外文翻譯---計(jì)算機(jī)輔助制造

1、<p>　　Integrated Computer Aided Manufacturing</p><p>　　1.INTRODUCTION</p><p>　　Today’s industry competes in a truly international marketplace. Efficient transportation networks have created

2、 a “world market” in which we participate on a daily basis. For any industrial country to compete in this market, it must have companies that provide economic high-quality products to their customers in a timely manner.

3、The importance of integrating product design and process design to achieve a design for production system cannot be overemphasized. However, even once a design is finaliz</p><p>　　Most U.S.-based manufacturi

4、ng companies look toward CAD/CAM and CIM to provide this flexibility in their manufacturing system . Today ,the use of computers in manufacturing is common . Manufacturing system are being designed that not only process

5、parts automatically ,but also move the parts from machine to machine and sequence the ordering of operations in the system.（ Figure 1） contains a plot of the economic regions of manufacturing. It should be noted that man

6、ual handcrafted goods will always</p><p>　　Figure 1 Volume versus variety regions for economic manufacturing</p><p>　　2.FLEXIBLE MANUFACTURING SYSTEMS</p><p>　　A flexible manufac

7、turing system, or FMS as they are more commonly known, is a reprogram-able manufacturing system capable of producing a variety of products automatically. Since Henry Ford first introduced and modernized the transfer line

8、, we have been able to perform a variety of manufacturing operations automatically. However, altering these systems to accommodate even minor changes in the product has been quite taxing. Whole machines might have to be

9、introduced to the system while other machi</p><p>　　Job shop type systems were capable of producing a variety of product ,but at a high cost.</p><p>　　Transfer lines could produce large volumes

10、of a product at a reasonable cost, but were limited to the production of one ,two, or very few different parts.</p><p>　　The advent of numerical control (NC) and robotics has provided us with reprogramming c

11、apabilities at the machine level with minimum setup time. NC machines and robots provide the basic physical building blocks for re-programmable manufacturing systems.</p><p>　　2.1.FMS Equipment</p>&l

12、t;p>　　2.1.1Machines </p><p>　　In order to meet the requirements of the definition of an FMS, the basic processing in the system must be automated. Because automation must be programmable in order to acco

13、mmodate a variety of product-processing requirements, easily alterable as well as versatile machines must perform the basic processing.</p><p>　　For this reason, CNC turning centers, CNC machining centers, a

14、nd robotic workstations comprise the majority of equipment in these systems. These machines are not only capable of being easily reprogrammed, but are also capable of accommodating a variety of tooling via a tool changer

15、 and tool-storage system. It is not unusual for a CNC machining center to contain to 12 or more tools (right-hand turning tools, left-hand turning tools ,boring bars, drills ,and so on ) . The automatic tool changer an&l

16、t;/p><p>　　Parts must also be moved between processing stations automatically. Several different types of material-handling systems are employed to move these parts from station to station. The selection of the

17、 type of material-handling system is a function of several system features. The material-handling system, first, must be able to accommodate the load and bulk of the part and perhaps the part fixture. Large, heavy parts

18、require large , powerful handling systems such as roller conveyors guided vehicle</p><p>　　2.1.2 Tooling and fixtures.</p><p>　　Versatility is the key to most FMSs, and as such the tooling used

19、in the system must be capable of supporting a variety of products or parts. The use of special forming tools in an FMS is not typical in practice. The contours obtained by using forming tools can usually be obtained thro

20、ugh a contour-control NC system and a standard mill. The standard mill then can be used for a variety of parts rather than to produce a single special contour. An economic of the cost and benefits of any special to</p

21、><p>　　One of the commonly neglected aspects of an FMS is the fixturing used. Because fixtures are part of the tooling of the system, one could argue that they should also be standard for the system. Work on cr

22、eating “flexible fixtures” that could be used to support a variety of components has only recently begun. See Chapter 5.One unique aspect of many FMSs is that the part is also moved about the system in the fixture (or pa

23、llet fixture). Fixtures are made to the same dimensions so that the material-</p><p>　　3.COMPUTER CONTROL OF FLEXIBLE MANUFACTURING SYSTEMS</p><p>　　3.1 FMS Architecture</p><p>　　A

