MEGR 3231 Final Exam
What are the primary format for 3D model transfer? What does it use?
-IGES -STEP B-Rep or boundary representation
What were some CAD software companies in the 70's
-Unigraphics -AutoTrol -CATIA -Computervision > Sun > Prime
Desktop Factory
-composite, nuylon bsed plastic powder -drum printing tech. is used to deposit build layers. a halogen..... -after drum deposit the layer is annealed with a heated plate at the top of the build envelope look up diagram
EOS: DMLS
-direct metal laser sintering -emanufacturing -materials: aluminium, Colbalt, Chrome, etc...
Arcam
-direct metal machine -uses fine metal powder and the electron beam melting process -initial problems with resolution: -98% efficiency -Bought by GE
Phenix
-uses laser to sinter a metal base powder to create metal parts directly look up
Scanning Steps
1.)Prepare for scanning a.)Color the part b.)Add reference targets c.) mount part d.)Locate part 2.) Collect data a.)Typically takes multiple passes 3.)Export points or facets 4.) Clean up Data a.)Outliers b.)holes 5.)Assemble data series
Cost Analysis Curve
3D printing has a constant cost. Traditional processes have a downward curve, meaning for more than roughly 100 parts, its cheaper to use a traditional process. The breakeven point however is based on the parts design. Remember than in traditional machining more material is less time, and in 3D Printing, less material is less time.
Build paths
45 x 90 is / and | 0 x 90 is | and - 90 x 0 is just |
What is raster? 1 bit and 3 bit
A field of points that can be turned on and off with different colors. The whole field presents a complete graphic. Think of it like an image. (bitmap) Depth of color depends on memory in bits per pixel. 1 bit (Monochrome) Black or White, 1 on-off switch 3bit (Primaries) Each pixel has 3 on-off switches **SCALING CAUSES DISTORTION**
What is vector?
A set of simple geometric features with mathematical features. Can be scaled without distortion
What is an infiltrant
A substance that penetrates an object to give it some property such as waterproofing.
Stratasys:Fused Deposition Modeling
A thin filament of a material is heated to just below melting point and deposited in slice patterns. Slice patterns are basically the internal structure of the print (think the honey combs). They can be set at different angles. Two materials a model material and a support material are used in creation. Since the table moves in the X-Y Direction there is a lot of vibration Can have water dissolvable supports Layers are not tight enough to be water tight.
3D Wireframe Modeling
A three dimensional vector graphic. The components are defined geometric shapes where numerical values are assigned. More of a 3D sketch Composed of points and curves No physical properties available
Popular Kernals used in CAD systems today?
ACIS Granite (PTC) Parasolid (Siemens)
Describe Electronic Engineering Drawings
Allows for easier drawing modification and duplication. Simplifies the transfer of data Reduce paper use [Not really though]
Wyn Swainson
Applied and won for a patent : "Method, medium, and apparatus for producing three dimension figure products." Predecessor to Lithography NO action was taken to make this technology commercial.
Acro: ADAM
Atomic Diffusion Additive Manufacturing
What were some CAD software companies in the 80's
Autodesk Bentley Dassault Parametric Technology
What does B Splines Stand for
Basis Splines
Non - Uniform Rational B-Splines (nurbs)
Basis Splines are generalized Bezier curves. Most common form is a third order spline. The segments are continuous by location, slope, and curvature. N-2 equations solved where N= # of points
Desktop Metal (stratasys)
Bound Metal Deposition FDM process -Prints metal and plastic in the typical filament style, then heats up until plastic melts away, leaving only metal. -plastics the support material and metal is a model material The original part shrinks since the plastic is lost after melting. Near net shape parts -Tight tolerancing
What do photopolymers do when exposed to light?
Brown
Faceted
Bunch of little surfaces (typically triangles) found by connecting the point cloud dots.
CAD Research in the 50's
CNC Programming
Charles Hull
Co founder of 3D systems. Inventor of stereolithography While working for UVP in 1983 he conceived of a laser modeler sinterer to existing surface curing tools. Patent issued in 1986 and machines came out in 1989.
What is CAD? What are two types of CAD?
Computer Aided Design The implementation of computers in the creation. modification, analysis, and optimization of a design. Drafting and Modeling
What is CAE? What are 3 types of CAE?
Computer Aided Engineering FEA - Finite Element Analysis. Can be mechanical of thermal. The mechanical analysis can be static or dynamic. CFD - Computational Fluid Dynamics Simulations.
What is CAM? What are 3 types of CAM?
