數(shù)控機床外文文獻翻譯、中英文翻譯

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1、外文資料CNC machine toolsWhile the specific intention and application for CNC machines vary from one machine type to another, all forms of CNC have common benefits. Here are hut a few of the more important benefits offered by CNC equipment.The first benefit offered by all forms of CNC machine tools is i

2、mproved automation. The operator intervention related to producing workpieces can be reduced or eliminated. Many CNC machines can run unattended during their entire machining cycle, freeing the operator to do other tasks. This gives the CNC user several side benefits including reduced operator fatig

3、ue, fewer mistakes caused by human error, and consistent and predictable machining time for each workpiece. Since the machine will he 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

4、 workpieces with conventional machine tools.The second major benefit of CNC technology is consistent and accurate workpieces. Todays CNC machines boast almost unbelievable accuracy and repeatability specifications. This means that once a program is verified, two, ten, or one thousand identical workp

5、ieces can be easily produced with precision and consistency.A third benefit offered by most forms of CNC machine tools is flexibility. Since these machines are run from programs, running a different workpiece is almost as easy as loading a different program. Once a program has been verified and exec

6、uted for one production run, it can be easily recalled the next time the workpiece is to be run. This leads to yet another benefit, fast change over. Since these machines are very easy to set up and run, and since programs can be easily loaded, they allow very short setup time. This is imperative wi

7、th todays just-in-time (JIT) product requirements.Motion control - the heart of CNCThe most basic function of any CNC machine is automatic, precise, and consistent motion control. Rather than applying completely mechanical devices to cause motion as is required on most conventional machine tools, CN

8、C machines allow motion control in a revolutionary manner2. All forms of CNC equipment have two or more directions of motion, called axes. These axes can be precisely and automatically positioned along their lengths of travel. The two most common axis types are linear (driven along a straight path)

9、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 commands. Generally speaking, the motion type (rapid, linear, and circular), the axes to mo

10、ve, the amount of motion and the motion rate (feedrate) are programmable with almost all CNC machine tools.A CNC command executed within the control tells the drive motor to rotate a precise number of times.The rotation of the drive motor in turn rotates the ball screw. And the ball screw drives the

11、 linear axis (slide). A feedback device (linear scale) on the slide allows the control to confirm that the commanded number of rotations has taken place3.Though a rather crude analogy, the same basic linear motion can he found on a common table vise. As you rotate the vise crank, you rotate a lead s

12、crew that, in turn, drives the movable jaw on the vise. By comparison, a linear axis on a CNC machine tool is extremely precise. The number of revolutions of the axis drive motor precisely controls the amount of linear motion along the axis.How axis motion is commanded - understanding coordinate sys

13、temsIt 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 arnount4. (This would he like having to tgure out how many turns of the handle on a table vise will cause the movable jaw to mov

14、e exactly one inch!) Instead, all CNC controls allow axis motion to he commanded in a much simpler and more logical way by utilizing sonic forni of coordinate system. The two most popular coordinate systems used with CNC machines arc the rectangular coordinate system and the polar coordinate system.

15、 By far, the more popular of these two is the rectangular coordinate system.The program zero point establishes the point of reference for motion commands in a CNC program. This allows the programmer to specify movements from a commt)fl location. If program zero is chosen wisely. usually coordinates

16、needed for the program can be taken directly from the print.With this technique, if the programmer wishes the tool to he sent to a position one inch to the right of the program zero point, X1.0 is commanded. lithe programmer wishes the tool to move to a position one inch above the program zero point

17、, Y 1.0 is commanded. The control will automatically deteniiine how many times to rotate each axis drive motor and ball screw to make the axis reach the commanded destination point . This lets the programmer command axis motion in a very logical manner.All discussions to this point assume that the a

18、bsolute mode of programming is used. The most common CNC word used to designate the absolute mode is G90.In the absolute mode, the end points for all motions will be specified from the program zero point. For beginners, this is usually the best and easiest method of specifying end points for motion

