臥式雙面23軸組合鉆床前主軸箱設計

臥式雙面23軸組合鉆床前主軸箱設計,臥式雙面23軸組合鉆床前主軸箱設計,臥式,雙面,23,組合,鉆床,主軸,設計 黃河科技學院畢業(yè)設計（文獻翻譯） 第9頁 汽車工業(yè)CAD教育和培訓 大衛(wèi)?A?菲爾德 通用汽車公司研究開發(fā)和規(guī)劃中心，美國 480-106-359 ，30500，48090-9055 摘要：20世紀50年代，被展望以及被卓越指定的計算機輔助設計（CAD）系統(tǒng)，他們在今天汽車制造業(yè)通過連續(xù)的改善和技術突破使得自己進入了中心的角色。這篇文章強調平行并且繼續(xù)的在計算機輔助設計系統(tǒng)的用戶的訓練和教育需要方面的演化。鑒于計算機輔助設計的在通用汽車快速發(fā)展歷史，這篇文章將計算機輔助設計用戶進行了分類，并且在汽車制造業(yè)方面提出他們當今和將來的需要。在教育和訓練需求方面的變化，造成教育和工業(yè)機構的挑戰(zhàn)。 關鍵詞：CAD教育, CAD訓練 基本介紹 在這篇文章里計算機輔助設計模型數(shù)學上意味著物理物體的準確的幾何描述，描述了包括數(shù)值數(shù)據(jù)和算法規(guī)定對象的幾何學。計算機輔助設計系統(tǒng)然后提供方法創(chuàng)造，操作并且交流這些幾何學描述。為了集中于與教育有關的計算機輔助設計以及在汽車工業(yè)計算機輔助設計用戶的需要，首先簡述計算機輔助設計在通用汽車的歷史。相似的內容可以被記載在其他制造業(yè)企業(yè)。 據(jù)一份在50年代后期通用汽車內部文件的書面大會，工程師概述了一個雄心勃勃的項目的詳細規(guī)格，，即現(xiàn)代原型CAD系統(tǒng)。資料可靠地來源于20世紀40年代后期，伺服機制和數(shù)字電子計算機的一次進行中的發(fā)展，為一個計算機輔助設計系統(tǒng)提供了的可行性和動力。雖然這個文件直接描述了通過控制設計和制造來節(jié)約成本的好處、減少勞動力、周圍更快的變化、以及工程師和設計人員之間通信的改善，文件沒有預計最后計算機輔助設計在設計和生產(chǎn)過程內的發(fā)展提供好處的大小。工程師， 特別是他們的大部分試驗工作即將減少的機械工程師， 將在工人，例如缺乏實踐的草圖設計師，利用計算機輔助設計系統(tǒng)在復雜的情況里進行技能的訓練。例如，計算機輔助設計系統(tǒng)使機械工程師能夠空前大規(guī)模使用有限元分析(FEA)。 在20世紀90年代，這個被提議的計算機輔助設計系統(tǒng)的細節(jié)基本上用來描述使用中的計算機輔助設計系統(tǒng)。這些細節(jié)反映了古怪的融合推動現(xiàn)有技術與要求，但不可能在那個時間達到，提供了一個健全的商業(yè)經(jīng)營情況下，為CAD所描述的改進工作流程和項一些詳細的數(shù)學描述。難以置信的是，直到近三十年后，一些技術仍然不符合規(guī)格！這份歷史資料的最初段落清楚打下一個依賴數(shù)學的計算機輔助設計系統(tǒng)的基礎。并且， 作為在制造業(yè)里的工程師，，那些作者此外強調技術工具，產(chǎn)品設計的發(fā)展，特別是生產(chǎn)工具和機械加工，都是基于現(xiàn)在叫做計算機輔助設計技術。重點在稱呼和數(shù)字控制的機器支配討論。然而是普通主題，保存時間，創(chuàng)建幾何學，數(shù)據(jù)，準確的維護并且控制， 為評價計算機輔助設計系統(tǒng)的質量提供一個極好的初始表。連續(xù)的改進和技術的突破，已經(jīng)為計算機輔助設計在今天的汽車的工業(yè)進入中心角色提供動力。連續(xù)的改進的最明顯的例子發(fā)生在計算機的速度，能力和流量方面。計算的動力使更顯著的工程問題的分析和在計算上吸收增加集中的計算機圖形環(huán)境成為可能。在20世紀80年代中期計算機圖形硬件和軟件期間最后使造型師在20世紀50年代展望的實時形象化成為可能。 軟件方面的發(fā)展融入了多種多樣的味道。數(shù)學通過提供新數(shù)學結構和算法起決定性作用。幾個世紀以來人們熟知的數(shù)學經(jīng)歷了新發(fā)展，并且擁有成功的研究成果。從數(shù)學的發(fā)展基礎上，軟件在速度，穩(wěn)定性，準確和適應性方面得到了顯著的改進。在硬件和軟件方面的專家，能指向商業(yè)的計算機輔助設計系統(tǒng)，有時用驚人的慣性或者勉強，最終達到的突破。另一方面，乏味但是同樣重要的任務(例如數(shù)據(jù)庫，表面和固體和堅定的計算的算法的數(shù)學畫像)的標準已經(jīng)驚人的使數(shù)學模型和生產(chǎn)過程依靠的幾何學信息得到了巨大的改善。 與工作直接相關的產(chǎn)品設計和制造業(yè)具有很高的視覺內容，從最早的設計階段到最后的生產(chǎn)，計算機輔助設計系統(tǒng)已成為過程的中心環(huán)節(jié)。然而， 完成他們的任務， 大多數(shù)當今的工程師不必了解計算機輔助設計模型和計算機輔助設計依靠的復雜的數(shù)學和計算機科學。從設計說明，到產(chǎn)品分析，到調整工具的生產(chǎn)，等等，結合這些任務，計算機輔助設計系統(tǒng)通過給合適的幾何學數(shù)據(jù)提供鏈并且無數(shù)軟件包接口而形象化。計算機輔助設計能夠創(chuàng)造和產(chǎn)品信息控制。允許實際直接視覺上的，以及最重要的是，準確與設計，發(fā)展，分析和生產(chǎn)進行通訊。這篇文章將把計算機輔助設計用戶進行劃分，根據(jù)計算機輔助設計將各種各樣專門技能水平的進行分組。以下部分，按照他們對數(shù)學知識和計算機科學CAD增長的需要處理與CAD相關這些小組的需要。文章以電話來結束全部計算機輔助設計用戶獲得一個更高的發(fā)展的空間推理的感覺。 多數(shù)人的計算機輔助設計 美國有超過100萬位培訓的工程師。即使計算機影響他們的全部工作，他們對計算機輔助設計的使用也從不非常依賴到完全依賴變化。最初，強調人的設計和計算機的計算，被叫做通用汽車的計算機設計，自從有了計算機輔助設計這一概念開始，制造工業(yè)就成為計算機輔助設計非常強大的用戶。對創(chuàng)造設計的重點再度出現(xiàn)了，也就是說，在CAD的發(fā)展的到開發(fā)CAD作為一件商品，CAD極大的成功在設計的全面過程中轉移了C的主體性。 汽車和卡車拆卸成為數(shù)千個部分。 即使進入20世紀80年代中期，草圖設計師將這些部分的幾何學、調整工具生產(chǎn)以及把部分零件裝配進汽車記錄在藍圖上。一旦計算機圖形變得具備交互式性和可靠性，這群草稿設計者和他們產(chǎn)生的這噸紙就分別成為設計者和電子記錄。航空航天工業(yè)在歷史上工程師曾經(jīng)也是設計者，與其不同的是，這些草圖設計師沒有接受任何工程師的教育。 在汽車制造業(yè)內，設計者一般使用計算機輔助設計系統(tǒng)創(chuàng)造和儲存幾何學數(shù)據(jù)。這些任務與通常使用計算機輔助設計挽回并且操作輸入的幾何學數(shù)據(jù)進工程分析軟件的工程師的工作形成對比。極端下，工程師在從一個設計者創(chuàng)建的模型產(chǎn)生的有限元網(wǎng)絡里利用一個節(jié)點，除產(chǎn)生自動網(wǎng)眼產(chǎn)生的基本數(shù)據(jù)之外，創(chuàng)造有攝影現(xiàn)實主義特別的技術意見。分開汽車的工程師和用不同的方式使用計算機輔助設計的設計者的這一劃分正在緩慢地改變。遵循這一劃分產(chǎn)生的那些問題和考慮計算機輔助設計的當今和歷史角色，將為這一劃分提供一個遠景。建議在工程師和設計者的教育和訓練方面的變化將從這個視角出現(xiàn)。在20世紀60年代后期和原始計算機輔助設計系統(tǒng)離開機構內部的研究與開發(fā)環(huán)境的早期的20世紀70年代期間， 草圖設計師和工程師使用計算機輔助設計創(chuàng)造幾何學。工程師把計算機輔助設計視為一件工具被更進一步為順流象結構分析那樣的應用發(fā)展，計算機控制機器加工等等。草圖設計師仍然從工程師那里收到說明并且為起草使用計算機輔助設計作為一件工具。 像一項主要的新技術的任何實施一樣，計算機輔助設計的最初實施需要許多小草圖設計師和工程師的訓練。在計算機輔助設計方面的連續(xù)的改進，不過，有主要的結果。軟件的最新推介和越來越多有關計算機輔助設計的應用軟件需要對連續(xù)訓練的承諾。