Computer Aided Manufacturing Application of computers to the creation and assembly of physical components. NC - "Numerical control" of computer driven machine tools. RP/AM - Rapid Prototyping / Additive Manufacture CAPP - Computer Aided Process Planning
IOT
Connecting Smart Devices to the Internet Use instrument data in the real world.
3D Geometry Storage Types and Definitions
Constructive Simple Geometry (CSG) - breaks into simple geometry Bound Representation (B-Rep) - think vertices, edges, and faces , boundaries. Decomposition - breaks into smaller elements to recreate shape. Think cutting into small squares.
19th Century Additive Manufacturing
Contour Maps. Basically 3D topographical maps.
Big Players in Kernals
Convergence Geometric Models (Dassault) Parasolid (Siemens) ACIS (Dassault) Granite (PTC)
CAD Research in the 70's
Corporate Development Computer Power Advances (Super computers are room sized)
What does climate control do for plastic printing?
Creates better parts. Temperature is desired to be constant due to thermal expansion.
Current and Past Players of Solid RP/AM Systems
Current: Stratasys Solido Reprap Makerbot FFF Past: Perception System Hydronetics
CRM
Customer Relations Management Who we tell what? What do we tell them?
Metal
DLMS.... Prox 3D metal Lesertec GK
What is the primary format used for 2D Drawing Data Transfer
DXF
Infinite Build
Different tool types Can create forms much quicker than traditional manufacturing ie 60 days vs 1 day Can use materials such as ultum, which is heat resistant and used on the rocketry team's rocket.
Acro: DLMS
Direct Laser Metal Sintering
Acro: DMD
Direct Metal Deposition Add material where youre actually printing it
DMD
Direct Metal Deposition Uses laser and powder metal flow
Acro: DMLS
Direct Metal Laser Sintering
What is DXF
Drawing Exchange Format Developed by Autodesk Allows foundational components of 2D CAD data transfer (drawings) -Points -Text -Colors, line weight -units
Acro: EBM
Electron Beam Melting (METAL)
ERM
Enterprise Resource Management What do we have? Where do we have it? Who can use it?
Direct Modeling (Non-Parametric)
Feature based, non-parametric modelers Features define the location size and orientation. Changes can be made on the fly without concern for the variations of other features.
Parametric Modeling
Features define the location, size, and orientation Changes can be made to the parameters of individual features Parameters can be named to make relations and features easier to understand.
Issues with product data management
File Compatibility (different types or versions) File Accesability (who can get it and where?)
Hideo Kodama
First account of working 3D printing system. Nagoya Municipal Research Institute Uses Stencils Light cured photo polymers
What is a PDM tool useful for?
For management of interrelated file based models within a specific discipline, such as mechanical design.
What is IGES
Format used for 3D model transfer. Initial Graphics Exchange Specification ASME Y14.26M A group of vendors and users started it in 1979. Officially published in 1980. Current at NIST. Boeing GE Xerox Computer Vision
What is STEP
Format used for 3D model transfer. Standard for The Exchange of Product module data ISO 10303 Development started in 1984 as successor of IGES More legible code
Stratasys
Founded by S. Scott Crump. Founded in 1989. Owns Objet, Makerbot, Solid Concepts, among others.
Acro: FDM
Fused Deposition Modeling
Acro FFF
Fused Filament Fabrication
What is scanner industry standard software?
Geomagic.
What are the primary attributes that must be captures when transferring from one format to another?
Geometry, Points, Lines, Curves Locations, Line Weights, Color
Markforged
Has printers than can print composites. -Fiberglass -Kevlar -Is low cost.
Bezier Curves
In 1971 French Engineer Pierre Bezier working for Renault developed a surface modeling program called UNISURF for car body design. Part of this was the development of parametric curves and surfaces with his name. Curves are governed by points. (The whole curve is influenced by every point) Data points control shape. Tangent vectors are not used. Order dependent on number of points. (Typically wants to use minimum # of points) The curve is created through the first and last points with the remaining points used for interpolated or extrapolated tangencies and contingencies.
Xerography
Introduced in the 50's Electrostatic attraction of ink/powder and transfer to paper. Powder sticks to the paper in the shape of the words due to electrostatic force. can also store data onto tape.
20th Century Additive Manufacturing : Mimeograph also known as the stencil duplicator
Invented by Thomas Edison Forces ink through a stencil onto paper. mostly mechanical slow different from spirit duplication in that it forces a replenish able supply of ink through the stencil master.
What if the future of file format transfer?
It is currently hard to send features. The next generation of CAD modelers are working to improve this issue as large and small companies attempt to transfer data from system to system.
With Stereolithography, what part of the process takes a while?