19、commands. However, there is another way of specifying end points for axis motion.In the incremental mode (commonly specified by G9 1), end points for motions are specified from the tools current position, not from program zero. With this method of commanding motion, the programmer must always he ask

20、ing “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 mode.Be careful when making motion commands. Begi

21、nners have the tendency to think incrementally. If 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 position.Aside from making it very easy to

22、determine the current position for any command, another benefit of working in the absolute mode has to do with mistakes made during motion commands. In the absolute mode, if a motion mistake is made in one command of the program, only one movement will be incorrect. On the other hand, if a mistake i

23、s made during incremental movements, all motions from the point of the mistake will also be incorrect.Assigning program zeroKeep in mind that the CNC control must be told the location of the program zero point by one means or another. How this is done varies dramatically from one CNC machine and con

24、trol to another. One (older) method is to assign program zero in the program. With this method, the programmer tells the control how far it is from the program zero point to the starting position of the machine. This is commonly done with a G92 (or G50) command at least at the beginning of the progr

25、am and possibly at the beginning of each tool.Another, newer and better way to assign program zero is through some form of offset.Commonly machining center control manufacturers call offsets used to assign program zero fixture offsets. Turning center manufacturers commonly call offsets used to assig

26、n program zero for each tool geometry offsets.Flexible manufacturing cellsA flexible manufacturing cell (FMC) can he considered as a flexible manufacturing subsystem. The following differences exist between the FMC and the FMS:I. An FMC is not under the direct control of the central computer. Instea

27、d, instructions from the central computer are passed to the cell controller.2. The cell is limited iii the number of part families it can manufacture.The following elements are normally found in an FMC: Cell controller Programmable logic controller (PLC) More than one machine tool A materials handli

28、ng device (robot or pallet)The FMC executes fixed machining operations with parts flowing sequentially between operations.High speed machiningThe term High Speed Machining (HSM) commonly refers to end milling at high rotational speeds and high surface feeds. For instance, the routing of 1xckets in a

29、luminum airframe sections with a very high material removal rate . Over the past 60 years, HSM has been applied to a wide range of metallic and non-metallic workpiece materials, including the production of components with specific surface topography requirements and machining of materials with hardn

30、ess of 50 HRC and above. With most steel components hardened to approximately 32-42 HRC, machining options currently include: Rough machining and semi-finishing of the material in its soft (annealed) condition heat treatment to achieve the final required hardness = 63 HRC machining of electrodes and

31、 Electrical Discharge Machining (EDM) of specific parts of dies and moulds (specifically small radii and deep cavities with limited accessibility for metal cutting tools) finishing and super-finishing of cylindrical/flat/cavity surfaces with appropriate cemented carbide, cermet, solid carbide, mixed

32、 ceramic or polycrystalline cubic boron nitride (PCBN)For many components, the production process involves a combination of these options and in the case of dies and moulds it also includes time consuming hand finishing. Consequently, production costs can be high and lead times excessive.It is typic

33、al in the die and mould industry to produce one or just a few tools of the same design. The process involves constant changes to the design, and because of these changes there is also a corresponding need for measuring and reverse engineering.The main criteria is the quality level of he die or mould

34、 regarding dimensional, geometric and surface accuracy. If the quality level after machining is poor and if it cannot meet the requirements, there will be a varying need of manual finishing work. This work produces satisfactory surface accuracy,but it always has a negative impact on the dimensional

35、and geometric accuracy.One of the main aims for the die and mould industry has been, and still is, to reduce or eliminate the need for manual polishing and thus improve the quality and shorten the production costs and lead times.Main economical and technical factors for the development of HSMSurviva

36、lThe ever increasing competition in the marketplace is continually setting new standards. The demands on time and cost efficiency is getting higher and higher. This has forced the development of new processes and production techniques to take place. HSM provides hope and solutions.MaterialsThe devel

