[方案]机械毕业英语论文翻译5000字-车床

[]机械毕业英语论文翻译5000字-车床 英文原文 1 Lthes Lthes re mchine tools designed primrily to do turning, fcing nd boring, Very little turning is done on other types of mchine tools, nd none cn do it with equl fcility. Becuse lthes lso cn do drilling nd reming, their verstility permits severl opertions to be done with single setup of the work piece. Consequently, more lthes of vrious types re used in mnufcturing thn ny other mchine tool. The essentil components of lthe re the bed, hedstock ssembly, tilstock ssembly, nd the leds crew nd feed rod. The bed is the bckbone of lthe. It usully is mde of well normlized or ged gry or nodulr cst iron nd provides s hevy, rigid frme on which ll the other bsic components re mounted. Two sets of prllel, longitudinl wys, inner nd outer, re contined on the bed, usully on the upper side. Some mkers use n inverted V-shpe for ll four wys, wheres others utilize one inverted V nd one flt wy in one or both sets, They re precision-mchined to ssure ccurcy of lignment. On most modern lthes the wy re surfce-hrdened to resist wer nd brsion, but precution should be tken in operting lthe to ssure tht the wys re not dmged. ny inccurcy in them usully mens tht the ccurcy of the entire lthe is destroyed. The hedstock is mounted in foxed position on the inner wys, usully t the left end of the bed. It provides powered mens of rotting the word t vrious speeds . Essentilly, it consists of hollow spindle, mounted in ccurte berings, nd set of trnsmission gers-similr to truck trnsmission—through which the spindle cn be rotted t number of speeds. Most lthes provide from 8 to 18 speeds, usully in geometric rtio, nd on modern lthes ll the speeds cn be obtined merely by moving from two to four levers. n incresing trend is to provide continuously vrible speed rnge through electricl or mechnicl drives. Becuse the ccurcy of lthe is gretly dependent on the spindle, it is of hevy construction nd mounted in hevy berings, usully preloded tpered roller or bll types. The spindle hs hole extending through its length, through which long br stock cn be fed. The size of mximum size of br stock tht cn be mchined when the mteril must be fed through spindle. The tilsticd ssembly consists, essentilly, of three prts. lower csting fits on the inner wys of the bed nd cn slide longitudinlly thereon, with mens for clmping the entire ssembly in ny desired loction, n upper csting fits on the lower one nd cn be moved trnsversely upon it, on some type of keyed wys, to permit ligning the ssembly is the tilstock quill. This is hollow steel cylinder, usully bout 51 to 76mm(2to 3 inches) in dimeter, tht cn be moved severl inches longitudinlly in nd out of the upper csting by mens of hnd wheel nd screw. The size of lthe is designted by two dimensions. The first is known s the swing. This is the mximum dimeter of work tht cn be rotted on lthe. It is pproximtely twice the distnce between the line connecting the lthe centers nd the nerest point on the wys, The second size dimension is the mximum distnce between centers. The swing thus indictes the mximum work piece dimeter tht cn be turned in the lthe, while the distnce between centers indictes the mximum length of work piece tht cn be mounted between centers. Engine lthes re the type most frequently used in mnufcturing. They re hevy-duty mchine tools with ll the components described previously nd hve power drive for ll tool movements except on the compound rest. They commonly rnge in size from 305 to 610 mm(12 to 24 inches)swing nd from 610 to 1219 mm(24 to 48 inches) center distnces, but swings up to 1270 mm(50 inches) nd