畢業(yè)設計(論文)外文資料翻譯系部： 機械工程系 專 業(yè)： 機械工程及自動化 姓 名： 學 號： 外文出處： Cutter Compensation Principle 附 件： 1.外文資料翻譯譯文；2.外文原文。 指導教師評語： 此翻譯文章簡單介紹了刀具的原理，并詳細介紹了刀具補償的三種方法，并對三種方法進行了詳細的描述，翻譯用詞比較準確，文筆也較為通順，為在以后工作中接觸英文資料打下了基礎。 簽名： 注：請將該封面與附件裝訂成冊。附件1：外文資料翻譯譯文刀具補償原理 刀具補償（又稱偏置），在20世紀6070年代的數控加工中沒有補償的概念，所以編程人員不得不圍繞刀具的理論路線和實際路線的相對關系來進行編程，容易產生錯誤。補償的概念出現以后很大地提高了編程的效率。具有刀具補償功能，在編制加工程序時，可以按零件實際輪廓編程，加工前測量實際的刀具半徑、長度等，作為刀具補償參數輸入數控系統，可以加工出合乎尺寸要求的零件輪廓。 刀具補償功能還可以滿足加工工藝等其他一些要求，可以通過逐次改變刀具半徑補償值大小的辦法，調整每次進給量，以達到利用同一程序實現粗、精加工循環(huán)。另外，因刀具磨損、重磨而使刀具尺寸變化時，若仍用原程序，勢必造成加工誤差，用刀具長度補償可以解決這個問題。刀具補償分為2種：刀具長度補償；刀具半徑補償。文獻刀具補償在數控加工中的應用（工具技術，2OO4年第38卷No7，徐偉，廣東技術師范學院）中提到在數控加工中有4種補償：刀具長度補償；刀具半徑補償；夾具補償；夾角補償（G39）。這四種補償基本上能解決在加工中因刀具形狀而產生的軌跡問題。1. 刀具長度補償1.1 刀具長度的概念刀具長度是一個很重要的概念。我們在對一個零件編程的時候，首先要指定零件的編程中心，然后才能建立工件編程坐標系，而此坐標系只是一個工件坐標系，零點一般在工件上。長度補償只是和Z坐標有關，它不象X、Y平面內的編程零點，因為刀具是由主軸錐孔定位而不改變，對于Z坐標的零點就不一樣了。每一把刀的長度都是不同的，例如，我們要鉆一個深為50mm的孔，然后攻絲深為45mm，分別用一把長為250mm的鉆頭和一把長為350mm的絲錐。先用鉆頭鉆孔深50mm，此時機床已經設定工件零點，當換上絲錐攻絲時，如果兩把刀都從設定零點開始加工，絲錐因為比鉆頭長而攻絲過長，損壞刀具和工件。此時如果設定刀具補償，把絲錐和鉆頭的長度進行補償，此時機床零點設定之后，即使絲錐和鉆頭長度不同，因補償的存在，在調用絲錐工作時，零點Z坐標已經自動向Z+（或Z）補償了絲錐的長度，保證了加工零點的正確。1.2 刀具長度補償指令通過執(zhí)行含有G43（G44）和H指令來實現刀具長度補償，同時我們給出一個Z坐標值，這樣刀具在補償之后移動到離工件表面距離為Z的地方。另外一個指令G49是取消G43（G44）指令的，其實我們不必使用這個指令，因為每把刀具都有自己的長度補償，當換刀時，利用G43（G44）H指令賦予了自己的刀長補償而自動取消了前一把刀具的長度補償。G43表示存儲器中補償量與程序指令的終點坐標值相加，G44表示相減，取消刀具長度偏置可用G49指令或H00指令。程序段N80G43Z56H05與中，假如05存儲器中值為16，則表示終點坐標值為72mm。1.3 刀具長度補償的兩種方式(1) 用刀具的實際長度作為刀長的補償（推薦使用這種方式）。使用刀長作為補償就是使用對刀儀測量刀具的長度，然后把這個數值輸入到刀具長度補償寄存器中，作為刀長補償。使用刀具長度作為刀長補償的理由如下： 首先，使用刀具長度作為刀長補償，可以避免在不同的工件加工中不斷地修改刀長偏置。這樣一把刀具用在不同的工件上也不用修改刀長偏置。在這種情況下，可以按照一定的刀具編號規(guī)則，給每一把刀具作檔案，用一個小標牌寫上每把刀具的相關參數，包括刀具的長度、半徑等資料，事實上許多大型的機械加工型企業(yè)對數控加工設備的刀具管理都采用這種辦法。這對于那些專門設有刀具管理部門的公司來說，就用不著和操作工面對面地告訴刀具的參數了，同時即使因刀庫容量原因把刀具取下來等下次重新裝上時，只需根據標牌上的刀長數值作為刀具長度補償而不需再進行測量。 其次，使用刀具長度作為刀長補償，可以讓機床一邊進行加工運行，一邊在對刀儀上進行其他刀具的長度測量，而不必因為在機床上對刀而占用機床運行時間，這樣可以充分發(fā)揮加工中心的效率。這樣主軸移動到編程Z坐標點時，就是主軸坐標加上（或減去）刀具長度補償后的Z坐標數值。 （2）利用刀尖在Z方向上與編程零點的距離值（有正負之分）作為補償值。這種方法適用于機床只有一個人操作而沒有足夠的時間來利用對刀儀測量刀具的長度時使用。這樣做當用一把刀加工另外的工件時就要重新進行刀長補償的設置。使用這種方法進行刀長補償時，補償值就是主軸從機床Z坐標零點移動到工件編程零點時的刀尖移動距離，因此此補償值總是負值而且很大。2 刀具半徑補償2.1 刀具半徑補償概念在輪廓加工時，刀具中心運動軌跡（刀具中心或金屬絲中心的運動軌跡）與被加工零件的實際輪廓要偏移一定距離，這種偏移稱為刀具半徑補償，又稱刀具中心偏移。如圖3-1所示，在加工內輪廓時，刀具中心向工件輪廓的內部偏移一個距離；而加工外輪廓時，刀具中心向工件的外側偏移一個距離，這個偏移，就是所謂的刀具半徑補償。圖中，粗實線為工件輪廓，虛線為刀具中心軌跡。本圖中的偏移量為刀具半徑值。而在粗加工和半精加工時，偏移量為刀具半徑和加工余量之和。ABC外輪廓加工內輪廓加工A/B/C/C/刀具刀具圖3-1 B功能刀具補償的交叉點和間斷點 由于數控系統控制的是刀具中心軌跡，因此數控系統要根據輸入的零件輪廓尺寸及刀具半徑補償值計算出刀心軌跡。由此可見，刀具半徑補償在數控加工有著非常重要的作用，根據刀具補償指令，數控加工機床可自動進行刀具半徑補償。特別是在手工編程時，刀具半徑補償尤為重要。手工編程時，運用刀具半徑補償指令，就可以根據零件的輪廓值編程，不需計算刀心軌跡編程，這樣就大大減少了計算量和出錯率。雖然利用CAD/CAM自動編程，手工計算量小，生成程序的速度快，但當刀具有少量磨損或加工輪廓尺寸與設計尺寸稍有偏差時或者在粗銑、半精銑和精銑的各工步加工余量變化時，仍需作適當調整，而運用了刀具半徑補償后，不需修改刀具尺寸或建模尺寸而重新生成程序，只需要在數控機床上對刀具補償參數做適當修改即可。既簡化了編程計算，又增加了程序的可讀性。刀具半徑補償有B功能（Basic）和C功能（Complete）兩種補償形式。由于B功能刀具半徑補償只根據本段程序進行刀補計算，不能解決程序段之間的過渡問題，要求將工件輪廓處理成圓角過渡如圖3-1所示，因此工件尖角處工藝性不好。而且編程人員必須事先估計出刀補后可能出現的間斷點和交叉點，并進行人為處理，顯然增加編程的難度；而C功能刀具半徑補償能自動處理兩程序段刀具中心軌跡的轉接，可完全按照工件輪廓來編程，因此現代CNC數控機床幾乎都采用C功能刀具半徑補償。這時要求建立刀具半徑補償程序段的后續(xù)至少兩個程序段必須有指定補償平面的位移指令（G00、G01，G02、G03等），否則無法建立正確的刀具補償。2.2 刀具半徑補償指令根據ISO規(guī)定，當刀具中心軌跡在程序規(guī)定的前進方向的右邊時稱為右刀補，用G42表示；反之稱為左刀補，用G41表示。G41是刀具左補償指令（左刀補），即順著刀具前進方向看(假定工件不動)，刀具中心軌跡位于工件輪廓的左邊，稱左刀補。如圖3.2(a)所示。G42是刀具右補償指令（右刀補），即順著刀具前進方向看(假定工件不動)，刀具中心軌跡位于工件輪廓的右邊，稱右刀補。