【正文】 trial rates are very high in parison to alternative coating ，有穩(wěn)定熔化狀態(tài)的任何材料都可以熱噴涂，范圍寬闊的純凈和合成材料一般都能噴涂用于研究及工業(yè)目的。(2)通過壓縮空氣將液態(tài)金屬噴涂在準(zhǔn)備好的基體上。壓縮空氣吹過電弧使其霧化并驅(qū)使自動(dòng)送料金屬絲微粒到準(zhǔn)備好的工件上。PVD coatings involve atombyatom, moleculebymolecule, or ion deposition of various materials on solid substrates in vacuum 、分子緊靠分子或離子沉淀于固態(tài)基體上。熱蒸發(fā)工藝也能在噴氣發(fā)動(dòng)機(jī)零件上覆蓋很厚(1mm)的耐熱材料涂層，例如MCrAIY—一種金屬、鉻、鋁和釔合金。反應(yīng)濺射法可以生成較薄(小于3μm(120μin))的、堅(jiān)硬薄膜涂層，像比最硬金屬還硬的氮化鈦(TIN)。Conventional CVD coating process requires a metal pound that will volatilize at a fairly low temperature and depose to a metal when it contacts with the substrate at higher 。Thus, the application of diamond CVD is limited to materials which will not soften at this temperature such as cemented ，要求材料在此溫度下不軟化例如硬質(zhì)合金。Highenergy processes are relatively new surface treatment can alter the properties of surfaces without changing the dimension of the highenergy processes, including electron beam treatment, ion implantation, and laser beam treatment, are briefly discussed as follows:高能加工是相對(duì)較新的表面處理方法。Ion implantation uses electron beam or plasma to impinge gas atoms to ions with sufficient energy, and embed these ions into atomic lattice of the substrate, accelerated by magnetic coils in a vacuum mismatch between ion implant and the surface of a metal creates atomic defects that harden the ：離子注入采用電子束或等離子體通過真空室內(nèi)磁性線圈加速以足夠的能量將氣體原子撞擊為離子，并把這些離子嵌入基體的原子點(diǎn)陣中。The results of highenergy processes are not well known or very well thepreliminary results look development is needed in highenergy processes, especially in implant dosages and treatment 。Based on their purpose, construction, number of tools that can simultaneously be mounted, and degree of automation, lathesor, more accurately, lathetype machine tools can be classified as follows: 根據(jù)它們的使用目的、結(jié)構(gòu)、能同時(shí)被安裝刀具的數(shù)量和自動(dòng)化的程度，車床—或更確切地說是車床類的機(jī)床，可以被分成以下幾類：(1)Engine lathes(2)Toolroom lathes(3)Turret lathes(4)Vertical turning and boring mills(5)Automatic lathes(6)Specialpurpose lathes(1)普通車床(2)萬能車床(3)轉(zhuǎn)塔車床(4)立式車床(5)自動(dòng)車床(6)特殊車床In spite of that diversity of lathetype machine tools, they all have mon features with respect to construction and principle of features can best be illustrated by considering the monly used representative type, the engine is a description of each of the main elements of an engine lathe, which is shown in ，但它們?cè)诮Y(jié)構(gòu)和操作原理上具有共同特性。It has guideways to allow the carriage to slide easily height of the lathe bed should be appropriate to enable the technician to do his or her job easily and 。The function of the gearbox is to provide a number of different spindle speeds(usually 6 up to 18 speeds).Some modern lathes have headstocks with infinitely variable spindle speeds, which employ frictional ,electrical ,or hydraulic (通常是6到18速)。Also, that hole has a tapered surface to allow mounting a plain lathe outer surface of the spindle is threaded to allow mounting of a chuck, a face plate, or the ，此孔為錐形表面可以安裝普通車床頂尖。