購(gòu)買(mǎi)設(shè)計(jì)請(qǐng)充值后下載，，資源目錄下的文件所見(jiàn)即所得，都可以點(diǎn)開(kāi)預(yù)覽，，資料完整，充值下載可得到資源目錄里的所有文件。。?！咀ⅰ浚篸wg后綴為CAD圖紙，doc,docx為WORD文檔，原稿無(wú)水印，可編輯。。。具體請(qǐng)見(jiàn)文件預(yù)覽，有不明白之處，可咨詢(xún)QQ:12401814
年級(jí) 專(zhuān)業(yè) 學(xué)號(hào) 姓名
Flexible manufacturing
As an introduction to the subsequent discussions of production systems and advanced manufacturing technologies it is useful to present a definition of the term manufacturing system.A manufacturing system can be defined as a series of value-adding manufacturing processes converting the raw materials into more useful forms and eventually finished products.
In the modern manufacturing setting, flexibility is an important characteristic . it means that a manufacturing system is versatile and adaptable , while also capable of handling relatively high production runs. A flexible manufacturing system is versatile in that it can produce a variety of parts .It is adaptable because it can be quickly modified to produce a completely different line of parts.
A flexible manufacturing system ( FMS) is an individual machine or group of machines served by an automated materials handling system that is computer controlled and has a tool handling capability. Because of its tool handling capability and computer control, such a system can be continually reconfigured to manufacture a wide variety of parts . This is why it is called a flexible manufacturing system.
A FMS typically encompasses :
(1) process equipment e.g., machine tools , assembly stations, and robots.
(2) material handling equipment eg, robots, conveyors, and AGVs (automated guided vehicles )
(3) a communication system
(4) a computer control system
Flexible manufacturing represents a major step toward the goal of fully integrated manufacturing. It involves integration of automated production processes . in flexible manufacturing, the automated manufacturing machine (i.e., lathe, mill,drill ) and the automated materials handling system share instantaneous communication via a computer network . This is integration on a small scale.
Flexible manufacturing takes a major step toward the goal of fully integrated manufacturing by integrating several automated manufacturing concepts:
(1) computer numerical control (CNC) of individual machine tools .
(2) distributed numerical control (DNC) of ,manufacturing systems.
(3) Automated materials handling systems
(4) Group technology (families of parts ).
When these automated processes ,machine , and concepts are brought together in one integrated system, An FMS is the result. Humans and computers play major roles in an FMS. The amount of human labor is much less than with a manually operated manufacturing system , of course. However ,humans still play a vital role in the operation of an FMS . human tasks include the following:
(1) equipment troubleshooting , maintenance, and repair.
(2) Tool changing and setup .
(3) Loading and unloading the system.
(4) Data input .
(5) Changing of parts programs.
(6) Development of programs.
Flexible manufacturing system equipment, like all manufacturing equipment , must be monitored for bugs，malfunctions, and breakdowns. when a problem is discovered，a human troubleshooter must identify its source and prescribe corrective measures. Humans also undertake the prescribed measures to repair the malfunctioning equipment .even when all system are properly functioning, periodic maintenance is necessary.
Human operators also set up machines，change tools，and reconfigure system as necessary. The tool handing capability of an FMS increases, but does not eliminate human involvement in tool changing and setup. The same is true of loading and unloading the FMS . Once raw material has been loaded onto the automated materials handing system, it is moved through the system in the prescribed manner. However, the original loading onto the materials handing system is still usually done by human operators, as is the unloading of finished products.
Humans are also needed for interaction with the computer. Humans develop part programs that control the FMS via computers. they also change the programs as necessary when reconfiguring the FMS to produce another type of part or parts. Humans play less labor-intensive roles in an FMS, but the roles are still critical.
Control at all levels in an FMS is provided by computers. Individual machine tools within an FMS are controlled CNC. The overall system is controlled by DNC. The materials handing system is computer controlled, as are other functions including data collection, system monitoring, tool control, and traffic control. Human computer interaction is the key to the flexibility of an FMS.
1 history development of flexible manufacturing
flexible manufacturing was born in the mid-1986s when the British firm Molins ，Ltd. Developed its system 24. System 24 was a real FMS. However, it was doomed from the outset because automation，integration, and computer control technology had not yet been developed to the point where they could properly support the system. The first FMS was a development that was ahead of its time. As such, it was eventually discarded as unworkable.