center distnces up to 3658mm(12 feet) re not uncommon. Most hve chip pns nd built-in coolnt circulting system. Smller engine lthes-with swings usully not over 330 mm (13 inches ) –lso re vilble in bench type, designed for the bed to be mounted on bench on bench or cbinet. lthough engine lthes re verstile nd very useful, becuse of the time required for chnging nd setting tools nd for mking mesurements on the work piece, thy re not suitble for quntity production. Often the ctul chip-production tine is less thn 30% of the totl cycle time. In ddition, skilled mchinist is required for ll the opertions, nd such persons re costly nd often in short supply. However, much of the opertor’s time is consumed by simple, repetitious djustments nd in wtching chips being mde. Consequently, to reduce or eliminte the mount of skilled lbor tht is required, turret lthes, screw mchines, nd other types of semiutomtic nd utomtic lthes hve been highly developed nd re widely used in mnufcturing. 2 Numericl Control One of the most fundmentl concepts in the re of dvnced mnufcturing technologies is numericl control (NC). Prior to the dvent of NC, ll mchine tools ere mnully operted nd controlled. mong the mny limittions ssocited with mnul control mchine tools, perhps none is more prominent thn the limittion of opertor skills. With mnul control, the qulity of the product is directly relted to nd limited to the skills of the opertor. Numericl control represents the first mjor step wy from humn control of mchine tools. Numericl control mens the control of mchine tools nd other mnufcturing systems through the use of prerecorded, written symbolic instructions. Rther thn operting mchine tool, n NC technicin writes progrm tht issues opertionl instructions to the mchine tool. For mchine tool to be numericlly controlled, it must be interfced with device for ccepting nd decoding the progrmmed instructions, known s reder. Numericl control ws developed to overcome the limittion of humn opertors, nd it hs done so. Numericl control mchines re more ccurte thn mnully operted mchines, they cn produce prts more uniformly, they re fster, nd the long-run tooling costs re lower. The development of NC led to the development of severl other innovtions in mnufcturing technology: Electricl dischrge mchining,Lser cutting,Electron bem welding. Numericl control hs lso mde mchine tools more verstile thn their mnully operted predecessors. n NC mchine tool cn utomticlly produce wide of prts, ech involving n ssortment of widely vried nd complex mchining processes. Numericl control hs llowed mnufcturers to undertke the production of products tht would not hve been fesible from n economic perspective using mnully controlled mchine tolls nd processes. Like so mny dvnced technologies, NC ws born in the lbortories of the Msschusetts Institute of Technology. The concept of NC ws developed in the erly 1950s with funding provided by the U.S. ir Force. In its erliest stges, NC mchines were ble to mde stright cuts efficiently nd effectively. However, curved pths were problem becuse the mchine tool hd to be progrmmed to undertke series of horizontl nd verticl steps to produce curve. The shorter the stright lines mking up the steps, the smoother is the curve, Ech line segment in the steps hd to be clculted. This problem led to the development in 1959 of the utomticlly Progrmmed Tools (PT) lnguge. This is specil progrmming lnguge for NC tht uses sttements similr to English lnguge to define the prt geometry, describe the cutting tool configurtion, nd specify the necessry motions. The development of the PT lnguge ws mjor step