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; System Engineering

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