37、opment of new, more difficult to machine materials has underlined the necessity to find new machining solutions. The aerospace industry has its heat resistant and stainless steel alloys. The automotive industry has different bimetal compositions, Compact Graphite Iron and an ever increasing volume o

38、f aluminum3. The die and mould industry mainly has to face the problem of machining high hardened tool steels, from roughing to finishing.QualityThe demand for higher component or product quality is he result of ever increasing competition. HSM. if applied correctly, offers a number of solutions in

39、this area. Substitution of manual finishing is one example, which is especially iniportant on dies and moulds or components with a complex 3D geometry.ProcessesThe demands on shorter throughput times via fewer setups and simplified flows (logistics) can in most cases, be solved by HSM. A typical tar

40、get within the die and mould industry is to completely machine fully hardened small sized tools in one setup. Costly and time consuming EDM processes can also he reduced or eliminated with HSM.Design & developmentOne of the main tools iii todays competition is to sell products on the value of novelt

41、y. The average product life cycle on cars today is 4 years, computers and accessories 1 .5 years, hand phones 3 months. One of the prerequisites of this development of fast design changes and rapid product development time is the HSM technique.Complex productsThere is an increase of multi-functional

42、 surfaces on components. such as new design of turbine blades giving new and optimized functions and features. Earlier designs allowed polishing by hand or with robots (manipulators). Turbine blades with new, more sophisticated designs have to be finished via machining and preferably by HSM . There

43、are also more and more examples of thin walled workpieces that have to be machined (medical equipment, electronics, products for defence, computer parts)Production equipmentThe strong development of cutting materials, holding tools, machine tools, controls and especially CAD/CAM features and equipme

44、nt, has opened possibilities that niust be met with new production methods and tcchniqucs.Definition of HSMSalomons theory. “Machining with high cutting speeds.” on which, in 1931, took out a German patent, assumes that “at a certain cutting speed (5-10 times higher than in conventional machining),

45、the chip removal temperature at the cutting edge will start to decrease.”Given the conclusion:” . seems to give a chance to improve productivity in machining with conventional tools at high cutting speeds.”Modern research, unfortunately, has not been able to verify this theory totally. There is a re

46、lative decrease of the temperature at the cutting edge that starts at certain cutting speeds for different materials.The decrease is small for steel and cast iron. But larger fir aluminum and other non-ferrous metals. The definition of HSM must be based on other factors.Given todays technology. “hig

47、h speed” is generally accepted to mean surface speeds between I and 10 kilomewrs per minute or roughly 3 300 to 33 000 feet per minute. Speeds above 10 km/min are in the ultra-high speed category, and are largely the realm of experimental metal cutting. Obviously, the spindle rotations required to a

48、chieve these surface cutting speeds are directly related to the diameter of the tools being used. One trend which is very evident today is the use of very large cutter diameters for these applications - and this has important implications for tool design.There are many opinions, many myths and many

49、different ways to define HSM.中文譯文數(shù)控機床雖然各種數(shù)控機床的功能和應用各不相同，擔它們有著共同的優(yōu)點。這里是數(shù)控設備提供的比較重要的幾個優(yōu)點。各種數(shù)控機床的第一個優(yōu)點足自動化程度提高了。零件制造過程中的人為干預減少或者免除了。整個加工循環(huán)中，很多數(shù)控機床處于幾無人照看狀態(tài)，這使操作員被解放出來，可以干別的工作。數(shù)控機床用戶得到的兒個額外好處是：數(shù)控機床減小了操作員的疲勞程度，減少了人為誤差，工件加工時間一致而且可頂測。由于機床在程序的控制下運行，與操作普通機床的機械師要求的技能水平相比，對數(shù)控操作員的技能水平要求（與基本加工實踐相關）也降低了。數(shù)控技術的第二個優(yōu)