24、n FMS is a complex network of equipment and processes that must be controlled via a computer or network of computers. In order to make the task of controlling an FMS more tractable, the system is usually divided into a t

25、ask-based hierarchy. One of the standard hierarchies that have evolved is the National Institute of Standards and Technology(NIST) factory-control hierarchy. (NIST was formerly the National Bureau of standards. NBS.) Th

26、is hierarchy consists of five levels and is illustrated in </p><p>　　The cell is the unit in the hierarchy where interaction between machines becomes part of the system. The cell controller provides the int

27、erface between the machines and material-handling system. As such ,the cell controller is responsible for sequencing and scheduling parts through the system. At the shop level integration of multiple cells occurs as well

28、 as the planning and management of inventory. The </p><p><b>　　Fig2</b></p><p>　　Figure 3 The relationship between the data-administration (DAS) in the NIST architecture :(1)the topo

29、logies of the Integrated Manufacturing Data Administration System(IMDAS) data-administration system;(2)the net work data-communication network; (3)the hierarchical system of data-driven control: data preparation is impli

30、ed in (4) the facility level of control facility level is the place in the hierarchy where the master production schedule is constructed and manufacturing resource planning is con</p><p>　　3.2 FMS Scheduling

31、 and control</p><p>　　Flexible manufacturing systems, like other manufacturing system can differ significantly complexity . This complexity is not only determined by the number of machines and the number of

32、parts resident in the system, but also by the complexity of parts and control requirements of the specific equipment . Some FMSs require only a simple programmable controller to regulate the flow of parts though the syst

33、em, whereas others require sophisticated computer control systems. In the following sections , </p><p>　　The most simple FMS consists of a processing machine, a load/unload area, and a material handler (a on

34、e-machine system is the most simple FMS that can be constructed ). Operation of this system consists of loading the part(s) that move down a conveyor the machine. Once the part is loaded onto the machine , the robot is r

35、etracted to a “safe position” and the machining begins.</p><p>　　Although this is a very simple system, it illustrates several interesting design and control decisions that must be considered. If only a sing

36、le part is to be processed in the system, a minimum number of switches and sensors necessary for the system. One requirement of the system is that the parts on the conveyor all have to be oriented in the same way. This i

37、s required so that the robot can pick up the part and deliver it to the NC machine in the same orientation every time. A proximity switch </p><p><b>　　計(jì)算機(jī)輔助制造</b></p><p><b>　　1

38、.緒論</b></p><p>　　當(dāng)今的工業(yè)的競(jìng)爭(zhēng)已經(jīng)是真正意義上的國(guó)際市場(chǎng)競(jìng)爭(zhēng)。 高效的運(yùn)輸網(wǎng)絡(luò)建立了一個(gè)我們每天都要參與的 “世界市場(chǎng)”。 對(duì)于任何工業(yè)化國(guó)家要參與這個(gè)市場(chǎng)競(jìng)爭(zhēng)，就必須采用一種適時(shí)的方式為其客戶提供經(jīng)濟(jì)、優(yōu)質(zhì)的產(chǎn)品。將產(chǎn)品設(shè)計(jì)和過程設(shè)計(jì)進(jìn)行集成的重要性，在產(chǎn)品系統(tǒng)被怎么強(qiáng)調(diào)都不為過。但是， 即使一種設(shè)計(jì)最終被落實(shí)， 制造業(yè)者一定愿意通過允許最后的工程設(shè)計(jì)變化，而沒有通過影響裝運(yùn)進(jìn)

