外文翻譯--模具制造科學(xué)

1 英文翻譯 The Science of Die Making The traditional method of making large automotive sheet metal dies by model building and tracing has been replaced by CAD/CAM terminals that convert mathematical descriptions of body panel shapes into cutter paths.Teledyne Specialty Equipments Efficient Die and Mold facility is one of the companies on the leading edge of this transformation. by Associate Editor Only a few years ago,the huge steel dies requited for stamping sheet metal auto body panels were built by starting with a detailed blueprint and an accurate full-scale master model of the part. The model was the source from which the tooling was designed and produced. The dies,machined from castings,were prepared from patterns made by the die manutacturers or somethimes supplied bythe car maker.Secondary scale models called” tracing aids” were made from the master model for use on duplicating machines with tracers.These machines traced the contour of the scale model with a stylus,and the information derived guided a milling cutter that carved away unwanted metal to duplicate the shape of the model in the steel casting. All that is changing.Now,companies such as Teledyne Specialty Equipments Effi cient Die and Mold operation in Independence,OH,work from CAD data supplied by customers to generate cutter paths for milling machines,which then automatically cut the sheetmetal dies and SMC compression molds. Although the process is uesd to make both surfaces of the tool, the draw die still requires a tryout and “benching” process.Also, the CAD data typically encompasses just the orimary surface of the tool,and some machined surfaces, such as the hosts and wear pads, are typically part of the math surface. William Nordby,vice president and business manager of dies and molds at Teledyne,says that “although no one has taken CAD/CAM to the point of building the entire tool,it will eventually go in that direction because the “big thrdd”want to compress cycle times and are trying to cut the amount of time that it takes to build the tooling.Tryout, because of the lack of development on the design end,is still a very time-consuming art,and vety much a trial-and-error process.” No More Models and Tracing Aids The results to this new technology are impressive. For example, tolerances are tighter and hand finishing of the primary die surface with grinders has all but been eliminated. The big difference, says Gary Kral, Teledynes director of engineering, is that the dimensional control has radically improved. Conventional methods of making plaster molds just couldnt hold tolerances because of day-to-day temperature and humidity variations.” For SMC molds the process is so accurate , and because there is no spring back like there is when stamping sheet metal, tryouts are not always required.SMC molds are approved by customers on a regulate basis without ever running a part .Such approvals are possible because of Teledynes ability to check the tool 2 surface based on mathematical analysis and guarantee that it is made exactly to the original design data. Because manual trials and processes have been eliminated, Teledyne has been able to consider foreign markets.” The ability to get a tool approved based on the mathe gives us the opportunity to compete in places we wouldnt have otherwise,” says Nordby. According to Jim Church, systems manager at Teledyne, the company used to have lots of pattern makers ,and still has one model maker.” But 99.9 percent of the companys work now is from CAD data. Instead