03单元汤彩萍数控英语——数控专业英语.doc

渤海石油职业学院教案用纸第 周 第 课时 UNIT 3-1一、 TECHNICAL WORDSimperative a 必要的verify V 校验，检验flexibility n 柔性fundamentals 基本原则，基本规则benefit 优点，好处equipment 设备automation 自动化entire 全部的，整个的predictable 可预料到的machinist 机械师accurate a . 准确的，精确的accuracy n . 准确，精确identical a . 完全相同的precision n . 精确二、 PHRASESvary from 随而不同justintime (一种制造模式) 准时生产(制造)制change over 切换，转换三、 Part A TextFocus of the unitMotion control is the heart of CNCAll CNC controls allow axis motion to be commanded by utilizing some form of coordinate systemThe CNC control must be told the location of the program zero pointBesides the absolute mode of programming，there is another way of specifying end points for axis motionCNC的核心是轴运动的控制，为此，必须建立坐标系指定编程零点，指定编程方式。Fundamental s of CNCWhile the specific intention and application for CNC machines vary from one machine type to another，all forms of CNC have common benefitsHere are but a few of the more important benefits offered by CNC equipmentThe first benefit offered by all forms of CNC machine tools is improved automationThe operator intervention related to producing workpieces can be reduced or eliminatedMany CNC machines can run unattended during their entire machining cycle，freeing the operator to do other tasksThis gives the CNC user several side benefits including reduced operator fatigue，fewer mistakes caused by human error，and consistent and predictable machining time for each workpieceSince the machine will be running under program control，the skill level required of the CNC operator (related to basic machining practice)is also reduced as compared to a machinist producing workpieces with conventional machine tools1The second major benefit of CNC technology is consistent and accurate workpiecesTodays CNC machines boast almost unbelievable accuracy and repeatability specificationsThis means that once a program is verified, two，ten，or one thousand identical workpieces can be easily produced with precision and consistencyA third benefit offered by most forms of CNC machine tools is flexibilitySince these machines are run from programs，running a different workpiece is almost as easy as loading a different programOnce a program has been verified and executed for one production run，it can be easily recalled the next time the workpiece is to be runThis leads to yet another benefit，fast change oversSince these machines are very easy to set up and run，and since programs can be easily loaded，they a1low very short setup timeThis is imperative with todays justintime (JIT)product requirements四、 NOTES1Since the machine will be running under program control，the skill level required of the CNC operator(related to basic machining practice)is also reduced as compared to a machinist producing workpieces with conventional machine tools由于机床在程序的控制下运行，与操作普通机床要求的技能水平相比，对数控操作员的技能水平要求 (与基本加工实践相关的)也降低了。五、 译文数控基础虽然各种数控机床的功能和应用各不相同，但它们有着共同的优点。这里是数控设备提供的比较重要的几个优点。各种数控机床的第一个优点是自动化程度提高了。零件制造过程中的人为干预减少或者免除了。整个加工循环中，很多数控机床处于无人照看状态，这使操作员被解放出来，可以干别的工作。数控机床用户得到的几个额外好处是：数控机床减小了操作员的疲劳程度，减少了人为误差，工件加工时间一致而且可预测。由于机床在程序的控制下运行，与操作普通机床的机械师要求的技能水平相比，对数控操作员的技能水平要求 (与基本加工实践相关) 也降低了。数控技术的第二个优点是工件的一致性好，加工精度高。现在的数控机床宣称的精度以及重复定位精度几乎令人难以置信。这意味着，一旦程序被验证是正确的，可以很容易地加工出2个、10个或1000个相匾的零件，而且它们的精度高，一致性好。大多数数控机床的第三个优点是柔性强。由于这些机床在程序的控制下工作，加工不同的工件易如在数控系统中装载一个不同的程序而已。一旦程序验证正确，并且运行一次，下次加工工件的时候，可以很方便地重新调用程序。这又带来另一个好处可以快速切换不同工件的加工。由于这些机床很容易调整并运行，也由于很容易装载加工程序，因此机床的调试时间很短。这是当今准时生产制造模式所要求的。六、 EXERCISESP25UNIT 3-2一、 TECHNICAL WORDScrank n 摇枘handwheel n 手轮feedback n 反馈analogy n 类比，类推jaw n 钳夹feasible a. 