39、度表，或者改變產(chǎn)品質(zhì)量來(lái)適應(yīng)他們的用戶。</p><p>　　大多數(shù)美國(guó)的生產(chǎn)公司基于趨向計(jì)算機(jī)輔助設(shè)計(jì)（CAD）/計(jì)算機(jī)輔助制（CAM）和CIM為他們的制造系統(tǒng)提供靈活性。今天，計(jì)算機(jī)用于制造已經(jīng)很平?！，F(xiàn)在不僅為零件生產(chǎn)設(shè)計(jì)制造系統(tǒng)，而且為零件從一臺(tái)機(jī)器運(yùn)送到另一臺(tái)機(jī)器的命令順序設(shè)計(jì)了制造系統(tǒng)，如圖（1），它還包含一個(gè)經(jīng)濟(jì)區(qū)域的制造經(jīng)濟(jì)計(jì)劃在美國(guó)和其他國(guó)家，手工產(chǎn)品總是還有一些市場(chǎng)的，此外真正的工業(yè)產(chǎn)品對(duì)于特

40、殊的“one-of-a-kind”技術(shù)項(xiàng)目還是需要的?！皁ne-of-a-kind”通過大量的貨物來(lái)表明、各種各樣的工業(yè)需要各種各樣的加工方法。 有些系統(tǒng)將看起來(lái)像我們的祖父母曾經(jīng)工作過的工廠，而其它則呈現(xiàn)出一種未來(lái)派的情景。在后文中，我們將展開討論柔性制造系統(tǒng)。</p><p><b>　　圖（1）</b></p><p><b>　　2.柔性制造系統(tǒng)&l

41、t;/b></p><p>　　柔性制造系統(tǒng)（FMS）像人們通常知道的那樣的，能使用一個(gè)可編程的制造系統(tǒng)自動(dòng)地生產(chǎn)各種各樣的產(chǎn)品。 自從亨利·福特率先提出并且使流水生產(chǎn)線實(shí)現(xiàn)現(xiàn)代化，我們就已經(jīng)能自動(dòng)執(zhí)行多種生產(chǎn)的生產(chǎn)。 不過，改變這些系統(tǒng)甚至只作較小的變動(dòng)，這些產(chǎn)品的生產(chǎn)都會(huì)變得相當(dāng)繁重。 當(dāng)其他機(jī)器或者零部件要經(jīng)過修理或者廢棄，以適應(yīng)這種蕭蕭的變化，整個(gè)機(jī)器才可能被引進(jìn)到系統(tǒng)。 在今天的競(jìng)爭(zhēng)性市

42、場(chǎng)里，能適應(yīng)客戶的各種變化是很必要的。傳統(tǒng)的制造系統(tǒng)以特征可劃分為以下兩種： 1.加工車間類型系統(tǒng)能生產(chǎn)多種產(chǎn)品，但是費(fèi)用高。 2.流水線能以合理費(fèi)用生產(chǎn)能大量產(chǎn)品， 但是僅局限于幾種不同零件的生產(chǎn)。 數(shù)控(NC)和機(jī)器人技術(shù)的時(shí)代已經(jīng)來(lái)臨，這為我們提供了在最小準(zhǔn)備時(shí)間里，使機(jī)器的程序重新調(diào)定。NC機(jī)床和機(jī)器人是重新可編程序的制造系統(tǒng)的基本物理組成部分。</p><p>　　2.1.柔性制造系統(tǒng)的

43、設(shè)備</p><p><b>　　2.1.1機(jī)床</b></p><p>　　為了滿足柔性制造系統(tǒng)定義的要求，該系統(tǒng)的基本工藝應(yīng)實(shí)現(xiàn)自動(dòng)化。因?yàn)樽詣?dòng)化必須是可編程的，以適應(yīng)不同的產(chǎn)品要求，而易于改變，以及通用機(jī)床必須執(zhí)行這些工藝。計(jì)算機(jī)數(shù)控（CNC）車削中心、計(jì)算機(jī)數(shù)控（CNC）加工中心、及機(jī)器人工作站構(gòu)成了這些設(shè)備。這些機(jī)器不僅僅是易于重新編程，同時(shí)也適應(yīng)置于刀具存