forwrd in the fur ther development from those used tody. The mchines hd hrdwired logic circuits. The instructionl progrms were written on punched pper, which ws lter to be replced by mgnetic plstic tpe. tpe reder ws used to interpret the instructions written on the tpe for the mchine. Together, ll of this represented gint step forwrd in the control of mchine tools. However, there were number of problems with NC t this point in its development. mjor problem ws the frgility of the punched pper tpe medium. It ws common for the pper tpe contining the progrmmed instructions to brek or ter during mchining process. This problem ws excerbted by the fct tht ech successive time prt ws produced on mchine tool, the pper tpe crrying the progrmmed instructions hd to be rerun through the reder. If it ws necessry to produce 100 copies of given prt, it ws lso necessry to run the pper tpe through the reder 100 seprte tines. Frgile pper tpes simply could not withstnd the rigors of shop floor environment nd this kind of repeted use. This led to the development of specil mgnetic plstic tpe. Wheres the pper crried the progrmmed instructions s series of holes punched in the tpe, the plstic tpe crried the instructions s series of mgnetic dots. The plstic tpe ws much stronger thn the pper tpe, which solved the problem of frequent tering nd brekge. However, it still left two other problems. The most importnt of these ws tht it ws difficult or impossible to chnge the instructions entered on the tpe. To mde even the most minor djustments in progrm of instructions, it ws necessry to interrupt mchining opertions nd mke new tpe. It ws lso still necessry to run the tpe through the reder s mny times s there were prts to be produced. Fortuntely, computer technology becme relity nd soon solved the problems of NC ssocited with punched pper nd plstic tpe. The development of concept known s direct numericl control (DNC) solved the pper nd plstic tpe problems ssocited with numericl control by simply eliminting tpe s the medium for crrying the progrmmed instructions. In direct numericl control, mchine tools re tied, vi dt trnsmission link, to host computer. Progrms for operting the mchine tools re stored in the host computer nd fed to the mchine tool n needed vi the dt trnsmission linkge. Direct numericl control represented mjor step forwrd over punched tpe nd plstic tpe. However, it is subject to the sme limittions s ll technologies tht depend on host computer. When the host computer goes down, the mchine tools lso experience downtime. This problem led to the development of computer numericl control. 3 Turning The engine lthe, one of the oldest metl removl mchines, hs number of useful nd highly desirble ttributes. Tody these lthes re used primrily in smll shops where smller quntities rther thn lrge production runs re encountered. The engine lthe hs been replced in tody’s production shops by wide vriety of utomtic lthes such s utomtic of single-point tooling for mximum metl removl, nd the use of form tools for finish on pr with the fstest processing equipment on the scene tody. Tolernces for the engine lthe depend primrily on the skill of the opertor. The design engineer must be creful in using tolernces of n experimentl prt tht hs been produced on the engine lthe by skilled opertor. In redesigning n experimentl prt for production, economicl tolernces should be used. Turret Lthes Production mchining equipment must be evluted now, more thn ever before, this criterion for estblishing the production qulifiction of specific method, the turret lthe merits high rting. In designing for low quntities