接著發(fā)生的訓練的機構體制為草圖設計師（現(xiàn)在叫的設計者），不僅使計算機輔助設計的介紹成為可能，而且與相互作用的那些工程師為一寬范圍的工程師的橫剖面；在第5 部分的計算機輔助設計訓練，包括產(chǎn)品，生產(chǎn)，釋放，工程師，僅以這些為例。 在此之外與計算機輔助設計聯(lián)系，另外小的方面，跟主要數(shù)學家和電腦專家一起，研發(fā)CAD。他們的需要從實質上不同計算機輔助設計用戶的新多數(shù)。 第3 部分決定新角色和需要。同時， 一非常大組織的工程師在設計內和使用計算機輔助設計系統(tǒng)的緊迫的發(fā)展的生產(chǎn)當時從社區(qū)的計算機科學家，工程師，數(shù)學家和科學家那里進化的商業(yè)軟件包。 這匯合由CAD幫助刺激了解決前面提到的二分化。通過簡化和去除設計師和工程師的乏味的工作。CAD講清楚決議要求在基本的課程之外的附加培訓和教育。已經(jīng)在教育機構的負擔的課程使新的要求難實施。這些另外的要求不可能替換技術基礎; 看見顯示的第5部分產(chǎn)業(yè)組織怎么應付訓練和教育。 Education and training for CAD in the auto industry David A. Field General Motors Research, Development and Planning Center, Mail Code: 480-106-359, 30500 Mount Road, Warren, MI 48090-9055, USA Abstract：CAD-systems envisioned and remarkably well specified in the 1950s have powered themselves into the central role they enjoy in today’s automotive industry through continuous improvements and technological breakthroughs. This paper emphasizes the parallel and continuing evolution in the training and educational needs of users of CAD-systems. In the context of early historical developments of CAD at General Motors, this paper categorizes CAD-users in the automobile industry and presents their current and future needs. The variance in their educational and training needs poses an ongoing challenge for educational and industrial institutions to meet. Keywords: CAD education; CAD training Introduction In this paper CAD-models mean mathematically precise geometrical descriptions of physical objects. The descrip-tions include numerical data as well as algorithms to prescribe the geometry of the objects. CAD-systems then provide the means to create, manipulate and communicate these geometric descriptions. In order to focus on CAD with respect to the education, training and needs of CAD-users in the automotive industry, first consider a very brief history of CAD at General Motors. Similar accounts can be chronicled at other manufacturing enterprises at other manufacturing enterprises. According to an internal document written at General Motors during the late 1950s, engineers outlined, with detailed specifications, an ambitious project that prototyped modern CAD-systems. The document credits an ongoing development from the late 1940s, servo-mechanisms and digital computers, for the feasibility and motivation of a CAD-system. Although the document immediately expressed the benefits of cost savings through control of design and manufacture, reduced manpower, faster turn-around,and improved communication among engineers and draftsmen (now called designers), the document did not anticipate the magnitude of benefits reaped by the eventual proliferation of CAD in the design and manufacturing processes. Engineers, especially mechanical engineers who would be relieved from much of their experimental work, would make sophisticated uses of CAD systems in situations where workers, such as draftsmen, lacked the knowledge, skills and training. For instance, CAD-systems enabled mechanical engineers to use finite element analysis (FEA) on an unprecedented large scale. The details of this proposed CAD-system essentially described CAD-systems in use during the 1990s. Details reflected a curious blend of pushing available technology with requirements yet unattainable at that time, provided a sound business case, described improved work flow and itemized some detailed mathematics for CAD. Incredibly, some technologies did not meet specifications until nearly thirty years later! The initial paragraph of this historical document clearly laid the foundation of a CAD-system dependent on mathematics. And, as engineers in a manufacturing industry, the authors