Flexible manufacturing remained an academic concept through the remainder of the 1960s and 1970s .However, with the emergence of sophisticated computer control technology in the late 1970s and early 1980s, flexible manufacturing became a viable concept. The first major user of flexible manufacturing in the united States were manufacturers of automobiles, trucks, and tractors.
2 rationale for flexible manufacturing
in manufacturing there have always been tradeoffs between production rates and flexibility, at one end of the issue are transfer lines capable of high production rates, but low flexibility. At the other end of the issue are independent CNC machines that offer maximum flexibility, but are capable only of low production rates. Flexible manufacturing falls in the middle. There has always been a need in manufacturing for a system that could produce higher volume and production runs than could independent machines，while still maintaining flexibility.
Transfer lines are capable of producing large volumes of parts at high production rates . The line takes a great deal of setup, but can turn out identical parts in large quantities . Tts chief shortcoming is that even minor design changes in a part can cause the entire line to be shut down and reconfigured .This is a critical weakness because it means that tranfer lines cannot produce different parts , even parts from within the same family，without costly， and time-consuming shutdown and reconfiguration.
Traditionally, CNC machines have been used to produce small volume of parts that differ lightly in design .such machines are ideal for this purpose because they can be quickly reprogrammmed to accommodate minor or even major design changes. However, as independent machines they cannot produce parts in large volumes or at high production rates.
An FMS can handle higher volumes and production rates than independent CNC machines, it cannot quite match such machines for flexibility, but they come close. What is particularly significant about the middle ground capabilities of flexible manufacturing is that most manufacturing situations require medium production rates to produce medium volumes with enough flexibility to quickly reconfigure to produce another part or product .Flexible manufacturing fills this this long standing void in manufacturing.
Flexible manufacturing ,with its ground capabilities, offers a number of advantages for manufacturers：
(1) flexibility within a family of parts.
(2) Random feeding of parts.
(3) Simultaneous production of different parts.
(4) Decresed setup time and lead time .
(5) More efficient machine usage.
(6) Decreased direct and indirect labor costs
(7) Ability to handle different materials .
(8) Ability to continue some production if one machine breaks down.
3 flexible manufacturing system components
A FMS has three major components:
(1) Machine tools
(2) Control system
(3) Materials handling system
3.1 machine tools
A flexible manufacturing system uses the same types of machine tools as any other manufacturing system, be it automated or manually operated . there include lathes ,mills,drills,saws, and so on. The type of machine tools actually include in an FMS depends on the setting in which the machine will be used . some FMSes are designed to meet a specific, well-defined need . in these cases the machine tools included in the system will be only those necessary for the planned operations . Such a system would be known as a dedicated system.
In a job-shop setting, or any other setting in which the actual application is not known ahead of time or must necessarily include a wide range of possibilities, machines capable of performing at least the standard manufacturing operations would be included . such systems are known as general purpose systems.
3.2 control system
The control system for an FMS serves a number of different control functions for system:
(1) Storage and distribution of parts programs
(2) Work flow control and monitoring
(3) Production control
(4) System/tool control/monitoring
The control area with the computer running the FMS control system is the center from which all activities in the FMS are controlled and monitored. The FMS control software is rather complicated and sophisticated since it has to carry out many different task simultaneously。despite the considerable research that has been carried out in this area ,there is no general answer to designing the functions and architecture of FMS software.
Some typical functions of a FMS control system are illustrated in fig.3.22
Fig.3.22 diagram of functions in advanced FMS Control software
The scheduler function involves planning how to produce the current volume of orders in the FMS , considering the current status of machine tools ,work-in-process, tooling fixtures, and so on. The scheduling can be done automatically or can be assisted by an operator .most FMS control systems combine automatic and manual scheduling; the system generates an initial schedule that can be changed manually by the operator. The dispatcher function involves carrying out the schedule and coordinating the activities on the shop floor, that is , deciding when and where to transport a pallet , when to start a process on a machining center, and so on .
The monitor function is concerned with monitoring work progress machine status, alarm messages, and so on, and providing input to the scheduler and dispatcher as well as generating various production reports and alarm messages. A transport control module manages the transporation of parts and palettes within the system. having an AGV system with multiple vehicles , the routing control logic can become rather sophisticated and become a critical part of the FMS control software . a load /unload module with a terminal at the loading area shows the operators which parts to introduce to the system and enables him or her to update the status of the control system when parts are ready for collection at the loading area . A storage control module keeps an account of which partes are stored in the AS/RS as well as their exact location. The tool management module keeps an account of all relevant tool data and the actual location of tools in the FMS.