如圖3.2(b)所示。G40是為取消刀具半徑補償指令。使用該指令后，41、42指令無效。圖3-2 刀具半徑的左右補償(a) 外輪廓補償(b) 內輪廓補償在使用G41、G42進行半徑補償時應采取以下步驟：（1）設置刀具半徑補償值：程序啟動前，在刀具補償參數區(qū)內設置補償值。（2）刀補的建立：刀具從起刀點接近工件，刀具中心軌跡的終點不在下一個程序段指定的輪廓起點，而是在法線方向上偏移一個刀具補償的距離。在該段程序中，動作指令只能用G00或G01。（3）刀補進行：在刀具補償進行期間，刀具中心軌跡始終偏離編程軌跡一個刀具半徑的偏移值。在此狀態(tài)下，G00、G01、G02、G03都可以使用。（4）刀補的取消：在刀具撤離工件、返回原點的過程中取消刀補。此時只能用G00、G01。2.3 功能刀具半徑補償對直線而言，刀具補償后的軌跡是與原直線平行的直線，只需要計算出刀具中心軌跡的起點和終點坐標值。如圖3-3所示，被加工直線段的起點在坐標原點，終點坐標為A。假定上一程序段加工完后，刀具中心在O點坐標已知。刀具半徑為r，現要計算刀具右補償后直線段OA的終點坐標A。設刀具補償矢量AA的投影坐標為,則圖3-3 直線刀具補償圖3-4 圓弧刀具補償對于圓弧而言，刀具補償后的刀具中心軌跡是一個與圓弧同心的一段圓弧。只需計算刀補后圓弧的起點坐標和終點坐標值。如圖3-4所示，被加工圓弧的圓心坐標在坐標原點O，圓弧半徑為R，圓弧起點A，終點B，刀具半徑為r。假定上一個程序段加工結束后刀具中心為A，其坐標已知。那么圓弧刀具半徑補償計算的目的，就是計算出刀具中心軌跡的終點坐標B。設BB在兩個坐標上的投影為，則以圖3-1的加工外輪廓為例，采用B功能刀具半徑補償方法，加工完第一個程序段，刀具中心落在B/、點上，而第二個程序段的起點為A/，兩個程序段之間出現了斷點，只有刀具中心走一個從B/、至A/的附加程序，即在兩個間斷點之間增加一個半徑為刀具半徑的過渡圓弧B1B2，才能正確加工出整個零件輪廓?？梢?，B刀補采用了讀一段，算一段，再走一段的控制方法，無法預計到由于刀具半徑所造成的下一段加工軌跡對本程序段加工軌跡的影響，相鄰兩程序段的刀具中心軌跡之間可能出現間斷點或交叉點。為解決下一段加工軌跡對本段加工軌跡的影響，在計算本程序段軌跡后，提前將下一段程序讀入，然后根據它們之間轉接的具體情況，再對本段的軌跡作適當修正，得到本段正確加工軌跡，這就是C功能刀具補償。C功能刀補更為完善，這種方法能根據相鄰輪廓段的信息自動處理兩個程序段刀具中心軌跡的轉換，并自動在轉接點處插入過渡圓弧或直線從而避免刀具干涉和斷點情況。 2.4 功能刀具半徑補償目前，通常的CNC系統中，實際所能控制的輪廓只有直線和圓弧，相應的有如下轉接線形：直線與直線轉接、直線與圓弧轉接、圓弧與圓弧轉接、圓弧與直線轉接。根據兩段軌跡的矢量夾角和刀具補償方向的不同，有以下幾種轉接過渡方式：縮短型、伸長型、插入型。 3 夾具偏置補償（坐標系偏置）正如刀具長度補償和半徑補償一樣，讓編程者可以不用考慮刀具的長短和大小，夾具偏置可以讓編程者不考慮工件夾具的位置而使用夾具偏置。當一臺加工中心在加工小的工件時，工裝上一次可以裝夾幾個工件，編程者不用考慮每一個工件在編程時的坐標零點，而只需按照各自的編程零點進行編程，然后使用夾具偏置來移動機床在每一個工件上的編程零點。夾具偏置是使用夾具偏置指令G54G59來執(zhí)行的。還有一種方法就是使用G92指令設定坐標系。當一個工件加工完成之后，加工下一個工件時使用G92來重新設定新的工件坐標系。4 夾角補償加工中兩平面相交為夾角，可能產生超程過切現象，導致加工誤差的產生，此時可采用夾角補償(G39)來解決。使用夾角補償(G39)指令時需注意，本指令為非模態(tài)指令，只在本程序段內有效，而且只能在G41或G42指令后才能使用，該指令主要用于加工中心和數控銑床。以上是數控加工中的四種補償方式，給我們的編程和加工帶來很大的方便，能大大地提高生產效率和產品合格率。附件2：外文原文（復印件）Cutter Compensation Principle The cutter compensation (calls bias), in the 20th century 60 the 70ss numerical control processing compensation concept,Therefore the programmers can not but revolve cutting tools theory route and the actual routes relative relations carry on the programming, easy to make the mistake. The compensation concept will appear later very greatly raised the programming efficiency. Has the cutter compensation function, when establishment processing program, may according to the components real profileprogramming, before the processing, survey the actual cutting tool radius, the length and so on, as the cutter compensation parameter input numerical control system, may process conforms with the size request the components outline.The cutter compensation function may also satisfy the processing craft and so on other requests, may through change the cutting tool radius compensation value size gradually the means that the adjustment each time to feed quantity, achieves the use identical procedure to realize, the precision work circulation thickly. Moreover, when because of the tool wear, the grind causes the tool dimension change, if still used the original procedure, will create the processing error inevitably, may solve his problem with the cutting tool length compensation. The cutter compensation divides into 2 kinds: cutting tool length compensation; cutting tool radius compensation. The literature "Cutter compensation in Numerical control Processings Application" (tool technology, 2OO4 year 38th volume No7, Xu is great, Guangdong technology Normal school) mentioned that has 4 kind of compensations in the numerical control processing: cutting tool length compensation; cutting tool radius compensation; jig compensation; included angle compensation (G39). These four kind of compensations basically can solve in the processing the path question which produces because of the cuttingtool shape. 