1 / 22

TAM302 Engineering Design Principles

TAM302 Engineering Design Principles. Syllabus Topic: CAD/CAM Systems. CAD-CAM Overview Rapid Prototyping & STL format Feature Based DFM/Costing. Course Instructor: Mike Philpott Director of Concurrent Design & Manufacture Lab Associate Professor of Mechanical Science & Engineering

adamdaniel
Download Presentation

TAM302 Engineering Design Principles

An Image/Link below is provided (as is) to download presentation Download Policy: Content on the Website is provided to you AS IS for your information and personal use and may not be sold / licensed / shared on other websites without getting consent from its author. Content is provided to you AS IS for your information and personal use only. Download presentation by click this link. While downloading, if for some reason you are not able to download a presentation, the publisher may have deleted the file from their server. During download, if you can't get a presentation, the file might be deleted by the publisher.

E N D

Presentation Transcript

  1. TAM302 Engineering Design Principles Syllabus Topic: CAD/CAM Systems • CAD-CAM Overview • Rapid Prototyping & STL format • Feature Based DFM/Costing Course Instructor: Mike Philpott Director of Concurrent Design & Manufacture Lab Associate Professor of Mechanical Science & Engineering mphilpot@uiuc.edu

  2. 3D CAD - Solid Modeling • Software used for the design of industrial products. Prime users are the automotive, aerospace and industrial engineering industries. Main Players: • AutoCAD /Inventor (AutoDesk) • Solidworks/CATIA® (Dassault) • ProE / Creo (PTC) • UnigraphicsNX/IDEAS Also PLM integration – e.g. Windchill and Team Center

  3. Rapid changing market place: short product life cycles Designer Products: complex shapes and textures -> molds and dies -> via CNC/RP Global Manufacturing: low cost outsourcing, high & low tech mfg. facilities Fierce competition: failing automotive industry, steel mills, shipbuilding, … A "use brain" generation, not willing to learn the trade which requires hand skill (?) Current Trends in CAD/CAM

  4. Product Lifecycle Management (PLM) • PLM describes a comprehensive framework of technology and services that permits manufacturing companies and their partners and customers to collaboratively conceptualize, design, build, and manage products throughout their entire lifecycle. • AMR (industry analyst) surveys report that, within manufacturing environments, PLM is the leading category of information technology spending growth, bucking the overall downturn in IT investment.

  5. PLM - The Digital Product • Within this new global economy, product development processes have been elevated as a leading competitive weapon. • A cross-functional value chain works collaboratively to generate the intellectual property that represents a new product or product variant. • This intellectual property, when captured digitally via software applications, begins to form a digital representation of the product. This “digital product” is typically a company’s most strategic asset; it defines at a minimum what products are, how they perform and differentiate, the projected development cost, the suppliers that will be involved, and the manufacturing processes that will be used. • The digital product must be complete, compelling, stable, and agreed to by all stakeholders before any serious manufacturing work can begin.

  6. Cost of Goods (COGS) Problem Company Revenue COGS Operating Vertical $B(% Rev) Profit Lockheed Martin $ 35.5 94.65% 5.09% A&D GM $161.5 92.94% -0.06% Auto Ford $147.1 92.39% -1.20% Auto Dana $ 9.1 92.02% -1.50% Auto Tier 1 Delphi * $ 21.6 89.32% 0.91% Auto Tier 1 Raytheon $ 20.2 83.66% 6.90% A&D Dell $ 49.2 81.68% 8.65% Computer Caterpillar $ 28.3 79.12% 8.55% Industrial Whirlpool $ 13.2 78.40% 5.73% Consumer GE $152.4 77.53% 13.20% various John Deere $ 17.7 76.77% 11.96% Industrial Eq. HP $ 64.1 75.41% 5.29% Computer/Office Eaton $ 9.8 72.14% 7.96% Auto Tier 1 Thomas & Betts $ 1.5 71.57% 9.50% Electrical / Electronics Pentair $ 2.3 71.25% 10.84% Industrial / Electronics Motorola $ 31.3 66.49% 10.00% Electronic / Telecom Baxter $ 9.5 58.83% 4.52% Medical Products Agilent $ 7.2 56.51% 5.38% Medical Products % COGS All A&D Auto Ind. EQ. High Tech Overhead 25 30 25 30 24 Material 50 45 50 40 45 Labor 20 20 20 25 20 2008