Tool management can be rather comprehensive since the number of tools normally exceeds the number of parts in the system, and furthermore , the module must the preparation and flow of tools .the DNC function provides interfaces between the FMS control program and machine tools and devices on the shop floor . the DNC capabilities of the shopfloor equipment are essential to a FMS,a “full” DNC communication protocols is enabling remote control of the machines is required
The fact that most vendors of machine tools have developed proprietary communication protocols is complicating the development and integration of FMSes including multi-vendor equipment .further more,the physical integration of multi-vendor equipment is different; for example , the differences in pallet load/unload mechanisms complicate the use of machine tools from different vendors, therefore, the only advisable approach for implementing a FMS is to purchase a turn-key system from one of the main machine tool manufacturers. These systems are reliable and well tested and should the system not function satisfactorily, a single vendor responsibility will facilitate remedy of malfunctions.
柔性制造
由于對(duì)生產(chǎn)系統(tǒng)和先進(jìn)制造技術(shù)的隨后進(jìn)行的討論的介紹，提出一個(gè)術(shù)語(yǔ)定義——制造系統(tǒng)是很有用的。制造系統(tǒng)可以被定義為一個(gè)增值工序，它將原材料轉(zhuǎn)換成更多有用的形式和最終成品。
? 在現(xiàn)代制造業(yè)的背景下，靈活性是一個(gè)重要的特征。這意味著制造系統(tǒng)靈活、適應(yīng)性強(qiáng)，同時(shí)也有處理相對(duì)較高的生產(chǎn)運(yùn)行的能力。一個(gè)柔性制造系統(tǒng)的通用性在于能生產(chǎn)各種零件。它適應(yīng)性強(qiáng)是因?yàn)樗梢匝杆傩薷模援a(chǎn)生完全不同的零件線。
一個(gè)柔性制造系統(tǒng)（FMS）是一個(gè)單獨(dú)的機(jī)器或處理系統(tǒng)，由計(jì)算機(jī)控制，具有自動(dòng)化的工具，材料處理能力擔(dān)任設(shè)備組。由于其處理能力和計(jì)算機(jī)控制的工具，這種系統(tǒng)可以不斷地重新配置，制造各種各樣的零件。這就是為什么它被稱(chēng)為柔性制造系統(tǒng)。
一個(gè)柔性制造系統(tǒng)通常包括：
（1）工藝設(shè)備如機(jī)床，裝配站和機(jī)器人
（2）材料處理設(shè)備如機(jī)器人，輸送機(jī)，和AGV（自動(dòng)導(dǎo)引車(chē)）
（3）通訊系統(tǒng)
（4）計(jì)算機(jī)控制系統(tǒng)
