先进制造技术复习题汇总.doc

MODEL 1 Computer Aided Design CAD1. Whats the definition of CAD?CAD is an advanced information handling technology to solve design problems for engineers. CAD combines peoples abilities of deducing and creation with computers functions of processing and information storage(计算机辅助设计(CAD)的结合能力和创造与推导计算机的功能、信息存储处理)2. Whats the historical development of CAD?(1)2D Drawing and 3D Wireframe (线框) modeling in 1960s(2)Surface modeling (曲面造型) in 1970s; (3)Solid modeling (实体造型) in 1980s; (4)Parameterized and variable modeling (变量参数化建模)in 1990s.3. What are the three methods of product design include? Please give their characterizes. Routine Design（常规设计）:only changing some parameters Innovative Design（革新设计）:changing some parts Creative Design（创新设计）:developing a new product4. Please give the phases (阶段) that product design process is divided into.Demand AnalysisConceptual DesignDetail DesignProduction Planning5. What are the three phases of conceptual design?Generate、Value、Select6. What are the functions (功能) of CAD?(1)Geometry modeling (2)Design review and analysis(3)Dynamic imitating(动态模拟) (4)Design documentation(设计文件编制)7. What are the three methods of geometry modeling? And give the disadvantage of each method.Wireframe Modeling(线框建模):Disadvantage: (1)Unable to express curve models(曲线模型表达) (2)A multivocal(多义的) modelAdvantage: Less information;Less storage space; Easy data-processing;Fast processing speed;Less need of computer hardware.Surface Modeling:disad： (1)Only suitable for shell(壳体); (2)No information about solid or hollow, inside or outside;(3)No information about quality and volume; (4)Unsuitable for analysis.Ad：More rigorous and integrated;Finding intersection points automatically;Suitable for complicated surface such as cars body and planes aerofoil.Solid Modeling: disad:(1)Lack of engineering information (tolerance(公差), roughness(粗糙度), material(材料) ;(2)Cant realize integration of CAD/CAM(不能实现CAD / CAM一体化).Ad: Integral information (geometry and topological information);Removing elements of hiding.8. What are the popular methods of solid modeling?Constructive solid geometry (CSG)Sweep representation9. How does FEA(有限元分析) work? And which parameters(参数) does FEA demand?1) Breaking an object up into many small rectangular or triangular elements;2) Analyzing the response of each finite element to the stress, heat, or other force; 3) Combining all elements and predicting the reaction of the whole object.10. Process of CADs Applicationw Geometry modeling based on design demand and saving geometry data;w Optimizing design project after finite-element analysis (FEA) and optimizing design (OD)(优化设计);w Value and revise design result;w Sending design data to other systems (CAPP, CAM, PDM).11. Technologies Involved in CADw Product information modeling technologyw Computer graphicsw Engineering analysis technologyw Database and data exchange technologyw Document disposal technologyw Software design technology12. Development Trend of CAD TechnologyComputerizing; Integrated(集成化); Intelligent; Networking; Visualization; Concurrent; Standard13 Methods of Computer Drafting(计算机绘图)parameterized method（参数化方法）geometric element combining method（几何元素拼接法）14 Advantage of Feature Modeling Putting emphasis on function design; Easy to realize integration of CAX; Decreasing products cost.15 Principle of FEABreaking an object up into many small rectangular or triangular elements;Analyzing the response of each finite element to the stress, heat, or other force;Combining all elements and predicting the reaction of the whole object.16 Parameters of FEA(有限元分析的参数)Geometry; Material; Loading conditions; Constraints(约束)17 Methods of Transfer1. Reading information directly from the drawing by either automatically or manually digitizing it.2. Writing a special program to translate from one format to another.3. Pre-processing the drawing file from the original into a standard format and post-processing the drawing file in the neutral format into a format acceptable to the second system.4. Constructing a standard product data model.18 Standard for Exchange of Product Model Data (STEP)Containing integrated product data;Independent of CAX; Basis of product database.MODEL 2 Automated ManufacturingBasic concepts：1、 the concepts , components and characteristics of NC,NC,CNC,MCU,DPU,CLU and MC概念、组成、特点Numerical Control 数控A system in which actions are controlled by the direct insertion of numerical data at some point. The system must automatically interpret at least some portion of this data.NC Machine Component 组件 The actual NC machine The machine control unit (MCU) The communication interface between the NC machine and the MCU A variety of accessories for performing specific jobs on the NC machineFour ways to program编程 an NC machine:Graphics program; manual Written program; DigitizingDirect Numerical Control (DNC) 【计算机】直接数控DNC refers to a manufacturing system that uses a central computer to control several machines simultaneously.Schematic of direct numerical control直接数字控制的原理One key advantage of DNC, is the ability to produce and print reports that provide valuable information to system puter numerical control计算机数控 A numerical control system wherein a dedicated, stored program computer is used to perform some or all of the basic numerical control functions in accordance with control programs stored in the read-write memory of the computer.”A CNC system consists of three components The control component The input component The output componentAdvent of Computer Numerical Control With CNC, each machine tool has a PLC or a microcomputer that serves the same purpose. CNC is sometimes referred to as softwired NC. Advantage of CNC: allow the