also stressed the development of technical tools, product design and, especially manufacturing tools and machines, based on what is now called CAD-technology. Emphasis on styling and numerically controlled machines dominated discus- sions. Yet common themes, saving time, creating geometry, maintenance of data, accuracy and control, provided an excellent initial list for assessing the quality of CAD- systems. Continuous improvements and technological break-throughs have powered CAD into the central role it enjoys in today’s automotive industry. The most obvious examples of continuous improvement occurred in the speed, capacity and through put of computers. Computational power enabled analyses of more significant engineering problems and absorbed the increasing computationally intensive computer graphics environments. During the mid-1980s computer graphics hardware and software finally enabled real time visualizations that stylists envisioned in the 1950s. Advances in software came in all sorts of flavors. Mathematics played a crucial role by providing new mathematical constructs and algorithms. Mathematics that had been known for centuries underwent new development and fed fruitful research. Software received significant improvements in speed, robustness, accuracy and adapta- bility from underlying mathematics. Subject matter experts, in hardware and software, can point to breakthroughs that commercial CAD-systems, sometimes with tremendous inertia or reluctance, eventually absorbed. On the other hand, standards for prosaic but equally important tasks such as databases, mathematical representations of surfaces and solids, and robust computational algorithms have made tremendous improvements in processing geometric in for- mation upon which mathematical models and manufactur- ing processes depend. Since work directly related to product design and manufacturing has very high visual content, CAD-systems have become central to processes from the earliest design phase to final production. Yet, to accomplish their tasks, the vast majority of current engineers need not have any knowledge of the sophisticated mathematics and computer science upon which CAD-models and CAD-systems depend. Ranging from design specifications, to product analyses, to production tooling, etc. CAD-systems integrate these tasks by providing links to appropriate geometric data, visualizations, and interfaces with a myriad of software packages. CAD enables creation and control of product information. It allows virtually instant visual and, most important, accurate communication for design, develop- ment, analysis and manufacturing. This paper will partition the world of CAD-users into groups that require various levels of CAD-expertise. The following sections address the CAD-related needs of these groups in order of their increasing need for knowing the mathematics and computer science of CAD. The paper concludes with a call for all CAD-users to obtain a higher developed sense of spatial reasoning. CAD for the majority The United States has more than one million practicing engineers. Even though computers have impacted all their jobs,their useof CAD varies from notat all tobeing highly dependent on CAD. Manufacturing industries have been exceptionally heavy users of CAD from the very inception of CAD, initially called Design Augmented by Computers at General Motors to emphasize design by humans and computation by computers. Emphasis on creating designs would be relieved from much of their experimental work, would make sophisticated uses of CAD systems in situations where workers, such as draftsmen, lacked the knowledge, skills