柔性制造向著完全集成制造目標(biāo)邁出了重要一步。它包括生產(chǎn)過(guò)程自動(dòng)化集成。在柔性制造，自動(dòng)加工機(jī)（即，車(chē)床，銑，鉆）和自動(dòng)化材料處理系統(tǒng)通過(guò)一個(gè)計(jì)算機(jī)網(wǎng)絡(luò)分享即時(shí)通信。這是一個(gè)小規(guī)模的整合。
柔性制造通過(guò)結(jié)合幾個(gè)自動(dòng)化生產(chǎn)理念，朝著全面集成制造目標(biāo)邁出了重要一步：
（1）單個(gè)機(jī)床的計(jì)算機(jī)數(shù)值控制（CNC）。
（2）制造系統(tǒng)的分布式數(shù)字控制（DNC）
（3）自動(dòng)化物料處理系統(tǒng)
（4）成組技術(shù)
當(dāng)這些自動(dòng)化的過(guò)程，機(jī)械和概念弄成一個(gè)完整的體系，柔性制造系統(tǒng)就是它們的產(chǎn)物。人類(lèi)和計(jì)算機(jī)在柔性制造系統(tǒng)發(fā)揮重大作用。當(dāng)然，人類(lèi)勞動(dòng)量遠(yuǎn)遠(yuǎn)不如了手工操作的制造系統(tǒng)。然而，人類(lèi)在柔性制造系統(tǒng)的運(yùn)作上仍然起著至關(guān)重要的作用。人類(lèi)的任務(wù)包括以下內(nèi)容：
（1）設(shè)備故障排除，維護(hù)和修理
（2）刀具更換和安裝
（3）裝卸系統(tǒng)
（4）數(shù)據(jù)輸入
（5）部分節(jié)目的變遷
（6）方案的發(fā)展
柔性制造系統(tǒng)設(shè)備像所有的生產(chǎn)設(shè)備，必須對(duì)錯(cuò)誤，故障，以及故障進(jìn)行監(jiān)控。當(dāng)發(fā)現(xiàn)一個(gè)問(wèn)題，一個(gè)人的疑難解答必須確定它的來(lái)源和記錄糾正的措施。人類(lèi)也在采取記錄下的措施來(lái)修復(fù)損壞的設(shè)備。即使所有的系統(tǒng)都運(yùn)轉(zhuǎn)正常，定期保養(yǎng)也是必要的。
人力經(jīng)營(yíng)者還建立了機(jī)器，改變刀具，并在必要時(shí)重新配置系統(tǒng)。一個(gè)柔性制造系統(tǒng)處理能力工具增加，但并不能消除人類(lèi)在換刀和設(shè)置方面的參與。柔性制造系統(tǒng)的裝卸同樣很真實(shí)。一旦原材料已加載到自動(dòng)化物料處理系統(tǒng)，它就會(huì)通過(guò)系統(tǒng)按照已經(jīng)描述好的方式移動(dòng)。然而，原裝載到自動(dòng)化物料處理系統(tǒng)仍然通常由人工操作完成，這也是成品裝卸。
人類(lèi)也需要與電腦互動(dòng)。人類(lèi)開(kāi)發(fā)通過(guò)計(jì)算機(jī)控制柔性制造系統(tǒng)工件程序。當(dāng)重新配置柔性制造系統(tǒng)以加工不同的工件時(shí)，他們還根據(jù)需要更改程序。人類(lèi)在柔性制造系統(tǒng)上起著一個(gè)少勞力密集的作用，但作用仍然至關(guān)重要。
在各級(jí)的柔性制造系統(tǒng)控制是由電腦提供的。在柔性制造系統(tǒng)中單獨(dú)的機(jī)床是由CNC控制的。整個(gè)系統(tǒng)是由DNC控制的由于其他功能，包括數(shù)據(jù)采集，系統(tǒng)監(jiān)控，控制工具，以及交通管制，因此自動(dòng)化物料處理系統(tǒng)是有計(jì)算機(jī)控制的。對(duì)一個(gè)柔性制造系統(tǒng)的靈活性的關(guān)鍵是人與電腦互動(dòng)。
1 柔性制造的發(fā)展歷史
當(dāng)英國(guó)莫林斯公司開(kāi)發(fā)了其系統(tǒng)24時(shí)，柔性制造便產(chǎn)生于19世紀(jì)八十年代中期。系統(tǒng)24是一個(gè)真正的柔性制造系統(tǒng)。然而，從一開(kāi)始就注定失敗，因?yàn)樽詣?dòng)化，集成和計(jì)算機(jī)控制技術(shù)尚未發(fā)展到可以正確地支持系統(tǒng)的地步。第一個(gè)柔性制造系統(tǒng)是一個(gè)發(fā)展領(lǐng)先于它的時(shí)間的。因此，它最終也因行不通而丟棄。