50、點是工件的一致性好，加工精度高?，F(xiàn)在的數(shù)控機床宣稱的精度以及重復定位精度幾乎令人難以置信。這意味著，一旦程序被驗證是正確的，可以很容易地加工出 2 個、 10 個或 1000 個相同的零件，而且它們的精度高，一致性好。大多數(shù)數(shù)控機床的第三個優(yōu)點是柔性強。由于這些機床在程序的控制下工作，加工不同的工件易如在數(shù)控系統(tǒng)中裝載一個不同的程序而己。一旦程序驗證正確，并且運行一次，下次加工工件的時候，可以很方便地重新調用程序。這又帶來另一個好處可以快速切換不同工件的加工。由于這些機床很容易調整并運行，也由于幾很容易裝載加工程序，因此機床的調試時間很短。這是當今準時生產(chǎn)制造模式所要求的。運動控制一CNC 的

51、核心任何數(shù)控機床最基本的功能是其有自動、精確、一致的運動控制。大多數(shù)普通機床完全運用機械裝置實現(xiàn)其所需的運動，而數(shù)控機床是以一種全新的方式控制機床的運動。各種數(shù)控設備有兩個或多個運動方向，稱為軸。這些軸沿著其長度方向精確、自動定位。最常用的兩類軸是直線軸（沿直線軌跡）和旋轉軸（沿圓形軌跡）。普通機床需通過旋轉搖柄和手輪產(chǎn)生運動，而數(shù)控機床通過編程指令產(chǎn)生運動。通常，幾乎所有的數(shù)控機床的運動類型（快速定位、穴線插補和圓弧插補）、移動軸、移動距離以及移動速度（進給速度）都是可編程的。數(shù)控系統(tǒng)中的 CNC 指令命令驅動電機旋轉某一精確的轉數(shù)，驅動電機的旋轉隨叩使?jié)L珠絲杠旋轉，滾珠絲杠將旋轉運動轉換成

52、直線軸（滑臺）運動?；_上的反饋裝置（直線光柵尺）使數(shù)控系統(tǒng)確認指令轉數(shù)己完成 。普通的臺虎鉗上有著同樣的基本直線運動，盡管這是相當原始的類比。旋轉虎鉗搖柄就是旋轉絲杠, 絲杠帶動虎虎鉗鉗口移動。與臺虎鉗相比，數(shù)控機床的直線軸是非常精確的，軸的驅動電機的轉數(shù)精確控制直線軸的移動距離。軸運動命令的方式理解坐標對 CNC 用 戶來說，為了達到給定的直線移動量而指令各軸驅動電機旋轉多少轉，從而使坐標軸運動，這種方法是不可行的。（這就好像為了使鉗口準確移動l英寸需要計算出臺虎鉗搖柄的轉數(shù)?。┦聦嵣希械臄?shù)控系統(tǒng)都能通過采用坐標系的形式以一種較為簡單而且合理的方式來指令軸的運動。數(shù)控機床上使用最泛的兩

53、種坐標系是直角坐標系和極坐標系。目前用得較多的是直角坐標系。編程零點建立數(shù)控程序中運動命令的參考點。這使得操作員能從一個公共點開始指定軸運動。如果編程零點選擇恰當，程序所需坐標通?？蓮膱D紙上直接獲得。如果編程員希望刀具移動到編程零點右方1英寸（ 25 . 4 毫米）的位置，則用這種方法指令 X1.0 即可。如果編程員希望刀其移動到編程零點上方 1 英寸的位置，則指令 YI . 0 。數(shù)控系統(tǒng)會自動確定（計算）各軸馭動電機和滾珠絲掃要轉動多少轉，使坐標軸到達指令的目標位置。這使編程員以非常合理的方式命令軸的運動。理解絕對和相對運動至此，所有的討論都假設采用的是絕對編程方式。用于指定絕對方式的址常

