先进制造技术--施平 三单元.ppt

1、1,Advanced Manufacturing Technology,先进制造技术 施平,Part 3,2,Contents,1. Introduction to AMT 2. Computer and communication 3. Computer-aided engineering 4. Automation 5. Modern manufacturing technologies,3,3. Computer-Aided Engineering,3.4 Computer-Aided Manufacturing,The fields computer being used in man

2、ufacturing industry Financial computation and transactions Inventory management Labor reporting Production scheduling Production routing Numerical control technology Application of computer technology in manufacturing field is regarded as a key weapon in the so called second industrial revolution.,4

3、,3. Computer-Aided Engineering,Man operated machine tools Lathe Milling machine Drilling machine Grinding machine The quality of machined parts by Manual machine tool are related and limited to the skill of the operator,3.4.1 Computer-Aided Manufacturing- manual machine tool,A manual lathe,5,3. Comp

4、uter-Aided Engineering,3.4.2 Computer-Aided Manufacturing-NC,NC (Numerical Control) a method of controlling the movements of machine components by directly inserting coded instructions into the system, the system interprets and converts these data into output signals, which control various machine c

5、omponents Tool point position control Secondly functions control Tool speed Feed rate Coolant flow Tool selection and changing gauging,Milling center EXAMPLE,Multi-axis machine EXAMPLE,Housing box EXAMPLE,6,3. Computer-Aided Engineering,3.4.2 Computer-Aided Manufacturing-NC,First NC MIT 1950, a 3 ax

6、es servo-controlled milling machine tool,7,3. Computer-Aided Engineering,3.4.2 Computer-Aided Manufacturing-NC,Some types of CNC machine tool CNC milling machine VMC: vertical machining center, 3,4,5 axes of motion HMC: horizontal machining center, 3,4,5 axes of motion (normally, CNC machine tool ha

7、s an ATC, or automatic tool changer),CNC lathe,VMC,HMC,8,3. Computer-Aided Engineering,The advantage of NC, CNC machine More accurate Faster Lower cost Higher uniformality and consistency Automatic,3.4.2 Computer-Aided Manufacturing- NC,9,3. Computer-Aided Engineering,3.4.2 Computer-Aided Manufactur

8、ing-NC,Components of NC system 1. Part Program preprogrammed instructions, telling the machine tool what to do, step by step. Certain programming language is used Coded on some media: punched tape; computer disk etc. (program stored in computer, the computer directly linked to the machine tool, this

9、 is called direct numerical control, or DNC. ) DNC: direct numerical control.,10,3. Computer-Aided Engineering,3.4 .2 Computer-Aided Manufacturing-NC,Components of NC system 2. CNC Control System The electromechanical device, reading and interpreting part program and converting it into mechanical ac

10、tions of the machine tool (most modern systems use a microprocessor as the control unit, this type of numerical control is called computer numerical control, or CNC ),11,3. Computer-Aided Engineering,3.4 .2 Computer-Aided Manufacturing-NC,2. CNC Control System Three subsystems of CNC control system

11、control unit: center piece of CNC system, (also called control system, MCU (machine control unit), controller). Usually, it is a computer and interface of the CNC system. Drive: Screw and motor Ball screw: eliminating backlash for high-precision positioning Stepping motor: rotates a fixed angle for

12、a electrical pulse input; easy to be controlled; discrete movement, used in low priced CNC trainer and assembly system Servo motor: more common used, smooth and continuous motion; feedback is needed (closed loop system). Alternating current servomotor is the standard choice for industrial CNC system

13、 Feedback Provides the control unit with information about the status of motion control system,12,3. Computer-Aided Engineering,3.4.2 Computer-Aided Manufacturing-NC,Components of NC system 3.processing equipment It is actually the machine tool, which perform the work Components of processing equipm

14、ent Spindle Cutting tool Worktable Chunk or other Fixture Motors and drivers,13,3. Computer-Aided Engineering,3.4 .2 Computer-Aided Manufacturing-NC,14,3. Computer-Aided Engineering,3.4 .2 Computer-Aided Manufacturing-NC,15,3. Computer-Aided Engineering,3.4 .2 Computer-Aided Manufacturing-NC,16,3. C