  7. Motivation for Product Lifecycle Management (PLM) Most cost are set by the early decisions in the NPI / Product Development Process Product changes are exponentially more expensive later in the NPI / Product Development Process

  8. To Survive? • Shorten Product Development Time: • Collaboration (PLM) • Integrate Industrial Design -> Engineering Design -> CAM -> Prototype to Production. • Develop technologies and skill sets for complex surface design and manufacture • Reduce manufacturing cost while maintaining high quality product –> Integrate cost estimation and cost accounting from earliest design phases (conceptual what-if phase)

  9. Rapid Prototyping & the STL File Format Additive, Layer by Layer Subtractive • SLA • FDM • LOM • SLS • 3D Printing • ….. NC/CNC STL format - the defacto standard

  10. Rapid Prototyping at BMW Cool video (click on pics)

  11. 3D Systems - StereoLithography (STL) EOS - Selective Laser Sintering (SLS) Stratasys - Fused Deposition Modeling (FDM) Helisys - Laminated Object Manufacturing Landfoam Topographics - Laminated Object Mfg (LOM) Eden - Objet – 3D Printing Sparx - Hot Plot Cubital - Solid Ground Curing Light Sculpting - Design-Controlled Automated Fab. DuPont/Teijin Seiki - SOMOS/Soliform Sony - Solid Creation System Mitsubishi - Solid Object Ultra-Violet Laser Plotting Mitsui - Computer Operated Laser Active Modeling Electro-Optical Systems - Stereos Rapid Prototyping Systems

  12. STL Format: B-rep, solid object • An STL file is saved with the extension “.stl," case-insensitive. • STL is a triangular facet based representation that approximates surface and solid entities only. Entities such as points, lines, curves, and attributes such as layer and color will be ignored during the output process • An STL file consists of a list of facet data. • Each facet is uniquely identified by a unit normal (a line perpendicular to the triangle and with a length of 1.0) and by three vertices (corners). • The normal and each vertex are specified by three coordinates each, so there is a total of 12 numbers stored for each facet.

