機(jī)械設(shè)計(jì)制造及其自動(dòng)化專業(yè)英語

1、機(jī)械設(shè)計(jì)制造及其自動(dòng)化專業(yè)英語chapter one materials and mechanical elements lesson llntroduction for materials designets and engineers are usually more interested in the behavior of materials under load or whon in amagnetic field in why they behave as they do. yet the better one understands the nature of materials

2、 and the reasons for their physical and mechanical properties the more quickly and wisely will he/she be able to choose the proper material for agiven design. gcncrally, a matcrial property is the measured magnitude of its response to astandard test performed according to astandard procedure in agiv

3、en environment. in engineering materials the loads are mechanical or physical in nature and the properties are recorded in handbooks or, for new materials, are made available by the supplier. frequcntly such information is tabulated for roomtemperature conditions only, so when the actual service con

4、ditions are at subfreezing or elevated temperatures, more information is needed.第一章材料和機(jī)械零件第一課材料介紹設(shè)計(jì)者和工程師們通常都會(huì)對(duì)在加載狀態(tài)下或處于磁場(chǎng)中的材料的性能更 感興趣，而不關(guān)心它們?yōu)槭裁淳哂羞@個(gè)性能。然而，一個(gè)人若能更好地理解這 些材料的性質(zhì)和它們的物理和機(jī)械的性能原因，了解得越清楚，他/她就能更快 速和準(zhǔn)確地選擇合適的材料。通常，材料性能是在給定的環(huán)境條件下按照規(guī)定 的方法進(jìn)行的標(biāo)準(zhǔn)試驗(yàn)所獲得的測(cè)定值。事實(shí)上，工程材料屮的加載實(shí)質(zhì)上是 機(jī)械的或物理的加載，并且性能是記錄在手冊(cè)上的，或者，對(duì)于新

5、材料來說， 是應(yīng)由供應(yīng)商來提供性能手冊(cè)的。一般來說類似的信息僅僅是在室溫條件下被 列表顯示的，因此，當(dāng)實(shí)際的操作條件是在冰點(diǎn)以下或在高溫條件下，則會(huì)需 要更多的信息。lesson 4gears helical gears have certain advantages； for example, when connecting parallei shafts they have ahigher loadcarrying capacity than spur gears with the same tooth numbers and cut with the same cuttc because

6、 of the overlapping action of the teeth, they are smoother in action and can operate at higher pitchline velocities than spur gears. the pitch-line velocity is the velocity of the pitch circle. since the teeth are inclined to the axis of rotation, helical gears create an axial thrust. tf used singly

7、, this thrust must be absorbed in the shaft bearings. the thrust problem can be overcome by cutting two sets of opposed helical tccth on the same blank.depending on the method of manufacture, the gear may be of the continuous-tooth herringbone variety or adouble-helical gear with aspace between the

8、two halves to permit the cutting tool to run outdouble-helical gears are well suited for the efficient transmission of power at high speeds.第四課齒輪斜齒輪有某些優(yōu)點(diǎn)；例如，在具有相同齒數(shù)且用同樣的刀具來加工的情況 下，連接平行軸的斜齒輪的承載能力要比直齒輪更高一些。由于輪齒的重疊作 用，斜齒輪在運(yùn)動(dòng)屮比直齒輪更平穩(wěn)，并且能夠以更高的節(jié)線速度來運(yùn)行。節(jié) 線速度就是節(jié)圓的線速度。由于輪齒向軸線的旋轉(zhuǎn)方向傾斜，故斜齒輪產(chǎn)生了 一個(gè)軸向推力。如果是單個(gè)的齒輪，這

9、個(gè)推力必定會(huì)被軸向軸承吸收。通過在 同一個(gè)坯件上切削兩組相對(duì)的斜齒輪，能夠克服推力的問題。根據(jù)不同的制造 方法，齒輪可以是連續(xù)的人字形齒輪，或者是在兩列斜齒之間留一間隙的雙斜 齒形齒輪，以便切削刀具通過。雙斜齒形齒輪更適合以高速度進(jìn)行高效地傳送。lesson 6dimensioning the design of amachinc includes many factors other than those of determining the loads and stresses and selecting the proper materials .before construetion

10、or manufacture can begin, it is necessary to have complete assembly and detai1 drawings to convey all necessary information to the shop men. the designer frequently is called upon to check the drawings before they are sent to the shop. much experience and familiarity with manufacturing processes are