54、用的數(shù)控代碼是 G90 。絕對方式下，所有運動終點的指定都是以編程零點為起點。對初學者來說，這通常是較好也是址容易的指定軸運動終點的方法，但還有另外一種指定軸運動終點的方法。 增量方式（通常用 G91 指定）下，運動終點的指定是以刀具的當前位置為起點，而不是編程零點。用這種方法指定軸運動，編程員往往會問“我該將刀其移動多遠的即離？ ，盡管增最方式多數(shù)時候很有用，但一般說來，這種方法指定軸運動較麻煩、困難，初學者應該重點使用絕對方式。指令軸運動時一定要小心。初學者往往以增量方式思考問題。如果工作在絕對方式（初學者應該如此），編程員應始終在問刀具應該移到什么位置？” ，這個位置是相對于編程零點這個

55、固定位置而言，而不是相對于刀具當前位置。絕對工作方式很容易確定指令當前位置，除此之外，它的另外一個好處涉及軸運動中的錯誤。絕對方式下，如果程序的一個軸運動指令出錯，則只有一個運動是不止確的。而另一方面，如果在增量運動過程中出錯，則從出錯的那一點起，所有的運動都是不止確的。指定編程零點記住必須以某種方式對數(shù)控系統(tǒng)指定編程零點的位置。指定編程零點的方式隨數(shù)控機床和數(shù)控系統(tǒng)的不同而很不相同。（較老的）一種方法是在程序中指定編程零點。用這種方法，編程員告訴數(shù)控系統(tǒng)從編程零點到機床起始點的即離。通常用 G92 （或 G50 ）在程序的一開始指定，很能在各把刀具的開頭指定編程零點。另一種較新、更好的指定編

56、程零點的方法是通過偏置的形式，。通常，加工中心用于指定編程零點的偏置被稱作夾具偏置，車削中心上用于指定編程零點的偏置被稱作刀具幾何偏置。柔性制造單元柔性制造單元 （ FMC ）被認為是柔性制造子系統(tǒng)。以下是 FMC 和 FMS 之間的別：1.FMC 不受中央計算機的直接拎制，中央計算機發(fā)出的指令被傳送到單元控制器。 2.FMC 能制造的零件族的數(shù)口有限。 FMC 一般由下列部分組成：單元控制器 . 可編程邏輯控制器（ PLC ） . 一臺以上的機床物流設備（機器人或托盤） FMC 按順序對零件流執(zhí)行固定的加工操作。高速加工術語“高速加工 ( HMS ) ”一 般是指在高轉速和大進給量下的立銑。

57、例如，以很高的金屬切除率對鋁合金飛機翼架的凹處進行切削。在過去的 60 年中，高速加工己經(jīng)廣泛應用于金屬與非金屬材料，包括有特定表面形狀要求的零件生產(chǎn)和硬度高于或等于 HRC 50 的材料切削。對于大部分淬火到約為 HRC 32- 42的鋼零件，當前的切削選項包括：在軟（退火）工況下材料的粗加工和半精加工達到最終硬度要求為 HRC 63 的熱處理模具行業(yè)的某些零件的電極加工和放電加工 ( EDM ) （特別是金屬切削刀具難以加工的小半徑圓弧和深凹穴）用適合的硬質合金、金屬陶瓷、整體硬質合金、混合陶瓷或多晶立方氮化硼（ PCBN ）刀具進行的圓柱平面 凹穴表面的精加工和超精加工。對于許多零件，生

