成組技術(shù)外文文獻(xiàn)翻譯、機(jī)械加工工藝方面外文翻譯、中英文翻譯

外文原文： Group Technology Group technology (GT) is a very important methodology in todays manufacturing significant. The reason for this is that group technology, when utilized to its fullest extent, can affect most areas of manufacturing, including design, process planning, scheduling, routing, factory layout, procurement, quality assurance, machine tool utilization, tool design, producibility engineering, and assembly. 1 Introduction Group technology is a simple concept that is used widely in various forms. For a variety of reasons, it is logical to collect and associate things based on features that they have in common. This approach is familiar to everyone for plants, animals, and chemicals. Such organizational structures have also been used for hardware and other obviously similar products within the manufacturing world. Group technology represents structured categorization of particular value to the manufacturing community. It is already widely used； perhaps 50% of manufacturing companies use some form of GT. Bath or lot production suffers from many inefficiencies due to part variety and the general-purpose nature (flexibility requirements) of machine tools in use on the shop floor. In fact, a Cincinnati Milacron study showed that 95% of the time a part spends on the shop floor is idle time, the other 5% is divided between setup and teardown of the machine tool. The future breakdown of the 5% of on-machine time was developed by Dunlap. Based on this estimate, only 24% of the 5% is time which actually involves cutting； i.e., parts are being machined during only 1.2% of the total time spent in manufacturing. Group technology makes possible the application of several methods of analysis which assist in making batch production more efficient by reducing part variety via part families and improving throughout and work-in-process inventory. It is for this reason that group technology is becoming a key concept in manufacturing. 2 Definition Manufacturing philosophy to some, fundamental building block for more efficient production to most, group technology is a simple concept which utilizes/exploits similarities for more efficient production in bath manufacturing. Group technology usually classifies parts in the form of a code which is assigned to each part based on its shape or production processing characteristics. In use, coding parts assists in the control of planning and processing. This added control, which exploits similarities, leads to economies in the overall manufacturing process. The actual operator on the shop floor may never know this code, but designers, engineers, and planners find it an invaluable tool, allowing them to do more productive and useful analysis. 3 General Benefits In practice, group technology is really nothing more than an information/indexing system. However, because of its focus on part design and processing similarities, analysis is possible which creates manufacturing economies of scale, encourages standardization, and eliminates duplication in design and process planning. Mass production enjoys the benefits of what are called economies of scale. Economies of scale achieved by processing a large number of parts over the same workstations or equipment. This result in less labor per part, more efficient machine utilization, and a faster turnover of inventory. Batch production in the past has not enjoyed economies of scale because of the need to remain flexible for changing part types and products. However, by grouping parts into families based on their similarities, much of the manufacturing processing of these parts can be done on entire families. This increases the number of parts processed with the same equipment conditions, thereby permitting some of the economies of scale of mass production. Standardization is achieved in both design and part process planning. Essentially, group technology creates an efficient design retrieval system since parts have been code based on shape. Similar design are located quickly and aspects such as part tolerances and producibility can be better understood, more easily applied, and kept more consistent from design to design. When standardized process planes are developed and include in the group technology code, new parts and repeat orders can follow similar processing routes through the shop floor, simplifying scheduling and flow through the shop. Group technology eliminates duplication. In both design and process planning, there is much les “reinventing of the wheel” since there is sufficient retrieval of standard designs and process plans. 