通過(guò)對(duì)20世紀(jì)60年代和70年代的其余部分，柔性制造仍然是一個(gè)學(xué)術(shù)概念。但是，隨著先進(jìn)的計(jì)算機(jī)控制技術(shù)在20世紀(jì)70年代末和80年代初出現(xiàn)，柔性制造成為一個(gè)可行的概念。柔性制造的第一個(gè)在美國(guó)的主要用戶(hù)是各國(guó)汽車(chē)制造商，卡車(chē)，和拖拉機(jī)。
2 柔性制造的原由
在制造業(yè)一直存在生產(chǎn)效率和靈活性之間的權(quán)衡。在1月底的問(wèn)題是傳輸線的高生產(chǎn)率的但靈活性低的能力。在這個(gè)問(wèn)題的另一端是獨(dú)立的數(shù)控機(jī)床能夠提供最大的靈活性，但唯一缺陷是生產(chǎn)率低。柔性制造在中期下跌。在制造上一直需要一個(gè)系統(tǒng)，它可以比獨(dú)立的機(jī)床產(chǎn)生更高的容量和生產(chǎn)運(yùn)行量，同時(shí)仍保持靈活性。
傳輸線具有以高生產(chǎn)率生產(chǎn)大量零部件的能力。這線需要大量的安裝程序，但可以打開(kāi)了大量相同的部件。它的主要缺點(diǎn)是，即使在一小部分設(shè)計(jì)變更也可能會(huì)導(dǎo)致整個(gè)傳輸線被關(guān)閉和重新配置。這是一個(gè)關(guān)鍵的弱點(diǎn)，因?yàn)檫@意味著即便是同組工件，無(wú)需進(jìn)行昂貴，費(fèi)時(shí)的關(guān)機(jī)和重新配置，傳輸線也不能加工不同的工件。
傳統(tǒng)上，數(shù)控機(jī)床已被用于生產(chǎn)在設(shè)計(jì)稍微不同的小型零件。為此這種機(jī)器是理想的，因?yàn)樗麄兡軌蜓杆僦匦戮幊桃赃m應(yīng)小的甚至是主要的設(shè)計(jì)變化。然而，作為獨(dú)立的機(jī)器，他們不能以大量或高生產(chǎn)率生產(chǎn)零部件。
一個(gè)柔性制造系統(tǒng)可以比獨(dú)立數(shù)控機(jī)床處理更高的產(chǎn)量和生產(chǎn)率。它不能完全匹配這種靈活性的機(jī)器，但他們接近。柔性制造的中間環(huán)節(jié)極其重要的是大部分制造環(huán)境用需要中型生產(chǎn)速率以足夠的靈活性和迅速重新配置加工另一個(gè)工件或產(chǎn)品的方式生產(chǎn)中批零件。柔性制造填補(bǔ)了制造業(yè)在這方面長(zhǎng)期存在的空白。
具有打基礎(chǔ)能力的柔性制造，為制造商提供了許多優(yōu)點(diǎn)：
（1）同一組工件的靈活性。（2）隨機(jī)零件供給。
（3）不同零件的同時(shí)生產(chǎn)。
（四）減輕設(shè)定時(shí)間和前置時(shí)間。
（5）更有效的機(jī)器使用。
（6）減少直接和間接的勞動(dòng)力成本。
（七）處理不同材料的能力。
（八，如果一臺(tái)機(jī)器上壞了繼續(xù)一些生產(chǎn)的能力。
3 柔性制造系統(tǒng)組件
一個(gè)柔性制造系統(tǒng)有三個(gè)主要部分組成：機(jī)床、控制系統(tǒng)、材料處理系統(tǒng)
3.1 機(jī)床
一個(gè)柔性制造系統(tǒng)無(wú)論是自動(dòng)或手動(dòng)操作都像其他任何制造系統(tǒng)一樣，使用同一類(lèi)型的機(jī)床。這些包括車(chē)床，磨，鉆，鋸等。實(shí)際上包含柔性制造系統(tǒng)的該類(lèi)型機(jī)床，依賴(lài)于使用的該機(jī)床的設(shè)置。一些FMS旨在滿(mǎn)足特定的，定義良好的需求。在這些情況下，包含該系統(tǒng)的機(jī)床將只有那些必要的行動(dòng)計(jì)劃。這種系統(tǒng)將稱(chēng)為一個(gè)專(zhuān)用系統(tǒng)。
在工作車(chē)間，或不知道時(shí)間提前或必然包括各種可能性的實(shí)際應(yīng)用的其他任何環(huán)境中，機(jī)器能執(zhí)行的標(biāo)準(zhǔn)至少制造業(yè)務(wù)將被包括在內(nèi)。這種系統(tǒng)被稱(chēng)為通用系統(tǒng)。
3.2 控制系統(tǒng)