such s 100 or 200 prts, it is most economicl to use the turret lthe. In chieving the optimum tolernces possible on the turrets lthe, the designer should strive for minimum of opertions. utomtic Screw Mchines Generlly, utomtic screw mchines fll into severl ctegories; single-spindle utomtics, multiple-spindle utomtics nd utomtic chucking mchines. Originlly designed for rpid, utomtic production of screws nd similr threded prts, the utomtic screw mchine hs long since exceeded the confines of this nrrow field, nd tody plys vitl role in the mss production of vriety of precision prts. Quntities ply n importnt prt in the economy of the prts mchined on the utomtic screw mchine. Quntities less thn on the utomtic screw mchine. The cost of the prts mchined cn be reduced if the minimum economicl lot size is clculted nd the proper mchine is selected for these quntities. utomtic Trcer Lthes Since surfce roughness depends gretly on mteril turned, tooling , nd feeds nd speeds employed, minimum tolernces tht cn be held on utomtic trcer lthes re not necessrily the most economicl tolernces. In some cses, tolernces of 0.05mm re held in continuous production using but one cut . groove width cn be held to 0.125mm on some prts. Bores nd single-point finishes cn be held to 0.0125mm. On high-production runs where mximum output is desirble, minimum tolernce of 0.125mm is economicl on both dimeter nd length of turn. 中文译文 1.车床 车床主要是为了进行车外圆、车端面和镗孔等项工作而的机床。车削很少在其他种类的机床上进行，而且任何一种其他机床都不能像车床那样方便地进行车削加工。由于车床还可以用来钻孔和铰孔，车床的多功能性可以使工件在一次安装中完成几种加工。因此，在生产中使用的各种车床比任何其他种类的机床都多。 车床的基本部件有:床身、主轴箱组件、尾座组件、溜板组件、丝杠和光杠。 床身是车床的基础件。它能常是由经过充分正火或时效处理的灰铸铁或者球墨铁制成。它是一个坚固的刚性框架，所有其他基本部件都安装在床身上。通常在床身上有内外两组平行的导轨。有些制造厂对全部四条导轨都采用导轨尖朝上的三角形导轨(即山形导轨)，而有的制造厂则在一组中或者两组中都采用一个三角形导轨和一个矩形导轨。导轨要经过精密加工以保证其直线度精度。为了抵抗磨损和擦伤，大多数现代机床的导轨是经过表面淬硬的，但是在操作时还应该小心，以避免损伤导轨。导轨上的任何误差，常常意味着整个机床的精度遭到破坏。 主轴箱安装在内侧导轨的固定位置上，一般在床身的左端。它提供动力，并可使工件在各种速度下回转。它基本上由一个安装在精密轴承中的空心主轴和一系列变速齿轮(类似于卡车变速箱)所组成。通过变速齿轮，主轴可以在许多种转速下旋转。大多数车床有8~12种转速，一般按等比级数排列。而且在现代机床上只需扳动2~4个手柄，就能得到全部转速。一种正在不断增长的趋势是通过电气的或者机械的装置进行无级变速。 由于机床的精度在很大程度上取决于主轴，因此，主轴的结构尺寸较大，通常安装在预紧后的重型圆锥滚子轴承或球轴承中。主轴中有一个贯穿全长的通孔，长棒料可以通过该孔送料。主轴孔的大小是车床的一个重要尺寸，因此当工件必须通过主轴孔供料时，它确定了能够加工的棒料毛坯的最大尺寸。 尾座组件主要由三部分组成。底板与床身的内侧导轨配合，并可以在导轨上作纵向移动。底板上有一个可以使整个尾座组件夹紧在任意位置上的装置。尾座体安装在底板上，可以沿某种类型的键槽在底板上横向移动，使尾座能与主轴箱中的主轴对正。尾座的第三个组成部分是尾座套筒。它是一个直径通常大约在51~76mm(2~3英寸)之间的钢制空心圆柱体。通过手轮和螺杆，尾座套筒可以在尾座体中纵向移入和移出几个英寸。 车床的规格用两个尺寸表示。第一个称为车床的床面上最大加工直径。这 是在车床上能够旋转的工件的最大直径。它大约是两顶尖连线与导轨上最近点之间距离的两倍。第二个规格尺寸是两顶尖之间的最大距离。车床床面上最大加工直径表示在车床上能够车削的最大工件直径，而两顶尖之间的最大距离则表示在两个顶尖之间能够安装的工件的最大长度。 普通车床是生产中最经常使用的车床种类。它们是具有前面所叙的所有那些部件的重载机床，并且除了小刀架之外，全部刀具的运动都有机动进给。它们的规格通常是:车床床面上最大加工直径为305~610mm(12~24英寸);但是，床面上最大加工直径达到1270mm(50英寸)和两顶尖之间距离达到3658mm的车床也并不少见。这些车床大部分都有切屑盘和一个安装在内部的冷却液循环系统。小型的普通车床—车床床面最大加工直径一般不超过330mm(13英寸)--被设计成台式车床，其床身安装在工作台或柜子上。 虽然普通车床有很多用途，是很有用的机床，但是更换和调整刀具以及测量工件花费很多时间，所以它们不适合在大量生产中应用。通常，它们的实际加工时间少于其总加工时间的30%。此外，需要技术熟练的工人来操作普通车床，这种工人的工资高而且很难雇到。然而，操作工人的大部分时间却花费在简单的重复调整和观察切屑过程上。因此，为了减少或者完全不雇用这类熟练工人，六角车床、螺纹加工车床和其他类型的半自动和自动车床已经很好地研制出来，并已经在生产中得到广泛应用。 2.数字控制 先进制造技术中的一个基本的概念是数字控制(NC)。在数控技术出现之前，所有的机床都是由人工操纵和控制的。在与人工控制的机床有关的很多局限性中，操作者的技能大概是最突出的问。采用人工控制是，产品的质量直接与操作者的技能有关。数字控制代表了从人工控制机床走出来的第一步。 数字控制意味着采用预先录制的、存储的符号指令来控制机床和其他制造系统。一个数控技师的工作不是去操纵机床，而是编写能够发出机床操纵指令的程序。对于一台数控机床，其上必须安有一个被称为阅读机的界面装置，用来接受和解译出编程指令。 发展数控技术是为了克服人类操作者的局限性，而且它确实完成了这项工作。数字控制的机器比人工操纵的机器精度更高、生产出零件的一致性更好、生产速度更快、而且长期的工艺装备成本更低。数控技术的发展导致了制造工艺中其他几项新发明的产生: 电火花加工技术、激光切割、电子束焊接 数字控制还使得机床比它们采用有人工操的前辈们的用途更为广泛。 一台数控机床可以自动生产很多类的零件，每一个零件都可以有不同的和复杂的加工过程。数控可以使生产厂家承担那些对于采用人工控制的机床和工艺来说，在经济上是不划算的产品生产任务。 同许多先进技术一样，数控诞生于麻省理工学院的实验室中。数控这个概念是50年代初在美国空军的资助下提出来的。在其最初的价段，数控机床可以经济和有效地进行直线切割。 然而，曲线轨迹成为机床加工的一个问题，在编程时应该采用一系列的水平与竖直的台阶来生成曲线。