L3+CAD+OVERVIEW PDF
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The Pennsylvania State University
Edward C. De Meter
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This document provides an overview of computer-aided design (CAD) concepts. It covers topics like geometric modeling, computer-aided engineering (CAE), and computer-aided manufacturing (CAM), along with examples and explanations of solid models.
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IE 305 PRODUCT DESIGN, SPECIFICATION AND QUALIFICATION COMPUTER AIDED DESIGN (CAD) and the DIGITAL THREAD Course Instructor Prof. Edward C. De Meter Dept. of Industrial & Manufacturing Engineering The Pennsylvania State University MO...
IE 305 PRODUCT DESIGN, SPECIFICATION AND QUALIFICATION COMPUTER AIDED DESIGN (CAD) and the DIGITAL THREAD Course Instructor Prof. Edward C. De Meter Dept. of Industrial & Manufacturing Engineering The Pennsylvania State University MODERN CAD TOOL What is it? ◼ Software that enables: ◼ geometric design of a part or product assembly through the creation, manipulation, and rendering of geometric models ◼ gateway into other computer-aided enterprise functions ◼ Computer Aided Engineering (CAE) ◼ Computer Aided Manufacturing (CAM) ◼ Computer Aided Metrology (CAM) ◼ ever expanding capability toward the creation and storage of product design attribute data and manufacturing data (i.e. Product Manufacturing Information (PMI)) MODERN CAD TOOL What drives it? GUI Software Library Parasolid Software Library Model Rendering Model Creation Model Manipulation Model Storage SolidWorks Graphical User Interface SolidWorks Software ◼ Graphical User Interface (GUI) software for basic user interaction ◼ Vendor platform specific {SolidWorks, AutoDesk, Unigraphics, CATIA, etc.} ◼ Geometric Modeling Kernel (GMK) software for solid model creation, storage, and rendering ◼ Parasolid, ACIS, GRANITE, etc. ◼ Used across multiple vendor specific platforms MODERN CAD TOOL What is a Solid Model? line 3 x3 a3∙x =b3 x2 point 3 point 2 a4∙x =b4 a2∙x =b2 line 2 line 4 point 4 point 1 x2 line 1 x4 a1∙x =b1 x1 x1 Rendered Solid Model Solid Model ◼ Solid model is a boundary representation comprised of: ◼ Surface Representation Data ◼ Line Representation Data ◼ End Point Representation Data ◼ Representation data include mathematical type and coefficients ◼ Example: ◼ element: line 1 ◼ form: a1∙x =b1; ◼ coefficients stored: a1,b1 MODERN CAD TOOL What is a Solid Model? line 3 x3 a3∙x =b3 x2 point 3 point 2 a4∙x =b4 a2∙x =b2 line 2 line 4 point 4 point 1 x2 line 1 x4 a1∙x =b1 x1 x1 Rendered Solid Model Solid Model ◼ Representation data also stores mathematical connectivity between elements: ◼ Example: ◼ element: point 1 is the corner point intersection of lines 1 & 2 ◼ coefficients: x1 = f(a1,b1, a2,b2) MODERN CAD TOOL What is a Solid Model? line 3 x3 a3∙x =b3 x2 point 3 point 2 a4∙x =b4 a2∙x =b2 line 2 line 4 point 4 point 1 x2 line 1 x4 a1∙x =b1 x1 x1 Rendered Solid Model Solid Model ◼ Points in general are identified as either: ◼ surface point ◼ interior point ◼ exterior point ◼ Example ◼ Surface Point: 𝐱 ∈ { 𝒂𝟏 ∙ 𝒙 = 𝒃𝟏 } ∪ {𝒂𝟐 ∙ 𝒙 = 𝒃𝟐 } ∪ {𝒂𝟑 ∙ 𝒙 = 𝒃𝟑 } ∪ {𝒂𝟒 ∙ 𝒙 = 𝒃𝟒 } ◼ Interior Point: 𝐱 ∈ { 𝒂𝟏 ∙ 𝒙 < 𝒃𝟏 } ∩ {𝒂𝟐 ∙ 𝒙 < 𝒃𝟐 } ∩ {𝒂𝟑 ∙ 𝒙 < 𝒃𝟑 } ∩ {𝒂𝟒 ∙ 𝒙 < 𝒃𝟒 } ◼ Exterior Point: 𝐱 ∈ { 𝒂𝟏 ∙ 𝒙 > 𝒃𝟏 } ∪ {𝒂𝟐 ∙ 𝒙 > 𝒃𝟐 } ∪ {𝒂𝟑 ∙ 𝒙 > 𝒃𝟑 } ∪ {𝒂𝟒 ∙ 𝒙 > 𝒃𝟒 } MODERN CAD TOOL What is a Solid Model? = + Dependent Solid Model Independent Solid Model Independent Solid Model ◼ Constructive Solid Geometry (CSG) ◼ Used to represent higher level, dependent solid models as Boolean: ◼ unions or intersections ◼ additions or subtractions ◼ of independently defined solid models Computer Aided Design How are Solid Models Used? Dynamometer