The intermediate part is a casting that can be moved transversely to enable alignment of the axis of the tailstock with that of the third part, the quill, is a hardened steel tube, which can be moved longitudinally in and out of the intermediate part as ，它可以調(diào)整尾架軸線與主軸箱軸線成一直線。套筒軸通過定位裝置能沿著它的移動(dòng)路徑被鎖定在任何點(diǎn)。When cutting screw threads, power is provided to the gearbox of the apron by the lead all other turning operations, it is the feed rod that drives the lead screw goes through a pair of half nuts, which are fixed to the rear of the ，動(dòng)力通過絲桿提供給溜板箱上的齒輪箱。當(dāng)操作桿脫離時(shí)，剖分螺母釋放同時(shí)大拖板停止運(yùn)動(dòng)。它與光桿和絲桿連接，能容易并快速地通過簡單轉(zhuǎn)換適當(dāng)?shù)牟僮鳁U選擇各種進(jìn)給。Turning tools can be classified into two main groups, namely, external cutting tools and internal cutting of these two groups include the following types of tools: 車削刀具可以分為兩個(gè)主要組別，即外部切削刀具和內(nèi)部切削刀具。粗車刀具按其進(jìn)給方向可以是右手型的或是左手型的。Cutoff tools, which are sometimes called parting tools, serve to separate the workpiece into parts and/or machine external annular ：切斷刀具，有時(shí)也稱為分割刀具，用于將工件分割成若干部分和/或加工外部環(huán)形槽。Form tools have edges especially manufactured to take a certain form, which is opposite to the desired shape of the machined ：成形刀具有專門制成特定形狀的刀刃，這種刀刃形狀與被加工工件所需外形正好相反。As the name suggests, the function of the chip breaker is to break long chips every now and then, thus preventing the formation of very long twisted ribbons that may cause problems during the machining ，斷屑槽的功能就是不時(shí)地折斷長切屑，以防形成很長的可能會(huì)在機(jī)加工操作中引起問題的纏繞切屑條。It must be borne in mind, however, that modern puterized numerically controlled lathes have more capabilities and can do other operations, such as contouring, for are conventional lathe ，必須記住現(xiàn)代計(jì)算機(jī)數(shù)控車床具有更多的功能并且可以進(jìn)行其它操作，例如仿型。工件旋轉(zhuǎn)一整圈產(chǎn)生一個(gè)圓心落在車床主軸上的圓；由于刀具的軸向進(jìn)給運(yùn)動(dòng)這種動(dòng)作重復(fù)許多次。In roughing cuts, it is remended that large depths of cuts(up to 6mm, depending upon the workpiece material)and smaller feeds would be the other hand, very fine feeds, smaller depths of cut(less than , or ), and high cutting speeds are preferred for finishing ，推薦使用較大切削深度()和較小進(jìn)給。Facing can be carried out either from the periphery inward or from the center of the workpiece is obvious that the machining marks in both cases take the form of a 。Groove cutoff and groovecutting operations, only cross feed of the tool is cutoff and grooving tools, which were previously discussed, are ：在切斷和開槽操作中，刀具只有橫向進(jìn)給。鉆孔刀具安裝在尾架上，然后對(duì)著工件進(jìn)給。當(dāng)錐角相對(duì)較大時(shí)切削外錐面和內(nèi)錐面推薦使用這種方法。(3)Offsetting the tailstock method is employed for external taper turning of long workpieces that are required to have small taper angles(less than 8176。)的較長工件外錐面車削采用這種方法。在這種場合下要遵循的步驟是將橫向滑板完全脫離大拖板，然后通過錐面車削附加裝置進(jìn)行引導(dǎo)。對(duì)具有較小錐角(即8176。兩者之間的關(guān)系基本上由被切削螺紋所需的節(jié)距決定。The pitch of the resulting thread being cut therefore always depends upon the ratio of the rotational speeds of the lead screw and the spindle: Pitch of the lead screw/ Desired pitch of workpiece=rpm of the workpiece/rpm of lead screw=spindletocarriage gearing ：絲桿的節(jié)距/工件所需節(jié)距=工件轉(zhuǎn)速/絲桿轉(zhuǎn)速=心軸到大拖板的傳動(dòng)比。 is mainly a forming operation in which no chips are involves pressing two hardened rolls with rough filelike surfaces against the rotating wo