11、 needed before one can become conversant with al 1 phases of production draw in gs.drawings should be careful 1y checked to see that the dimensioning is done in amarincr that will be most convenient and understandablc to the production departments. it is obvious that adrawing should be made in such

12、away that it has one and only one interpretation. in particular, shop personnel should not be required to make trigonometric or other involved calculations before the production machincs can be set up.第六課標(biāo)注要設(shè)計(jì)一個(gè)機(jī)床除了要考慮那些己確定的負(fù)載和應(yīng)力并且選擇合適的材料 以外，還包括很多其他的因素。在構(gòu)造和加工開始以前，必須要把完整的裝配 圖和詳細(xì)的零件圖的全部有用的信息傳達(dá)給工人。設(shè)計(jì)者經(jīng)

13、常要在圖紙未被送 到車間以前檢查核對(duì)圖紙。每個(gè)人在熟悉生產(chǎn)圖紙的齊個(gè)階段之前都必須具有 豐富的經(jīng)驗(yàn)并精通加工工藝。應(yīng)該仔細(xì)檢查圖紙，為生產(chǎn)部門作標(biāo)注時(shí)須用一種最合適和最易理解的方 式進(jìn)行，很明顯，一張圖紙應(yīng)該是有且只有一種解釋的。尤其是不能要求車間 工人先進(jìn)行三角或其他復(fù)雜的計(jì)算后才能去調(diào)整機(jī)床。chapter two machinc tool, cutting tool，jig and fixture lcsson lengine lathe (center lathe)an engine lathe is shown diagrammatically in fig. 2. la： it c

14、onsists of ahorizontal bed supporting the headstock, the tailstock, and the carriage. all machine tools must have ameans of supporting or holding the workpiece. in fig. 2. 1 the workpiece is gripped at one end by achuck mounted on the end of the main spindle of the machine and is supported at the ot

15、her end by acenter mounted in the tailstock. the tailstock can be clamped at various posi tionsalong the bed to accommodate workpieces of various lengths. short workpieces need only be gripped by the chuck.primary motion,the rotation of the workpiece(motion c，), is provided by the movement of aserie

16、s of gears driving the mainspindle, thegears being drivcn by anrear of the machine. the main spindle the headstock. levers on the front of rotational speeds to be sele cted.electrie motor mounted at the and the gears are all mounted in the headstock allow various第二章機(jī)床，切削刀具，鉆模和夾具第一課車床（普通車床）一個(gè)普通車床的結(jié)構(gòu)如

17、圖2. la所示：它由支撐著主軸箱的臥式床身、尾座 以及拖板三部分組成。所有的機(jī)床必須都要有一種支撐或夾緊工件的方式。在 圖2.1中，工件通過安裝在機(jī)床主軸末端的卡盤在一端被夾緊，并且由裝配在 尾架上的頂尖在另一端被支撐。根據(jù)被加工工件長(zhǎng)度的不同，尾架沿著床身被 裝夾在不同的位置。短的工件僅需要由卡盤夾緊。主運(yùn)動(dòng)，即工件的旋轉(zhuǎn)運(yùn)動(dòng)（也就是c'點(diǎn)的運(yùn)動(dòng)），是由輪系驅(qū)動(dòng)主軸實(shí)現(xiàn) 工件旋轉(zhuǎn)的，齒輪通過裝夾在車床尾部的電機(jī)來帶動(dòng)它旋轉(zhuǎn)。主軸和齒輪都裝 夾在主軸箱中。主軸箱前部的手柄能夠根據(jù)實(shí)際需要選擇不同的旋轉(zhuǎn)速度。lesso n 2ilorizo ntal milling mach in e

18、 (llorizo ntal miller)there arc two main types of milling machincs： horizontal and vertical. these words again refer to the orientation of the main spindle. in the horizontal-milling machine shown in fig. 2. 5 the milling cutter is mounted on ahorizontal arbor driven by the main spindle. the tools a

19、re therefore rotated(motion c)and the work fed continuously(motions x，or y，).the simplest operation,slab milling, is used to generate ahorizontal surface on the workpiece, as shown in fig. 2. 5. the figure shows the conventional slab-milling operation； if the workpiece had been fed in the opposite d

20、irection, it would tend to climb onto the work surface, and this type of slab milling is callcdclinibniilling. some evidence suggcsts that the forces and power consumption are less in climb milling than in conventional milling. however, high rigidity of the machine tool and work and toolholding devi