Assembly Model ◼ Used to construct the geometries of parts and define product assembly mating relationships Computer Aided Design How are Solid Models Used? Exploded Dynamometer Assembly Model and Bill of Materials ◼ Used to construct exploded product assembly models and Bill of Materials (BOM) Computer Aided Design How are Solid Models Used? ◼ Used to create electronic part and assembly drawings with other design attribute specifications such as geometric tolerances, surface texture tolerances, and material requirements Computer Aided Engineering Analysis What is it? ◼ Application of simulation analysis to understand the relationship between product geometry and material specifications and physical phenomena that affect product performance ◼ Examples include: ◼ Mechanical response to external loads and motion ◼ Thermal response to external and internal heat sources ◼ Electrical response to external and internal EM fields or other sources of electrical current Computer Aided Engineering Analysis What is a Solid Model used for? FEA Model Mesh with Displayed Display for Deformed Part Geometry and a Boundary and Loading Conditions Color Density Plot of Von Mises Stresses ◼ Simulation analysis requires: ◼ Product geometry and material data ◼ Fundamental mathematical models that link product data to product physical behavior ◼ Automated model formulation to prepare a system of models for analysis ◼ Automated solver to predict how product behavior responds to product data ◼ Solid models are used for automated CAE model formulation and results display ◼ Example: Finite Element Analysis of Static Deformation Behavior Computer Aided Manufacturing What is it? Automated Milling Process Automated Selective Laser Melting Process ◼ Many manufacturing machines that process parts are computer controlled and programmable ◼ Many have machine motion and process parameters that are dependent upon part geometry ◼ Examples ◼ Computer Numerically Controlled (CNC) machining center ◼ Selective Laser Melting (SLM) machine ◼ CAM software is used to automatically generate the control program Computer Aided Manufacturing What is a Solid Model used for? MasterCam Machining Op Simulation ◼ Automated program creation requires: ◼ Product geometry and material data ◼ Advanced machine motion planning analysis to derive the trajectories of the manufacturing process head relative to the part ◼ Automated process simulation to verify tool paths and process variables ◼ Automated program creation using derived tool path and process variable data ◼ Solid models are used for automated motion planning and simulation display ◼ Example: MasterCam machining process program generation Computer Aided Metrology What is it? CMM with Contact Scanning Probe CMM with Laser Line Scanner Probe ◼ Many manufacturing machines that measure point coordinate data from part geometry are computer controlled and programmable ◼ Many have machine motion and measurement process parameters that are dependent upon part geometry ◼ Examples ◼ Coordinate Measuring Machines (CMM) using contact scanning probes or laser scanning probes ◼ CAM software is used to automatically generate the control program Computer Aided Metrology What is a Solid Model used for? CMM Motion Simulation Color Density Plot showing Part Profile Error ◼ Solid models are used for: ◼ Automated motion planning and simulation display ◼ Direct comparison to measured coordinate data to assess geometric error MODERN CAD TOOL Where is going? ◼ Modern CAD software is transitioning from a solid modeler to: ◼ complete Product Manufacturing Information (PMI) platform that enables the specification and storage of all relevant product attribute data ◼ integrated suites of PMI, CAE, and CAM