15、omputer-Aided Engineering,3.4 .2 Computer-Aided Manufacturing-NC,Step motor close-loop system,22,3. Computer-Aided Engineering,3.4 .2 Computer-Aided Manufacturing-NC,NC system type open-loop system The signals are sent to the servomotors by the controller, but the movements and final positions of th

16、e worktable are not checked for accuracy (without feedback) close-loop system Equipped with various transducers, sensors, and counters that measure accurately the position of the worktable (output), this transduced signals are called feedback signals Through feedback control, the feedback signal is

17、compared against the input signal, when proper position is reached, the movement stops. The differentiation of the input and output feedback signal is the driving signal.,23,3. Computer-Aided Engineering,3.4 .2 Computer-Aided Manufacturing-NC,Measurement of feedback signals,24,Multi-axis NC Machine

18、Center,25,Examples: ,Multi-axis NC Machine Center For complicated part machining,Example: 5 axis machining,Example: 3D word sculpturing,Example: German Maka Car-model making,26,3. Computer-Aided Engineering,Benefit of multi-axis machine tool Increase part making diversity and the ability to machine

19、complex parts more efficiently Increase throughput by eliminating part setups and handlings Reduce in-process inventory costs while raising just-in-time part scheduling Optimize part quality and accuracy Fewer machines in manufacturing chain, low cost Lower fixture cost, fewer dedicated fixtures and

20、 tools,3.4 .2 Computer-Aided Manufacturing-NC,27,3. Computer-Aided Engineering,Disadvantages Expensive Complex programming High training fees Usage: aerospace industry: propeller Ship manufacturing: submarine propeller Defense industry: missile parts manufacturing,3.4 .2 Computer-Aided Manufacturing

21、-NC,28,3. Computer-Aided Engineering,Machining Cell A group of machine tools linked by both control and part handling facilities Machining center multifunctional CNC machine with automatic tool-changing capability and rotating tool magazine Vertical Horizontal Universal Tends Individual machine can

22、perform more functions, so fewer machines in one cell and less floor space needed. High speed and precision Robotics and transfer system Easy to program and operate,3.4 .2 Computer-Aided Manufacturing- Machining Cells and Machining centers,29,3. Computer-Aided Engineering,3.4.2 Computer-Aided Manufa

23、cturing-computer-aided testing and inspection,Inspection An organized examination or formal evaluation exercise. It involves the measurements, tests, and gauges applied to certain characteristics in regards to an object or activity. Testing In general, testing is finding out how well something works

24、. Assessing the functionality of the manufactured product,Whats the difference?,30,3. Computer-Aided Engineering,3.4.2 Computer-Aided Manufacturing-computer-aided testing and inspection,What characteristics we want to inspect? Dimensional measures of an object length Width Depth diameter Geometric s

25、hape Roughness Concentricity squareness,31,3. Computer-Aided Engineering,3.4.2 Computer-Aided Manufacturing-computer-aided testing and inspection,How we inspect? Off-line inspection On-line inspection Specific variable inspection during operation, without unloading and reloading workpieces.,Example

26、of On-line inspection Continuously measuring diameter of a turned part by using the cutting tool tip as the measuring instrument,32,3. Computer-Aided Engineering,3.4.2 Computer-Aided Manufacturing-computer-aided testing and inspection,Computer-aided inspection: Using sensors for measuring characteri

27、stics of parts Contact inspection: the sensor (probe) contacts with workpieces. Example: the probe of a CMM (coordinate measuring machine) contacts with the workpiece,33,3. Computer-Aided Engineering,3.4.2 Computer-Aided Manufacturing-computer-aided testing and inspection,Noncontact inspection Machi

28、ne vision system using video camera in rivet aligning on fuselage Laser beam laser positioning Ultrasonic technique dimensional features flaws detecting X-ray radiation technique Thickness flaws detecting Electrical field technique Voids cracks detecting by using eddy currents,34,3. Computer-Aided E

29、ngineering,3.4.3 Computer-Aided Manufacturing- CAD/CAM system,What is CAD/CAM system? A combination of Computer-Aided Design and Computer-Aided Manufacture as a whole system How does it work? Sharing information automatically from design stage to manufacturing stage CAD database is stored, and used