1. cutting tool length compensation 1.1 cutting tool length concept The cutting tool length is a very important concept. We in programs to components, must first assign the components the programming center, then can establish the work piece programming coordinate system, but this coordinate system is only a work piece coordinate system, zero generallyon work piece. The length compensation is only and the Z coordinate related, it does not look like in X, Y plane the programming zero spot, because the cutting tool is by the main axial cone hole localization, but does not change, is dissimilar regarding Z coordinates zero. Each knifes length is different, for example, we must drill a depth are the 50mm holes, then attacks the silk depth is 45mm, respectively uses a length is the 250mm drill bit nd a length is the 350mm screw tap. Uses the drill bit to drill depth of hole 50mm first, this time the engine bed already established the work piece zero spot, when exchanges the screw tap attacks the silk, if two knives both from suppose the zeroing to start to process, because the screw tap the ratiorills the head length to attack the silk to be excessively long, damages the cutting tool and the work piece. This time if the hypothesis cutter compensation, arries on the screw tap and drill bits length the compensation, after this time engine bed zero hypothesis, even if the screw tap and the drill bit length are different, because compensates existence, when transfer screw tap work, zero selected the Z coordinate to be already automatic to Z+ (or Z) has compensated thescrew tap length, has guaranteed a processing zero correctness. 1.2 cutting tool length compensation instruction Includes G43 through the execution (G44) and the H instruction realizes the cutting tool length compensation, simultaneously we give a Z coordinate figure, such cutting tool after compensation moves to leaves the work piece surface distance is the Z place. Other instruction G49 is cancels G43 (G44) the instruction, actually we do not need to use this instruction, because has every time the cutting tool own length compensation, when trades the knife, (G44) the H instruction entrusted with the own knife long compensation using G43 to cancel the preceding cutting tools length compensation automatically. G43 expressed that in the memory compensates the quantity and program directive end point coordinate figure adding together, G44 expresses the cancellation, cancels the cutting tool length bias available G49 instruction or the H00 instruction. Segment N80 G43 Z56 H05 and, if in 05 memories the value is 16, then the expression end point coordinate figure is 72mm. 1.3 cutting tool length compensation two ways (1) uses