and training. For instance, CAD-systems enabled mechanical engineers to use finite element analysis (FEA) on an unprecedented large scale. Cars and trucks disassemble into thousands of parts. Even into the mid-1980s draftsmen recorded on blueprints geometries of the separt sand the tooling to manufacture and assemble the parts into automotive vehicles. Once computer graphics became interactive and reliable, throngs of drafts- men and the tons of paper they generated became designers and electronic records, respectively. Unlike the aerospace industry where designers have historically been engineers as well, these draftsmen had little if any engineering education. In the automobile industry designers generally use CAD- systems to create and store geometric data. These tasks contrast with the work of engineers who typically use CAD to retrieve and manipulate geometric data for input into engineering analyses software. At the extremes engineers manipulate nodes in finite element meshes generated from models created by a designer who, in addition to producing the basic data for automatic mesh generation, creates special technical views having photographic realism. This dicho- tomy separating automotive engineers and designers who use CAD in different ways is slowly changing. Putting in abeyance the problems that this dichotomy produces and reflecting on the current and historical roles of CAD will provide a perspective to deal with this dichotomy. Recommended changes in the education and training of engineers and of designers will emerge from this perspective. During the late 1960s and early 1970s when primitiv CAD systems left in-house research and developmen environments, small cohorts of draftsmen and engineer used CAD to create geometry. Engineers saw CAD as a tool to be further developed for downstream applications such as structural analyses, computer controlled machining etc Draftsmen still received specifications from engineers an used CAD as a tool for drafting. As with any implementation of a major new technology, the initial implementations of CAD required training of small groups of draftsmen and engineers. Continual improvements in CAD, however, had major consequences. New releases of software and an increasing number of CAD-related applications software required commitments to continued training. The ensuing organizational structure for training enabled introductions to CAD not only for draftsmen, now called designers, and the engineers they interacted with but also for a very broad cross section of engineers; see training for CAD in Section 5. This broad new audience included product, manufacturing, release and powertrain engineers, just to name a few. Out of this ubiquitous contact with CAD, additional small cohorts of engineers, along with mainly mathematicians and computer scientists, contributed expertise that converged to make CAD happen. Their needs differed substantially from the vast new majority of CAD-users. Section 3 will address their new role and needs. Meanwhile, a much larger group of engineers in the design and development of products emerged with an urgency to use CAD-systems as enablers for commercial software packages that evolved from those small communities of computer scientists, engineers, mathematicians and scientists. This convergence fueled by CAD helps resolve the ichotomy mentioned earlier. By simplifying and removing edious work for designer sand engineers ,CAD makes clear that the resolution require sad ditional training and education beyond basic curricula. Already burdened curricula at educational institutions make new requirements difficult to implement.