44、儲(chǔ)系統(tǒng)及刀具更換器中的不同刀具。通常CNC加工中心備有60多把或更多刀具（銑刀、鉆頭、鏜刀等）。對(duì)于CNC車削中心，備有12把或更多的刀具（右車刀、左車刀、鏜桿、鉆頭等）。書動(dòng)機(jī)床的自動(dòng)換刀器及刀庫(kù)使它們對(duì)材料的工藝裝備作出自然的選擇。</p><p>　　零件必須在加工站點(diǎn)之間自動(dòng)化的移動(dòng)，采用了數(shù)種不同的物料輸送系統(tǒng)，把這些零件從一個(gè)站點(diǎn)輸送到另一個(gè)站點(diǎn)。物料輸送系統(tǒng)的選擇是數(shù)種系統(tǒng)特征函數(shù)。首先，物料輸送系

45、統(tǒng)的選擇必須適應(yīng)零件（或許是零件的夾具）的負(fù)荷及批量。大型的、重型的零件需要大型的、強(qiáng)力的輸送系統(tǒng)，如滾子輸送、導(dǎo)向小車、軌道驅(qū)動(dòng)車輛系統(tǒng)。構(gòu)成的機(jī)床數(shù)量及機(jī)床布置也提供了另一種設(shè)計(jì)上的考慮。如果用單一的物料輸送機(jī)來(lái)運(yùn)送零件到系統(tǒng)內(nèi)的所有機(jī)床，則運(yùn)輸機(jī)的工作覆蓋面至少必須是和整個(gè)系統(tǒng)一樣大。通常一臺(tái)機(jī)器人定位于一兩臺(tái)機(jī)床或一個(gè)裝卸站。一臺(tái)輸送機(jī)或自動(dòng)導(dǎo)向車可以擴(kuò)大到數(shù)英里的工廠區(qū)域。物料輸送也可以以即時(shí)的方式將零件從一臺(tái)機(jī)床輸送到另一臺(tái)

46、機(jī)床。如果系統(tǒng)內(nèi)的機(jī)床耗費(fèi)大量的時(shí)間在等待輸送零件的到來(lái)，則其生產(chǎn)率是不會(huì)高地。如果有許多種零件包括在系統(tǒng)內(nèi)，而且這些零件要經(jīng)常輸送到機(jī)床上，物料系統(tǒng)要能夠支持這些活動(dòng)。通常由采用極快的輸送裝置或靠平行地使用幾種裝置來(lái)實(shí)現(xiàn)。例如：用一臺(tái)機(jī)器人支持一臺(tái)機(jī)床，而不是用一臺(tái)機(jī)器人運(yùn)送零件到系統(tǒng)內(nèi)的所有機(jī)床。</p><p>　　2.1.2刀具及夾具</p><p>　　用途多樣性是柔性制造系統(tǒng)的

47、關(guān)鍵，由此，在系統(tǒng)中使用的刀具必須能夠支持多種零件及產(chǎn)品的生產(chǎn)。在柔性制造系統(tǒng)中，使用專用的或成型刀具并不典型。使用成型刀具得到輪廓，通?？梢酝ㄟ^輪廓書空系統(tǒng)或標(biāo)準(zhǔn)的銑刀得到。標(biāo)準(zhǔn)的銑刀可以用于各種不同的零件而不是只能加工單一的輪廓。使用任何專用刀具其利潤(rùn)和成本的經(jīng)濟(jì)分析都是必須的，以確定最佳的刀具組合。然而，因書空機(jī)床僅有有限數(shù)量的刀具可供存取，極少數(shù)的刀具應(yīng)當(dāng)包括在內(nèi)。</p><p>　　柔性制造系統(tǒng)通常容

48、易忽視的一個(gè)方面是所使用的夾具。因?yàn)閵A具是系統(tǒng)中工具的一部分。人們會(huì)爭(zhēng)議這樣一個(gè)事實(shí)，對(duì)系統(tǒng)中的夾具也應(yīng)標(biāo)準(zhǔn)化。工件裝在創(chuàng)制出的“柔性?shī)A具”中，這種僅在幾年前才開始使用的夾具可以支持多種零件。許多柔性制造系統(tǒng)的獨(dú)特方面是零件裝在夾具（或隨行夾具）中而在系統(tǒng)中運(yùn)動(dòng)，夾具做成相同的尺寸，這樣物料輸送系統(tǒng)可以專門化去輸送單一的幾何形體，零件精確的定位在夾具上，同時(shí)隨同夾具從一個(gè)站點(diǎn)運(yùn)動(dòng)大另一個(gè)站點(diǎn)。這種類型的夾具，通常稱為隨行夾具?，F(xiàn)在所應(yīng)用

