Basic Machine Tool Elements Most machine tools are constructed by using two or more components. These components , although they may have different function in such as a lathe , mill or drill press , have common characteristics Because of the demand for metal removal machines such as lathes , machining centers ,milling machines ,grinders , and the many others shown throughout this book , there has been continuous development in flexible machining centers .the mass-produced and special machine tools are constructed of basic elements . this chapter describes those elements . Important requirements for machine tool structures include rigidity, shape , operator and part accessibility , ease of chip removal , and safety . In terms of machine tool performance , static and precision . Stability of the machine structure is necessary to appreciate the breadth of modern machining methods in the manufacture of products . Structures For Cutting Machines Castings , forgings , and hot-or cold-formed shapes usually require machining .The variety of sizes , shapes , and materials calls for diversity in machining. Machine tools differ not only in the number of cutting edges they employ , but also in the way the tool and workpiece are moved in relation to each other . In some machines (vertical machining centers , drill presses , boring machines , milling machines, shapers, and grinders) the workpiece remains virtually motionless and the tool moves . in others (planers , lathes , and boring mills ) the tool is virtually fixed and the workpiece moves. But it should be pointed out that seldom are these simple elements applied without modification . The dingle-piont tool-shaping machines are the easiest to visualize , the lathe and the boring machine are kinematic inversions employing the single-point tool . the work rotates in the lathe, but the cutting toll is stationary . In the boring machine the tool rotates while the work is stationary . Although the lathe tool and the boring machine worktable are not truly stationary , this is overlooked for the moment . To feed a tool carriage past rotating work is usually more acceptable than to feed rotating work with headstock and supports past a stationary tool post . The shaper and planer use single-point cutting tool . The smaller workpiece is more efficiently machined on the shaper than on the planer . The general appearance of the machine is changed by reversing the kinematic relationship of work and tool . However , the cutting action principle is identical . With the introduction of the milling cutter by Eli Whitney in the early 1800s , the rotating tool was used only as a boring tool . But Whitney gave it a new application . The milling cutter was no longer used for cutting keyways , slitting ,sawing , slab and face milling , gear cutting , and shaping irregularly-formed pieces . Use of the rotating tool combined with traversing work . The cylindrical grinder adopts motions of the lathe and boring machine except for the substituting of rotating tools (the grinding wheel ) for single-point tools . The characteristics of these basic cutting machines are listed in Tab . Tab Cutting and Feed Movement for Conventionnal Machines Machine Cutting Movement Feed Movement Types of Operation Lathe Workpiece rotates Tool and carriage Cylindrical surface, drilling, boring , reaming Boring machine Tool rotates Table Drilling , boring, reaming ,and facing planer Table traverses Tool Flat surfaces(planning) Shaper Tool traverses Table Flat surfaces(shaping) Horizontal Milling Tool rotates Table Flat surfaces, gears, cams, drilling, boring Horizontal boring machine Tool rotates Tool traverses Flat surfaces Cylindrical grinder Tool (grinding wheel) rotates Table and /or tool Cylindrical surface(grinding) Drill press Tool rotates Tool Drilling boring facing and threading Saw Tool Table and /or piece Cut off Broaching machine Tool Tool External and internal surfaces 機床的基本部件 大多數(shù)機床由兩個或多個組件構(gòu)成。這些組件，雖然他們可能有不同的功能如車床，銑或鉆床，但他們有著共同的特點。 由于對如車床，加 工中心，銑床，磨床，整本書中顯示的許多其他金屬切削機床的需求，出現(xiàn)了柔性加工中心，在不斷發(fā)展。大規(guī)模生產(chǎn)及專用機床的構(gòu)造的基本要素。本章將介紹這些元素。 機床結(jié)構(gòu)的重要的要求包括剛度，形狀，操作員和部分附屬物，易于排屑和安全性。在機床性能，靜態(tài)和精度方面。 機器結(jié)構(gòu)的穩(wěn)定性是必要的，對產(chǎn)品制造的現(xiàn)代加工方法的廣度的理解。 切割機的結(jié)構(gòu)。 鑄件，鍛件，熱或冷成形形狀通常需要加工。不同的大小，形狀和材料需要不同的加工。 機械加工設(shè)備不僅在擁有的切削刀的數(shù)量上不同，而且在工具和工件的相對運動方式上也有所不同。在一些 機床中（立式加工中心，鉆床，鏜床，銑床，牛頭刨床，和磨床）工件依然保持靜止而刀具運動。在另外一些機床中（刨床，車床，鏜床）刀具是相對固定和工件移動。 但是，應(yīng)該指出的是，很少有不加修改地應(yīng)用了這些簡單的元素。 單刃成型工具的機床是最容易想象的。 車床和掘進機是采用單點工具運動倒置。 在旋轉(zhuǎn)的車床工作，但切割工具是固定的。 在掘進機中刀具旋轉(zhuǎn)，而工作是固定的。雖然車刀和鏜床工作臺都沒有真正固定的，但是這被忽略了。為了找到一個工具運輸過去旋轉(zhuǎn)的工作通常是比較可以接受，而不是找旋轉(zhuǎn)啟閉工作和過去的固定刀架支持。成型機和面 使用單刃刀具。小工件在插床上比刨床上更易加工。機器的整體外觀通過扭轉(zhuǎn)了工件和刀具運動的關(guān)系而被改變。然而，切割作用原理是相同的。 隨著銑刀由禮惠特尼在 19 世紀(jì)初引進，旋轉(zhuǎn)工具，只能作為一個沒用的工具，但惠特尼給了它一個新的應(yīng)用。銑刀不再是僅僅用于加工圓形的孔，而且還用來加工鍵槽、窄縫、鋸削、銑平面、齒輪以及成型不規(guī)則的零件。 除了采用旋轉(zhuǎn)工具（砂輪）代替單刃刀具外，外圓磨床和車床、鏜床的運動方式是一樣的。 這些