銑削機(jī)械加工工藝工裝夾具課程畢業(yè)設(shè)計(jì)外文文獻(xiàn)翻譯@中英文翻譯@外文翻譯

附錄 A 英文原文 MILLING Milling is a machining process that is carried out by means of a multiedge tool known as a milling cutter .In this process,metal removal is achieved through combining the rotary motion of the milling cutter and linear motions of the workpiece simultaneously.Milling operations are employed in producing flat ,contoured and helical surfaces as well as for thread-and gear-cutting operations. Each of the cutting edges of a milling cutter acts as an individualsingle-point cutter when it engages with the workpiece metal .Therefore ,each of those cutting edges has appropriate rake and relief angles .Since only a few of the cutting edges are engaged with the workpiece at a time ,heavy cuts can be taken without adversely affecting the tool life .In fact ,the permissible cutting speeds and feeds for milling are there to four times higher than those for turning or drilling .Moreover,the quality of the surfaces machined by turning ,shaping ,or drilling. A wide variety of milling cutters is available in industry with the fact that a milling machine is a very versatile machine milling machine the backbone of a machining workshop. As far as the direction of cutter rotation and workpiece feed are concerned ,milling is performed by either of a machining workshop. Up milling (conventional milling) .In up milling the workpiece is fed against the direction of cutter rotation ,as shown in Fig.5. l(a) .As we can see in that figure ,the depth of cut (and consequently the load ) gradually increases on the successively engaged cutting edges .Therefore ,the machining process involves no impact loading ,thus ensuring smoother operation of the machine tool and longer tool life .The quality of the machined surface obtained by up milling is not very high .Nevertheless ,up milling is commonly used in inciustry ,especially for rough cuts. Down milling(climb milling) .As can be seen in Fig.5.1b ,in down milling the cutter rotation coincides with the direction of feed at the contact point between the tool and the workpiece .It can also be seen that the maximum depth of cut is achieved directly as the cutter engages with the workpiece .This result in a kind of impact ,or sudden loading .Therefore ,this method cannot be used the milling machine is equipped with a backlash eliminator on the feed screw. The advantages of this method include higher quality of the machined surface and easier clamping of workpieces,since the cutting forces act downward. Types of milling cutters There is wide variety of milling cutter shapes.Each of them is designed to perform effectively a specific.Generally,a milling cutter can be described as a multiedge cutting tool having the shape of a solid of revolution,with the cutting teeth arranged either on the periphery or on an end face or on both.following is a quick survery of the commonly used types of milling cutters. Plain milling cutter.A plain milling cutter is a disk-shaped cutting tool that may hace either straght or helical teeth,as shown in Fig.5.2a.This type is always mounted on horizental milling machines and is used for machining flat surfaces. Face milling cutters.A face milling cutter is also used for machining flat surfaces,it is bothed at the end of a shot arbor,which is in turn mounted on a vertical milling machine.Fig.5.2b indicates a milling cutter of this type. Plain metal slitting saw.Fig.5.2c indicates a plain metal slitting saw cutter.We can see that it actually involves a very thin plain milling cutter. Side milling cutter.Aside milling cutter is used for cutting slots,grooves,and splines.As