290 likes | 643 Vues
CAD/CAM. Design Process and the role of CAD. Design Process. Engineering and manufacturing together form largest single economic activity of western civilization Distinguishing feature of wealthy economies . Design Process. Engineers and designers have turned to machines for assistance
E N D
CAD/CAM Design Process and the role of CAD
Design Process • Engineering and manufacturing together form largest single economic activity of western civilization • Distinguishing feature of wealthy economies
Design Process • Engineers and designers have turned to machines for assistance • Machines are computers and their task is information processing
Design Process • Clarification of task • Conceptual design • Embodiment of design • Detail design
Design Process • Reduction of time for product design and development has led to: • Simultaneous engineering or • Concurrent engineering
Modeling and Communication • Models represent a physical artifact before it exists • Models vary in construction depending on what component is to be evaluated, manipulated or refined • Models can exist as different representations
Modeling and Communication • Major role of models is communication between participants of the design process • Design is sharing information and models are the means of communicating information
Types of Design Models • Dependant on the property to be evaluated or communicated • Function • Structure • How parts are assembled • Materials • Surface condition • Dimensions
Types of Design Models • Engineering is primarily concerned with form and structure • Most appropriate method to represent these has been graphical
Types of Design Models • Form design is done with drawings that define shape, and arrangement of component parts of the design • Structure of the assembly is concerned with the way these are connected together and with flows (energy or material) between parts; SystemEngineering
Types of Design Models • Target receiver for the communication will determine the technique used to generate the model • It is crucial to avoid misinterpretation and ambiguity • Design models must conform to agreed standards
Application of Design Models • Consider the receiver of communication • Two main classifications: • Evaluating • Actions taken to asses properties or merit • Generative • Actions that provide information from the model for downstream use (manufacture)
Application of Design Models • Visual assessment to ensure no obvious weak areas • Assessment of the mass of the components • Evaluation of loads in components • Evaluation of stresses using FEA
Traditional Design Process • “Over the wall approach” • Communication barriers are as high as the wall • Concurrent engineering breaks down barriers enabling more responsive product development and higher product quality
Modeling using CAD • Design is progressively refined in the abstract until it is completely defined for manufacture or construction
Modeling using CAD • Models of the functional and other customer requirements for the design • These may change and develop as the design progresses • Models of the constraints on the design • Available materials or manufacturing capability
Modeling using CAD • Models of loads imposed on the design • Models used to evaluate the performance of design • Stress, thermal analysis, aerodynamic assessment
Objective of CAD • Apply computers to both modeling and communication of designs • Basic level use computers to automate or assist in tasks such as drawings, diagrams, parts list, BOM • Advanced level provide new techniques to assist designer in the process of design
CAD system Architecture • Hardware • Computer and peripherals • Software • Programs running on hardware • Data • Data structure created and manipulated by the software • Human knowledge and activities
Secret Software Data Base • Model definition • To add geometric elements to a model of the form of a component • Model manipulation • Move, copy, delete, edit or modify elements in the design model
Secret Software Data Base • Picture generation • To generate images of design model on a screen or hard copy device • User interaction • Handle commands input by user and present output to user
Secret Software Data Base • Data base management • Process the files that make up the data base • Applications • Those elements of software that do not modify the model but generate information for evaluation analysis or manufacture
Conclusion • Cad provides techniques for developing various ways to model a design • Cad can describe a design while it is still an abstract concept and communicating this description throughout the entire process