cutting tools virtual length (recommendation to use this way) as the knife long compensation. Uses the knife long is uses the tool setting gauge as the compensation to survey cutting tools length, then inputs this value to the cutting tool length compensation register, takes the knife long compensation. The use cutting tool length the reason which long compensates as the knife is as follows: First, uses the cutting tool length to take the knife long compensation, may avoid in the different work piece processing repairing unceasingly cuts again the long bias. This kind of cutting tool uses on the different work piece does not need to repair cuts again the long bias. In this case, may defer to certain cutting tool serial number rule, makes the file for each cutting tool, inscribes with a small product label every time cutting tools related parameter, including material and so on cutting tools length, radius, many large-scale machine-finishing enterprises uses this means in fact to the numerical control processing equipments cutting tool management. This was equipped with the cutting tool Control sections company specially regarding these, had no need with the operator face-to-face to tell the cutting tool the parameter, when even if simultaneously the knife storage capacity quantity reason took down the cutting tool and so on will install next time, only need act according to the product label the knife long value as the cutting tool length compensation not to again carry on the survey. Next, uses the cutting tool length to take the knife long compensation, may let one side the engine bed carry on the processing movement, at the same time carries on other cutting tools linear measure on the tool setting gauge, but does not need because of takes the engine bed running time on the engine bed to the knife, like this may display the machining center fully the efficiency. Such main axle moves to when programs the Z fiducial mark, after is the main axle coordinate adds on (or subtracts) the cutting tool length compensation Z coordinate value. (2) uses the knife point (to have the positive and negative division) in the Z direction with the programming zero distance value to take the compensation value. This method is suitable in the engine bed has a person to operate, but does not have the enough time to survey time cutting tools length using the tool setting gauge uses. Does this, when processes other work piece with a knife must carry on the knife long compensation the establishment. Uses when this method carries on the knife long compensation, the compensation value is the main axle from the engine bed Z coordinate zero spot moves to the work piece programming zero hour knife point migration distance, therefore this compensation value negative value moreover is very always big. 2 cutting tool radius compensation 2.1 cutting tool radius compensation concept When contour machining, the cutting tool central motion path (cutting tool center or tinsel centers path) with is processed the components the real profile to displace certain distance, this kind of displacement is called the cutting tool radius compensation, also calls the cutting tool