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机械毕业设计英文翻译
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机械毕业设计30英文翻译外文文献翻译125,机械毕业设计英文翻译
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1 The fast mould integrates the systematic precision and guarantees that the system is studied Summary : Recommend with RP fast of technology and cast maturity manufacture functional CAE system of products of craft, have analysed the factor influencing precision of the products, has proposed analysing the precision at stage of three main shaping with the non-linear finite element, adopt pattern-recognition theory, error theory, neural network method to deal with the error and feedback the problem, carry on error compensate revise and prediction of machining accuracy , improve final method of product quality. Keyword: CAE; RT; Feedback 1 preface Fast prototype technology (& of Rapid Prototyping Manufacturing, abbreviate RP or RPM as, urged directly by the part CAD model, adopt the material accurate prototype or part manufacturing technology which piles up the complicated three-dimensional entity, it is each on the basis of being dispersed /pile up by shaping manufacturing approach not new-type of the principles. Rapid shaping technique already can make and include resin, plastics, paper, paraffin wax, pottery prototype of material successfully very much, but can only do the function experiment in the limited metal used for substituting really of occasion and other type function parts as the functional part. With increase and constant development of technology of demand, fast prototype technology to fast prototype / direction in which the part is being made develop. Utilize RP technological shaping function part, especially metal a kind of main method of part a switch technology, called the fast technology of mould(RT, Rapid tooling). Because traditional mould complicated consuming time and long costly to make course, become design and bottleneck that make often, use RP technology make fast economic mould become RP main motive force nts 2 of technical development one of. Paul think from PR to RT shaping the second leap of technical development fast. The final purpose of making and shaping is products and service offered and meet the demands. RP technology become front technology of manufacturing industry with a great deal of superiority their, but because limitation restriction extensive application their of material; Traditional technology such as cast, forge and press and develop for a long time, relatively ripe already, but cant meet the needs of fast flexibility of information age , within future one period, must conbine rapid shaping technique and traditional shaping technology together , realize melting quickly and make. 2 RP and RT system integration New product development most high cost have, man-hour longest stage to make the physical model involved, namely prototype manufacture process. RP technology use fast inspection and fast manufactures of different model that part design for mainly. Its basic principle and forming process are: Designed the computer three-dimensional curved surface entitys model of the necessary part by CAD software first , namely electronic model; According to technological requirement, go on the strata it according to certain thickness , turn the original three-dimension electronic model into two-dimentional level information (sectional information); And then carry on certain treatment of the data after the strata, put into and process parameters, produce the numerical control code; Until computer control, numerical control system process by level way process each thin layer and make they automatic sticking and shaping in succession in an orderly manner. RT changes RP prototype into the technology of the tool and mould with various kinds of methods . A method among them is to change the prototype into a pottery type, utilize the method to cast to change into a metal type . And RT manufacture of technology intergration accurate to cast mould method meet modern industry towards many variety, turn batch request of development into with RP prototype, it known as it is flexible tool method 5 ,its craft of routes. 