lesson31工程師在機械制造業(yè)中的作用.doc

Lesson31 the roles of engineers in manufacturing第三十一課 工程師在機械制造業(yè)中的作用Many engineers have as their function the designing of products that are to be brought into reality through the processing or fabrication of materials .In this capacity they are a key factor in the material selection-manufacturing procedure .A design engineer ,better than any other person ,should know what he or she wants a design to accomplish .He knows what assumptions he has made about service loads and requirements ,what service environment the product must withstand ,and what appearance he wants the final product to have .In order to meet these requirements he must select and specify the material(s) to be used .In most cases ,in order to utilize the material and to enable the product to have the desired form ,he knows that certain manufacturing processes will have to be employed .In many instances ,the selection of a specific material may dictate what processing must be used .At the same time ,when certain processes are to be used ,the design may have to be modified in order for the process to be utilized effectively and economically .Certain dimensional tolerances can dictate the processing .In any case ,in the sequence of converting the design into reality ,such decisions must be made by someone .In most instances they can be made most effectively at the design stage ,by the designer if he has a reasonably adequate knowledge concerning materials and manufacturing processes .Otherwise ,decisions may be made that will detract from the effectiveness of the product ,or the product may be needlessly costly .It is thus apparent that design engineers are a vital factor in the manufacturing process ,and it is indeed a blessing to the company if they can design for producibilitythat is ,for efficient production .許多工程師的職責是進行產(chǎn)品設計,而產(chǎn)品是通過對材料的加工制造而生產(chǎn)出來的。設計工程師在材料選擇-制造方法等方面起著關鍵的作用。一個設計工程師應該比其他的人更清楚地知道他的設計需要達到什么目的。他知道他對使用荷載和使用要求所做的假設,產(chǎn)品的使用環(huán)境,產(chǎn)品應該具有的外觀形貌。為了滿足這些要求,他必須選擇和規(guī)定,所使用的材料。通常,為了利用材料并使產(chǎn)品具有所期望的形狀,設計工程師知道應該采用哪些制造方法。在許多情況下,選擇了某種特定材料就可能意味著已經(jīng)確定了某種必須采用的加工方法d同時,當決定采用某種加工方法后,很可能需要對設計進行修改,以使這種加工方法能夠被有效而經(jīng)濟地應用。某些尺寸公差可以決定產(chǎn)品的加工方法?？傊?在將設計轉變?yōu)楫a(chǎn)品的過程中,必須有人做出這些決定。在大多數(shù)情況下,如果設計人員在材料和加工方法方面具有足夠的知識,他會在設計階段做出最為合理的決定。否則,做出的決定可能會降低產(chǎn)品的性能,或者使產(chǎn)品變得過于昂貴。顯然,設計工程師是制造過程中的關鍵人物,如果他們能夠進行面向生產(chǎn)(即可以進行高效率生產(chǎn))的設計,就會給公司帶來效益。Manufacturing engineers select and coordinate specific processes and equipment to be used ,or supervise and manage their use .Some design special tooling that is used so that standard machines can be utilized in producing specific products .These engineers must have a broad knowledge of machine and process capabilities and of materials ,so that desired operations can be done effectively and efficiently without overloading or damaging machines and without adversely affecting the materials being processed .These manufacturing engineers also play an important role in manufacturing .制造工程師們選擇和調整所采用的加工方法和設備,或者監(jiān)督和管理這些加工方法和設備的使用。一些工程師進行專用工藝裝備的設計,以使通用機床能夠被用來生產(chǎn)特定的產(chǎn)品。這些工程師們在機床、工藝能力和材料方面必須具有廣泛的知識,以使機器在沒有過載和損壞,而且對被加工材料沒有不良影響的情況下,更為有效地完成所需要的加工工序。這些制造工程師們在制造業(yè)中也起到重要作用。A relatively small group of engineers design the machines and equipment used in manufacturing .They obviously are design engineers and ,relative to their products ,they have the same concerns of the interrelationship of design ,materials ,and manufacturing processes .However ,they have an even greater concern regarding the properties of the materials that their machines are going to process and the interreaction of the materials and the machines .少數(shù)工程師們設計在制造業(yè)中使用的機床和設備。顯然,他們是設計工程師。而且對于他們的產(chǎn)品而言,他們同樣關心設計、材料和制造方法之間的相互關系。然而,他們更多地關心他們所設計的機床將要加工的材料的性能和機床與材料之間的相互作用。Still another group of engineersthe materials engineersdevote their major efforts toward developing new and better materials .They ,too ,must be concerned with how these materials can be processed and with the effects the processing will have on the properties of the materials .還有另外一些工程師一一材料工程師,他們致力于研制新型的和更好的材料,他們也應該關心這些材料的加工方法和加工對材料性能的影響。Although their roles may be quite different ,it is apparent that a large proportion of engineers must concern themselves with the interrelationship between materials and manufacturing processes .盡管工程師們所起的作用可能會有很大差別,但是,大部分工程師們都必須考慮材料與制造工藝之間的相互關系。Low-cost manufacturing does not just happen .There is a close and interdependent relationship between the design of a product ,selection of materials ,selection of processes and equipment ,and tooling selection and design .Each of these steps must be carefully considered ,planned ,and coordinated before manufacturing starts .This lead time ,particularly for complicated products ,may take months ,even years ,and the expenditure of large amount of money may be involved .Typically ,the lead time for a completely new model of an automobile is about 2 years ,for a modern aircraft it may be 4 years .低成本制造并不是自動產(chǎn)生的。在產(chǎn)品設計、材料選擇、加工方法和設備的選擇,工藝裝備選擇和設汁之間都有著非常密切的相互依賴關系。這些步驟中的每一個都必須在開始制造前仔細地加以考慮、規(guī)劃和協(xié)調。這種從產(chǎn)品設計到實際生產(chǎn)的準備工作,特別是對于復雜產(chǎn)品,可能需要數(shù)月甚至數(shù)年的時間,并且可能花費很多錢。典型的例子有,對于一種全新的汽車,從設計到投產(chǎn)所需要的時間大約為2年,而一種現(xiàn)代化飛機則可能需要4年。With the advent of computers and machines that can be controlled by either tapes made by computers or by the computers themselves ,we are entering a new era of production planning .The integration of the design function and the manufacturing function through the computer is called CAD/CAM(computer aided design/computer aided manufacturing) .The design is used to determine the manufacturing process planning and the programming information for the manufacturing processes themselves .Detailed drawings can also be made from the central data base used for the design and manufacture ,and programs can be generated to make the parts as needs .In addition ,extensive computer aided testing and inspection(CATI) of the manufactured parts is taking place .There is no doubt that this trend will continue at ever-accelerating rates as computers become cheaper and smarter .隨著計算機和由計算機產(chǎn)生的紙帶與由計算機本身控制的機器的出現(xiàn),我們進人了一個生產(chǎn)計劃的新時代。采用計算機將產(chǎn)品的設計功能與制造功能集成,被稱為“D/CAM(計算機輔助設計/計算機輔助制造)。這種設計被用來制定加工工藝規(guī)程和提供加工過程本身的編程信息?？梢愿鶕?jù)供設計與制造用的中心數(shù)據(jù)庫內的信息繪制零件圖,需要時可以生成加工這些零件時所使用的程序。此外,對加工后零件的計算機輔助試驗與檢測也得到了廣泛的應用。隨著計算機價格的降低和性能的提高,這種趨勢將毫無疑問地得到不斷加速的發(fā)展。