of model makers, engineers work in front of computer monitors.” He says that improvenents in tool quality and reduction in manufacturing time are significant. Capabilities of the process were demonstrated by producing two identical tools. One was cut using conventional patterns and tracing mills, and the other tool was machined using computer generated cutting paths. Although machining time was 14 percent greater with the CAM-generated path, polishing hours were cut by 33 percent. In all ,manufacturing time decreased 16.5 percent and tool quality increased 12 percent. Teledynes CAD/CAM system uses state-of-the-art software that allows engineers to design dies and molds, develop CNC milling cutter paths and incorporate design changes easily. The system supports full-color, shaded three-dimensional modeling on its monitors to enhance its design and analysis capabilities. The CAD/CAM system also provides finite element analysis that can be used to improve the quality of castings , and to analyze the thermal properties of molds. Inputs virtually from any customer database can be used either directly or through translation. CMM Is Critical Teledynes coordinate measuring machine(CMM),says Church,”is what has made a difference in terms of being able to move from the traditional manual processes of mold and die making to the automated system that Teledyne uses today.” The CMM precisely locates any point in a volume of space measuring 128 in, by 80 in, by 54 in, to an accuracy of 0.0007 in. It can measure parts, dies and molds weighing up to 40 tons. For maximum accuracy,the machine is housed in an environmentally isolated room where temperature is maintained within 2 deg.F of optimum. To isolate the CMM from vibration, it is mounted on a 100-ton concrete block supported on art cushions. According to Nordby, the CMM is used not only as a quality tool, but also as a process checking tool. “ As a tool goes through the shop, it is checked several times to validate the previous operation that was performed.” For example, after the initial surface of a mold is machined and before any finish work is done, it is run through the CMM for a complete data check to determine how close the surface is to the required geometry. The mold is checked with a very dense pattern based on flow lines of the part. Each mold is checked twice, once before benching and again after benching. Measurements taken from both halves of the mold are used to calculate theoretical stock thickness at full closure of the mold to verify its accuracy with the CAD design data. Sheet Metal Dies Are Different 3 “Sheet metal is a different ballgame,” says Nordby, “because you have the issue of material springback and the way the metal forms in the die. What happens in the sheet metal is that you do the same kinds of things for the male punch as you would with SMC molds and you ensure that it is 100 percent to math data. But due to machined surface tolerance variations, the female half becomes the working side of the tool. And there is still a lot of development required after the tool goes into the press. The math generated surfaces apply primarily to the part surface of the tool.” EMS Tracks the Manufacturing Process Teledynes business operations also are computerized and carried over a network consisting of a VAX server and PC terminals. IMS (Effective Management Systems) software tracks orders, jobs in progress, location of arts, purchasing, receiving, and is now being upgraded to include accounting functions. Overall capabilities of