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2 Framework for Virtual Design and Manufacturing
Pages 11-22

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From page 11...
... to aid in the creation of products and systems.1 "Manufacturing" refers broadly to all the activities required to conceive a product that will meet the needs of a customer, convert those needs into a producible design, deliver products to the customers, support products in the field, upgrade or repair them as needed, and eventually retire and recycle them. This broad definition provides the opportunity to fully exploit the emerging virtual technologies to their full potential.
From page 12...
... Engineering and manufacturing models and simulations are used routinely in this and the following steps to verify performance, predict failure modes, and match production plans and equipment to requirements. ­ Specify the requirements for reliability, maintainability, and other customer use and life-cycle support requirements.
From page 13...
... It is important to understand that the required tools cover many nontechnical domains such as human resource management, program management, cost analysis, market analysis, and so on. Some, like immersion or virtual reality caves, are used to help customers decide what they really want and whether they have asked for self-consistent requirements.
From page 14...
... . Microprocessors can be completely designed in software using design rules, once the production processes have been verified on test chips that have the required device sizes, materials, and line widths and spacing.
From page 15...
... 9 Stefan Thomke, Experimentation Matters: Unlocking the Potential of New Technologies for Innovation, Harvard Business School Press, Boston, Mass., 2003. 10William Powers, VP of Research, Ford Motor Company, Keynote speech to Japan­USA Symposium on Flexible Automation, Boston, Mass., July 7, 1996.
From page 16...
... Accomplishing bridging requires exploring a huge space of interacting design and manufacturing options.11 Virtual tools are the only way of supporting a thorough exploration. Thus virtual tools play important or essential roles in conceptualizing products, conducting the design, planning the production, ensuring manufacturability, and carrying out production, deployment, and field management of the product.
From page 17...
... FRAMEWORK FOR VIRTUAL DESIGN AND MANUFACTURING 17 TABLE 2-1 Activities Involved in Creating, Producing, and Supporting a Product Step or Process Non-Virtual Methods Virtual Methods Obtain customer needs, including Interviews, observations Web questionnaires, very performance, cost, and schedule realistic simulations combined expectations with self-design Develop performance Interviews, observations Requirements-tracking requirements software combined with tools for tracking interactions Expand requirements to include Interviews, review of past product Data mining, lessons-learned such things as reliability, flexibility, needs databases and expectations regarding upgrades Develop concepts Sketches on paper, brainstorming Digital sketches, data searches, cognitive aids, videoconferences, knowledge based tools Generate functional and physical Sketches, notes, brainstorming, Decomposition simulations, decompositions to meet technology surveys, interviews links to technology data, links performance and capabilities to interaction data; architecture requirements evaluation systems Assign quantitative specifications Calculations from requirements; Computer simulations of to top-level requirements existing design histories system and component behavior; simulations of user environment Assign targets to distributed Existing stand-alone calculations, Preliminary cost models, requirements such as cost, past field data, guesses technology histories and weight, reliability, safety, and roadmaps, tabulated field data durability Identify top-level risks: maturity of Past field data, data on past Risk models based on data the technology, performance, similar products, discussions with cost, schedule experts Assess in-house and vendor Internal audits, use of ISO 9XXX Real-time data on machines, design, modeling, testing, protocols processes, statistical process manufacturing, and assembly control, process capabilities capabilities and costs Decide what will be made in- Internal audits Strategic and tactical models house and what will be outsourced Identify critical vendor­partners Discussions with experts, past None and long lead items project data Generate program plan with tasks, Gantt charts, precedence Task and behavior interaction schedule, information exchanges, diagrams, existing project models that predict possible design reviews templates rework and schedule delays continues
From page 18...
... 18 RETOOLING MANUFACTURING TABLE 2-1 continued Step or Process Non-Virtual Methods Virtual Methods Flow top-level requirements down Analysis by experts Detailed multifunctional models to subfunctions and subsystems of technical behavior Generate derived requirements Analysis by domain experts, None defined as consequences of top- subsystem engineering level decisions but not requested by customers Identify risks at subsystem levels Analysis by domain experts None and below Generate verification and Analysis by domain experts None validation plans Do detailed design of components Drawings CAD plus functional and subsystems performance simulations, tolerance analysis software Determine that detail design Discussions between domain Simulations, process specifications can be met by experts in engineering and algorithms, cost analysis and available and economical manufacturing comparison algorithms, process processes capability data Identify and evaluate suppliers, Request qualifications, past Use virtual data exchange, get and evaluate bids experience online bidding and negotiation Generate manufacturing, Use of manually collected data Simulations and cost-estimating assembly, and test plans from past projects, standard systems, discrete-event templates, vendor capabilities, simulation and domain experts Verify and validate component Multiple tests, including Cross-functional factory and subsystem performance accelerated life prototypes simulations, stress analysis software, heat simulations Design manufacturing and Use experts and domain Use simulations of materials assembly systems to make, specialist suppliers to physically processing, material handling, assemble, and test each part and make, assemble, and test each assembly, human operators assembly part and assembly Obtain and train employees Drawing from existing staff, Use models to choose the right recruitment, direct training people, and simulations and videos to train them Integrate product subsystems and Testing of subsystems, prototype 3D solids CADCAM plus CFD, verify performance assemblies, mockups computer analysis and simulation Install and validate manufacturing Installation and validation done Simulation and validation tools and assembly systems on-site and reworked until they to check correctness and safety are correct
From page 19...
... In fact, it is the multiplicity of phenomena that makes simulation of these products difficult.12 In many cases the state of the art is a set of individual simulations whose interpretation involves human expertise to combine the separate results. The kinds of things simulated include the following phenomena: Mechanical vibration, noise, and acoustics of machinery, including interior cabin noise in aircraft and automobiles Fluid flow in compressors, pumps, and other aerodynamic surfaces, to determine mechanical and thermodynamic efficiency Fluid noise, such as wind rushing over the exterior of an automobile or fluid flowing in pipes in a submarine Optical ray tracing in telescopes, gun and missile sights, and cameras Kinematics of mechanisms such as car engines, aircraft landing gear, telescope mounts, 12 Elsewhere in this report, such multiple phenomena, including electrical, electromagnetic, and other phenomena, as well as the disciplines that deal with them, are referred to as "multiple domains."
From page 20...
... Today's products could not be designed without these simulations and design aids, but there is additional potential for significant interaction between some technical domains. Opportunities arise in the following areas: 13Jon Niemeyer and Daniel Whitney, "Risk Reduction of Jet Engine Product Development Using Technology Readiness Metrics," ASME Design Engineering Technical Conference, paper no.
From page 21...
... For example, both interfacial heat transfer and interfacial friction properties depend on the detailed distribution of asperities on the contacting surfaces, surface contamination, and a variety of other surface properties that change from part to part, and perhaps moment to moment, in real production processes. Simulations can be used effectively in such an environment to assess the sensitivity of the design to variations in parameters whose values are uncertain.
From page 22...
... For example, interfacial heat transfer characteristics are very important in many solidification processes. The microstructure of the product depends on the local thermal history, which can depend in a very complicated way on the surface heat transfer characteristics.


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