构成台阶的每一个线段越短，曲线就越光滑。台阶中的每一个线段都必须经过计算。 在这个问题促使下，于1959年诞生了自动编程工具(PT)语言。这是一个专门适用于数控的编程语言，使用类似于英语的语句来定义零件的几何形状，描述切削刀具的形状和规定必要的运动。PT语言的研究和发展是在数控技术进一步发展过程中的一大进步。最初的数控系统下今天应用的数控系统是有很大差别的。在那时的机床中，只有硬线逻辑电路。指令程序写在穿孔纸带上(它后来被塑料带所取代)，采用带阅读机将写在纸带或磁带上的指令给机器翻译出来。所有这些共同构成了机床数字控制方面的巨大进步。然而，在数控发展的这个阶段中还存在着许多问题。 一个主要问题是穿孔纸带的易损坏性。在机械加工过程中，载有编程指令信息的纸带断裂和被撕坏是常见的事情。在机床上每加工一个零件，都需要将载有编程指令的纸带放入阅读机中重新运行一次。因此，这个问题变得很严重。如果需要制造100个某种零件，则应该将纸带分别通过阅读机100次。易损坏的纸带显然不能承受严配的车间环境和这种重复使用。 这就导致了一种专门的塑料磁带的研制。在纸带上通过采用一系列的小孔来载有编程指令，而在塑料带上通过采用一系列的磁点眯载有编程指令。塑料带的强度比纸带的强度要高很多，这就可以解决常见的撕坏和断裂问题。然而，它仍然存在着两个问题。 其中最重要的一个问题是，对输入到带中指令进行修改是非常困难的，或者是根本不可能的。即使对指令程序进行最微小的调整，也必须中断加工，制作一条新带。而且带通过阅读机的次数还必须与需要加工的零件的个数相同。幸运的是，计算机技术的实际应用很快解决了数控技术中与穿孔纸带和塑料带有关的问题。 在形成了直接数字控制(DNC)这个概念之后，可以不再采用纸带或塑料带作为编程指令的载体，这样就解决了与之有关的问题。在直接数字控制中，几台机床通过数据传输线路联接到一台主计算机上。操纵这些机床所需要的程序都存储在这台主计算机中。当需要时，通过数据传输线路提供给每台机床。直接数字控制是在穿孔纸带和塑料带基础上的一大进步。然而，它敢有着同其他信赖于主计算机技术一样的局限性。当主计算机出现故障时，由其控制的所有机床都将停止工作。这个问题促使了计算机数字控制技术的产生。 微处理器的发展为可编程逻辑控制器和微型计算机的发展做好了准备。这两种技术为计算机数控(CNC)的发打下了基础。采用CNC技术后，每台机床上都有一个可编程逻辑控制器或者微机对其进行数字控制。这可以使得程序被输入和存储在每台机床内部。它还可以在机床以外编制程序，并将其下载到每台机床中。计算机数控解决了主计算机发生故障所带来的问题，但是它产生了另一个被称为数据管理的问题。同一个程序可能要分别装入十个相互之间没有通讯联系的微机中。这个问题目前正在解决之中，它是通过采用局部区域网络将各个微机联接起来，以得于更好地进行数据管理。 3.车削加工 普通车床作为最早的金属切削机床的一种，目前仍然有许多有用的和为人要的特性和为人们所需的特性。现在，这些机床主要用在规模较小的工厂中，进行小批量的生产，而不是进行大批量的和产。 在现代的生产车间中，普通车床已经被种类繁多的自动车床所取代，诸如自动仿形车床，六角车床和自动螺丝车床。现在，设计人员已经熟知先利用单刃刀具去除大量的金属余量，然后利用成型刀具获得表面光洁度和精度这种加工方 法的优点。这种加工方法的生产速度与现在工厂中使用的最快的加工设备的速度相等。 普通车床的加偏差主要信赖于操作者的技术熟练程度。设计工程师应该认真地确定由熟练工人在普通车床上加工的试验件的公差。在把试验伯重新设计为生产零件时，应该选用经济的公差。 六角车床 对生产加工设备来说，目前比过去更注重评价其是否具有精确的和快速的重复加工能力。应用这个来评价具体的加工方法，六角车床可以获得较高的质量评定。 在为小批量的零件(100~200件)设计加工方法时，采用六角车床是最经济的。为了在六角车床上获得尽可能小的公差值，设计人员应该尽量将加工工序的数目减至最少。 自动螺丝车床 自动螺丝车床通被分为以下几种类型:单轴自动、多轴自动和自动夹紧车床。自动螺丝车床最初是被用来对螺钉和类似的带有螺纹的零件进行自动化和快速加工的。但是，这种车床的用途早就超过了这个狭窄的范围。现在，它在许多种类的精密零件的大批量生产中起着重要的作用。工件的数量对采用自动螺丝车床所加工的零件的经济性有较大的影响。如果工件的数量少于1000件，在六角车床上进行加工比在自动螺丝车床上加工要经济得多。如果计算出最小经济批量，并且针对工件批量正确地选择机床，就会降低零件的加工成本。 自动仿形车床 因为零件的表面粗糙度在很大程度上取决于工件材料、刀具、进给量和切削速度，采用自动仿形车床加工所得到的最小公差一定是最经济的公差。 在某些情况下，在连续生产过程中，只进行一次切削加工时的公差可以达到0.05mm。对于某些零件，槽宽的公差可以达到0.125mm。镗孔和休用单刃刀具进行精加工时，公差可达到0.0125mm。在希望获得最大主量的大批量生产中，进行直径和长度的车削时的最小公差值为0.125mm是经济的。 数控机床的改造 外文翻译 2.1, microscopic view of the necessity of From the micro perspective, CNC mchine tools thn trditionl mchines hve the following prominent superiority, nd these dvntges re from the NC system includes computer power. 2.1.1 cn be processed by conventionl mchining is not the curve, surfce nd other complex prts Becuse computers re superb computing power cn be ccurtely clculted instntneous ech coordinte xis movement exercise should be instntneous, it cn compound into complex curves nd surfces. 2.1.2 utomted processing cn be chieved, but lso flexible utomtion to increse mchine efficiency thn trditionl 3 to 7 times. Becuse computers re memory nd storge cpcity, cn be imported nd stored procedures remember down, nd then click procedurl requirements to implement the order utomticlly to chieve utomtion. CNC mchine tool s replcement procedures, we cn chieve nother work piece mchining utomtion, so tht single pieces nd smll btch production cn be utomted, it hs been clled "flexible utomtion." 2.1.3 high precision mchining prts, the size dispersion of smll, esy to ssemble, no longer needed "repir." 2.1.4 processes cn be relized more focused, in prt to reduce the frequent removl mchine. 2.1.5 hve utomtic lrm, utomtic control, utomtic compenstion, nd other self-regultory functions, thus chieving long unttended processing. 