21、ces is required for this operation.第二課臥式銃床銃床有兩種主要類型：臥式和立式。這兩種銃床再一次提到了主軸的方向。 如圖2. 5所示的臥式銃床，銃刀被裝在水平方向的刀桿上，這個(gè)刀桿由主軸來 驅(qū)動(dòng)。刀具因此是旋轉(zhuǎn)的(c運(yùn)動(dòng))，并且工件是連續(xù)地進(jìn)給(x'、y'方向的運(yùn) 動(dòng))。平面銃的加工方式最簡(jiǎn)單，用來加工工件的水平表面，如圖2. 5所示。該 圖給出了平面逆銃加工；如果工件以相反的方向進(jìn)給，刀具就像在工件表面上 爬行一樣，這種類型的平而銃也叫順銃。一些證據(jù)表明，順銃中的力和功率 的消耗比逆銃中的少。然而，這就要求機(jī)床、工件和夾具要具有更高的碩度。

22、lesson 3shaping machine(shaper)the shaper is asmall machine on which the primary motion is linear(fig. 2. 17). the single-point tool is gripped in atoolhead mounted on the end of aram. the ram is made to move backward and forward(x motion)either by amechanical drive system or dhydraulic piston and c

23、ylinder. the cutting stroke is the forward stroke, and with either mechanical or hydraulic shapers the forward ram speed is slower than the speed on the return stroke, causing the production time to be reduced as much as possible. a quick-return mechanism often used in mechanical shapers is shown in

24、 fig. 2. 18. in all shapers the length of the stroke can be adjusted to suit the particular workpiece being machined. the feed is applied to the workpiece in increments at the end of the return stroke of the ram by arachet-and-pawl mechanism driving the lead screw in the crossrail.shapers are most c

25、ommon1y used to machine flat surfaces on smal 1 comp onents and are onl y sui tabl e for lowbato n qua nt ities.for the machining of ahorizontal surface（fig. 2. 17）, the workpiece is fed horizontally（y" motion）； for vertical surfaces, the workpiece is fed vertically（z5 motion）.第三課牛頭刨床（成型機(jī)）牛頭刨床是

26、一個(gè)小型機(jī)床，它的主運(yùn)動(dòng)是直線運(yùn)動(dòng)（圖2.17）。它的單刃刨 刀被夾緊在刀架上，裝卡在滑枕的末端。機(jī)械的驅(qū)動(dòng)或者液壓的活塞缸使得滑 枕在x軸方向上進(jìn)行前后移動(dòng)。它向前供進(jìn)的行程即為切削行程，并伴隨著機(jī) 械或者液壓的成型機(jī)，滑枕向前的速度要比它回程的速度慢得多，這就會(huì)使加 工時(shí)間盡可能的快，以提高工作效率。通常，用在機(jī)械牛頭刨床的快冋機(jī)械如 圖2. 18所示。在所有的牛頭刨床屮，回程的長(zhǎng)度均可根據(jù)需要做出相應(yīng)的調(diào)整 以適應(yīng)不同的待加工工件。在滑枕返程的末端，進(jìn)給被應(yīng)用于工件的增量上， 通過橫導(dǎo)軌內(nèi)的絲桿來驅(qū)動(dòng)棘輪棘爪機(jī)構(gòu)。牛頭刨床大多用于加工普通的小零件的平面表面，并且僅適合小批量加工 牛產(chǎn)。對(duì)

27、于一個(gè)機(jī)件的水平表面的加工（圖2.17）,工件沿水平方向進(jìn)行進(jìn)給 （沿y'軸方向運(yùn)動(dòng)）；對(duì)于垂直表面的加工，工件以垂直的方向進(jìn)給（z'軸方向）。lcsson 4automatic machincs afinal class of automatic lathe is the multispindle automatic. these lathes are basically flexible, rotary- transfer machines where each spindle holding acollet or chuck is indexed around the v

28、arious tooling positions so that during each indexi ng cycle acompleted comp orient is produced. drum cams in stead of disk cams are used in these machines.another class of machine tool that can be mechanized is the internal or external cylindrical grinder. when fitted with mechanisms for loading wo

29、rkpieces automatically and wi th automatic wheel-dressing devices, these machines can continually produce finished components. the workpieces are often stacked in amagazine, and the operator simply ensures that the magazine is replenished with workpieces at suitable intervals. because the components

