件上的切削热，切削振动几乎消失；切削加工发生了本质性的飞跃。根据目前
6、机床的情况来看，要充分发挥先进刀具的高速加工能力，需采用高速加工，增大单位时间材料被切除的体积(材料切除率Q)。在选择合理切削用量的同时，尽量选择密齿刀（在刀具每英寸直径上的刀齿数3），增加每齿进给量，提高生产率及刀具寿命。有关试验研究表明：当线速度为165m/min，每齿进给为0.04mm时，进给速度为341m/min，刀具寿命为30件。如果将切削速度提高到350m/min，每齿进给为0.18mm，进给速度则达到2785m/min，是原来加工效率的817%，而刀具寿命增加到了117件。（2）选择性能好的刀具材料在数控机床切削加工中，金属切削刀具的作用不亚于瓦特发明的蒸气机。制造刀具的材料必须
7、具有很高的高温硬度和耐磨性，必要的抗弯强度、冲击韧性和化学惰性，良好的工艺性(切削加工、锻造和热处理等)，并不易变形。目前国内外性能好的刀具材料主要有：金属陶瓷、硬质合金涂层刀具、陶瓷刀具、聚晶金刚石（PCD）和立方氮化硼（CBN）刀具等。它们各具特点，适应的工件材料和切削速度范围各不相同。CBN适用于切削高硬度淬硬钢和硬铸铁等，如加工高硬钢件(5067HRC)和冷硬铸铁时主要选用陶瓷刀具和CBN刀具，其中加工硬度6065HRC以下的工件可用陶瓷刀具，而65HRC以上的工件则用CBN刀具进行切削；PCD适用于切削不含铁的金属，及合金、塑料和玻璃钢等，加工铝合金件时,主要采用PCD和金刚石膜涂层
8、刀具；碳素工具钢和合金工具钢现在只用作锉刀、板牙和丝锥等工具；硬质合金涂层刀具（如涂层TiN、TiC、TiCN、TiAIN等）虽然硬度较高，适于加工的工件范围广，但其抗氧化温度一般不高，所以切削速度的提高也受到限制，一般可在400500m/min范围内加工钢铁件，而Al2O3涂层的高温硬度高，在高速范围内加工时，其耐磨性较TiC、TiN涂层都好。此外，刀具切削部分的几何参数对切削效率的高低和加工质量有很大影响，高速切削时的刀具前角一般比普通切削时小10，后角大58。为防止刀尖处的热磨损，主、副切削刃连接处应采用修圆刀尖或倒角刀尖，以增大局部刀尖角，增大刀尖附近切削刃的长度和刀具材料体积，以提高
9、刀具刚性和减少刀具破损率。（3）加快涂层技术的开发刀具涂层技术自从问世以来，对刀具性能的改善和加工技术的进步起着非常重要的作用，涂层刀具已经成为现代刀具的标志，在刀具中所占比例已超过50%。在21世纪初，涂层刀具的比例将进一步增加，有望在技术上突破CBN涂层技术，使CBN的优良性能在更多的刀具和切削加工中得到应用(包括精密复杂刀具和成形刀具)，这将全面提高加工黑色金属的切削水平。此外，纳米级超薄超多层和新型涂层材料的开发应用的速度将加快，涂层将成为改善刀具性能的主要途径。（4）选择高精度刀片刀片精度低，跳动量太大，面铣刀加工的平面光洁度将降低，甚至出现沟状。高精度数控机床上刀片的跳动量应控制在
10、25m。随着数控机床的发展，相应出现刀片的表面改性涂层处理（基体为高速钢、C类硬质合金、i基类金属陶瓷），很大程度上提高了刀片精度。与此同时，出现了各种新型可转位刀片结构，如用于车削的高效刮光刀片、形状复杂的带前角铣刀刀片、球头立铣刀刀片、防甩飞的高速铣刀刀片等。可转位刀片进入了材料、涂层、槽型综合开发的新阶段，可根据加工材料和加工工序合理组合材料、涂层、槽型的功能，开发出具有最佳加工效果的刀片，以满足高速、高寿命切削加工生产技术的不同要求。（5）提高加工表面质量在保持相同的切削效率(即相同Q值)下，提高切削速度可改善切屑形成过程和增加切削阻尼，抑制颤振，相应地减少每个刀齿的进给量能降低切削表
11、面轨迹形成的残留高度，改善表面粗糙度，从而有利于精密零件和模具的加工。（6）建立合理的刀具储备这里的刀具是指高切削效率刀具，而这些刀具的价格较高，相同直径的铣刀，好刀具的价格可能是普通刀具的几倍甚至十几倍。如果一个企业长期存放一大批好刀具，而这些刀具又可能长时间用不上，则造成资金积压。但如果平常一把刀具也不储备，或储备数量太少，很快就用完了，而新刀具一时又买不到，这样必然会影响数控加工的效率。绝大多数企业的加工中心的刀库均可容纳40把刀具以上，并有60、90、120等不同刀数的刀库可供选择。刀具之间交换时间越来越短，德国STEINEL公司的BZ26，日本MAKINO公司的MCC86，美国CIN
12、CINNATI公司的MAXIM500型加工中心的换刀时间只需34s。（7）设计简易的磨刀夹具机夹铣刀盘效率高，使用方便，深受操作者欢迎，但刀片消耗量大，使用成本高，而且多数情况下刀片的损坏是由于刃口磨损造成的，因此刀片的重磨再利用对工厂来说可获得较高经济效益。硬质合金刀片的硬度高，磨削效率低，采用单片磨削将达不到节约的目的，需设计出高效简单的夹具，实现一次装夹多个刀片。（8）加工方式的选择 加工方式可分为顺铣与逆铣两种。而加工中心的机械传动系统和结构本身就有较高的精度和刚度，相对运动面的摩擦系数小，传动部件的间隙小，运动惯量小，并有适当的阻尼比，因此可以采用顺铣的方式加工，以提高加工效率。此外
13、根据加工经验，顺铣比逆铣时刀具寿命要提高1倍多，采用不对称的立铣方法，刀具寿命可提高23倍。（9）选择合理的加工路线数控机床特别是4轴以上加工中心，一般是一次装夹、多方位加工，并且都有刀库，可自动更换刀具，一次加工成形。因此确定正确简洁的加工路线，是保证加工质量和提高效率的基础。编程时确定加工路线的原则主要有：应能保证零件的加工精度和表面粗糙度的要求；应尽量缩短加工路线，减少刀具空程移动时间；应使数值计算简单，程序段数量少，以减少编程工作量。如对于位置精度和尺寸公差要求高的孔加工来说，孔直径小于1820mm的加工工艺路线为：钻中心孔钻孔扩孔铰孔，而对于孔直径大于1820mm的加工工艺路线则为
14、钻孔扩孔粗镗孔精镗孔。此外，通过对加工工艺的综合应用，减少工件的安装次数，可有效缩短搬运和装夹时间。例如将五面五轴加工中心与立车复合构成万能加工中心，可实现一次装卡完成零件的大部分（或全部）加工。（10）工件装夹的选择数控加工时由于工序集中的原因，在对零件进行定位、夹紧设计以及夹具的选用和设计等问题上要全面考虑。首先，应尽量采用组合夹具，由于通用夹具的柔性差、定位精度相对较低，当产品批量比较大、加工精度要求高时可以设计专用夹具。其次，在选择工装时应有利于刀具交换和在线测量，避免发生碰撞干涉。（11）加工中心的辅助设备要配套在加工中心采用如刀具预调仪，自动测量装置，精密的检测仪等测量装置。采用自
15、动测量装置时，操作员无须对零件的定位保证非常精准，也不需要操作员时刻移动和调节零件以配合加工程序的某些固定坐标系，可以减少装夹时间。借助测量，原来包括装夹时间在内需要2.5小时的一个工序降低到了1.5小时。此外，这些测量装置的应用还可以降低加工误差。（12）操作人员技能与知识培训加工中心的加工效率在很大程度上取决于切削时间占加工中心工作时间的比例，这个比值越大，加工效率也就越高。同时，现代加工设备科技含量越来越高，对人员的素质要求也越来越高。而实际生产中，由于人员技术水平低，操作不熟练，花在程序调试、加工中换工件等非加工时间上的时间过长，致使加工中心加工效率低下。另外，他们的专业知识太少，对数
16、控加工的原理、数控工艺、数控刀具和切削参数的选择等方面缺乏科学性的指导。因此，建立一套完善的培训体系，编写适应现代切削加工技术发展的新教材，加强技术人员对理论知识的学习，加强企业内部和外部的技术交流是十分必要的。附件2：外文原文（复印件）Machining center standards （1）sub-roughing and finishing machining center. （2）large machining processes: Open-rough- heat - Semi-aging treatment- finishing molding -surface finish -