4 Application of GT in Process Planning Although many areas of business operation can benefit from GT, manufacturing, the original application area, continues to be the place where GT is most widely practiced. Two important tasks in manufacturing planning and manufacturing engineering are scheduling and process planning. Job scheduling sets the order in which parts should be processed and can determine expected completion times for operation and orders. Process planning, on the other hand, decides the sequence of machines to which a part should be routed when it is manufactured and the operations that should be performed at each machine. Process planning also encompasses tool, jig, and fixture selection as well as documentation of the time standards (run and setup time) associated with each operation. Process planning can directly affect scheduling efficiency and, thus, many of the performance measures normally associated with manufacturing planning and control. Some of the largest productivity gains have been reported in the creation of process plans that determine how a part should be produced. With computer-aided process planning (CAPP) and GT it is possible to standardize such plans, reduce the number of new ones, and store, retrieve, edit, and print them out very efficiently. Process planning normally is not a formal procedure. Each time a new part is designed, a process planner will look at the drawing and decide which machine tools should process the parts, which operations should be performed, and in what sequence There are two reasons why companies often generate excess process plans. First, most companies have several planners, and each may come up with a different process plan for the very same part, Second, process； planning is developed with the existing configuration of machine tools in mind. Over time, the addition of new equipment will change the suitability of existing plans. Rarely are alterations to old process plans made. One company reportedly had 477 process plans developed for 523 different gears. A close look revealed that more than 400 of the plans could be eliminated. Process planning using CAPP can avoid these problems. Process planning with CAPP takes two different forms； With variant-based planning, one standardized plan (and possibly one or more alternate plans) is created and stored for each part family. When the planner enters the GT code for a part, the computer will retrieve the best process plan. If none exists, the computer will search for routings and operations for similar parts. The planne r can edit the scheme on the CRT screen before printout. With generative planning, which can but does not necessarily rely on coded and classified parts, the computer forms the process plan through a series of questions the computer poses on the screen. The end product is also a standardized process plan, which is the best plan for a particular part. The variant-based approach relied on established plans entered into the computer memory, while the generative technique creates the process plans interactively, relying on the same logic and knowledge that a planner has. Generative process planning is much more complex than variant-based planning； in fact, it approaches the art of artificial intelligence. It is also much more flexible； by simply changing the planning logic, for instance, engineers can consider the acquisition of a new machine tool. With the variant-based method, the engineers must look over and possibly correct all plans that the new tool might affect. CAPP permits creation and documentation of process plans in a fraction of the time it would take a