30、 are small and the machining forces light, magnetic chucks are often employed to facilitate automatic work holding.第四課自動(dòng)機(jī)床最后一組的自動(dòng)車床是多主軸自動(dòng)機(jī)床。這類機(jī)床基木上是靈活的旋轉(zhuǎn)自 動(dòng)機(jī)，它的每一根軸上都有一個(gè)夾頭或卡盤，可以繞不同位置的刀具轉(zhuǎn)位，因 此，每轉(zhuǎn)位一次就加工出一個(gè)零件。在這類機(jī)床中，凸輪軸取代了盤形凸輪被 使用。另一類可以實(shí)現(xiàn)機(jī)械化的機(jī)床是內(nèi)部的或外部的外圓磨床。當(dāng)裝上帶有自 動(dòng)砂輪修整裝置的自動(dòng)裝載工件的機(jī)械時(shí)，這些機(jī)床能夠不斷地生產(chǎn)成品組件。 工件堆

31、放在自動(dòng)儲(chǔ)存送料裝置上，而操作者只需在適當(dāng)?shù)臅r(shí)間內(nèi)將工件補(bǔ)放到 送料裝置上。因?yàn)檫@些組件很小，并且加工力道很輕，磁性夾頭通常采用自動(dòng) 方式，以方便運(yùn)行。lesson 5jigs and fixtures when several identical workpieces are to be produced the need to mark out each part is eliminated by the use of jigs and fixtures, but if acasting or forging is involved, a trial workpiece is marked

32、 out, to cnsure that the workpiece can be produced from it, and to ensure that ribs, cores, etc. have not become misplaced.jigs and fixtures are alike in that they both incorporate devices to ensure that the workpiece is correctly located and clamped, but they differ in that jigs incorporate means o

33、f tool guiding during thepractice, the onlyactual cutting operation, and fixtures do not.in cutting tools that can be guided while actually cutting aredri11s,reamers, and similar cutters； and so jigs are associated wi thoperations. fixturesdrilling operations, and fixtures with all other may incorpo

34、rate means of setting the cutting tools relative to the location system.第五課鉆模和夾具當(dāng)若干相同的工件需要加工吋，通過使用鉆模和夾具可不必對(duì)每個(gè)工件都 進(jìn)行劃線。但如果加工的是鑄件或鍛件，則仍需對(duì)試件進(jìn)行劃線，以確保加工 出合格的樣件，而不致造成加強(qiáng)筋、內(nèi)孔等位置偏移。鉆模和夾具類似，都是確保工件正確定位和夾緊的裝置，但也有不同之處, 鉆模具有在實(shí)際加工過程中仍能導(dǎo)引刀具的元件，而夾具則沒有。實(shí)際上，在 切削過程屮只有對(duì)鉆頭、較刀以及類似的刀具才能進(jìn)行導(dǎo)引，所以鉆模通常與 鉆削加工相關(guān)聯(lián)，而夾具是與其他所有加工方法相關(guān)聯(lián)

35、的。夾具可納入設(shè)置相 對(duì)定位系統(tǒng)的調(diào)刀手段。chapter three conventional and nonconventional machining lesson iterm and definitions all metal-cutting operations can be likened to the process shown in fig. 3. 1, where the tool is wedge-shaped, has astraight cutting edge, and is constrained to move relative to the workpiece

36、in such away that alayer of metal is removed in the form of achip. fig. 3. lb depicts the general case of cutting known as oblique cutting. a special case of cutting, where the cutting edge of the tool is arranged to be perpendicular to the direction of relative work- tool motion(fig. 3. la), is kno

37、wn as orthogoneil cutting. sincc orthogonal cutting represents atwo-dimensional rather than athree-dimensional problem, it lends itself to research investigations where it is desirable to eliminate as many of the independent variables as possible. the relatively simple arrangement of orthogoneil cut

38、ting is thcrcforc widely used in theoretical and experimcntai work.the tool flank plays no part in the process of chip removal； however, the angle between the flank and the new workpiece surface can significantly affect the rate at which the cutting tool wears and is defined as the clearance angle o

39、r, more precisely, the working normal clearanee.thus from fig. 3. 2 the sum of the rake, clearance, and wedge angles is equal to 90 deg, where the wedge angle is the included angle betwecn the face emd the flank.第三章常規(guī)和非常規(guī)加工第一課術(shù)語和定義所有的金屬切削加工過程都可以用圖3.1所示的過程來表示，即刀具是楔 形的口具有直線切削刃，并口刀具相對(duì)于工件運(yùn)動(dòng)，每運(yùn)動(dòng)一次便會(huì)切下一層

