Advanced Manufacturing Choices
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Advanced Manufacturing Choices Additive Manufacturing Techniques J.Ramkumar Dept of Mechanical Engineering IIT Kanpur [email protected] 2 Table of Contents 1. Introduction: What is Additive Manufacturing 2. Historical development 3. From Rapid Prototyping to Additive Manufacturing (AM) – Where are we today? 4. Overview of current AM technologies 1. Laminated Object Manufacturing (LOM) 2. Fused Deposition Modeling (FDM) 3. 3D Printing (3DP) 4. Selected Laser Sintering (SLS) 5. Electron Beam Melting (EBM) 6. Multijet Modeling (MJM) 7. Stereolithography (SLA) 5. Modeling challenges in AM 6. Additive manufacturing of architected materials 7. Conclusions 3 From Rapid Prototyping to Additive Manufacturing What is Rapid Prototyping - From 3D model to physical object, with a “click” - The part is produced by “printing” multiple slices (cross sections) of the object and fusing them together in situ - A variety of technologies exists, employing different physical principles and working on different materials - The object is manufactured in its final shape, with no need for subtractive processing How is Rapid Prototyping different from Additive Manufacturing? The difference is in the use and scalability, not in the technology itself: Rapid Prototyping: used to generate non-structural and non-functional demo pieces or batch-of-one components for proof of concept. Additive Manufacturing: used as a real, scalable manufacturing process, to generate fully functional final components in high-tech materials for low-batch, high-value manufacturing. 4 Why is Additive Manufacturing the Next Frontier? EBF3 = Electron Beam Freeform Fabrication (Developed by NASA LaRC) 5 Rapid Prototyping vs Additive Manufacturing today AM breakdown by industry today Wohlers Report 2011 ~ ISBN 0-9754429-6-1 6 From Rapid Prototyping to Additive Manufacturing A limitation or an opportunity? Rapid Prototyping in a nutshell 1. 3D CAD model of the desired object is generated 2. The CAD file is typically translated into STL* format 3. The object described by the STL file is sliced along one direction (the ‘z’ or ‘printing’ direction) 4. Each slice is manufactured and layers are fused together (a variety of techniques exist). The material can be deposited by dots (0D), lines (1D) or sheets (2D) *The STL (stereo lithography) file format is supported by most CAD packages, and is is widely used in most rapid prototyping / additive A voxel (volumetric pixel or, more manufacturing technologies. correctly, Volumetric Picture STL files describe only the surface geometry of Element) is a volume element, a three dimensional object without any representing a value on a regular representation of color, texture or other common grid in three dimensional space. CAD model attributes. The STL file describes a This is analogous to a pixel, discretized triangulated surface by the unit which represents 2D image data normal and vertices coordinates for each in a bitmap. triangle (ordered by the right-hand rule). 7 Compromises in Additive Manufacturing Another key compromise is among process speed, volume and tolerances. • Laminated Object Modeling (LOM) • Fused Deposition Modeling (FDM) • 3D Printing (3DP) • Selective Laser Sintering (SLS) • Electron Beam Melting (EBM) • Multijet Modeling (MJM) • Stereolithography (SLA, STL) • Micro-stereolithography (serial and projected) • Two photon lithography 8 Laminated Object Manufacturing (LOM) 1. Sheets of material (paper, plastic, ceramic, or composite) are either precut or rolled. 2. A new sheet is loaded on the build platform and glued to the layer underneath. 3. A laser beam is used to cut the desired contour on the top layer. 4. The sections to be removed are diced in cross-hatched squares; the diced scrap remains in place to support the build. 5. The platform is lowered and another sheet is loaded. The process is repeated. 6. The product comes out as a rectangular block of laminated material containing the prototype and the scrap cubes. The scrap/support material is separated from the prototype part. 9 Laminated Object Manufacturing (LOM) Current market leaders - Mcor Technologies (Ireland) Laminated Object Manufacturing (LOM) - Solido (Israel) was developed by Helisys of Torrance, CA, - Strataconception (France) in the 1990s. Helisys went out of business - Kira Corporation (Japan) in 2000 and their LOM equipment is now serviced by Cubic Technologies. Equipment picture Mcor Technologies Matrix 300+ (uses A4 paper and water-based adhesive) Courtesy, Cubic Technologies 10 Laminated Object Manufacturing (LOM) KEY METRICS ADVANTAGES Maximum build size 40in x 40in x 20in • Relatively high-speed process • Low cost (readily available materials) Resolution in (x,y) +/- .004 in • Large builds possible (no chemical Resolution in z Variable reactions) • Parts can be used immediately after the Speed Medium process (no need for post-curing) Cost Low • No additional support structure is required (the part is self-supported) Available materials Paper, Plastic Sheet DISADVANTAGES KEY APPLICATION AREAS • Removal of the scrap material is laborious • The ‘z’ resolution is not as high as for other • Pattern Making technologies • Decorative Objects • Limited material set • Need for sealing step to keep moisture out 11 Fused Deposition Modeling (FDM) 5. The sacrificial support material (if available) 1. A spool of themoplastic wire (typically is dissolved in a heated sodium hydroxide acrylonitrile butadiene styrene (ABS)) with (NaOH) solution with the assistance of a 0.012 in (300 μm) diameter is ultrasonic agitation. continuously supplied to a nozzle 2. The nozzle heats up the wire and extrudes a hot, viscos strand (like squeezing toothpaste of of a tube). 3. A computer controls the nozzle movement along the x- and y-axes, and each cross- section of the prototype is produced by melting the plastic wire that solidifies on cooling. 4. In the newest models, a second nozzle carries a support wax that can easily be removed afterward, allowing construction of more complex parts. The most common support material is marketed by Stratasys under the name WaterWorks 12 Fused Deposition Modeling (FDM) Current market leaders The fused deposition modeling (FDM) technology - Stratasys, Inc. was developed by S. Scott Crump in the late 1980s and was commercialized in 1990. The double material approach was developed by Stratasys in 1999. "Ribbon Tetrus" (Carlo Séquin) www.nybro.com.au Stratasys Dimension SST 1200 Courtesy, Dr. Robin Richards, University College London, UK 13 FDM process parameters 14 Fused Deposition Modeling (FDM) KEY METRICS ADVANTAGES Maximum build size 20” x 20” x 20” • Economical (inexpensive materials) • Enables multiple colors Resolution in (x,y) +/- (0.002” - 0.005”) • Easy to build DIY kits (one of the most Resolution in z +/- (0.002” - 0.01”) common technologies for home 3D printing) Speed Slow • A wide range of materials possible by Cost Medium loading the polymer Available materials Thermoplastics (ABS, PC, ULTEM…) KEY APPLICATION AREAS • Conceptual Models www.redeyeondemand.com • Engineering Models • Functional Testing Prototypes DISADVANTAGES • Materials suite currently limited to thermoplastics (may be resolved by loading) 15 Fused Deposition Modeling (FDM) Do it Yourself FDM rapid prototyping systems FAB@Home RepRap • First multi-material printer available to the public • Open-source system • Open-source system • Founded in 2005 by Dr. A. Bowyer at the University of • Project goal: open-source mass-collaboration Bath (UK) developing personal fabrication technology aimed at bringing personal fabrication to your home (project • Project goal: Deliver a 3D printer that can print itself! started by H. Lipson and E. Malone at Cornell in 2006). • 1st machine in 2007 (Darwin) • Popular Mechanics Breakthrough Award 2007 • Replication achieved in 2008 16 Fused Deposition Modeling (FDM) Do it Yourself FDM rapid prototyping systems Cubify Cube • Commercially available fully built for $1,200 • Resolution 0.2mm • 16 colors • Prints in ABS and PLA • Awarded 2012 Popular Mechanics Breakthrough Award 17 3D Printing (3DP) 1. A layer of powder (plaster, ceramic) is spread across the build area 2. Inkjet-like printing of binder over the top layer densifies and compacts the powder locally 3. The platform is lowered and the next layer of dry powder is spread on top of the previous layer 4. Upon extraction from the machine, the dry powder is brushed off and recycled 18 3D Printing (3DP) Current market leaders - Z Corporation Z Corporation first introduced high- - Exone resolution, 24-color, 3DP (HD3DP™) in - Voxeljet 2005 (600 dpi). Z Corp was later bought by 3D Systems. Olaf Diegel Atom 3D printed guitar Zcorp Z510 19 3D Printing (3DP) KEY METRICS ADVANTAGES Maximum3D Printing build size 14 in x(3DP) 10 in x 8 in • Can create extremely Resolution in (x,y) 640 dpi realistic multi-color parts (24-bit color) Resolution in z Variable using inkjet technology Speed Fast • Can generate complex components with Cost Low internal degrees of Available materials Plaster, sand, oxide freedom ceramics, sugar • Economical and starch for food • Versatile Printed with Z Corp 650 printing KEY APPLICATION AREAS DISADVANTAGES • Widely used to print colorful and complex • Very limited materials suite parts for demonstration purposes • Low resolution (lowest of all AM technologies) • Molds for sand casting of metals • Negligible mechanical properties (unusable for any structural application) 20 Selective Laser Sintering (SLS) 1. A continuous layer of powder is deposited on the fabrication