可行的 utilize v. 使用establish v. 建立 reference n. 参考location n. 地点determine v. 确定rectangular a. 矩形的， 成直角的polar a. 两极的print n. 图纸二、 PHRASESset up 安装调整，装夹ball screw 滚珠丝杠lead screw 丝札table vise 台虎钳drive motor 驱动电机inmanner 以方式By far 目前figure out 计算出，想出point of reference (reference point ) 参考点coordinate system 坐标系三、 Part A TextMotion control-the heart of CNCThe most basic function of any CNC machine is automatic，precise，and consistent motion contr01Rather than applying completely mechanical devices to cause motion as is required on most conventional machine tools，CNC machines allow motion control in a revolutionary manner2。All forms of CNC equipment have two or more directions of motion，called axesThese axes can be precisely and automatically positioned along their lengths of travelThe two most common axis types are linear(driven along a straight path)and rotary (driven along a circular path)Instead of causing motion by turning cranks and handwheels as is required on conventional machine tools，CNC machines allow motions to be commanded through programmed commandsGenerally speaking，the motion type(rapid，linear, and circular)，the axes to move，the amount of motion and the motion rate (feedrate) are programmable with almost all CNC machine toolsA CNC command executed within the control tells the drive motor to rotate a precise number of timesThe rotation of the drive motor in turn rotates the ball screwAnd the ball screw drives the linear axis (slide)A feedback device (1inear scale) on the slide allows the control to confirm that the commanded number of rotations has taken place3Refer to fig3-1Though a rather crude analogy, the same basic linear motion can be found on a common tableviseAs you rotate the vise crank，you rotate a lead screw that，in turn，drives the movable jaw on the viseBy comparison，a linear axis on a CNC machine tool is extremely preciseThe number of revolutions of the axis drive motor precisely controls the amount of linear motion along the axisHow axis motion is commanded-understanding coordinate systemsIt would be infeasible for the CNC user to cause axis motion by trying to tell each axis drive motor how many times to rotate in order to command a given linear motion amount4(This would be like having to figure out how many turns of the handle on a table vise will cause the movable jaw to move exactly one inch!) Instead，all CNC controls allow axis motion to be commanded in a much simpler and more logical way by utilizing some form of coordinate systemThe two most popular coordinate systems used with CNC machines are the rectangular coordinate system and the polar coordinate systemBy far, the more popular of these two is the rectangular coordinate systemThe program zero point establishes the point of reference for motion commands in a CNC programThis allows the programmer to specify movements from a common locationIf program zero is chosen wisely，usually coordinates needed for the program can be taken directly from the printWith this technique，if the programmer wishes the tool to be sent to a position one inch to the right of the program zero pointX 1.0 is commandedIf the programmer wishes the tool to move to a position one inch above the program zero point，Y 1.0 is commandedThe control will automatically determine how many times to rotate each axis drive motor and ball screw to make the axis reach the commanded destination point5This lets the programmer command axis motion in a very logical mannerRefer to fig3-2，3-3四、 NOTES2.Rather than applying completely mechanical devices to cause motion as is required on most conventional machine tools，CNC machines allow motion control in a revolutionary manner大多数普通机床完全运用机械装置实现其所需的运动，而数控机床是以一种全新的方式控制机床的运动，这里关系代词as引起定语从句指代motion，在定语从句中作主语，下文有类似的用法，参见Unit 4 Pnrt B。