we can see in Fig.5.2d,it is quite sililar to the plain milling cutter,the difference between the being that this type has teeth on the side .As was the case with the plain cutter ,the cutting teeth can be straight or helical. Angle milling cutter .An angle milling cutter is employed in cutting dovetail grooves ,ratchet wheels ,and the like .Fig.5.2e) indicates a milling cutter of this type. T-slot cutter .As shown in Fig.5.2f) ,a T-slot cutter involves a plain milling cutter with an integral shaft normal to it .As the name suggests ,this type is used for milling T-slots. End mill cutters .End mill cutters find common application in cutting slots ,grooves ,flutes ,splines ,pocketing work ,and the like .Fig.5.2g indicates an end mill cutter .The latter is always mounted on a vertical milling machine and can have two or four times ,which may be either straight or helical. Form milling cutters Th: teeh of a form milling cuuter have a certain shape ,which is identical to the metal to be removed during the milling operation. Examples of this type include gear currer ,gear hobs, convex and concave cutters, and the like .Form milling cutters are mounted on horizontal milling machines,as is esplained later when we discuss gear cutting. Material of Milling Cutters The commonly used milling cutters are made of high-speed steel, which is generally adequate for most jobs .Milling cutters tipped with sintered cabides nonferrous alloys as cutting teeth are usually employed for mass production,gh cutting speeds are requied.Cutting tool material may be classified in different ways main element. The main element may be carbon steel.high-speed steel meaJum-alloy steel .high-speed steel, a cemented carbide. Of course, iron is the main constitutent .of the first three. Carbon steel tools Carbon steel tools have a limited use, as they are characterized by. Low hot hardness and poor hardnability. Carbon contents range from o.s percent to 1.3 prcent. Tools of this type can be used for light work where temperatures produced do not exceed 204C. Medium-alloy steels These steels are not satisfactory for operations finishing operations. They can be used successfully. High-speed steels High-speed steel tools are characterized by superior wear resistance and hot hardness. High-speed steel tools contain Up to 18 percent tungsten and 51.5 percent chromium as the principal alloying element, Other alloying element such as molybdenum and cobalt give special qualities, These cutters will retain keen cutting edges at temperatures up to 593 C ( 1100F ) .Also the proper cutting fluids can increase their life and improve use to a considerable extent. Cast Alloys A number of nonferrous alloys know as stellhes have developed for use asculting tools ,these alloys usually contain 2 to 4 percent carbon 14 to 29 percent tungsten 27 to 32 percent chromium 40 to 50 percent cobalt; the tools must be used as cast ;and cannot ;be near treated, they are not affected by heat up to 815C (1500F), high-speed steel tools are somewhat harder that Stellite up to 537 C(ll00F).above this temperatures, stelite retails hardness much better ,highcutting speeds are possible with this type of tool than with high speed steel tools. Stelite, being cast ,has a tendency to shatter under shock ,thus ,it must be well supported in the toolhoider. It can be tip-brazed or weided to a shank steel. It may also be fashioned as a removable bit in a special toolhoider. Cemented Carbides Cemented carbide tools are know by trade named such as Carpoioy, Kennametal,Vascoioy-Ronet,and Firtnite. There are two genral grades of metal-cutting cemented in use: 1. The C grace is made up of tung-sten carbide with cobait grace is used in machining cast ircn and nonterrous metals. 