30、by CAM to form instructions for operating and controlling production machinery, material handling equipment, and for operating, testing, inspection etc,35,3. Computer-Aided Engineering,3.4.3 Computer-Aided Manufacturing- CAD/CAM system,Typical applications of CAD/CAM Programming for NC, CNC, industr

31、ial robot Design of tools, fixtures, EDM electrodes Quality control, inspection, Process planning, scheduling Plant layout,A paperless CAD/CAM of Boeing 777 is a fantastic example of this art of industrial production,36,3. Computer-Aided Engineering,3.4.3 Computer-Aided Manufacturing- CAD/CAM softwa

32、re,Selection of CAD/CAM Software UG Pro/E Cimatron MasterCAM CATIA,37,3. Computer-Aided Engineering,3.4.4 Computer-Aided Manufacturing- CAPP,What is process planning? Systematic determination of methods by which a product is to be manufactured economically and competitively Concerning with selecting

33、 methods of production Tooling Machinery Sequence of operations Assembly An intermediate stage between designing and manufacturing Process plan for the same part can be varied due to Different planner Different available equipments of different facilities Different lot size Application of new techno

34、logies,38,3. Computer-Aided Engineering,3.4.4 Computer-Aided Manufacturing- CAPP,What is a Route Sheet? A card on which the sequence of process and operations, machines to be used, standard time for each operation, and similar information are documented,39,3. Computer-Aided Engineering,3.4.4 Compute

35、r-Aided Manufacturing- CAPP,What is CAPP? CAPP stands for Computer-Aided Process Planning Two types of CAPP systems Variant Process Planning System Also known as retrieval process planning. Based on concepts of group technology and parts classification. Retrieval of existing plan for modification Ge

36、nerative process Planning System Process plan is automatically generated in a traditional logical procedure (its the trend of CAPP),Further information of CAPP,40,3. Computer-Aided Engineering,3.4.4 Computer-Aided Manufacturing- CAPP,Advantages of CAPP System Productivity of process planner enhanced

37、 Lead times, planning costs reduced Consistency of product quality and reliability improved Retrieval of similar plan modification, new plan easily established Route sheet more quickly prepared, neater and clearer. Other functions, such as cost estimating, work standards, can be incorporated into CA

38、PP,41,3. Computer-Aided Engineering,3.4.5 Computer-Aided Manufacturing- CE,Concurrent Engineering a systematic approach to integrated product development that emphasizes the response to customer expectations embodies team values of co-operation, trust and sharing in such a manner that decision-makin

39、g is by consensus, involving all perspectives (function, manufacturing, assembly, scheduling, quality, cost, maintenance, etc) in parallel, from the beginning of the product life-cycle CE provides a collaborative, co-operative, collective and simultaneous engineering working environment CE deal with

40、 Concurrent engineering management and process control Concurrent design Rapid manufacturing,42,3. Computer-Aided Engineering,3.4.5 Computer-Aided Manufacturing- CE,Five key elements on which CE approach is based a process Product development is a process, effective and efficient process can be obta

41、ined by concurrent engineering management and process controlling a multidisciplinary team Engineering design ,Manufacturing engineering, finance, marketing, R&D, logistic, purchasing, QC an integrated design model Integration of decision-making consensus from different aspects a facility a software

42、 infrastructure Electronic tool/CAD tools Shared database PDES: product data exchange specification /communication language,43,3. Computer-Aided Engineering,3.4.5 Computer-Aided Manufacturing- CE,Features of CE multidisciplinary team Tools CAD tools enable team member sharing the design-related info

43、rmation/database Electronic tool/CAD tools PDES: product data exchange specification /communication language Design method DFM: rule for avoiding difficult and cost manufacturing DFA: rule for avoiding difficult and cost assembling DFI: rule for avoiding difficult and cost inspection DFx: Quality Me

44、thod Quality is addressed from the start of the product design, it is better guaranteed Maintainability: simple and effective is the goal. e-documentations, such as Virtual Reality, Augmented Reality are applied. Cost analysis All functions must consider the cost impact and effect of their decision

45、to the total product cost. The mathematical model predicting future cost is applied,44,The Features of CE,Virtual Reality documentation,Virtual Reality documentation,45,3. Computer-Aided Engineering,3.4.6 Computer-Aided Manufacturing- GT,Group Technology a concept seeks to take advantages of the des