off-centering. As shown in Figure 3-1, when processing outline, the cutting tool center displaces a distance to the work piece outlines interior; But outside processes time the outline, the cutting tool center displaces a distance to the work piece flank, this displacement, is the so-called cutting tool radius compensation. In the chart, the thick line is the work piece outline, the dashed line is the cutting tool center path. In this chart displacement quantity for cutting tool radius value. But of when rough machining and semi-finishing, displacement quantity sum of for cutting tool radius and the machining allowance. ABCA/B/C/C/Cutting toolIn contour machiningCutting toolOutside contour machiningFigure 3-1 B function cutter compensation intersection and point of discontinuityWhat because numerical control systems control is the cutting tool center path, therefore the numerical control system must calculates the knife heart path according to the input components overall size and the cutting tool radius compensation value. Thus it can be seen, the cutting tool radius compensation has the very vital role in the numerical control processing, according to the cutter compensation instruction, the numerical control processing engine bed may carry on the cutting tool radius compensation automatically. Specially when manual programming, cutting tool radius compensation especially important. When manual programming, using the cutting tool radius compensation instruction, may act according to the components the outline value programming, cannot calculate the knife heart path programming, like this greatly reduced the computation load and the error ratio. Although using the CAD/CAM automatic programming, the manual computation load is small, generating routines speed is quick, but when the cutting tool has the few attrition or the processing overall size and the design size have the deviation slightly or in the rough milling, half fine mill and time the fine mill various labor step machining allowance change, must make the appropriate readjustment, but after having utilized the cutting tool radius compensation, cannot revise the tool dimension or the modelling size, but the generating routine, only needs on the numerically-controlled machine tool to make the suitable revision again to the cutter compensation parameter then. Both simplified the programming computation, and increased the procedure readability.The cutting tool radius compensation has the B function (Basic) and the C function (Complete) two kind of compensation forms. Because the B function cutting tool radius compensation only acts according to this section of procedures to carry on the knife to make up the computation, cannot solve between the segment transition problem, requests 3-1 work piece outline processing full circle angle transition as shown in Figure, therefore the work piece acute angle place technology capability is not good. Moreover the programmers must estimate beforehand after the knife makes up, possibly appears the point of discontinuity and the intersection, and carry on artificial processing, obviously increases the programming the difficulty; But the C function