2. The Sgrade is made up of tung-sten. Titanium,and tantalum carbides cobalt as a binder. This grade is used on steels withThe cobalt content may vary from 3 percent to 16 percent. The larger the amount of cobait. The tougher and more wear-resistant beccmes the tool. TheSgraces usually contain form 0 percent to 16 percent tianlum carbide and 0percent to 10 percent tantalum carbide. The mean grain size is important. Toolsof icential cnemical composition but of different grain size will have differentpropentes. Coarser grain materi tl is more snock resistant. Cemented carbices have the following cnaractenstics High naraness over a wide range of temperatures. High thermal concuctivity. Low thermal expansion. Stiffness. Cemented carbide shculd be used at much higher operating speeds than high speed steel tool. The depth of cut is the thickness of the meal layer that is to be removed in one cut o The maximum allowable depth of cue depends upon the material being machined and is commonly taken up to 5/16in. (or 8mm)in toughing operations and 1/16in(aboutl.5mm)in finishing operations .Another parameter that affects milling operations is the width of cut .The Latter is the width of the workpiece in contact with the cutter in a direction normal to the feed. We can easily see that the width of cut should decrease with increasingdepth of cut to keep the load and power requirement below by the cutter and the machine tool, respectively. Types of Milling Machines There are several types of milling machines in industry. They are generally classified based on their construction and design features .They vary from the common general-purpose types to duplicators and machining operation that involve a tool magazine and are capable of carrying out many machining operation with a single workpiece setup. For example Plain horizontal milling machine, Universal milling machine, Vertial milling machine, Duplicators,Machining centers. 附錄 B 漢語翻譯 銑 削 銑削是用銑刀進(jìn)行多刃旋轉(zhuǎn)加工的工藝。在這種工藝中，金屬的切除是通過銑刀的旋轉(zhuǎn)運(yùn)動(dòng)以及此同時(shí)工件的直線運(yùn)動(dòng)的組合來實(shí)現(xiàn)。銑削加工可用于生成平面、曲面和螺旋面，也用于螺紋和切齒加工。 當(dāng)與工件金屬嚙 合切入時(shí)，銑刀的每個(gè)刀刃相當(dāng)于單刃刀片，因此，每個(gè)單刃片有一定的前角和后角，因?yàn)橹挥星邢魅械囊恍〔糠峙c工件在同一時(shí)間接觸，所以大切削量不會(huì)嚴(yán)重影響刀具的壽命。事實(shí)上，銑削加工的切削量與進(jìn)給量比車和鉆加工高出到 4倍。并且銑削加工的工件表面質(zhì)量通常高于那些被車，刨和鉆的工件表面質(zhì)量。 在工業(yè)上各種各樣的銑刀得到了廣泛的運(yùn)用。這也與事實(shí)一致，銑削加工是個(gè)通用性極強(qiáng)的加工工具，也使得銑床成為工廠機(jī)加車間的生產(chǎn)主干。 根據(jù)刀具的旋轉(zhuǎn)方向與工件的進(jìn)給方向，銑削以下兩種工件方式。 逆銑 (常規(guī)銑削 )，工件的進(jìn)給方向是與旋轉(zhuǎn) 方向相反，如外文資料中圖 5 1a 所示，當(dāng)連續(xù)的與切削相觸時(shí)，切削深度逐漸增大。因此，機(jī)加過程可以保證平穩(wěn)的操縱與更長(zhǎng)的刀具壽命。逆銑加工的工件表面質(zhì)量一般不是太高。雖然如此，逆銑還是在工業(yè)中普遍被使用，特別是在粗加工中。 順銑。如外文資料中圖 5 1b 所示，順銑時(shí)，在刀具和工件接觸時(shí)可以看作直接獲得最大的切削深度。這將是一種影響，或者是突然加載。因此，除非銑床加裝了齒隙消除裝置在進(jìn)給絲桿上，要不這種方法決不能被使用。此種方法的好處包括較高質(zhì)量的加工表面，較容易的裝卡工件。因?yàn)榍邢髁κ窍蛳碌摹?銑刀的類型 銑刀 的形狀多種多樣。它們中的每一個(gè)都為進(jìn)行有效的特殊銑削操作面設(shè)計(jì)。通常銑刀被稱為多刃刀具，其形狀為旋轉(zhuǎn)體，切削刃做在旋轉(zhuǎn)體的周邊上式端面上，或者周邊和端面上均有。下面是常用銑刀的一個(gè)快速概括。 普通銑刀，普遍銑刀是一碟狀物的切削工具，其分為直齒與螺旋齒。如圖外文資料中 5 2a 所示。這種銑刀通常固定在臥銑床上并且用于表面的平面加工。 平面銑刀。平面銑刀也用于表面的平面加工，它被固定在矩軸的末端，這樣可以逐次安裝到立式銑床上。外文資料中圖 5 2b 顯示了此種銑刀。 鋸片銑刀。外文資料中圖 5 2c 給出了一個(gè)普通金屬切 割的鋸片。我們可以看出確實(shí)為十分薄化的普通銑刀。 側(cè)面銑刀。側(cè)面銑刀被用作槽和鍵槽之類的加工。我們可以參看外文資料中圖 5 2d它與普通銑刀十分相似，所不同的是此種銑刀的齒是在邊上。由于和普通銑刀很象，切割齒也有直齒和螺旋齒。 角銑刀。角銑刀用于燕尾槽，棘輪的加工。外文資料中圖 5 2e 給出了此種類型的銑刀。 T 形銑刀。如外文資料中圖 5 2f 所示。 T 形銑刀是普通銑刀刀盤加上整軸而成，并彼此垂直，正如其名子，這種銑刀被用作銑丁形口。 端銑刀。端銑刀通常用于開口、開槽、出屑槽、鍵槽，內(nèi)腔的加工，如圖 5 2g 所示。其 末端通常安裝在立式銑床上并有兩到四個(gè)出屑槽，其也有直與螺旋之分。 成形銑刀。成形銑刀的齒有特定的形狀，這個(gè)形狀與銑削時(shí)要切削的那部分金屬形狀一致。其典型的包括：齒輪銑刀、齒輪滾刀、凹方與凸方刀和及其類似的。成形銑刀被安裝在