3A CNC command executed within the control tells the drive motor to rotate a precise number of timesThe rotation of the drive motor in rum rotates the ball screwAnd the ball screw drives the linear axis(slide)A feedback device(1inear Scale)on the slide allows the control to confirm that the commanded number of rotations has taken place数控系统中的CNC指令命令驱动电机旋转某一精确的转数，驱动电机的旋转随即使滚珠丝杠旋转，滚珠丝杠将旋转运动转换成直线轴(滑台)运动。滑台上的反馈装置(直线光栅尺)使数控系统确认指令转数已完成。4.It would be infeasible for the CNC user to cause axis motion by trying to tell each axis drive motor how manv times to rotate in order to command a given linear motion amount对数控用户来说，为了达到给定的直线移动量而指令各轴驱动电机旋转多少转，从而使坐标轴运动，这是不可行的。5.The control will automatically determine how many times to rotate each axis drive motor and ball screw to make the axis reach the commanded destination point数控系统会自动确定(计算)各轴驱动电机和滚珠丝杠要转动多少转，使坐标轴到达指令的目标位置。五、 译文运动控制CNG的核心 任何数控机床最基本的功能是具有自动、精确、一致的运动控制。大多数普通机床完全运用机械装置实现其所需的运动，而数控机床是以一种全新的方式控制机床的运动。各种数控设备有两个或多个运动方向，称为轴。这些轴沿着其长度方向精确、自动定位。最常用的两类轴是直线轴(沿直线轨迹)和旋转轴(沿圆形轨迹)。 普通机床需通过旋转摇柄和手轮产生运动，而数控机床通过编程指令产生运动。通常，几乎所有的数控机床的运动类型 (快速定位、直线插补和圆弧插补)、移动轴、移动距离以及移动速度(进给速度) 都是可编程的。 数控系统中的CNC指令命令驱动电机旋转某一精确的转数，驱动电机的旋转随即使滚珠丝杠旋转，滚珠丝杠将旋转运动转换成直线轴(滑台)运动。滑台上的反馈装置 (直线光栅尺) 使数控系统确认指令转数已完成，参见图3-1。普通的台虎钳上有着同样的基本直线运动，尽管这是相当原始的类比。旋转虎钳摇柄就是旋转丝杠，丝杠带动虎钳钳口移动。与台虎钳相比，数控机床的直线轴是非常精确的，轴的驱动电机的转数精确控制直线轴的移动距离。轴运动命令的方式理解坐标系对CNC用户来说，为了达到给定的直线移动量而指令各轴驱动电机旋转多少转，从而使坐标轴运动，这种方法是不可行的。(这就好像为了使钳口准确移动1英寸需要计算出台虎钳摇柄的转数!) 事实上，所有的数控系统都能通过采用坐标系的形式以一种较为简单而且合理的方式来指令轴的运动。数控机床上使用最广泛的两种坐标系是直角坐标系和极坐标系。目前用得较多的是直角坐标系。编程零点建立数控程序中运动命令的参考点。这使得操作员能从一个公共点开始指定轴运动。如果编程零点选择恰当，程序所需坐标通常可从图纸上直接获得。如果编程员希望刀具移动到编程零点右方1英寸 (25.4毫米) 的位置，则用这种方法指令x1.0即可。如果编程员希望刀具移动到编程零点上方1英寸的位置，则指令Y1.0。数控系统会自动确定 (计算) 各轴驱动电机和滚珠丝杠要转动多少转，使坐标轴到达指令的目标位置。这使编程员以非常合理的方式命令轴的运动，参见图3-2和图3-3。六、 EXERCISESP25-26UNIT 3-3一、 TECHNICAL WORDSversus prep. 对， 以为对手assume v. 假设designate v. 指定absolute a. 绝对的incremental a. 增量的mode n. 方式，方法cumbersome a. 繁琐的，麻烦的concentrate v. 集中tendency n. 趋势offset n 偏置fixture n 夹具means n. 方法dramatically adv. 戏剧性的geometry n. 几何二、 PHRASESAside from 处之外三、 Part A TextUnderstanding absolute versus incremental motionAll discussions to this point assume that the absolute mode of programming is used6。The most common CNC word used to designate the absolute mode is G90In the absolute mode，the end points for all motions will be specified from the program zero pointFor beginners，this is usually the best and easiest method of specifying end points for motion commandsHowever，there is another way of specifying end points for axis motionIn the incremental mode (commonly specified by G91)，end points for motions are specified from the tools current position，not from program zeroSee fig.3-4With this method of commanding motion，the programmer must always be asking “How far should I move the tool?”While there are times when the incremental mode can be very helpful，generally speaking，this is the more cumbersome and difficult method of specifying motion and beginners should concentrate on using the absolute mode7Be careful when making motion commandsBeginners have the tendency to think incrementallyIf working in the absolute mode (as beginners should)，the programmer should always be asking “To what position should the tool