cutting tool radius compensation can the automatic reduction two segment cutting tool center paths transfer, be possible to defer to the work piece outline to program completely, therefore the modern CNC numerically-controlled machine tool nearly uses the C function cutting tool radius compensation. By now requested the establishment cutting tool radius compensation segment the following two segments to have at least assigns the compensation plane the shift order (G00, G01, G02, G03 and so on), otherwise is unable to establish the correct cutter compensation.2.2 cutting tool radius compensation instructionStipulated according to ISO, when cutting tool center path stipulated in the procedure direction of advance right side when is called the right knife to make up, indicated with G42; Otherwise is called the left knife to make up, indicated with G41.G41 is the cutting tool left compensation instruction (left knife makes up), namely is suitable the cutting tool direction of advance to look that (hypothesis work piece motionless), the cutting tool center path located at the work piece outlines left side, said that the left knife makes up. As shown in Figure 3.2(a).G42 is the cutting tool right compensation instruction (right knife makes up), namely is suitable the cutting tool direction of advance to look that (hypothesis work piece motionless), the cutting tool center path located at work piece outlines right side, said that the right knife makes up. As shown in Figure 3.2(b).G40 is to cancel the cutting tool radius compensation instruction. After using this instruction, G41, G42 instruction ignore.(b) In outline compensation(a) Outside outline compensationFigure 3-2 cutting tool radiuss about compensatesWhen uses G41, G42 carry on the radius compensation should adopt the following step:(1) establishes the cutting tool radius compensation value: Before the procedure start, establishes the compensation value in the cutter compensation parameter area. (2) the knife makes up establishment: The cutting tool from a knife close work piece, the cutting tool center paths end point not the outline beginning which assigns in the next segment, but displaces a cutter compensation in the normal direction the distance. In this section of procedures, the action command can only use G00 or G01. (3) the knife makes up carries on: Carries on the period in the cutter compensation, the cutting tool center path deviates throughout a programming path cutting tool radius drift rate. Under this condition, G00, G01, G02, G03 may use.(4) the knife makes up cancellation: In the cutting tool evacuates the work piece, to return to the zero point in the process to cancel the knife to make up. This time can only use G00, G01.2.3 B function cutting tool radius compensationSpeaking of the straight line, after cutter compensations path is and the original straight line parallel straight line, only needs to calculate the cutting tool center paths beginning and the end point coordinate figure.As shown in Figure 3-3, is processed the tangential path the beginning in the origin of coordinates, the end point coordinate is A. After supposing a segment processes, cutting to