17、 parting surface- polished finish. （3） mold surface should not have had a knife biting, cutting tumor, striker should not have down round, Daojuan glitches, if such problems comes, it is a failed deal. （4）forming face, the allocation of surface and matching the face, hand fairing, caltrop clear, the
18、 surface roughness of 0.8, non-molding surface and matching the mouth and face can not appear front acute angle required to smooth the transition. （5）sub-type surface machining process: Rough - semi-finishing -molding surface - polished finish （6）avoid the empty part of the gains and influential aes
19、thetic knife marks. （7）wick-point hole to adopt the country heart bit, it allows the ball knife. （8） the error of part not have to be more than 0.02 then a knife. （9）each part must have a line drawing processing benchmark, the benchmark process should be smooth, no obvious marks of knives, roughness
20、 requires more than 0.8. CNC machining center to improve ways of cutting efficiency CNC machining, as the representative of the advanced productive forces of modern manufacturing industry, in mechanical, aerospace and die, etc. play a very important role. Since the 90s, Europe, the United States, an
21、d Japan is racing to develop and apply a new generation of high-speed CNC machine tools, speeding up the pace of development of high-speed machine tools. High-speed spindle unit motor spindle speed 15000 100000r/min, high-speed and high plus / minus the rate of feed of the rapid traverse speeds of m
22、oving parts 60 120m/min, cutting feed rate of up to 60m/min, feed rate high-speed machining center of up to 80m/min, air speed up to 100m/min or so. U.S. CINCINNATI companies HyperMach machine feed rate is up to 60m/min, quick to 100m/min, spindle speed has reached 60000r/min. In the processing prec
23、ision, the past 10 years, the general level of processing precision CNC machine tools from 10m to 5m, Precision machining centers from the 3 5m to 1 1.5m, and the ultra-precision machining accuracy has begun to enter the nano-scale ( 0.01m). The new generation of high-speed CNC machine tools in part
24、icular the development and application of high-speed machining centers are closely related with the ultra-high-speed cutting. 1. Domestic and international differences in levels of machining center cutting Nowadays the advanced countries turning and milling, cutting speed has reached 5000 8000m/min
25、above; rpm spindle in 30000r/min (some as high as 100,000 r / min) or more. For example: In the milling plane, the foreign cutting speed generally greater than 1000 2000m/min, only the equivalent of foreign domestic 1 / 12 1 / 15, that is, the domestic dry 12 to 15 hours of live abroad, equivalent t
26、o dry a hours. According to the survey, many of the actual cutting machining centers less than 55% of working time. Therefore, how to improve processing efficiency, reduce rejection rate becomes large number of enterprises to explore issues. CNC machining center for cutting efficiency of the domesti
27、c part of the investigation found that prevalence of low precision, such as knives, blades beating a large amount of processing roughness is low, process equipment is not complete and many other issues. 2. ways to improve the cutting efficiency (1) a reasonable choice Cutting , Represented by the cu