46、ign and processing similarities among the parts to be produced. The concept was first developed in Europe in 1900, the term GT first used in 1959 a manufacturing philosophy making small & medium size batch production possible by using design and manufacturing similarities among parts,46,3. Computer-

47、Aided Engineering,3.4.6 Computer-Aided Manufacturing- GT,GT similar parts can be coded to a selection code, manufactured in the some dedicated machining cell,Example These four parts can be in the same group, because They are similar in size and shape The raw material is a casting the internal hole

48、will be bored in one direction Face milling is required,47,3. Computer-Aided Engineering,3.4.6 Computer-Aided Manufacturing- GT,Some packages of parts classification and coding system are now available in the market design standardization design retrieval capabilities (retrieval-modification-new des

49、ign) for CAPP, tool design and choice, material requirement planning. etc A particular part is classified and coded according to Design attribute Geometric shape Size (length, diameter) Material Tolerance surface finish, etc. Manufacturing attribute sequence of operations treatment similarities mach

50、ine time similarity of cutting tools and fixtures, etc.,48,3. Computer-Aided Engineering,3.4.6 Computer-Aided Manufacturing- GT,GT impact to arrangement of equipments Traditional product flow in batch manufacturing Arrangement according to equipments types GT layout attribute operation sequence and

51、machine routing arrangement according to part family. For certain part, choose a layout according to GT code.,49,3. Computer-Aided Engineering,3.4.6 Computer-Aided Manufacturing- GT,Advantages of GT Standardization of design & minimization of design duplication Design and process planning (for certa

52、in part family) experiences can be stored in database for novices retrieval Process plans are standardized and scheduling more efficient Manufacturing costs are more easily estimated Productivity and cost reducing enhanced in small-batch production,50,3. Computer-Aided Engineering,3.4.7 Computer-Aid

53、ed Manufacturing- RP/M,Rapid Prototyping one real prototype is worth a thousand pictures Two important challenging tasks Substantial reduction of product development time Improvement on flexibility for manufacturing small batch size products and a variety of types of products,RP/M is a solution,51,3

54、. Computer-Aided Engineering,3.4.7 Computer-Aided Manufacturing- RP/M,Rapid Prototyping & Manufacturing CAD model .STL format (sectional picture) making prototype parts layer by layer according to .STL files. Some RP/M available SLA: stereolithography SLS: selective laser sintering LOM: laminated ob

55、ject manufacturing FDM: fused deposition modeling 3DP: three dimensional printing,52,3. Computer-Aided Engineering,3.4.7 Computer-Aided Manufacturing- RP/M,SLA Stereolithography CAD designdigital part model Section picture by slicing file format: *.STL Making each sliced layer picture real by applyi

56、ng Photocurable polymer Laser beam Integrating all layers to get the designed “object”,53,3. Computer-Aided Engineering,3.4.7 Computer-Aided Manufacturing- RP/M,Supporting columns,Postcuring,Hand sanding and polishing (stair-stepping effect mitigation),54,3. Computer-Aided Engineering,3.4.7 Computer

57、-Aided Manufacturing- RP/M,SLS selective laser sintering Supporting column not needed Powder temperature a few degrees below melting point heated by infrared panels Grainy appearance, surface smoothing needed,55,3. Computer-Aided Engineering,3.4.7 Computer-Aided Manufacturing- RP/M,LOM laminated obj

58、ect manufacturing Stack of paper Cross hatch for the unwanted area for easy removal Trimming, hand finishing,56,3. Computer-Aided Engineering,3.4.7 Computer-Aided Manufacturing- RP/M,FDM fused deposition modeling,57,3. Computer-Aided Engineering,3.4.7 Computer-Aided Manufacturing- RP/M,3DP three- di

59、mensional printing,58,3 D printer EDEN250,Example 1,Example 1,Example 1,59,Object made by Bjet 3D printer,60,3. Computer-Aided Engineering,3.4.7 Computer-Aided Manufacturing- RP/M,Practical Applications of RP/M Visualization A prototype is worth a thousand pictures (CAD picture) Verification The most reliable way to verify design by prototype inspection, error can be early detected an