40、切屑。圖3. lb描述了斜刃切削作為切削刀具的一般情況。切削屮有一個(gè)特例， 即刀具的切削刃相對(duì)于刀具的運(yùn)動(dòng)方向是垂直的（圖3. la）,這也叫直角切削。 由于直角切削反映的是二維而不是三維的結(jié)構(gòu)問題，這樣相對(duì)簡(jiǎn)單的直角切削 也因此被廣泛地用于理論和實(shí)驗(yàn)的工作中。刀具后刀面在切屑被去除的過程中不起作用；然而，后刀面與新加工工件 表面所夾的夾角嚴(yán)重地增加了刀具的磨損率，這個(gè)角被定義為后角，或者，更 確切地說，稱為工作法向后角。然而從圖3.2可以看出，前角，后角和楔形角三者的和正好等于90° ,這 個(gè)楔形角包含了前刀面和后刀面所夾的夾角。lesson 2production turning

41、 operations the era of modern machine tools is relatively recent, dating back to the industrial revolution in england. the first screw-cutting lathe was invented by maudsley in 1798. the modern engine lathe takes its name from its gear-driven headstock that typically provides 16 spindle speeds. alth

42、ough an engine lathe can bring one to four tools mounted in its one toolpost to bear on aworkpiccc, it can provide only asinglc feed motion at one time. a typical turned part frequently requires several operations, each of which needs adifferent tool and feed motion. the replacement and resetting of

43、 the tooling and handling of the work in and out of the machine adds asignificant cost to the finished part. moreover, the cost per piece may be three to six times the cost of using amore specialized machine tool. when anumber of identical parts are needed, positioning of the tools for each operatio

44、n not only involves time but may also result in workpieces that will not pass inspection. thus, an engine lathe is suitable for low production only.第二課車削加工現(xiàn)代車床的年代并不遙遠(yuǎn)，可追溯到英國(guó)工業(yè)革命吋期。世界上第一臺(tái)螺 紋切削車床是由莫茲利于1798年發(fā)明的?，F(xiàn)代主軸車床得名于它的齒輪驅(qū)動(dòng)主 軸箱運(yùn)動(dòng)且具有典型的16種主軸速度。雖然一個(gè)車床的一個(gè)刀架在加工一個(gè)工 件時(shí)可攜帶一至四把刀具，但在一段時(shí)間內(nèi)它只能實(shí)現(xiàn)一次進(jìn)給運(yùn)動(dòng)。一個(gè)典 型的車削

45、零件需反復(fù)加工多次才能完成，每-次加工都需要一把不同的刀具和 進(jìn)給運(yùn)動(dòng)。換刀和重新調(diào)刀以及工件的裝卸都給工件增加了巨大的成本。此外, 每一步所花費(fèi)的成本可能會(huì)是使用一個(gè)更加專業(yè)化機(jī)床成本的三至六倍。當(dāng)需 要加工一定數(shù)目的相同零件時(shí)，對(duì)每一次加工的對(duì)刀和調(diào)刀來說不僅僅浪費(fèi)時(shí) 間而且還會(huì)導(dǎo)致很多工件不合格。因此，車床只適合于小批量牛產(chǎn)。lesson 4e1ectrical-discharge machining electrical-discharge machining(edm), or spark machining, as it is also called, removes materia

46、l with repetitive spark discharges from apulsating dc power supply, with adielectric flowing between the workpiece and the tool.the principle of the edm process is illustrated by the simplified diagram in fig. 3. 17. the tool is mounted on the chuck attached to the machine spindle whose motion is co

47、ntrol1ed by aservocontrol 1 ed feed drive. the workpiece is placed in atank filled with adiclcctrie fluid； a depth of at least 50mm over the work surface is maintained to eliminate the risk of fire. the tool and workpiece are connected to apulsating dc power supply. dielectric fluid is circulated un

48、der pressure by apump, usually through ahole(or holes)in the toolelectrode. a spark gap of about 0. 025 to 0. 05 mm is maintained by the servomotor.第四課放電加工放電加工(edm),也叫電火花加工，顧名思義，它是通過從脈沖直流電源中 反復(fù)的電火花釋放來去除工件的材料的，且在工件與刀具之間有絕緣液體介質(zhì) 的存在。放電加工過程的原理如圖3. 17所示的簡(jiǎn)圖。裝配在卡盤上的刀具，連接到 機(jī)床主軸上，且機(jī)床主軸的運(yùn)動(dòng)是由伺服控制進(jìn)給驅(qū)動(dòng)的。工件被放置在一個(gè)