49、的許多隨行夾具都加工出標(biāo)準(zhǔn)的T型槽，同時(shí)使用標(biāo)準(zhǔn)的夾具組件創(chuàng)建出適應(yīng)于切削加工的零件的定位及夾緊的條件。</p><p>　　3.柔性制造系統(tǒng)的計(jì)算機(jī)控制</p><p><b>　　3.1 FMS構(gòu)架</b></p><p>　　FMS是一個(gè)必須被通過一臺(tái)計(jì)算機(jī)或者計(jì)算機(jī)網(wǎng)絡(luò)控制的設(shè)備和過程的復(fù)雜的網(wǎng)絡(luò)。 為了使控制FMS的任務(wù)更易處理，系統(tǒng)

50、通常被分成一個(gè)個(gè)基于任務(wù)的階層。 已經(jīng)逐步成的標(biāo)準(zhǔn)之一的是國(guó)家標(biāo)準(zhǔn)與技術(shù)局(NIST)工廠控制階層。 (NIST以前叫國(guó)家標(biāo)準(zhǔn)局， NBS.) 這個(gè)階層由5 步組成， 在圖（2）表示了系統(tǒng)由物質(zhì)機(jī)器加工設(shè)備，圖（3）系統(tǒng)的最低的組成部分。 工作站設(shè)備恰好處于過程水平面存在并且起著預(yù)防綜合和設(shè)備接口的作用。 例如棘瓜固定設(shè)備和編程要素也是工作站的一部分。 工作站通常提供人力機(jī)器接口和機(jī)器零件接口。 而脫機(jī)程序適合NC那種易于AML給機(jī)器人

51、工作的工作站水平。 小屋是在在機(jī)器之間的相互作用階層的單位，并成為系統(tǒng)的一部分。 小屋控制器提供了那些機(jī)器和物質(zhì)處理系統(tǒng)之間的接口。 照此，小屋控制器負(fù)責(zé)系統(tǒng)的排序和調(diào)度部分。車間水平的集成和多房間重現(xiàn)生成了存貨清單的計(jì)劃和管理。 </p><p><b>　　圖（2）</b></p><p><b>　　圖（3）</b>&l

52、t;/p><p>　　3.2 FMS安排和控制 柔性制造系統(tǒng)，像其他制造系統(tǒng)一樣，能區(qū)別出零件之間較大的復(fù)雜性。 這復(fù)雜性不僅包括系統(tǒng)中機(jī)器的數(shù)量和確定的數(shù)量， 而且包括那些復(fù)雜性的部分和控制要求的那些具體設(shè)備。一些FMS只要求有一個(gè)簡(jiǎn)單的可編程控制器就行了，而其它的還要求有復(fù)雜的計(jì)算機(jī)控制系統(tǒng)。在以后的章節(jié)里，還要提出一些FMS及其控制的例子。 最簡(jiǎn)單的FMS由一臺(tái)處理器、裝載/卸載區(qū)域和原料

53、處理機(jī)(一個(gè)最簡(jiǎn)單的FMS可以只由一臺(tái)機(jī)器構(gòu)成)。 這系統(tǒng)的操作包括了往下的一個(gè)傳輸裝置。一旦零件被裝到機(jī)器上，機(jī)器人縮回到一個(gè)“安全的位置”，然后機(jī)器開始加工。 </p><p>　　雖然這是一個(gè)非常簡(jiǎn)單的系統(tǒng)，但是它例舉了幾種有趣的設(shè)計(jì)和必須考慮的控制部件。如果在系統(tǒng)中，只有一個(gè)部分在運(yùn)作，那么系統(tǒng)就只需要最小數(shù)量的開關(guān)和傳感器。系統(tǒng)所需要的是，所有傳輸帶上的零件使用同樣的方法定位。這還需要使機(jī)器人每一次都用