the EMS system include bill-of-material planning and control, inventory management, standard costing, material history, master production scheduling, material requirements planning, customer order processing, booking and sales history, accounts receivable, labor history, shop floor control, scheduling, estimating, standard routings, capacity requirements planning, job costing, purchasing and receiving, requisitions, purchasing and receiving, requisitions, purchasing history and accounts payable. According to Frank Zugaro, Teledynes scheduling manager, the EMS software was chosen because of its capabilities in scheduling time and resources in a job shop environment. All information about a job is entered into inventory management to generate a structured bill of material. Then routes are attached to it and work orders are generated. The system provides daily updates of data by operator hour as well as a material log by shop order and word order. Since the database is interactive, tracking of materials received and their flow through the build procedure can be documented and cost data sent to accounting and purchasing. Gary Kral, Teledynes director of engineering, says that EMS is really a tracking device, and one of the systems greatest benefits is that it provides a documented record of everything involving a job and eliminates problems that could arise from verbal instructions and promises. Kral says that as the system is used more, they are finding that it pays to document more things to make it part of the permanent record. It helps keep them focused. 4 模具制造科學(xué) 傳統(tǒng)的通過制造模具加工大 型板材的方法已經(jīng)被可以把實(shí)體的形狀信息轉(zhuǎn)換為切削路徑的CAD/CAM 所取代了。這個(gè)專門的高效的靈活的公司就是這種轉(zhuǎn)換技術(shù)前言的一部分。 在幾年以前，大型的需要自動(dòng)送料的巨大金屬模具在詳細(xì)的藍(lán)圖上和一個(gè)準(zhǔn)確的全面的模形上開始建造，這個(gè)模形是工具被設(shè)計(jì)和生產(chǎn)的起源。 模具是由澆鑄轉(zhuǎn)化來的，它由模形制造演化而來，而且由模具制造商和汽車生產(chǎn)商贊助。第二種類型的模型叫做路線輔助追蹤，他由替代追蹤的模型發(fā)展而來，這些機(jī)器用探頭掃描機(jī)器的輪廓，所獲得的信息控制加工機(jī)切去不需要的金屬以便復(fù)制模型。 現(xiàn)在所有這些都被改變了， 現(xiàn)在像 TSEED 這類大公司獨(dú)立運(yùn)作，用客戶提供的 CAD 數(shù)據(jù)產(chǎn)生加工機(jī)的加工路線，用于自動(dòng)加工板材模和 SMC 復(fù)合材料。 雖然這個(gè)工藝只被應(yīng)用于加工工件的倆個(gè)表面，但模具還需要一個(gè)實(shí)驗(yàn)過程，而且， CAD 數(shù)據(jù)只包含工件原始表面的數(shù)據(jù)和像墊圈這類的機(jī)加工過的表面和一些數(shù)學(xué)模型的部分。 威廉是在泰勒德尼的模具制造工業(yè)的代主官，他說“雖然沒人把 CAD/CAM 用于制造所有工件，但他終將向這個(gè)方向發(fā)展，因?yàn)槿揞^要壓縮循環(huán)時(shí)間而且試圖減少制造工具的時(shí)間。因?yàn)槿鄙傧蛟O(shè)計(jì)結(jié)果的發(fā)展，試驗(yàn)仍然是一向非常費(fèi)時(shí)間的工作，也是一個(gè)不斷 改進(jìn)的過程。 不再需要模型和輔助追蹤 這項(xiàng)技術(shù)的結(jié)果是令人振奮的。舉個(gè)例子，公差過于苛刻使得手工加工模具表面是無論如何也無法完成的。格爾說，最大的不同在于泰勒迪尼的工程師的空間控制被很快的發(fā)展了。傳統(tǒng)的加工塑料模具的發(fā)發(fā)不能滿足公差的要求，這是因?yàn)闅鉁氐牟煌腿藶榈夭顒e。 對于 SMC，制造過程是如此的精確以至于試驗(yàn)有時(shí)候可以省略，因?yàn)樵诙ㄎ话宀牡臅r(shí)候沒有滑移。SMC 技術(shù)已經(jīng)在沒有進(jìn)行任何運(yùn)行基礎(chǔ)的情況下被客戶所證實(shí)了。這些人同時(shí)可能的，因?yàn)樘├盏夏峁居心芰υ跀?shù)學(xué)分析的基礎(chǔ)上檢查這些工件的表面并保證是按照原 始的設(shè)計(jì)數(shù)據(jù)設(shè)計(jì)的。 因?yàn)槿斯さ牟僮骱凸に嚤慌懦?，泰勒迪尼能夠考慮海外市場，在數(shù)學(xué)基礎(chǔ)上制造工具的能力是我們有機(jī)會在以前沒有涉及的領(lǐng)域發(fā)展，蓋瑞說。 據(jù)泰勒德尼的系統(tǒng)主管吉姆說，公司以前有許多圖案設(shè)計(jì)師和一個(gè)模型設(shè)計(jì)師。但現(xiàn)在 99.9%的公司業(yè)務(wù)是由 CAD 進(jìn)行的。代替了以前的模型設(shè)計(jì)師，現(xiàn)在工程師們在電腦顯示器前面工作。 他說，在工件質(zhì)量的提高和生產(chǎn)時(shí)間的縮短是至關(guān)重要的。工藝的能力已經(jīng)被生產(chǎn)倆個(gè)完全一樣的工件所證明。一個(gè)是使用傳統(tǒng)的加工圖案的追蹤方法而另一個(gè)是用計(jì)算機(jī)產(chǎn)生的路徑進(jìn)行加工。雖然機(jī)加工時(shí)間后 一種方法只領(lǐng)先 14%，但是磨光時(shí)間減少了 33%?？傊?，生產(chǎn)時(shí)間減少了 16.5%，工件的質(zhì)量提高了 12%。 泰勒德尼的 CAD/CAM 系統(tǒng)使用了階段操作軟件，是工程師們可以設(shè)計(jì)模具，研究 CNC 切削路徑，并方便的改變設(shè)計(jì)。系統(tǒng)支持所有顏色，可以在顯示器上產(chǎn)生三維模型以增強(qiáng)效果，還有分析功能。CAD/CAM 系統(tǒng)也提供有限單元分析，這可以提高加工質(zhì)量和分析加工的主要特征