  13. BLOCK facet normal 0.000000e+00 -1.000000e+00 0.000000e+00 outer loop vertex 0.000000e+00 0.000000e+00 -1.000000e+00 vertex 1.000000e+00 0.000000e+00 0.000000e+00 vertex 0.000000e+00 0.000000e+00 0.000000e+00 endloop endfacet facet normal 0.000000e+00 0.000000e+00 1.000000e+00 outer loop vertex 1.000000e+00 1.000000e+00 0.000000e+00 vertex 0.000000e+00 0.000000e+00 0.000000e+00 vertex 1.000000e+00 0.000000e+00 0.000000e+00 endloop endfacet facet normal -1.000000e+00 0.000000e+00 0.000000e+00 outer loop vertex 0.000000e+00 1.000000e+00 0.000000e+00 vertex 0.000000e+00 0.000000e+00 -1.000000e+00 vertex 0.000000e+00 0.000000e+00 0.000000e+00 endloop endfacet facet normal 0.000000e+00 0.000000e+00 1.000000e+00 outer loop vertex 1.000000e+00 1.000000e+00 0.000000e+00 vertex 0.000000e+00 1.000000e+00 0.000000e+00 vertex 0.000000e+00 0.000000e+00 0.000000e+00 endloop endfacet facet normal 0.000000e+00 -1.000000e+00 0.000000e+00 outer loop vertex 0.000000e+00 0.000000e+00 -1.000000e+00 vertex 1.000000e+00 0.000000e+00 -1.000000e+00 vertex 1.000000e+00 0.000000e+00 0.000000e+00 endloop endfacet facet normal 1.000000e+00 0.000000e+00 0.000000e+00 outer loop vertex 1.000000e+00 1.000000e+00 -1.000000e+00 vertex 1.000000e+00 0.000000e+00 0.000000e+00 vertex 1.000000e+00 0.000000e+00 -1.000000e+00 endloop endfacet facet normal 1.000000e+00 0.000000e+00 0.000000e+00 outer loop vertex 1.000000e+00 1.000000e+00 0.000000e+00 vertex 1.000000e+00 0.000000e+00 0.000000e+00 vertex 1.000000e+00 1.000000e+00 -1.000000e+00 endloop endfacet facet normal 0.000000e+00 0.000000e+00 -1.000000e+00 outer loop vertex 0.000000e+00 1.000000e+00 -1.000000e+00 vertex 1.000000e+00 0.000000e+00 -1.000000e+00 vertex 0.000000e+00 0.000000e+00 -1.000000e+00 endloop endfacet facet normal 0.000000e+00 0.000000e+00 -1.000000e+00 outer loop vertex 1.000000e+00 1.000000e+00 -1.000000e+00 vertex 1.000000e+00 0.000000e+00 -1.000000e+00 vertex 0.000000e+00 1.000000e+00 -1.000000e+00 endloop endfacet facet normal -1.000000e+00 0.000000e+00 0.000000e+00 outer loop vertex 0.000000e+00 1.000000e+00 -1.000000e+00 vertex 0.000000e+00 0.000000e+00 -1.000000e+00 vertex 0.000000e+00 1.000000e+00 0.000000e+00 endloop endfacet facet normal 0.000000e+00 1.000000e+00 0.000000e+00 outer loop vertex 1.000000e+00 1.000000e+00 -1.000000e+00 vertex 0.000000e+00 1.000000e+00 -1.000000e+00 vertex 0.000000e+00 1.000000e+00 0.000000e+00 endloop endfacet facet normal 0.000000e+00 1.000000e+00 0.000000e+00 outer loop vertex 1.000000e+00 1.000000e+00 0.000000e+00 vertex 1.000000e+00 1.000000e+00 -1.000000e+00 vertex 0.000000e+00 1.000000e+00 0.000000e+00 endloop endfacet endsolid BLOCK An Example STL File – Block.stl

  14. The density of triangle facets change according to the geometry And it Changes with Chord Height affecting final surface resolution

  15. STL Format: B-rep, solid object • There are two storage formats available for STL files, which are Ascii and Binary. ASCII file is human-readable but larger than binary • Each facet is part of the boundary between the interior and the exterior of the object. The orientation of the facets (which way is "out" and which way is "in") is specified redundantly • First, the direction of the normal is outward. Second, which is most commonly used now-a-day, list the facet vertexes in counter- clockwise order when looking at the object from the outside (right-hand rule).

  16. Vertex to VertexRule Each triangle must share two vertices with each of its adjacent triangles. In other words, a vertex of one triangle cannot lie on the side of another. • to check: • F must be even • E must be a multiple of three • 2*E must equal 3*F F, E, V, and B are the number of faces, edges, vertices, and separate solid bodies. A violation of the vertex-to-vertex rule.

  17. “Leaky” Models The triangulated edge of two surface patch do not match, thus produce gaps between faces. Two facets crossed in the 3D space. All facets in a STL data file should construct one or more non-manifold entities according to Euler's Rule for legal solids: F-E+V=2B F, E, V, and B are the number of faces, edges, vertices, and separate solid bodies. If the relation does not hold, we say that the STL model is 'leaky'. When a 'leaky' STL file is processed by slicing algorithms, the result produces slice boundaries that are not fully closed.

  18. Direct Machining From STL file

  19. Moving Side Cores

  20. Avoiding Moving Side Cores and Lifters (1)

  21. Avoiding Moving Side Cores and Lifters (2)

More Related