It takes longer to wipe than to actually print. Some new ones have two baths. The light must be the correct wavelength.
The foundational database for CAD modeling?
Kernal
Acro LDT
Laser Deposition Technology
Acro: LMD
Laser Metal Deposition
Acro: LDM
Laser Metal Diffusion Machining
LOM:
Layered Object Modeling Layered Object Manufacturing Laminated Object Modeling
Perception Systems -BPM
Located in South Carolina Patented in 1987 A rotational print head allows small molten wax particles to be projected onto the model with non-vertical trajectory. Wax supports can be dissolved after the print.
COLA Cold Spray
METAL COaxially Laser Assisted cold spray Particles are accelerated at high speeds to impact the surface. The particles deform on impact. Basically, its sandblasting with metal so fast that it deforms instead of abrading. You could process the material before as to soften it so that the spray sticks better. Can spray in 3D
LENS
METAL Laser Engineering Net Shape Can use multiple materials Can build off from existing parts -Useful for retooling turbines Resolution no better than plastic DMD - direct metal deposition
LDM
METAL Laser Metal Diffusion Machining Powder exits from nozzle and is immediately sintered. Can multi axis print Can add to existing parts Not good to breathe Very little waster powder
DTM- 3d Systems- (SLS)
METAL Selective Laser Sintering Developed at UT Austin, and intially marketed by Desktop Manufacturing (DTM). Company bought by 3D in the 1990's and the technology is under continual development by 3D and research at UTA Lasers rotate to hit the whole print area. The powder is heated at a constant higher temp. No support structure Can recycle powder.
What CAD data is stored in PDM?
Models, Assemblies, Drawings, Design Changes
3D Solid Modeling
Most are parametric based. Entities created are retained as individual entities for later manipulation A database is created for each model Features contain the positive / negative aspect. A hole and a cylinder have the same shape but a hole is a negative feature and a cylinder is a positive one.
Synthetic Curves
Non-conic curves are represented as "degree 3" or third order (cubic) polynomials.
Describe Sketchpad {Ivan Sutherland]
Object oriented programming Computer power was finally available 2D sketches Horizontal and vertical line, arcs, zoom capability More of computer aided drawing and drafting
What are some parts poorly suited for 3D printing
Off the shelf componenets such as nuts and bolts Hardware Sheet metal
Powders are typically?
Organic (celluose)
How to optimize metal parts?
Orient parts in a way so that overhand features are minimized Chamfer small overhands at 45 degrees. Redesign channels to be teardrop or diamond shapes. (For washing liquid)
Equation of an ellipse curve
P(u) = [Xc + R1cos(2*π*u), Yc + R2sin(2*π*u)]
Equation of a circular curve
P(u) = [Xc + Rcos(2*π*u), Yc + Rsin(2*π*u)]
DOE Inventions Process
PAPER Rolls of paper or plastic or composites used A binder is applied to paper as it is rolled on top of the previous layers The sheet is adhered with heated roller Layers are cut with inert gas laser (CO2) You have to cut into the finished build to get the final part out. Also has to have large features since it isnt very accurate Like wood
Metal Part Design Plan for Finishing Operations Pros and Cons for Green vs Brown Finishing (also processes)
Post process either in a green or sintered state Green State: Either wet sanding or machining Pro: Faster Con: Fragile, bad tolerance Brown State: Polishing, machining, tumbling, grinding Pro: Better Surface Finish Con: Slower, Harder to work with
PDM
Product Data Management - An internal tool used to integrate and propagate design data.
PLM
Product Lifecycle Management - Contains the PDM data and includes data for every step of the project from design to production to sales to retirement.
For Digital Laser Scanners, how should references be on the model?
Randomly Orientated
What are the forms of 2D CAD?
Raster Vector
What is the primary format used for simple surface transfer?
STL Stereolithography
dAVID
Scultify Uses pellets rather than filaments
SDL
Selective Deposition Lamination Uses cutters for paper board The cutters can wear out You could put ink on the model since its paper You still have to get rid of the excess paper Water based binder used shapes cut with a blade
Acro: SLM
Selective Laser Melting (METAL)
Acro: SLS
Selective Laser Sintering (METAL)
3D Surface Modeling
Set of three dimensional primary elements (points and curves) Surfaces are created by combining these curves Surfaces have no thickness so they are assumed to be solid only if it is a closed volume. No material properties
CAD Research in the 60's
Sketchpad [Ivan Sutherland]
Metal Part Washing
Small holes make it hard for the fluid to reach the whole part. Add channels to the part to speed up washing.