3 integrated system make functional precision of product analyse Can find out from CAD final precision of product decide by manufacture error at each stage from model to fast prototype course in products. (1)CAD modeling among the course, because of modeling limitation of software, can describe accurate often as to complicated curved surface; (2)STL division of file among the course, because STL file layout mistake that modelling appear in the course sensitive to geometry, mistake these bring through STL file into and get RP modelling among the craft, some influence nts 3 RP modelling course 3 these of craft seriously, 4 these . And STL file one approach the wanton surface of the room the triangle with level, therefore can only it is at CAD geometrical property among system therefore 3 on part since express approximate therefore. (3)RP craft through to pile up and succeed the object prototype next life material, a lot of craft course is also following the changing of the material , such as FDM and SLA craft. So, the forming process of RP is not only that the machinery of a material piles up course, a height coupling, non-linear thermodynamics course. There are thes influence factor of the precision of this course: Thickness of material parameter, power of laser, strata, scanning route,etc. (4)Change precision loss of craft depend on and change craft material, conversion method used,etc. (5)It is the stage that the precision loses the most in the whole craft course that the metal pours the course. Usually, the first several in 10*10 error of stage - 2 mm order of magnitude, and metal solidify size change of course in several even a dozen mm.s of order of magnitude, so, the improvement of the precision of the final products depends on this stage to a great extent. There are thes factor influencing its precision: Material nature, for instance material density, elastic mould amount, heat conduction rate, specific heat, line coefficient of expansion,etc., especially the high temperature hot thing parameter of the metal, the heat transfer characteristic between the metal and type, position of watering, rising head ,etc. 4 integrate the precision of the systematic products and guarantee the system In the actual production, adopt and try on law come and guarantee final precision of product by mistake often. With the development of technology of the computer and to lowering costs, realizing the requests of digitization, course controllability, necessary to adopt computer integrated manufacturing approach, go on computer simulation emulation study to whole course. CAE (Computer Aided Engineering, project computer auxiliary ) including fairy victory make, flexible manufacturing, at the same time project, make etc. fictitiously. Introduce CAE technology, can draw the craft route again. If regard the middle course as the black box , from the craft route to the products of CAD model; This fast, many return circuit error with corresponding course controls and the reponse system. 5 errors feedback system research In this CAE system, the error exists at every stages. In CAD modelling , divide in the course of STL file , it is because of the limitation of the modelling software that precision is lost, improve the quality of the software, can reduce the error . nts 4 At RP prototype fabrication stage , change craft stage and metal to pour stage, involve the hot, strength coupling question, quote the non-linear finite element method , under the three-dimensional flute Karls coordinate, according to the conservation principle of energy, can draw : (1) Exert hot stress and external force(such as border terms) that temperature cause as the strength load the object and then, try to get total deformation amount. After drawing the errors of every stages, can set up error reponse system . The error reponse system belongs to and closes the control system of the ring . A main content of it is the research that transmits function out of shape. Under it is at flute not three-dimensional Karl coordinate, whether calculate and error after being the out of shape can express for deformation that get for: e(x,y,z) =P ideal (x, y, z)- p reality (x, y,z) (2) If use d (x, y, z) to show the change matrix of the real whole form , g (x, y, z) shows the matrix of controlling, the feedback control of the whole course can be described as: d (x, y, z) =g(x,y,z) e (x, y,z) (3) E (x, y, z) is the algebraical sum of each course, namely, if does not consider the error of CAD modelling course , and e 1 (x, y,z),e 2 (x, y,z),e 3 (x, y,z) show respectively there arent RP the error, the conversion craft error and the metal of course where the prototypes makes, e(x,y,z) =(x, y,z)+e 3 (x,y, z) (4) The present question is, set up proper g (x, y, z),make d (x, y, z) can disappear to and smaller than range that a certain error allows quickly , namely satisfied: of d (x, y, z) (5) G (x, y, z) embodies us to the whole understanding of deforming the course, it must real-time reflection products out of shape with CAD model out of shape coupling relation. And will change with the changes of the border condition out of shape and material parameter . Because the whole course is that more than one variable, complicated three-dimension input more close the control system of the ring non-linearly, perhaps there is a coupling relation between each variable, so, influence g nts 5 (x, y,z) factor the a lot of,very it it is difficult to be describe with unified mathematics formula, so, the author puts forward the method to use neural network, train g (x, y,z),make d (x, y,z) reach require . Utilize the neural network to have advantage taught oneself to practise, can reduce the error and feedback the demand for the craft data of the question greatly , and benefit systematic expansion. And because close correcting function to the error of system of ring , may cause systematic unstability . Adopt neural self-adaptation of network, learning method, can raise system stupid and getting wonderful. 6 conclusions RP technology is a fast-developing new developing manufacturing technology, RP, and RT integrated system that technology combine together to make functional main method of part with RP technology nowadays, the precision of raising this fast flexible system is nowadays urgent problem that is solved . This text has analysed that influences the factor of the precision of the products in this flexible manufacturing system, have proposed analysing the precision at stage of three main shaping with the non-linear finite element, adopt pattern-recognition theory, error theory, neural network method to deal with the error and feedback the problem, carry on error compensate revise and prediction of machining accuracy , improve final method of product quality. Selected from the electromechanical project nts 6 快速模具集成系统精度保证体系研究 摘要 : 介绍了利用 RP技术的快速性和铸造工艺的成熟性制造功能性产品的 CAE系统，分析了影响产品精度的因素，提出了用非线性有限元分析三个主要成型阶段的精度，采用模式识别理论、误差理论、神经网络方法处理误差反馈问题，进行误差补偿修正和加工精度的预报，提高最终产品质量的方法。 关键词： CAE； RT;反馈 1 前 言 快速原型技术（ Rapid Prototyping & Manufacturing,简称 RP 或 RPM）是指在计算机控制与管理下，由零件 CAD模型直接驱动，采用材料精确堆积复杂三维实体的原型或零件制造技术，是一种基于离散 /堆积成型原理的新型制造方法。 快速成型技术已经能非常成功地制作包括树脂、塑料、纸类、石蜡、陶瓷等材料的原型，但往往不能作为功能性零件，只能在有限的场合用来替代真正的金属和其它类型功能零件做功能实验。随着需求的增加和技术的不断发展，快速原型技术正向快速原型 /零件制造的方向发展。 利用 RP技术成型功能零件尤其是金属零件的一种主要 方法是转换技术，称为快速模具（ RT， Rapid tooling）技术。由于传统模具制作过程复杂、耗时长、费用高，往往成为设计和制造的瓶颈，因此应用 RP技术制造快速经济模具成为 RP技术发展的主要推动力之一。 Paul1认为从 RP到 RT是快速成型技术发展的第二次飞跃。 制造和成型的最终目的是要提供满足要求的产品和服务。 RP技术以其诸多优越性而成为制造业的前沿技术，但因为材料的局限性制约了其更广泛的应用；传统技术如铸造、锻压等经过长期发展，已相对成熟，但不能适应信息时代的快速柔性要求，在未来一段时期内，必须 将快速成型技术与传统成型技术结合起来，实现敏捷化制造。 2 RP与 RT系统集成 新产品开发中成本最高、工时最长的阶段就是制造所涉及的物理模型，即原型制造过程。 RP 技术主要用于零件设计的快速检验以及各种模型的快速制造。其基本原理和成型过程是：先由 CAD软件设计出所需零件的计算机三维曲面实体模型，即电子nts 7 模型；然后根据工艺要求，将其按一定厚度进行分层，把原来的三维电子模型变成二维平面信息（截面信息）；再将分层后的数据进行一定的处理，加入加工参数，生成数控代码；在计算机控制下，数控系统以平面加工方式有序地连续加 工出每个薄层并使它们自动粘接而成型。 RT就是用各种方法把 RP原型转换成工模具的技术。其中一个方法是将原型转换成陶瓷型，再利用铸造的方法转换成金属型。利用 RP原型与 RT技术集成的制造精密铸造模具方法适应了现代工业向着多品种、变批量发展的要求，被称为 “ 柔性工具 ”方法 5,其工艺路线 . 3 集成系统制造功能性产品的精度分析 从 CAD模型到快速原型到产品的过程可以看出，最终产品的精度是由每个阶段的制造误差决定的。 (1)CAD 建模过程中，由于建模软件的局限性，对于复杂的曲面常常不能精确地加以描述； (2)STL 文件的划分过程中，由于 STL 文件格式对几何造型过程中出现的错误不敏感，这些错误通过 STL文件带入到 RP造型工艺中，有的将严重影响 RP工艺的造型过程 3， 4。而且， STL 文件用平面三角形面片来逼近空间的任意表面，因而只能近似地表示零件在 CAD系统中的几何特征 3。 (3)RP工艺是通过材料的堆积来生成物体原型，许多工艺过程还伴随着材料的相变，如 FDM 和 SLA 工艺。所以， RP 成型过程不只是一个材料的机械堆积过程，还是一个高度耦合、非线性的热力学过程。这一过程的精度影响因素有：材料参数、激 光功率、分层厚度、扫描路径等。 (4)转换工艺中的精度损失取决于转换工艺所使用的材料、转换方法等。 (5)金属浇注过程是整个工艺过程中精度损失最大的阶段。通常，前几个阶段的误差在 1010 -2mm 数量级，而金属凝固过程的尺寸变化在几个甚至十几个毫米数量级，因此，最终产品精度的提高很大程度上取决于这个阶段。影响其精度的因素有：材料性质，如材料密度、弹性模量、导热率、比热、线膨胀系数等，尤其是金属的高温热物性参数，金属与型腔之间的传热特征，浇、冒口的位置等。 4 集成系统产品精度保证体系 实际生产中 ，常
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