【正文】 e, and protect your hands from sharp cutting edges. Use only sharp cutting tools. Check that cutting tools are installed correctly and securely. Do not operate any machine controls unless you understand their function and what they will do. The Early Development Of Numerically Controlled Machine Tools The highly sophisticated CNC machine tools of today, in the vast and diverse range found throughout the field of manufacturing processing, started from very humble beginnings in a number of the major industrialized countries. Some of the earliest research and development work in this field was pleted in USA and a mention will be made of the UK39。s TOOLPRO, software designed to help select the best tool grade, speed, and feed rates for different work materials in turning application. Another very important feature of TOOLPRO is the display of the horsepower requirement for each machining selection. This allow the programmer to select a bination of cutting speed, feed rate, and depth of cut that equals the machine39。 it is capable of uninterrupted machining error free, hour after hour. A machine tool is productive only while it is making chips. Since the chipmaking process is controlled by the proper feeds and speeds, time savings can be achieved by faster rapid feed rates. Rapid feeds have increased from 60 to 200 to 400 and are now often approaching 1000 inches per minute (IPM). These high feed rates can pose a safety hazard to anyone within the working envelope of the machine tool. Complex contoured shapes were extremely difficult to product prior to CNC machining .CNC has made the machining of these shapes economically feasible. Design changes on a part are relatively easy to make by changing the program that directs the machine tool. A CNC machine produces parts with high dimensional accuracy and close tolerances without taking extra time or special precautions, CNC machines generally need less plex workholding fixtures, which saves time by getting the parts machined sooner. Once a program is ready and production parts, each part will take exactly the same amount of time as the previous one. This repeatability allows for a very precise control of production costs. Another advantage of CNC machining is the elimination of large inventories。附錄 2 外文翻譯（外文部分） ADVANCED MACHINING PROCESSES As the hardware of an advanced technology bees more plex, new and visionary approaches to the processing of materials into useful products e into mon use. This has been the trend in machining processes in recent years.. Advanced methods of machine control as well as pletely different methods of shaping materials have permitted the mechanical designer to proceed in directions that would have been totally impossible only a few years ago. Parallel development in other technologies such as electronics and puters have made available to the machine tool designer methods and processes that can permit a machine tool to far exceed the capabilities of the most experienced machinist. In this section we will look at CNC machining using chipmaking cutting tools. CNC controllers are used to drive and control a great variety of machines and mechanisms, Some examples would be routers in wood working。 it does not get fatigued。 tooling engineers. Help in tool selection or optimum tool working conditions can also be obtained from tool manufacturer software. Examples would be Kennametal39。s Rigidity Analysis software ealculates tool deflection for end mills as a function of tool stiffness and tool force. To this point we looked at some general qualifications that a programmer should possess. Now we examine how a CAM system works. Point Control Company39。s positionafter drilling the hole, anther rapid move takes place to the next hole39。 With any capital cost item, such as a CNC machine tool, it is necessary for a pany to undergo a feasibility study in order to ascertain whether the purchase of new plant is necessary and can be justified over a relatively short payback period. These thoughts and other circial decisions will be the subject of the next section which is concerned with the economic justification for CNC. 附錄 3 外文翻譯（中文部分） 機床實踐 隨著先進科技的硬件變得復雜化，把原料加工成為有用產品的理想的、新的加工 手段得到了普遍應用。 在這個部分我們來看數控機床切削使用的工具。由于計算機能力和容量的巨大增長，機床的控制技術很頻繁地發(fā)生著變化。兩軸的加工機床，其特點是低轉速、高馬力軸有高進給率，高轉速軸允許高效的高速切削刀具如鉆石和小直徑的刀具的使用（如圖 O2）。數控機床不會在一次加工完成后停下來計劃下一次的運動，它不會疲勞，它是不中斷的機床，機床只有在它切削的時候才有生產性。 在 CNC 機床之前，復雜形狀的加工是極困難的。 CNC 使機床不需要復雜的夾具，這使零件很快被加工從而節(jié)約了時間。在傳統(tǒng)制造中，為了增加效率，通常一大批零件被同時加工。自從手工 CNC 機床被一大批廠家生產以來，許多不同的 CNC 控制單元就被使用了。為了在有著不同控制器（如 FAWC、 OKUMA、或 DYNAPATH）生產一個可互換的零件，將需要完全不同的 CNC 代碼 。一個 CNC程序員看著一個零件的圖紙，并且設計必要的機床操作來制造這個零件（如圖O3）。對程序員要求的另一個最重要領域是制造過程的知識。一個優(yōu)秀的程序員將花相當數量的時間來研究關于新的、改進的刀具和刀具材料的快速設計者發(fā)表的書籍。例如： Kennametal’ s 被設計來幫助不同的使用其車間的工廠選擇最佳的機床；“ TOOCPRO”的另一個很重要的特征是為每個機床選擇馬力需求等等這些就允許設計者選擇一個結合了切削速度、進給率和切削深度等因素的機床。如果不只一臺機床在同時工作的話了解一臺機床的功率需求是必要的。在這一點上我們觀察一些廣泛的設計人員應掌握的規(guī)格。接著這個零件圖被研究來做成機床加工工序，粗加工 或精加工、鉆、沖、磨等操作。這描述了一個所設計機床操作的生動模型。當端面磨時，切削運動通常被定義為弧。 有時， CAM 的程序順序和實際加工的順序是各不相同的。程序員嘗試各種粗基準，以便選出最有效的切削加工方法。 當刀具路徑及其順序定好后，機床的代碼應被做好。也用 MACHINE DEFINE 文件表示 CNC 代碼命令。這個計劃加工時間可通過 改變安裝后達到更智能的移動速度或創(chuàng)造一種更有效的刀具軌跡來調整。格式化的 CAM 通過它的 CAM CONNECTION，可以讀一個 CAD 文件和轉移它的圖形到它的輪廓基準中去。另外，使用SHOWPATH 功能可以顯示每個刀具的路徑和他們的順序。機床表面不應該被用作工作臺。使用鋒利的切削刀具時，檢查切削刀具是否正確和安全的安裝。第二次世界大戰(zhàn)后的一個主要問題是，商業(yè)和軍隊迅速發(fā)展，在勞動力密集的加工中，現代工業(yè)界所需的自動化與精確度不可獲得。麻省理工大學開始進入研究，而 Parsons 公司使之發(fā)展起來。 與美國機床刀具控制發(fā)展的同時， UK 中的 ALIFRED Herber 產生了第一臺 NC機床。在航空所需要的復雜的控制系統(tǒng)發(fā)展的同時，點與點控制器發(fā)展起來，更廣泛的用于加工當中。所以，趨勢下一點的方向必須是相同的。 加工中心的概念是早期工作的結果，它允許機床在一個安裝上對工件進行多種加工，而不需要把工件轉移到另外的刀具下。它可被認為是系列但作用刀具通過計算機上控制的運輸系統(tǒng)連接起來的復合機床。事實上它的利用水平很低，機床刀具昂貴會導致加工頻繁時的“頸瓶”現象，于是進一步限制了整個操作。當兩個相關的因素存在后，在一個生產環(huán)境中，讓 CNC 實現靈活且輕松的編程的夢想變成為現實。隨著它的不斷發(fā)展成熟，使在高級的 CNC 系統(tǒng)上可安上人工智能。