database created during the design and drafting of a part to be used in formulating the NC program to make the part.A library of NC programs can now be created and easily stored for reuse.Master copies can be made of a specific NC programs so that it can be revised to create a new NC program.Machine-control unit (MCU) 机器控制单元Reads the part program and controls the machine tool operation.The data processing unit (DPU) 数据处理单元a DPU consists of a data input device include:Paper-tape readerData-readingDecoding circuits to determine the required axis movementsThe control loop unit (CLU) 控制回路单元A CLU consists of an interpolator, position-control loops for all axes of motion, velocity-control loops, deceleration and backlash take-up circuits, and auxiliary function control devices.MC: defined as multifunction多功能 CNC machines with automatic tool-changing capabilities and rotating tool magazine2 Classifications分类 of NC Machines数控机床的分类four types of control systems possible in a CNC operation:Point to point machines; Point to point straight line; 2 axis contouring with switchable plane; 3axis contouring continuous pathClassified by the types of servo controller: 分类类型的伺服控制器Open loop control; Semi closed loop control; Fully Closed loop control3 The Three Part of a CNC Program大纲 Program Setup Material Removal System Shutdown系统关闭Flexible Manufacturing System柔性制造系统4、the concepts , components and characteristics of FMS and its flexibilityFMS Definition：A flexible manufacturing system (FMS) is an individual machine or group of machines served by an automated materials handling system that is computer controlled and has a tool handling capability.A FMS has four major components : 主要部件 Process equipment : Machine tools , assembly stations, inspection station and robots, Control System (Computer controlled system) Storage and distribution of parts programs Workflow control and monitoring Production control System/tool control/monitoring Automated material handling robots, conveyors,RGV, AGV and AS/RS Human operators (critical roles) Manufacturing System Features：制造系统特点Transfer Line Machines dedicated to handle one or two product types Maximum utilization and high production rates Direct labor involvement is minimal Low unit cost of productionCNC Machines High level of flexibility.Any job can be processed within the range of CNC machinery Low utilization and low production rate Unit cost is much higherFMS True mid-volume mid-variety manufacturing systems Consists: Series of flexible machineries Automated material handling systems Automated tool changer Coordinate measuring machines Part washers All the equipments are controlled by a central controller Permits both sequential and random routing of a wide variety of parts To settle tradeoffs between production rats and flexibility. Most manufacturing situations require medium production rates to produce medium volumes with enough flexibility to quickly reconfigure for change of product.5、the layout of FMS and its features. FMS的布局及其特点 Progressive(渐进的) Layout: Best for producing a variety of parts Closed Loop Layout: Parts can skip stations for flexibility Used for large part sizes Best for long process times Ladder Layout: Parts can be sent to any machine in any sequence Parts not limited to particular part families Open Field Layout: Most complex FMS layout Includes several support stations6 Advantages and disadvantages of FMSs implementation实施Advantages: Faster, lower- cost changes from one part to another which will improve capital utilization Lower direct labor cost, due to the reduction in number of workers Reduced inventory, due to the planning and programming precision Consistent and better quality, due to the automated control Lower cost/unit of output, due to the greater productivity using the same number of workers Savings from the indirect labor, from reduced errors, rework, repairs and rejects Disadvantages: Limited ability to adapt to changes in product or product mix (ex. machines are of limited capacity and the tooling necessary for products, even of the same family, is not always feasible in a given FMS) Expensive, costing millions of dollars Technological problems of exact component positioning and precise timing necessary to process a component Sophisticated manufacturing systems 7 Benefits of FMS效益 To reduce set up and queue times Improve efficiency Reduce time for product completion Utilize human workers better Improve product routing Produce a variety of Items under one roof Improve product quality Serve a variety of vendors simultaneously Produce more product more quicklyIndustrial Robots工业机器人8. the components, classification and application of industrial robots组成、分类及应用工业机器人Definition: a robot is a software-controllable mechanical device that uses sensors to guide one or more end-effectors through programmed motions in a workspace in order to manipulate physical objects.Components：组件 The manipulator is the equivalent of the machine tool in CNC. It consists of a series of segments, jointed or sliding relative to one another, that performs the work such as grasping and/or moving objects. The manipulator is composed of the main frame (the arm of the robot), and the wrist. The tools, called the end-effectors, are attached to the wrist. The end-effectors perform a prescribed（规定的） task ordinarily done by the human worker. Classification：分类Structurally, the robot can be classified according to the coordinate system of the main frame. The types of coordinate systems are: Cartesian笛卡尔coordinate manipulator, which consists of three linear axes, Cylindrical coordinate manipulator, which consists of two linear axes and one rotary axis, Spherical coordinate manipulator which