planner to do the work manually and vastly reduces the number of errors and the number of new plans that must be stored. When you consider that plans normally are handwritten and that process planners spend as much as 30% of their time preparing them, CAPPS contribution of standardized formats for plans and more readable documents is important. CAPP, in effect, functions as advanced text editor. Furthermore, it can be linked with an automated standard data system that will calculate and record the run times and the setup times for each operation. CAPP can lead to lower unit costs through production of parts in an optimal way. That is, cost savings come not only via more efficient process planning but also through reduced labor, material, tooling, and inventory costs. GT can help in the creation of programs that operate numerically (NC) machinery, n area related to process planning. For example, after the engineers at Otis Engineering had formed part families and cells, the time to produce a new NC tape dropped from between 4 and 8 hours to 30 minutes. The company thereby improved the potential for use of NC equipment on batches with small manufacturing quantities. 編 者：吳非曉等 機(jī)械英語(yǔ) 2 外語(yǔ)教學(xué)與研究出版社 2002.7 譯文： 成組技術(shù) 在當(dāng)今的制造環(huán)境下，尤其是對(duì)批量生產(chǎn)來(lái)說(shuō)，成組技術(shù)（ GT）是一個(gè)很重要的生產(chǎn)方式而且它正變得越來(lái)越重要。其原因在于，當(dāng)成組技術(shù)發(fā)揮最大作用的時(shí)候，能夠影響大多數(shù)的制造領(lǐng)域，其中包括設(shè)計(jì)、工藝規(guī)劃、調(diào)度、路線、工廠布局、采購(gòu)、質(zhì)量保證、車床應(yīng)用、刀具設(shè)計(jì)、生產(chǎn) 能力設(shè)計(jì)及組裝。 1 簡(jiǎn)介 成組技術(shù)是一個(gè)以各種形式廣泛應(yīng)用的簡(jiǎn)單概念?；诟鞣N原因，我們有理由根據(jù)事物的共同特征把它們收集并聯(lián)系在一起。對(duì)于植物、動(dòng)物和化合物來(lái)說(shuō)，每個(gè)人都很熟悉這種方法。在制造業(yè)內(nèi)，這種組織結(jié)構(gòu)也被用于硬件和其它明顯相似的產(chǎn)品中。成組技術(shù)對(duì)于生產(chǎn)團(tuán)體來(lái)說(shuō)，代表著具有具體價(jià)值的組織分類。它早就被廣泛應(yīng)用，大約有 50%的生產(chǎn)企業(yè)在使用某種形式的成組技術(shù)。 由于零件多種多樣以及生產(chǎn)車間使用的車床的通用特性（靈活性要求），造成了批量和規(guī)模生產(chǎn)效率差的情況很多。一份辛辛那提麥爾克倫的研究表明，實(shí)際 上一個(gè)零件花費(fèi)在生產(chǎn)車間的時(shí)間有 95%是閑置的，另外 5%的時(shí)間在車床的裝配和拆卸之間進(jìn)行分配。 Dunlap對(duì)這 5%的機(jī)上時(shí)間進(jìn)一步的分解進(jìn)行了研究。據(jù)此估計(jì)， 5%的機(jī)上時(shí)間中只有 24%的時(shí)間用于切割。也就是說(shuō)，只有 1.2%的總時(shí)間用于零部件的加工。成組技術(shù)能夠利用幾中不同分析的方法，通過(guò)零件族來(lái)減少零件的種類，從而使批量生產(chǎn)更具有效率，提高生產(chǎn)能力并緩解加工過(guò)程的庫(kù)存問(wèn)題。正是由于這個(gè)原因，成組技術(shù)才在生產(chǎn)中成為一個(gè)至關(guān)重要的概念。 2 定義 成組技術(shù)在某種程度上是一種生產(chǎn)觀念，而在很大程度上是高效率生產(chǎn)的 基本構(gòu)件，它是一個(gè)簡(jiǎn)單的概念，它在批量生產(chǎn)過(guò)程中利用或使用相似性提高制造效率。成組技術(shù)通常利用代碼將零件分類。代碼是根據(jù)零件的形狀或生產(chǎn)過(guò)程的特征分配給每個(gè)零件的。使用中，代碼零件有助于對(duì)規(guī)劃和加工的控制。這種利用相似性的附加控制能給整個(gè)生產(chǎn)過(guò)程帶來(lái)許多經(jīng)濟(jì)效益。車間里的實(shí)際操作者可能永遠(yuǎn)也不知道這個(gè)代碼，但是設(shè)計(jì)者、工程師和規(guī)劃人員把它當(dāng)成一種最寶貴的工具，能夠使他們進(jìn)行更加有用和富有成效的分析。 3 益處 實(shí)際上，成組技術(shù)其實(shí)就是一個(gè)信息或索引系統(tǒng)。然而，由于它著眼于零件設(shè)計(jì)和加工的相似性就有可能進(jìn)行分 析，規(guī)模生產(chǎn)的經(jīng)濟(jì)效益，促進(jìn)標(biāo)準(zhǔn)化并避免重復(fù)設(shè)計(jì)和工藝規(guī)劃。 批量生產(chǎn)有利于規(guī)模經(jīng)濟(jì)。規(guī)模經(jīng)濟(jì)效益通過(guò)用同一車間或設(shè)備加工大量零件來(lái)實(shí)現(xiàn)。這意味著每個(gè)零件所用勞動(dòng)力較少，機(jī)械利用率更高，庫(kù)存周轉(zhuǎn)更快。過(guò)去的批量生產(chǎn)并沒(méi)有獲得規(guī)模生產(chǎn)的經(jīng)濟(jì)效益，原因在于需要保持靈活性來(lái)更換零件的種類和產(chǎn)品。然而，通過(guò)根據(jù)相似性對(duì)零件進(jìn)行分組，在整個(gè)族內(nèi)就可以完成這些零件的大部分生產(chǎn)加工。這就增加了同一個(gè)生產(chǎn)設(shè)備條件下加工零件的數(shù)量，因此就能帶來(lái)規(guī)模生產(chǎn)所追求的一些經(jīng)濟(jì)效益。 標(biāo)準(zhǔn)化是在設(shè)計(jì)和零件工藝規(guī)劃中完成的。重要的是，由 于零件根據(jù)形狀被編碼，成組技術(shù)提供了一個(gè)有效率的設(shè)計(jì)檢索系統(tǒng)。相似的設(shè)計(jì)很快就能找到，一些諸如零件公差和可制造性問(wèn)題得到了更好的解決，利用更方便，而且從設(shè)計(jì)到設(shè)計(jì)都保持一致性。一旦制定了標(biāo)準(zhǔn)化的工藝規(guī)劃并被編入成組技術(shù)代碼中，新零件和重復(fù)命令就能通過(guò)生產(chǎn)車間在相似的加工路線上運(yùn)行，簡(jiǎn)化了車間的計(jì)劃和流程。 成組技術(shù)減少重復(fù)。在設(shè)計(jì)和加工計(jì)劃中只有較少的“操縱輪的重新設(shè)定”，因?yàn)橛凶銐虻臉?biāo)準(zhǔn)化的設(shè)計(jì)和工藝規(guī)程供檢索。 4 成組技術(shù)在工藝規(guī)劃中的應(yīng)用 雖然很多商業(yè)領(lǐng)域可以從成組技術(shù)中獲益，但是制造這一 GT最初的 應(yīng)用領(lǐng)域仍然是 GT 最為廣泛實(shí)踐的地方。制造計(jì)劃與制造工程的兩個(gè)重要任務(wù)是調(diào)度和工藝規(guī)劃。作業(yè)調(diào)度安排零件所加工的流程，并可確定工序期望完成的時(shí)間和流程；在另一方面，工藝規(guī)劃決定了零件制造時(shí)所應(yīng)發(fā)送的機(jī)器流程以及在每臺(tái)機(jī)器上所應(yīng)完成的工序。工藝規(guī)劃還包括刀具、夾具和定位器的選擇以及有關(guān)每道工序的時(shí)間標(biāo)準(zhǔn)（運(yùn)轉(zhuǎn)時(shí)間與準(zhǔn)備時(shí)間）的文件編制。工藝規(guī)