28、rrent high-speed of dry cutting, hard machining and other new cutting technology has shown a lot of advantages and strong vitality, as manufacturing technology to improve processing efficiency and quality, the main way to reduce costs. Practice has proved that, when the cutting speed increased by 10
29、 times the feed rate increased 20-fold, far beyond the traditional cutting of the forbidden zone, the cutting mechanism of a fundamental change. The result: a unit of power, metal removal rate increased by 30% to 40%, 30% lower cutting forces, cutting tool life increased by 70%, significantly reduce
30、d stay in the workpiece on the cutting heat, cutting vibration almost disappeared ; cutting occurred in the nature of a leap. Based on the current machine situation, should give full play to the high-speed processing capability of advanced tools required to use high-speed processing, and increased p
31、er unit time the volume of material was removed (material removal rate Q). In selecting a reasonable amount of cutting the same time, as we choose fine-toothed blade (in the tool diameter per inch knife teeth 3), to increase the amount of feed per tooth, improve productivity and tool life. The pilot
32、 study: When the line speed of 165m/min, feed per tooth of 0.04mm, the feed speed of 341m/min, tool life of 30. If the cutting speed up to 350m/min, feed per tooth of 0.18mm, feed rate can reach 2785m/min, processing efficiency is the original 817%, while the tool life increased to 117. (2) Select g
33、ood performance tool material In the CNC machining, metal cutting tools of the role of no less than Watts invention of steam engine. Manufacture of the tool material must have a very high temperature hardness and wear resistance, the necessary bending strength, impact toughness and chemical inertnes
34、s, good manufacturability (machining, forging and heat treatment, etc.), is not easy to deform. Good performance at home and abroad tool materials are: metal-ceramic, carbide-coated cutting tools, ceramic cutting tools, polycrystalline diamond (PCD) and cubic boron nitride (CBN) cutting tools and so
35、 on. They each have character and adapt to the scope of the workpiece material and cutting speed varies. CBN cutting for high hardness such as hardened steel and hard cast iron, such as the processing of high-hard steel (50 67HRC) and chilled cast iron, the main choice of ceramic cutting tools and C
36、BN tools, the processing hardness 60 65HRC the following artifacts are available ceramic tool , while the workpiece is above 65HRC using CBN cutting tools for cutting; PCD for machining non-ferrous metals and alloys, plastics and glass, steel, processed aluminum alloy, the main use of PCD and diamon
37、d film-coated cutting tools; carbon tool steel and alloy tool steel is now used only for FILE, die, and Taps and other tools; carbide coated tools (such as coatings TiN, TiC, TiCN, TiAIN, etc.) Although the higher hardness, suitable for a wide range of machining workpiece, but the its anti-oxidation