CAD Research in the 80's
Software Companies
Solid RP/AM Systems
Starts with build material in the solid state. Creates models through thermal or mechanical process. Results in a part of the same initial material, but in a different shape. IE: Powder based systems have like properties but not exact. This has EXACT properties.
What is STL
Stereolithography Created by 3D systems as the standard for CAD to rapid prototyping surface edge points
SLA
Stereolithography apparatus Developed by Chuck Hull The laser hits a targeting mechanism to direct it. Must have a level surface for the laser to hit. Problem is that you have to have a reservoir of build material.
What does the cross sectional area influence?
Strength
What can print direction determine?
Stress concentrations
SCM
Supply Chain Management Who do we get stuff from?
Metal Part Design for Sintering
Support top heavy cantilevers Fillet sharp edges
Metal Injection Molding
Supports are designed to be broken away from main part. Part must be designed larger since it shrinks during manufacture. Metal Injection molding has 200 materials availible whereas powder bed fusion only has roughly 15. Markforged is a player.
What are the forms of 3D CAD?
Surface Solid Wireframe
Contact / Probe Scanner
Takes probe and touches material to find where features are. Takes a long time. Could cause deformation. Good for 50 points for less.
Metal Injection Molding
The parts shrink, so they have to be printed bigger than designed.
What is a kernal? What does it do?
The software engine for 3D objects. Creating objects Manipulating objects model management model visualization
Solido
Thin rolls of plastic stretched over work surface - This is laminated object manufacturing Uses tool cutters -Razors that can wear out Adhesive applied between layers -extra material removed by peeling layers
Image scanners are good for how many points?
Thousands
How do you convert design data to product instructions?
Through CAPP, Computer aided process planning
How are kernels typically transferred>
Through an intermediate file transfer format.
Why can the number of points used in STL files be an issue?
Too few points can cause an increase in cord height. Too many points is hard on the computer.
What is difficult about kernals? What makes it difficult?
Transferring from one kernal to another is hard. Each kernal has its own data structure for individual feature manipulation.
Metal 3D printing
UNCC machine sits on ceramic surface. it prevents it from melting, but if it comes off the ceramic then it will melt in the machine.
Where was SLS develeoped?
UT Austin
Markforged Metal Injection Molding
Uses ADAM Atomic Diffusion Additive Manufacturing Steps: 1.) Design 2.) Print [green part] 3.) Wash [brown part] 4.) Sinter [metal part] 5.) Part [Finished Part] These finished parts can be post processed. Milling, sanding, etc.
Spirit Duplicator
Uses alcohol based solvent to produce copies. It works by the use of a master sheet. The master sheet was drawn or written on, and the second sheet was impregnated with wax and colors. The pressure of the writing transferred the colored wax from the second sheet to the first. This creates the master sheet. The application of solvent through the master sheet creates copies when rolled on.
Z corp
Uses powder. A Binder is applied to hold parts together. After part is removed, a secondary infilitrant is used. - The most common is a low viscosity cyancylate -For more strength, an epoxy can be used - Wax also used for investment casting Additional powders include: - pre-cast metal, which creates investment casts for non-ferrous metals -water cure powder- which uses water for secondary infiltrant for easy and clean use. Parts from the machine are as strong as other materials. Not as strong as adhesives. Supports can be designed to be dissolved. Process: 1.) Thin layer of powder 2.) Rolls over (slides) 3.) Repeat until done was squire by 3d systems 2012. still advertised.
How are printed metal supports designed?
Weaker, as to be broken off after sintering.
What is Bound Metal Deposition
Where metal particles, plastic, and wax are extruded, and then the plastic and wax are melted out. Leaving only the metal in the final shape, only sintered. Has a size reduction.
Mainframe Computers by 1960's
With the development of 2D CAD. Printing and plotting for digital files was needed. With incoming development of 3D CAD, the ability for physical transfer was needed.
Terry Wohlers
World leader in 3d printing advice
Circular features should be printed in what plane?
X-Y plane
Implicit Non Parametric Equation of a circle
X² + Y² - R² =0
Explicit Non Parametric Equation of a circle
Y = ±√(R²-x²) z=0
Arc Curve Formula
[ Xc + Rcos( Ao + Au) , Yc +Rsin(Bo + Bu)]
In additive less material is ____ print time, and in traditional machining, more material is ___ print time.
less, less
Equation of a coil
x = Rcos(2*π*n*u) y = Rsin(2*π*n*u) z = L*u n = number of coils u = parametric value (0 to 1) L = length of the coil
parametric equation of a circle
x = Xc +Rcosθ, y = Yc + Rsinθ, Z = 0, 0≤θ≤2π