2.1.6 derived from the benefits of more thn five. Such s: reducing the lbor intensity of the workers, sve the lbor force (one cn look fter more thn one mchine), decrese of tooling, shorten Tril Production of new product cycle nd the production cycle, the mrket demnd for quick response, nd so on. These dvntges re our predecessors did not expect, is very mjor brekthrough. In ddition, CNC mchine tools or the FMC (Flexible Mnufcturing Cell), FMS (flexible mnufcturing system) nd CIMS (Computer Integrted Mnufcturing System), nd other enterprises, the bsis of informtion trnsformtion. NC mnufcturing utomtion technology hs become the core technology nd bsic technology. 2.2, the mcro view of the necessity From mcro perspective, the militry industril developed countries, the mchinery industry, in the lte 1970s, erly 1980s, hs begun lrge-scle ppliction of CNC mchine tools. Its essence is the use of informtion technology on the trditionl industries (including the militry, the Mchinery Industry) for technologicl trnsformtion. In ddition to the mnufcturing process used in CNC mchine t ools, FMC, FMS, but lso included in the product development in the implementtion of CD, CE, CM, virtul mnufcturing nd production mngement in the implementtion of the MIS (Mngement Informtion System), CIMS, nd so on. nd the products tht they produce n increse in informtion technology, including rtificil intelligence nd other content. s the use of informtion technology to foreign forces, the depth of Mchinery Industry (referred to s informtion technology), nd ultimtely mkes their products in the interntionl militry nd civilin products on the mrket competitiveness of much stronger. nd we in the informtion technology to trnsform trditionl industries thn bout 20 yers behind developed countries. Such s possession of mchine tools in Chin, the proportion of CNC mchine tools (CNC rte) in 1995 to only 1.9 percent, while Jpn in 1994 reched 20.8 percent, every yer lrge number of imports of mechnicl nd electricl products. This lso explins the mcro CNC trnsformtion of the need. Third, CNC mchine tools nd production lines of the trnsformtion of the mrket 3.1, CNC trnsformtion of the mrket My current mchine totl more thn 380 million units, of which only the totl number of CNC mchine tool 113,400 Tiwn, or tht Chin's CNC rte of less thn 3 percent. Over the pst 10 yers, Chin's nnul output of bout 0.6 CNC mchine tools to 0.8 million units, n nnul output vlue of bout 1.8 billion yun. CNC mchine tools nnul rte of 6 per cent. Chin's mchine to ol esements over ge 10 ccount for more thn 60% below the 10 mchines, utomtic / semi-utomtic mchine less thn 20 per cent, FMC / FMS, such s hndful more utomted production line (the United Sttes nd Jpn utomtic nd semi-utomtic mchine, 60 percent bove). This shows tht we the mjority of mnufcturing industries nd enterprises of the production, processing equipment is the gret mjority of trditionl mchine tools, nd more thn hlf of militry ge is over 10 yers old mchine. Processing equipment used by the prevlence of poor qulity products, less vriety, low-grde, high cost, supply long period, in view of the interntionl nd domestic mrkets, lck of competitiveness, nd direct impct on compny's products, mrkets, efficiency nd impct The survivl nd development of enterprises. Therefore, we must vigorously rise the rte of CNC mchine tools. 