先进制造技术复习题汇总.docx

1、先进制造技术复习题汇总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

2、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 inclu

3、de? 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 DesignPr

4、oduction 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 d

5、isadvantage 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

6、 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 Modelin

7、g: 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?Constructiv

8、e 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

9、and predicting the reaction of the whole object.10. Process of CADs Application Geometry modeling based on design demand and saving geometry data; Optimizing design project after finite-element analysis (FEA) and optimizing design (OD)(优化设计); Value and revise design result; Sending design data to ot

10、her systems (CAPP, CAM, PDM).11. Technologies Involved in CAD Product information modeling technology Computer graphics Engineering analysis technology Database and data exchange technology Document disposal technology Software design technology12. Development Trend of CAD TechnologyComputerizing; I

11、ntegrated(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

12、 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;

13、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 stand

14、ard 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.MODE

15、L 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 som

16、e 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 Writ

17、ten 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

18、 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 syst

19、em 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

20、 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

21、 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 reader Data-reading Decoding circuits to determine the required axis movementsThe control loop unit (CLU) 控制回路单元A CLU consis

22、ts 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 Classifi

23、cations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 clos

24、ed 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 ind

25、ividual 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 c

26、ontrolled 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

27、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 cos

28、t 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 r

29、andom 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

30、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

31、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 Savin