58、產(chǎn)過程牽涉到這些選項的組合，在模具制造案例中，它還包括費時的精加工，結果導致生產(chǎn)成本高和準備時間長。在模具制造業(yè)中典型的是僅生產(chǎn)一個或幾個同一產(chǎn)品。生產(chǎn)過程中，產(chǎn)品的設計不斷改變，由于產(chǎn)品改變，模具制造中需要測量與反求工程。加工的主要標準是模具的尺寸和表面粗糙度方面的質量水平。如果加工后的質量水平低，不能滿足要求，就需手工精加工。手工精加工可產(chǎn)生令人滿意的表面粗糙度，但是對尺寸和幾何精度總是產(chǎn)生不好的影響。模具制造業(yè)的主要目標之一，一直是并且仍然是減少或免除手工拋光，從而提高質量、降低生產(chǎn)成木和縮短準備時間。影響高速加工發(fā)展的主要經(jīng)濟和技術因素生存日益激烈的市場競爭導致不斷設立新的標準，對時間

59、和成本效率的要求越來越高，這就迫使新工藝和生產(chǎn)技術不斷發(fā)展。高速加工提供了希望和解決方案 材料新型難加工材料的開發(fā)迫切需要尋找新的切削解決方案。航空航天業(yè)使用耐熱合金鋼和不銹鋼，汽車工業(yè)使用了不同的雙金屬材料、小石墨鑄鐵，并增加了鋁用量。模具制造業(yè)必須面對切削高硬度的淬決鋼的問題從粗加工到精加工。質量對質量的高要求是空前激烈竟爭所導致的結果。高速加工如果使用得正確，可以在這個領域提供一些解決方案。替代手工精加工是一個例子，這對有復雜 3D 幾何形狀的模其尤為重要。工藝通過減少裝卡次數(shù)和簡化物流（后勤）來縮短產(chǎn)品產(chǎn)出時間的要求在大部分情況下可由 高速加工解決。模具制造業(yè)內的一個典型目標是在一次裝

60、卡中完成所有完全淬火小零件的切削。使用高速切削，可以減少和免除費時、費錢的放電加工（EDM)。設計與發(fā)展今競爭中的主要方法之一是銷售新奇的產(chǎn)品?，F(xiàn)在小汽車的平均生命周期是 4 年，計算機和配件 1 年半，手機 3 個月 這種快速的產(chǎn)品設計周期和開發(fā)周期的先決條件是高速切削技術。復雜產(chǎn)品零件多功能表面增加了，例如新設計的渦輪葉片有新的、優(yōu)化的功能與特性。早期的設計允許用手工或機器人（機械手）來拋光。新型、形狀復雜的渦輪葉片必須通過切削來完成精加工，最好是用高速切削完成。薄壁工件必須用切削進行精加的例子越來越多（醫(yī)療設務、電子、國防產(chǎn)品 、計算機零件）。產(chǎn)品設備切削材料、刀柄刀具、機床、數(shù)控系統(tǒng)，

61、特別是 CAD / CAM功能和設備的巨大發(fā)展己經(jīng)使采用新的生產(chǎn)方法和技術成為可能和必須。高速加工的原始定義 1931 年 Salomom 的高速加工理論獲得了一項德國專利，他認為“在高于常規(guī)切削速度 5 一10 倍的切削速度下，刀刃的切削溫度將開始下降 由以上得出結論：“ 用常規(guī)刀具以高切削速度加工，從而提高生產(chǎn)率，這是可能的 ”可惜，現(xiàn)代研究還沒能全面驗證這個理論。對于不同的材料，從某一切削速度開始切削刃上的溫有所降低。對于鋼和鑄鐵來說，這種溫度降低不大。但是對鋁和其他非金屬來說則是大的。高速切削的定義須依據(jù)其他因素。按照現(xiàn)在的技術，普遍認為“高速”，是指表面速度在1- 10 千米分鐘（ k /min ) ，或者約 3300 一 330 英尺分鐘（ ft / min ）。 10 千米分鐘以上的速度屬于超高速范疇，還在實驗室金屬切削范圍顯然獲得這些表面切削速度所要求的主軸轉速直接與使用的刀具直徑有關。當前較顯著的趨勢是采用大直刀具這對刀具的設計有著重要的啟發(fā)。關于高速切削的定義，存在許多觀點、許多謎團和許多不同的方法。