3.2, import equipment nd production lines of the trnsformtion of NC mrket Since Chin's reform nd opening up, mny foreign enterprises from the introduction of technology, equipment nd production lines for technologicl trnsformtion. ccording to incomplete sttistics, from 1979 to 1988 10, the introduction of technologicl trnsformtion projects re 18,446, bout 16.58 billion US dollrs. These projects, the mjority of projects in Chin's economic construction ply due role. Some, however, the introduction of projects due to vrious resons, not equipment or norml opertion of the production line, nd even prlyzed, nd the effectiveness of enterprises ffected by serious enterprise is in trouble. Some of the equipment, production lines introduced from brod, the digestion nd bsorption of some bd, spre prts incomplete, improper mintennce, poor operting results; only py ttention to the introduction of some imported the equipment, pprtus, production lines, ignore softwre, technology, nd mngement, resulting in items integrity, nd potentil equipment cn not ply, but some cn not even strt running, did not ply due role, but some production lines to sell the products very well, but not becuse of equipment filure production stndrds; becuse some high energy consumption, low pss rte products incur losses, but some hve introduced longer time, nd the need for technologicl upgrding. Some of the cuses of the equipment did not crete welth, but consumption of welth. These cn not use the equipment, production lines is burden, but lso number of significnt ssets in stock, welth is repired. s long s identifying the min technicl difficulties, nd solve key technicl problems, we cn minimize the investment nd mke the most of their ssets in stock, gin the gretest economic nd socil benefits. This is gret trnsformtion of the mrket. Fourth, NC trnsformtion of the content nd gifted missing 4.1, the rise of foreign trde reform In the United Sttes, Jpn nd Germny nd other developed countries, nd their mchine trnsform tion s new economic growth sector, the business scene, is in golden ge. The mchine, s well s technology continues to progress, is mchine of the "eternl" issue. Chin's mchine tool industry trnsformtion, but lso from old industries to enter the CNC technology minly to the new industries. In the United Sttes, Jpn, Germny, with CNC mchine tools nd technologicl trnsformtion of production lines vst mrket, hs formed CNC mchine tools nd production lines of the new industry. In the United Sttes, trnsforming mchine tool industry s renewble (Remnufcturing) industry. Renewble industry in the fmous compnies: Borsches engineering compny, toms mchine tool compny, Devlieg-Bullvd (Bo) services group, US equipment compnies. Compnies in the United Sttes-run compnies in Chin. In Jpn, the mchine tool industry trnsformtion s mchine modifiction (Retrofitting) industry. Conversion industry in the fmous compnies: Okum engineering group, Kong 3 Mchinery Compny, Chiyod Engineering Compny, Nozki engineering compny, Hmd engineering compnies, Ymmoto Engineering Compny. 4.2, the content of NC Mchine tools nd production line NC trnsformtion min contents of the following: One is the restortion of the originl fetures of the mchine tools, production line of the fult dignosis nd recovery; second NC, in the ordinry mchine ugends significnt instlltions, or dditions to NC system, trnsformed into NC mchine tools, CNC mchine tools; its Third, renovtion, to improve ccur cy, efficiency nd the degree of utomtion, mechnicl, electricl prt of the renovtion, re-ssembly of mechnicl prts processing, restore the originl ccurcy of their production requirements re not stisfied with the ltest CNC system updte; Fourth, the technology updtes or technicl innovtion, to enhnce performnce or grdes, or for the use of new technology, new technologies, bsed on the originl technology for lrge-scle updte or technologicl innovtion, nd more significntly rise the level, nd grdes of upgrding. 