38、 temperature is not high, so the improvement of cutting speed is also limited, generally in the range of 400 500m/min within the processing of iron and steel parts, while the Al2O3 coating high-temperature, high hardness, high-speed processing within the scope, its wear-resistant nature than the TiC
39、 TiN-coated very well. In addition, the tool cutting part of the geometric parameters on the level of cutting efficiency and processing quality has a great influence, high-speed cutting tool when the anterior horn generally smaller than normal cutting 10 , posterior horn of the big 5 8 . Corner Off
40、ice in order to prevent thermal wear, Lord, Vice cutting edge connections should be rounding or chamfer tip tip in order to increase local knife sharp corners, increasing the length of the cutting edge near the tip and the tool material volume, in order to improve the tool rigidity and reduce the ra
41、te of tool breakage. (3) to accelerate the development of coating technology Tool coating technology since its inception, the tool performance improvements and advances in processing technology plays an important role in coated tools has become a symbol of modern tools in the tool in the proportion
42、of more than 50%. In the 21st century, the proportion of coated tools will further increase is expected to CBN coating technology breakthroughs in technology, so that the good performance of CBN tools in more and cutting process has been applied (including the sophisticated tools and forming tools),
43、 This will comprehensively improve the level of processing ferrous metal cutting. In addition, the nano-scale multi-layer and a new ultra-thin coating materials will accelerate the speed of development and application of the coating will become the main way to improve the tool performance. (4) Selec
44、t high-precision blades Blade precision is low, beating too big, face milling of flat finish will reduce or even sulcus. High-precision CNC machine tools on the blade runout should be controlled within 2 5m. With the development of CNC machine tools, the corresponding blade surface modification coat
45、ing appeared treatment (substrate for high-speed steel, WCo type carbide, Ti-based metals ceramics), greatly improves the precision blades. Meanwhile, the emergence of new types of indexable inserts structures, such as for turning the efficient light scraping blade, the shape of complex with anterio
46、r horn cutter blade, ball-end cutter blade, anti-rejection high-speed cutter blade flying and so on. Indexable inserts into the material, coating, trough a new stage of comprehensive development, in accordance with processing materials and manufacturing processes for the rational combination of mate
47、rials, coatings, trough features, developed with the best machining results of the blade, to meet the High-speed, high-life of cutting the different requirements of production technology. (5) to improve surface quality While maintaining the same cutting efficiency (ie the same Q value), increasing c
48、utting speed can be improved chip formation process and increase the cutting damping, flutter suppression, with a corresponding reduction in the inlet of each cutter tooth to the cutting surface can lower the amount of trace residues in the formation of height, to improve the surface roughness, thus facilitating the
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