be moved?”This position is relative to program zero，NOT from the tools current positionAside from making it very easy to determine the current position for any command，another benefit of working in the absolute mode has to do with mistakes made during motion commandsIn the absolute mode，if a motion mistake is made in one command of the programonly one movement will be incorrectOn the other hand，if a mistake is made during incremental movementsall motions from the point of the mistake will also be incorrectAssigning program zeroKeep in mind that the CNC control must be told the location of the program zero point by one means or anotherHow this is done varies dramatically from one CNC machine and control to another。One(older)method is to assign program zero in the programWith this method, the programmer tells the control how far it is from the program zero point to the starting position of the machineThis is commonly done with a G92 (or G50) command at least at the beginning of the program and possibly at the beginning of each too1Another，newer and better way to assign program zero is through some form of offsetRefer to fig.3-5Commonly machining center control manufacturers call offsets used to assign program zero fixture offsetsTurning center manufacturers commonly call offsets used to assign program zero for each tool geometry offsets四、 NOTES6.All discussions to this point assume that the absolute mode of programming is used至此，所有的讨论都假设采用的是绝对编程方式。7While there are times when the incremental mode can be very helpful，generally speaking，this is the more cumbersome and difficult method of specifying motion and beginners should concentrate on using the absolute mode尽管增量方式多数时候很有用，但一般说来，用这种方法指定轴运动较麻烦、困难，初学者应该重点使用绝对方式。8.Keep inlind that the CNC control must be told the location of the program zero point by one means or anotherHow this is done varies dramatically from one CNC machine and control to another记住必须以各种方式对数控系统指定编程零点的位置。指定编程零点的方式随数控机床和数控系统的不同而很不相同。五、 译文理解绝对和相对运动 至此，所有的讨论都假设采用的是绝对编程方式。用于指定绝对方式的最常用的数控代码是G90。绝对方式下，所有运动终点的指定都是以编程零点为起点。对初学者来说，这通常是最好也是最容易的指定轴运动终点的方法，但还有另外一种指定轴运动终点的方法。 增量方式 (通常用G91指定) 下，运动终点的指定是以刀具的当前位置为起点，而不是编程零点，见图3-4。用这种方法指定轴运动，编程员往往会问“我该将刀具移动多远的距离?”，尽管增量方式多数时候很有用，但一般说来，这种方法指定轴运动较麻烦、困难，初学者应该重点使用绝对方式。 指令轴运动时一定要小心。初学者往往以增量方式思考问题。如果工作在绝对方式 (初学者应该如此)，编程员应始终在问“刀具应该移动到什么位置?”，这个位置是相对于编程零点这个固定位置而言，而不是相对于刀具当前位置。绝对工作方式很容易确定指令当前位置，除此之外，它的另外一个好处涉及轴运动中的错误。绝对方式下，如果程序的一个轴运动指令出错，则只有一个运动是不正确的。而另一方面，如果在增量运动过程中出错，则从出错的那一点起，所有的运动都是不正确的。指定编程零点 记住必须以某种方式对数控系统指定编程零点的位置。指定编程零点的方式随数控机床和数控系统的不同而很不相同。(较老的) 一种方法是在程序中指定编程零点。用这种方法，编程员告诉数控系统从编程零点到机床起始点的距离。通常用G92 (或G50) 在程序的一开始指定，很可能在各把刀具的开头指定编程零点。 另一种较新、更好的指定编程零点的方法是通过偏置的形式，见图3-5。通常，加工中心上用于指定编程零点的偏置被称做夹具偏置，车削中心上用于指定编程零点的偏置被称做刀具几何偏置六、 EXERCISESP25-26Unit 3. Translate the following words into English.1. drill2. mill3. bore4. turn5. tap6. grind7. ream 8. file. Write the correct form of each word as requested.rotation complexityautomaticaxesmachinereverseverificationproducespecificationvibrationlubricatemechanicassignment measurement . Decide whether the following statements are true (T) or false (F):1. ( T ) 2. ( F ) 3. ( F ) 4. ( T ).Fill in the brackets with words that have the similar meaning with the underlined words, changing their forms if necessary.1.( method或way或means 或manner ) 2.( specify或command ) 3.( work zero ) 4.( movement或traverse ) 5.( way或style或method )6.( movement ) 7.( end ) 8.( using ) 9.( sets up 或creates ) 10.( Remember ) 11.( way 或method或technique ) 12.( generally ) 13.( common )14.(