consists of one linear and two rotary axes, Articulated （关节）or jointed robots which consists of three rotary axes, and Gantry robot SCARA robot.Applications ：应用 Loading and unloading Spray painting Welding Material handling Inspection Machine Assembly9 the concepts and characteristics of CIMS, MAP, TOP, IGES,STEP,GT,CAPP,MRP,MRPII Computer Integrated集成 Manufacturing计算机一体化制造(CIM): A computerized integration of all aspects of design, material selection, planning, manufacturing, production, quality assurance, management and marketing. Including several distinct components:包括几种不同组件1. Manufacturing management/human resource management.2. Marketing3. Strategic planning4. Finance5. Product/process design and planning6. Manufacturing planning and control7. Factory automationBenefits of CIM1. Product quality increases2. Lead times are reduced3. Direct labor costs are reduced4. Product development times are reduced5. Inventories are reduced6. Overall productivity increases7. Design qualityManufacturing Automation Protocol制造自动化协议(MAP)MAP is a communications standard developed to promote compatibility among different automated manufacturing systems.MAP offers several benefits to manufacturers in a CIM environment , include: Better shop floor communication Decreased risk during installation Lower cost Decreased installation time Easier upkeep and expansion MAP also allows communication among systems at all levels within a factory.Technical and Office Protocol (TOP) 技术职员与工作室协议 TOP is a standard that was developed to promote integration among business and office components.Initial Graphics Exchange Specification (IGES) 初始图形交换规范IGES is developed to promote communication between CADD systems manufactured by different vendors and is limited to the product and process definition component of the CIM Wheel.Standard for the Exchange of Product Data (STEP) 产品数据的标准交换Group Technology （GT）成组技术The relationship between similar parts and parts familiesUse of the computer in process planning is called computer-aided process planning, or CAPP计算机辅助工艺计划Two types类型 of CAPP systems are available: The variant systemThe generative systemHow CAPP works:First ,with CAPP the part is designed on a CAD/CAM systemSecond, the mathematical model is transferred from the CAD/CAM system to the CAPP systemThen , the computer matches the characteristics of the part to the machines and processes Final , the CAPP system prints out the process sheets and routing sheetsMRP (material requirements planning) 物料需求计划 involves using the bill of material, production schedule, and inventory record, detailed schedule of the raw materials and components needed for a jobMRP II (Manufacturing resources planning) 制造资源计划not only determine the material requirements ,but also encompass financial tracking and accounting.Key concepts relating to MRP II include:1.independent and dependent demand;2.Lead times;3.Common-use itemsComprehension1、the advantages and disadvantages of the NC,CNC,DNC,FMS,industrial robots, CIMS and so on.2、the relationship between the NC,DNC,CNC, FMS and CIMS 3、The features and comparison对比 of the FMS,TRANSFER LINE，general purpose machines, FMC and so on.4、The relationship between the FM,FMC,FML,FMM,AGV,AS/RS,RGV, Conveyors,5、the relationship between the MRP and MRPII。MODEL 3 Non-conventional非惯用的 machining and Nanotechnology纳米技术 and Micro-electro微电子器件工艺学 Mechanical System (MEMS)Non-conventional machining非常规加工Mechanical processesAbrasive jet machining(AJM) 磨料喷射加工Water jet machining(WJM)Abrasive water jet machining(AWJM) 磨料水射流切割Abrasive flow machining(AFM)Ultrasonic超声波machining(USM)1. What is the difference among AJM, WJM,AWJM, AFM in the aspect of machining capability and workpiece material？machining capability and workpiece material：AJM：可以加工：Hard and brittle metals, alloys, and nonmetallic (非金属)materials (e.g., germanium, silicon, glass, ceramics, and mica(云母)，especially suitable for thin sections.不能加工：Disadvantages:Stray cuttingLow removal rateTaperShort nozzle standoff when usedfor cuttingSoft, resilient materials, such as rubber and some plastics, resist the chipping action and thus are not effectively processed by AJM.Advantages:Machine heat sensitive and fragile materialsVery low capital costNo part chatter or vibrationGood for difficult-to-reach areasMachine very hard materialsWJMUsed primarily to cut and slit porous nonmetal such as wood paper ,leather,foam and food. It can also striping and deburring Water jet machining provides omni-directional（万向） cutting capabilities at very high speed with a resulting edge quality that is usually superior to other conventional cutting processes.Disadvantages:Equipment expensiveNot suit for hard , nonporousmaterialsNoise and high pressure requireSafety considerationsAdvantages:No tool resharping costsMinimum kerfwidthEasily automatedOmni-directional cuttingGreen process(dust free)High cutting rateNo heat affect zoneAWJMThe coherent, abrasive water jets that exits the AWJM nozzle has the ability to cut various materials, such as metal, rock, glass, ceramics, and composites, with great speed and depending upon the material, in thickness of up to 20cm.Nozzle Materials喷嘴材料: tungsten carbide or born carbideTwo major design concepts : Single -jet side feed nozzle; Multiple-jet, central-feed nozzleDisadvantages:Stray cuttingHigh costHazard from rebounding abrasiveHigh level noiseLow nozzle lifeAdvantages:Omni-directional cuttingNo thermal damageNo deburring requiredCuts without delaminationAFMAbrasive flow machining(AFM) is a finishing process that removes small quantities of materials by flow a semisolid, abrasive-laden putty through or across a workpiece. 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