【文章內(nèi)容簡介】 ing Cells and Machining centers 28 3. ComputerAided Engineering ComputerAided Manufacturingputeraided testing and inspection ? Inspection – An anized 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. – Assessing the functionality of the manufactured product What’ s the difference? 29 3. ComputerAided Engineering ComputerAided Manufacturingputeraided testing and inspection ? What characteristics we want to inspect? – Dimensional measures of an object ? length ? Width ? Depth ? diameter – Geometric shape ? Roughness ? Concentricity ? squareness 30 3. ComputerAided Engineering ComputerAided Manufacturingputeraided testing and inspection ? How we inspect? – Offline inspection – Online inspection ? Specific variable inspection during operation, without unloading and reloading workpieces. Example of Online inspection Continuously measuring diameter of a turned part by using the cutting tool tip as the measuring instrument 31 3. ComputerAided Engineering ComputerAided Manufacturingputeraided testing and inspection ? Computeraided inspection: – Using sensors for measuring characteristics of parts ? Contact inspection: – the sensor (probe) contacts with workpieces. ? Example: the probe of a CMM (coordinate measuring machine) contacts with the workpiece 32 3. ComputerAided Engineering ComputerAided Manufacturingputeraided testing and inspection ? Noncontact inspection – Machine vision system ? using video camera in rivet aligning on fuselage – Laser beam ? laser positioning – Ultrasonic technique ? dimensional features ? flaws detecting – Xray radiation technique ? Thickness ? flaws detecting – Electrical field technique ? Voids ? cracks detecting by using eddy currents 33 3. ComputerAided Engineering ComputerAided Manufacturing CAD/CAM system ? What is CAD/CAM system? – A bination of ComputerAided Design and ComputerAided Manufacture as a whole system ? How does it work? – Sharing information automatically from design stage to manufacturing stage – CAD database is stored, and used by CAM to form instructions for operating and controlling production machinery, material handling equipment, and for operating, testing, inspection etc 34 3. ComputerAided Engineering ComputerAided Manufacturing CAD/CAM system ? Typical applications of CAD/CAM – Programming for NC, CNC, industrial 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 35 3. ComputerAided Engineering ComputerAided Manufacturing CAD/CAM software ? Selection of CAD/CAM Software – UG – Pro/E – Cimatron – MasterCAM – CATIA 36 3. ComputerAided Engineering ComputerAided Manufacturing CAPP ? What is process planning? – Systematic determination of methods by which a product is to be manufactured economically and petitively – Concerning with selecting 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 technologies 37 3. ComputerAided Engineering ComputerAided 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 38 3. ComputerAided Engineering ComputerAided Manufacturing CAPP ? What is CAPP? – CAPP stands for ComputerAided 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 – Generative process Planning System ? Process plan is automatically generated in a traditional logical procedure (it’ s the trend of CAPP) 39 3. ComputerAided Engineering ComputerAided Manufacturing CAPP ? Advantages of CAPP System – Productivity of process planner enhanced – 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