49、 充滿了絕緣介質(zhì)的槽箱屮；要確保絕緣介質(zhì)沒過工件表面至少50毫米，以消除 火災(zāi)隱患。將刀具和工件連接到脈沖直流電源的兩端。絕緣介質(zhì)是在一個(gè)泵的 壓力下開始循環(huán)的，通常經(jīng)由刀具電極中的一個(gè)孔(或兒個(gè)孔)中開始?；鸹ǖ?間隙大約是0. 025至0. 05毫米，是在伺服電機(jī)工作的狀態(tài)下保證的。chapter four manufacturing lesson dassembly after individual parts have been mantifactured, they are assembled into aproduct. assembly is an importemt phase

50、 of the overall manufactuning operation and requires consideration of the ease, speed, and cost of putting parts together. many products are also designed so that they can be taken apart for maintenance and servicing.there are several methods of assembly, each wi th i ts owncharacteristics and requi

51、ring diffcrcnt opemtions. the use of abolt and nut,for example, requires preparation of holes that must match in location and size.hole generation requires operations such as dri1 ling or punching,which take additional time, require separate operations, and produce scrap. furthermore, the presenee o

52、f holes could reduce the useful life of components because of stress concentration, leading to fatigue failure of the part. on the other hand,products assembled with bolts and nuts can be taken apart and reassembled with relative ease.parts may be assembl ed by hand or by automatic equipment. the ch

53、oice depends on factors such as the complexity of the product and the number of parts to be assembled, the protection required to prevent damage or seratching of finished surfaces of the parts, and the relative costs of labor and machinery required for automated assembly. variations in the dimension

54、s of parts may be tolerated in hand assembly since the operator can make minor adjustments. in automated assembly, however, parts must have consistently uniform dimensions. otherwise, their movement through the assembly equipment can be impeded and parts not assembled properly.第四章制造業(yè)第四課裝配在單個(gè)零件被加工完成以

55、后，就要被裝配成產(chǎn)品。裝配在整個(gè)的制造加工 過程屮至關(guān)重要，需要考慮將零件裝配到一起的難易程度、速度以及成本。很 多產(chǎn)甜也會(huì)為方便日后的維修和保養(yǎng)被設(shè)計(jì)成易于拆卸的形式。裝配有很多種方法，每一種方法都有其自己的特點(diǎn)且需要不同的操作方式。 例如，螺栓和螺母的使用，要求孔與孔之間必須在位置和尺寸上相互匹配。孑l 的牛成需要多種加工形式，像鉆孔或沖孔等，這會(huì)花費(fèi)額外的時(shí)間且需要單獨(dú) 操作，并很容易產(chǎn)生廢料。再者，由于應(yīng)力集中，孔的存在可能會(huì)減少零件的 使用壽命，從而導(dǎo)致零件的疲勞失效。另一方面，用螺栓螺母裝配起來的產(chǎn)品 拆卸和重組都比較容易。零件的裝配方法可采用手工加工法或自動(dòng)化設(shè)備加工法兩種。選擇

56、哪種裝 配方法取決于許多因素，如產(chǎn)品的復(fù)雜程度及待裝件的數(shù)量、需防止零件受損 或防止精加工表面被劃傷的情況，勞動(dòng)力和自動(dòng)化裝配所需機(jī)械設(shè)備的相對(duì)成 本等。零件尺寸的變化在手工裝配中是可以允許的，因?yàn)楣と丝梢宰鲆恍┪⑿?的調(diào)整。然而在自動(dòng)裝配線中，零件的尺寸就必須要完全一致。否則，裝配設(shè) 備就會(huì)阻礙這些零件的運(yùn)動(dòng)，并且零件也不能被正確的裝配。chapter five control and computer technology in manufacturing lesson 1control system closed-loop control closed-loop control syst

57、em requires negative feedback be create an error and subsequent control action. the plant responds with an output which is returned via negative feedback, and the process continues in an endless loop. the following are the main benefits of closed-loop control：1.increases accuracy.2. reduces effects of noise.3. increases plant bandwidth.4. can be applied with minimal input/output relationships of the plant under control.there are two disadvantages in terms of practical implementation of this control system：1. high cost.2. requires qualified persormcl to cnsure stability.