金屬切削加工畢業(yè)設(shè)計(jì)外文翻譯

1、<p>　　Metal-cutting process </p><p>　　Metal-cutting processes are extensively used in the manufacturing industry. They are characterized by the fact that the size of the original workpiece is sufficien

2、tly large that the final geometry can be circumscribed by it ,and that the unwanted meterial is removed as chips,particles ,and so on. The chips are a necessary means to obtain the desired tolerances, and surfaces. The a

3、mount of scrap may vary from a few percent to 70%~80% of the volume of the original work material.</p><p>　　Owing to the rather poor material utilization of the metal-cutting processes, the anticipated scarc

4、ity of materials and energy, and increasing costs,the development in the last decade has been directed toward an increasing application of metal-forming processes. However, die costs and the capital cost of machines rema

5、in rather high; consequently, metal-cutting processes are, in many cases, the most economical, in spite of the high material waste,which only has value as scrap. Therefore, it must </p><p>　　In metal-cutting

6、 processes, the imprinting of imformation is carried out by a rigid medium of transfer, which is moved relative to the workpiece, and the mechanical energy is supplied through the tool. The final geometry of the tool and

7、 the pattern of motions of the tool and the workpiece. The basic process is mechanical: actually, a shearing action combined with fracture.</p><p>　　As mentioned previously, the unwanted material in metal-cu

8、tting processes is removed by a rigid cutting tool ,so that the desired geometry, tolerances, and surface roughness are obtained. Examples of processes in this group are turning, drilling, reaming, milling, shaping, plan

9、ing, broaching, grinding, honing, and lapping. </p><p>　　Most of the cutting or machining processes are bases on a two-dimensional surface creation,which means that two relative motions are necessary betwe

10、en the cutting tool and the work material. These motions are defined as the primary motion, which mainly determines the cutting speed, and the feed motion, which provides the cutting zone with new material.</p>&l

11、t;p>　　In turning the primary motion is provided by the rotation of the workpiece,and in planing it is provided by the translation of the table; in turning the feed motion is a continuous translation of the tool, and i

12、n planing it is an intermittent translation of the tool.</p><p>　　Cutting Speed The cutting speed v is the instantaneous velocity of the primary motion of the tool relative to the workpiece(at a selected poi

13、nt on the cutting edge).</p><p>　　The cutting speed for turning,drilling, and milling processes can be expressed as</p><p>　　V=πdn m/min</p><p>　　Where v is cutting speed in m/min,d

14、 the diameter of the workpiece to be cut in meters, and n the workpiece or spindle rotation in rev/min. thus v, d, and n may relate to the work material or the tool, depending on the specific kinematic pattern. In grindi

15、ng the cutting speed is normally measured in m/s.</p><p>　　Feed The feed motion f is provided to the tool or the workpiece and, when added to the primary motion, leads to a repeated or continuous chip remova

16、l and the creation of the desired machined surface. The motion may proceed by steps or continuously. The feed speed vf is defined as the instantaneous velocity of the feed motion relative to the workpiece(at a selected p

17、oint on the cutting edge) </p><p>　　For turning and drilling, the feed f is measured per revolution (mm/rev) of the workpiece or the tool; for planing and shaping f is measured per storke (mm/stroke) of the

18、 tool or the workpiece. In milling the feed is measured per tooth of the cutte fz (mm/touth); that is,fz is the displacement of the workpiece between the cutting action of two successive teeth。The feed speed vf（mm/min）of

19、 the table is therefore the product of the number of the teeth z of the cutter ,the revolutions per minute of</p><p>　　A plane containing the directions of the primary motion and the feed motion is define as

20、 the working plane, since it contains the motions responsible for the cutting action.</p><p>　　Depth of Cut (Engagement) In turning the depth of cut a (sometimes also called back engagement) is the distance

21、that the cutting edge engages or projects below the original surface of the workpiece. The depth of cut determines the final dimensions of the workpiece. In turning, with an axial feed, the depth of cut is a direct measu

22、re of the decrease in radius of the workpiece and with radial feed the depth of cut is equal to the decrease in the length of workpiece. In drilling, the depth of cut i</p><p>　　Chip Thickness h1 in the unde

23、formed state is the thickness of the chip measured perpendicular to the cutting edge and in a plane perpendicular to the direction of cutting. The chip thickness after cutting (i.e., the actual chip thickness h2) is larg

24、er than the undeformed chip thickness, which means that the cutting ratio or chip thickness ratio r=h1/h2 is always less than unity.</p><p>　　Chip Width The chip width b in the undeformed state is the width

25、of the chip measured along the cutting edge in a plane perpendicular to the direction of cutting.</p><p>　　Area f Cut For single-point tool operations, the area of cut A is the product of the undeformed chip

26、 thickness h1 and the chip width b (i.e., A=h1b).The area of cut can also be expressed by the feed f and the depth of cut a as follows:</p><p>　　h1=f sink and b=a/sink (27.2) </p><p

27、>　　where k is the major cutting edge angle (i.e.,the angle that the cutting edge forms with the working place).</p><p>　　Consequently, the area of cut is given by</p><p><b>　　A=fa &

28、lt;/b></p><p><b>　　金屬切削加工</b></p><p>　　金屬切削加工被廣泛應(yīng)用于制造業(yè)。他們的特點(diǎn)是工件在加工前有足夠的尺寸，可以將工件的最終幾何形狀尺寸包含在里面。不需要的材料以顆粒，切屑的方式被去除。去除切屑是獲得所要求的工件幾何形狀，尺寸公差和表面質(zhì)量的一個必要的手段。廢料的數(shù)量多少不一，可能會占工件體積的從百分之幾到70 ％