對(duì)于一個(gè)柔性制造系統(tǒng)來(lái)說(shuō)孔子系統(tǒng)服務(wù)于許多不同的系統(tǒng)控制功能：（1）工件程序的儲(chǔ)存和分配（2）流量控制和監(jiān)測(cè)工作（3）生產(chǎn)控制（4）系統(tǒng)/工具控制/監(jiān)測(cè)
計(jì)算機(jī)運(yùn)行FMS控制系統(tǒng)控制的領(lǐng)域是在柔性制造系統(tǒng)中的所有活動(dòng)進(jìn)行控制和監(jiān)測(cè)的中心。 FMS的控制軟件是相當(dāng)復(fù)雜和精密的，因?yàn)樾枰M(jìn)行大量的研究。盡管已經(jīng)在這一領(lǐng)域進(jìn)行了許多不同的研究，但是對(duì)設(shè)計(jì)功能和柔性制造系統(tǒng)軟件的體系結(jié)構(gòu)沒(méi)有普遍性的答案。柔性制造系統(tǒng)的體系結(jié)構(gòu)。
一個(gè)典型的FMS控制系統(tǒng)的一些功能說(shuō)明在例圖3.22
例3.22圖 先進(jìn)的柔性制造系統(tǒng)控制軟件圖標(biāo)功能
考慮到機(jī)床當(dāng)前狀態(tài)，加工過(guò)程中，工裝夾具等，調(diào)度功能涉及計(jì)劃如何在柔性制造系統(tǒng)中生產(chǎn)目前的訂單。調(diào)度，可自動(dòng)完成，也可以由經(jīng)營(yíng)者協(xié)助。最大多數(shù)的柔性制造控制系統(tǒng)把自動(dòng)和手動(dòng)調(diào)度相結(jié)合，系統(tǒng)生成一個(gè)初步的時(shí)間表，它可以由操作員手動(dòng)改變。涉及的調(diào)度功能進(jìn)行日程安排和協(xié)調(diào)在車(chē)間的活動(dòng)，，即決定何時(shí)何地的運(yùn)輸托盤(pán)，什么時(shí)候開(kāi)始加工中心的進(jìn)程等等。
該監(jiān)控功能在于監(jiān)測(cè)工作進(jìn)展情況，機(jī)器狀態(tài)，報(bào)警信息等和提供投入的調(diào)度，以及各種生產(chǎn)報(bào)表和報(bào)警信息。一個(gè)傳輸控制模塊管理系統(tǒng)內(nèi)的部件和調(diào)色板的輸送。有多個(gè)車(chē)輛自動(dòng)導(dǎo)引車(chē)系統(tǒng)，路由控制邏輯可以變得相當(dāng)復(fù)雜，成為柔性制造系統(tǒng)控制軟件的關(guān)鍵部分。加載/卸載終端模塊在裝載區(qū)顯示了操作者把那種工件傳輸?shù)较到y(tǒng)，使他或她當(dāng)工件在加載區(qū)準(zhǔn)備接收信息時(shí)更新了控制系統(tǒng)的狀態(tài)。存儲(chǔ)控制模塊保持一定數(shù)量的工件信息存儲(chǔ)在AS&RS中當(dāng)，以及他們的確切位置。該工具管理模塊保留了所有有關(guān)的刀具數(shù)據(jù)資料和刀具在柔性制造系統(tǒng)的實(shí)際位置的賬戶(hù)。
刀具管理是比較全面，因?yàn)橥ǔ５牡毒邤?shù)量超過(guò)了在系統(tǒng)中工件數(shù)量，而且，該模塊必須控制刀具的準(zhǔn)備和流動(dòng)。DNC功能是在FMS的控制程序和機(jī)床與車(chē)間設(shè)備之間提供接口。車(chē)間里的設(shè)備的DNC功能對(duì)一個(gè)柔性制造系統(tǒng)是必不可少的，一個(gè)能遠(yuǎn)程控制的“完整”DNC通信協(xié)議是需要的。
該機(jī)床的大部分廠商已經(jīng)開(kāi)發(fā)的專(zhuān)有通信協(xié)議的事實(shí)正使包括多廠商設(shè)備FMS的開(kāi)發(fā)和整合復(fù)雜化。而且，多廠商設(shè)備的物理集成是不同的；例如，在托盤(pán)裝載/卸載機(jī)械的差異市來(lái)自不同廠商的機(jī)器刀具的使用變復(fù)雜。因此，實(shí)施一個(gè)柔性制造系統(tǒng)唯一可行的辦法是從主要機(jī)床制造商之一購(gòu)買(mǎi)交鑰匙系統(tǒng)。這些系統(tǒng)是可靠和行之有效的制度，并應(yīng)不令人滿(mǎn)意的，單一供應(yīng)商的責(zé)任將有助于故障的補(bǔ)救。
9