4.3, NC trnsformtion of the gifted missing 4.3.1 reduce the mount of investment, shorter delivery time Compred with the purchse of new mchine, the generl cn sve 60% to 80% of the costs nd trnsforming low-cost. Especilly for lrge, specil mchine tools prticulrly obvious. Generl trnsformtion of lrge-scle mchine, spent only the cost of the new mchine purchse 1 / 3, short delivery time. But some specil circumstnces, such s high-speed spindle, utomtic try switching systems nd the production of the instlltion costs too costly nd often rise the cost of 2 to 3 times compred with the purchse of new mchine, only bout 50 percent of svings investment. 4.3.2 stble nd relible mechnicl properties, structure limited By the use of bed, column, nd other bsic items re hevy nd solid csting components, rther thn kind of welding components of the mchine fter the high-performnce, qulity, nd cn continue to use the new equipment。 一、机床数控化改造的必要性 2.1、微观看改造的必要性 从微观上看，数控机床比传统机床有以下突出的优越性，而且这些优越性均来自数控系统所 包含的计算机的威力。 2.1.1 可以加工出传统机床加工不出来的曲线、曲面等复杂的零件。 由于计算机有高超的运算能力，可以瞬时准确地计算出每个坐标轴瞬时应该运动的运动量， 因此可以复合成复杂的曲线或曲面。 2.1.2 可以实现加工的自动化，而且是柔性自动化，从而效率可比传统机床提高3,7倍。 由于计算机有记忆和存储能力，可以将输入的程序记住和存储下来，然后按程序规定的顺序 自动去执行，从而实现自动化。数控机床只要更换一个程序，就可实现另一工件加工的自动 化，从而使单件和小批生产得以自动化，故被称为实现了"柔性自动化"。 2.1.3 加工零件的精度高，尺寸分散度小，使装配容易，不再需要"修配"。 2.1.4 可实现多工序的集中，减少零件 在机床间的频繁搬运。 2.1.5 拥有自动报警、自动监控、自动补偿等多种自律功能，因而可实现长时间无人看管加 工。 2.1.6 由以上五条派生的好处。 如:降低了工人的劳动强度，节省了劳动力(一个人可以看管多台机床)，减少了工装，缩短了新产品试制周期和生产周期，可对市场需求作出快速反应等等。 以上这些优越性是前人想象不到的，是一个极为重大的突破。此外，机床数控化还是推行FMC(柔性制造单元)、FMS(柔性制造系统)以及CIMS(计算机集成制造系统)等企业信息化改造的基础。数控技术已经成为制造业自动化的核心技术和基础技术。 2.2、宏观看改造的必要性 从宏观上看，工业发达国家的军、民机械工业，在70年代末、80年代初已开始大规模应用数控机床。其本质是，采用信息技术对传统产业(包括军、民机械工业)进行技术改造。除在制造过程中采用数控机床、FMC、FMS外，还包括在产品开发中推行CD、CE、CM、虚拟制造以及在生产管理中推行MIS(管理信息系统)、CIMS等等。以及在其生产的产品中增加信息技术，包括人工智能等的含量。由于采用信息技术对国外军、民机械工业进行深入改造(称之为信息化)，最终使得他们的产品在国际军品和民品的市场上竞争力大为增强。而我们在信息技术改造传统产业方面比发达国家约落后20年。如我国机床拥有量中，数控机床的比重(数控化率)到1995年只有1.9,，而日本在1994年已达20.8,，因此每年都有大量机电产品进口。这也就从宏观上了机床数控化改造的必要性。 三、机床与生产线数控化改造的市场 3.1、机床数控化改造的市场 我国目前机床总量380余万台，而其中数控机床总数只有11.34万台，即我国机床数控化率不到3,。近10年来，我国数控机床年产量约为0.6,0.8万台，年产值约为18亿元。机床的年产量数控化率为6,。我国机床役龄10年以上的占60,以上;10年以下的机床中，自动/半自动机床不到20,，FMC/FMS等自动化生产线更屈指可数(美国和日本自动和半自动机床占60,以上)。可见我们的大多数制造行业和企业的生产、加工装备绝大数是传统的机床，而且半数以上是役龄在10年以上的旧机床。用这种装备加工出来的产品普遍存在质量差、品种少、档次低、成本高、供货期长，从而在国际、国内市场上缺乏竞争力，直接影响一个企业的产品、市场、效益，影响企业的生存和发展。所以必须大力提高机床的数控化率。 3.2、进口设备和生产线的数控化改造市场 我国自改革开放以来，很多企业从国外引进技术、设备和生产线进行技术改造。据不完全统计，从1979,1988年10年间，全国引进技术改造项目就有18446项，大约165.8亿美元。 这些项目中，大部分项目为我国的经济建设发挥了应有的作用。但是有的引进项目由于种种原因，设备或生产线不能正常运转，甚至瘫痪，使企业的效益受到影响，严重的使企业陷入困境。一些设备、生产线从国外引进以后，有的消化吸收不好，备件不全，维护不当，结果运转不良;有的引进时只注意引进设备、仪器、生产线，忽视软件、工艺、管理等，造成项目不完整，设备潜力不能发挥;有的甚至不能启动运行，没有发挥应有的作用;有的生产线的产品销路很好，但是因为设备故障不能达产达标;有的因为能耗高、产品合格率低而造成亏损;有的已引进较长时间，需要进行技术更新。种种原因使有的设备不仅没有创造财富，反而消耗着财富。 这些不能使用的设备、生产线是个包袱，也是一批很大的存量资产，修好了就是财富。只要找出主要的技术难点，解决关键技术问题，就可以最小的投资盘活最大的存量资产，争取到最大的经济效益和社会效益。这也是一个极大的改造市场。 四、数控化改造的内容及优缺 4.1、国外改造业的兴起 在美国、日本和德国等发达国家，它们的机床改造作为新的经济增长行业，生意盎然，正处在黄金时代。由于机床以及技术的不断进步，机床改造是个"永恒"的课题。我国的机床改造业，也从老的行业进入到以数控技术为主的新的行业。在美国、日本、德国，用数控技术改造机床和生产线具有广阔的市场，已形成了机床和生产线数控改造的新的行业。在美国，机床改造业称为机床再生(Remnufcturing)业。从事再生业的著名公司有:Bertsche工程公司、yton机床公司、Devlieg-Bullvd(得宝)服务集团、US设备公司等。美国得宝公司已在中国开办公司。在日本，机床改造业称为机床改装(Retrofitting)业。从事改装业的著名公司有:大隈工程集团、岗三机械公司、千代田工机公司、野崎工程公司、滨田工程公司、山本工程公司等。 4.2、数控化改造的内容 机床与生产线的数控化改造主要内容有以下几点: 其一是恢复原功能，对机床、生产线存在的故障部分进行诊断并恢复;其二是NC化，在普通机床上加数显装置，或加数控系统，改造成NC机床、CNC机床;其三是翻新，为提高精度、效率和自动化程度，对机械、电气部分进行翻新，对机械部分重新装配加工，恢复原精度;对其不满足生产要求的CNC系统以最新CNC进行更新;其四是技术更新或技术创新，为提高性能或档次，或为了使用新工艺、新技术，在原有基础上进行较大规模的技术更新或技术创新，较大幅度地提高水平和档次的更新改造。 4.3、数控化改造的优缺 4.3.1 减少投资额、交货期短 同购置新机床相比，一般可以节省60,,80,的费用，改造费用低。特别是大型、特殊机床尤其明显。一般大型机床改造，只花新机床购置费用的1/3，交货期短。但有些特殊情况，如高速主轴、托盘自动交换装置的制作与安装过于费工、费钱，往往改造成本提高2,3倍，与购置新机床相比，只能节省投资50,左右。 4.3.2 机械性能稳定可靠，结构受限