29、? 80 ％不等。</p><p>　　金屬切削加工中，由于材料利用率較差，加之預(yù)計(jì)到缺乏原料和能源和成本的增加，在過去十年發(fā)展中，金屬成形加工應(yīng)用越來越廣。但是，金屬成形加工的模具的成本和設(shè)備成本仍然相當(dāng)高，因此盡管金屬切削加工材料浪費(fèi)嚴(yán)重，但在許多情況下仍然是最經(jīng)濟(jì)的。因此金屬切削加工將在今后幾年保持其在制造業(yè)的重要地位。此外，金屬切削加工自動化生產(chǎn)系統(tǒng)的發(fā)展比金屬成形加工自動化生產(chǎn)系統(tǒng)的發(fā)展快得多。<

30、/p><p>　　在金屬切削加工中，信息的傳遞是通過剛性傳遞介質(zhì)（刀具）實(shí)現(xiàn)的，刀具相對工件運(yùn)動，機(jī)械能通過刀具作用于工件。因此，刀具的幾何形狀和刀具與工件運(yùn)動方式?jīng)Q定了工件的最終形狀。這個基本過程是機(jī)械過程，事實(shí)上是一個剪切和斷裂相結(jié)合的過程。</p><p>　　如前所述，多余材料在金屬切削加工中是通過去剛性切削刀具去除掉的，以獲得使所需的幾何形狀，公差和表面粗糙度的結(jié)果。屬于這種加工方法

31、的例子有：車削，鉆孔，鉸孔，銑削，牛頭刨削，龍門刨削，拉削，磨削，珩磨和研磨。</p><p>　　大多數(shù)切削加工或機(jī)械加工是在二維表面成型法上建立的，這意味著是必要的切割工具和工件材料得有兩種相對運(yùn)動。一種被稱為主要運(yùn)動，主要確定的切削速度和另一種被稱為進(jìn)給運(yùn)動，它提供了切割帶新的材料。</p><p>　　車削時工件的主運(yùn)動是回轉(zhuǎn)運(yùn)動，龍門刨床刨削時，工作臺的直線運(yùn)動是主運(yùn)動;車削時，

32、刀具的連續(xù)直線運(yùn)動是進(jìn)給運(yùn)動。而在龍門刨床的刨削中，刀具的間歇運(yùn)動是進(jìn)給運(yùn)動。</p><p>　　切削速度：切削速度v切削刀具（切削刃上在選定的點(diǎn)） 相對于工件的瞬時速度 。</p><p>　　切削速度車削，鉆孔，銑加工可表示為</p><p>　　V = πdn m/min</p><p>　　式中V為切削速度，單位為米/分; d是

33、該工件將要切削部分的直徑，單位是米;n工件或主軸轉(zhuǎn)速，單位是轉(zhuǎn)/分。但是v，d,n的意義可能有所不同，這取決于具體的運(yùn)動模式。在磨削的切削速度通常是米/秒。</p><p>　　進(jìn)給量f除了主運(yùn)動，當(dāng)?shù)毒呋蚬ぜ鬟M(jìn)給運(yùn)動時，將會導(dǎo)致了重復(fù)或連續(xù)的切屑被去除從而創(chuàng)造理想的加工表面。進(jìn)給運(yùn)動可以是間歇的或是連續(xù)的。進(jìn)給速度vf的定義是選定切削刃上一點(diǎn)相對于工件的速度。</p><p>　　對于

34、車削和鉆削，進(jìn)給量f以工件或刀具的每轉(zhuǎn)的相對移動量來表示；對于龍門刨削和牛頭刨削，進(jìn)給量f以刀具或工件每次行程的相對移動量來表示；對于銑削來說，以刀具的每齒進(jìn)給量fz來表示。每齒進(jìn)給量fz是相鄰兩齒之間的距離。所以工作臺的進(jìn)給速度vf是刀具齒數(shù)z，刀具每分鐘轉(zhuǎn)數(shù)n和進(jìn)給速度fz的乘積。</p><p>　　包含主運(yùn)動方向和進(jìn)給運(yùn)動方向的平面被定義為工作平面，因?yàn)樵撈矫姘瑳Q定切削作用的兩種基本運(yùn)動。</p&

35、gt;<p>　　切削深度（吃刀深度）車削的切削深度a（有時也被稱為背吃刀量）是刀具切削刃切進(jìn)或深入工件表面的距離。切削深度決定了最后的尺寸工件。在切削加工中采用軸向進(jìn)給時，切削深度可以通過直接測量工件半徑減少量來確定；在切削加工中采用徑向進(jìn)給時，切削深度等于工件長度的減少量。在鉆削中，切削深度等于鉆頭的直徑。對于銑削，切削深度定義為側(cè)吃刀量ae，它等于銑刀徑向吃刀深度，而銑刀軸向吃刀深度（背吃刀量）被稱為ap。</

36、p><p>　　切屑厚度未變形狀態(tài)時的切削厚度h1，就是在垂直于切削方向的平面內(nèi)垂直于切削刃測量得到的切屑厚度。切削后的切屑厚度（即切屑的實(shí)際厚度h2）大于未變形時的切屑厚度，這意味著削減比或切屑厚度比R = h1/h2總是小于一。 切削寬度 未變形狀態(tài)的切削寬度b 是在與切削方向垂直的平面內(nèi)眼切削刃測得的切屑寬度。</p><p>　　切削面積 對于單刃刀具的切削加工，切削面積A是

37、為變形的切屑厚度h1和切削寬度b的乘積（即A=h1*b）。切削面積也可以用進(jìn)給量f和切削深度a來表示如下：</p><p>　　H1=f*sink 及 b=a/sink</p><p>　　式中k為主偏角（即切削刃與工作平面成的夾角）。</p><p>　　因此，可以由下式求出切削面積：</p><p><b>　　A=f*