Additive Manufacturing Technology Overview

1. Additive Manufacturing Technology Overview Mike Klecka United Technologies Research Center East Hartford, CT June 18, 2014

2. Presentation Overview Additive Manufacturing Technology Comparison of Additive Manufacturing Methods Typical Post Processing Requirements Multiple Material Designs Additive Manufacturing with Cold Spray Suitability of Parts for Additive Manufacturing Design and Redesign for AM AM Process Selection

3. Increasing Pressure on Manufacturing Additional challenges • Increasingly complex part geometries and systems • Expanded material options • Manufacturability concerns • Slow adoption of new techniques • Qualification of new processes • Potential benefits from additive manufacturing • Reduced machining time, energy, & cost • Reduced material consumption • Material solutions and combinations not otherwise possible • Increased part complexity Requirements • Shorter time to market • Higher performance requirements • Increased product life, durability • Reduced weight • Lower cost • Higher yield and quality • Improved energy efficiency • Less waste, environmentally friendly

4. Additive Manufacturing Overview • Additive manufacturing is broadly defined as the addition of functional material to a substrate, after which is either incorporated into the substrate as the finished part or is separated from the substrate to yield a free standing part • Added ribs to a sheet or panel for stiffening • Added lugs to a tube for mounting • 3D printing of entire components on a build plate • Majority of techniques utilize powder feedstock • Some use wire, sheet, or strip stock • Powder Bed Techniques • Laser powder bed, DMLS, EBM • Advantages – Small features, tight tolerance, fully inert environment • Disadvantages – Low deposition rate, limited part size, single material Added Material Build Core • Powder Deposition Techniques • Cold spray, LENS, Laser applied powder • Advantages – Moderate part sizes, in situ alloying, moderate deposition rates, dissimilar materials • Disadvantages – Lower dimensional accuracy, less tolerance control • Non-Powder Based Techniques • Laser wire feed, EB wire, ultrasonic, laminated object • Advantages – High deposit rates, low cost feedstock • Disadvantages – Poor part tolerance, required post machining, moderate property potential

5. Comparison of Additive Manufacturing Powder Bed • DMLS, LPB, EBM, powder bed fusion • Potential for widest variety of geometry • Limited to one material • Low deposition rates (0.05 - 0.5 kg/hour) • Part size limited by dimensions of powder bed • Advantages – Small features, tight tolerance, high geometric fidelity, fully inert environment • Disadvantages – Stress relief & heat treatment often required, slow build rates, limited part size http://en.wikipedia.org/wiki/Selective_laser_sintering Laser Powder Injection • LENS, laser applied powder (LAP) • Multiple build directions • Multiple material deposition • Moderate deposit rates (0.5 – 1 kg/hour) • Advantages – Moderate geometric fidelity, shield gas environment, cladding/repair/resurfacing • Disadvantages – Moderate feature size, moderate property potential, gravity concerns with build direction Laser Applied Powder

6. Comparison of Additive Manufacturing Cold Spray • High plastic work during deposition • High deposition rates (3 – 15 kg/hour) • Limited to line-of-sight processing • Lower geometric fidelity • Advantages – Solid state processing, good mechanical properties, multi-material, bonding of dissimilar materials Laser/EB Wire Additive Ultrasonic & Laminated Object • LAW, MIG, EB Wire • High rates (3 – 10 kg/hour) • Low cost feedstock • Low feature tolerance • Moderate property potential • UC, UAM, LOM • High build rates • Sheet, strip feedstock • Limited geometry • Solid state ASM Handbook, Vol.6A, Welding Fundamentals and Processes (2011) Granular Material Bonding • Powder bed inkjet & binder jetting • 3D printing sand, casting molds/cores • Plaster based printing (PP) • Low material properties, low cost • Sintered metal, polymer, & ceramics

7. Comparison of Additive Manufacturing Direct Write • Conductive ink printing, conformal surfaces • Potential for wide variety of geometries • Excellent resolution depending on technique • Multiple material deposition • Micro cold spray Actuators, Motors & MEMS Sensors & Arrays Fused Deposition • Thermoplastic-based (neat or filled) • Layer-by-layer deposition • Extrusion & shrinkage limits high resolution • Capable of complex geometries and low density cores • Multiple material deposition, limited properties Prototype parts Cores http://en.wikipedia.org/wiki/Fused_deposition_modelling Stereolithography • SLA, Large Area MasklessPhotopolymerization (LAMP) • Ceramics and polymers, UV curing materials • Complex geometries with good resolution • Restricted material selection, resin is often expensive http://en.wikipedia.org/wiki/Stereolithography

8. Metal Based AM Comparison Laser Powder Bed Electron Beam Powder Bed Laser Applied Powder Deposition Rate Feature Resolution Ultrasonic Fabrication Wire Feed Techniques Cold Spray • AM technology publicizes less raw material waste compared to conventional machining • Cold Spray: Deposition efficiency and overspray can vary significantly based on material • Laser Applied Powder: Capture rates between 40% and 80%, depending on process conditions • Powder Bed: Un-sintered powder has potential to be reclaimed and reused - gives rise to additional questions of repeatability and quality • Wire Feed: Captures better than 90%, similar with ultrasonic; often requires post machining • Common constraints for each AM technique • Part Size: Powder beds limited in size, typically less than 12 inches, while wire feed can accommodate 10 foot long sections or more • Build Speed: Powder beds often take many hours (often more than 24 for large structures), LAP may take up to 12 hours or more, wire feed less than 6 hours • Material Properties: Melting processes result in strength similar to cast, solid state processes (cold spray & ultrasonic) may be better 8

9. Typical Post Processing Requirements Example: Powder Bed • Often overlooked aspect of AM: Post processing requirements • Stress relieving via heat treatment to prevent part distortion • Due to rapid cooling rates, AM parts often contain large residual stresses • Conducted while part remains affixed to build plate • Removal of part from build plate, typically via EDM • Heat treatment to reach required microstructure and mechanical properties • As deposited, AM parts often resemble cast microstructures • Directionality is common, with grain structures oriented in the build direction • May require HIP to reduce porosity and improve density • Homogenization and solution treatment to reduce grain orientation • Hardening/precipitation/strengthening/quench/temper heat treatment, as required • Finish machining to meet required geometry and tolerances • Peening, grit blasting, and tumbling to improve surface finish • Inspection for defects/flaws Part distortion in laser applied powder after removal from build plate

10. Multiple Material Designs • Additive techniques offering multiple material solutions: • Injected powder laser additive (LAP, LENS, etc.) • Cold spray deposition • Ultrasonic consolidation • Multiple material part fabrication • Weight reduction • Light weight base/core material • Hard, wear resistant surface • Integrated component designs • Potential for advanced materials

11. CS deposit Support with sharp drop-off Additive Manufacturing with Cold Spray Potential for buildup of uniform section possible through proper gun manipulation Cold spray tensile sample, deposited on steel mandrel with engineered release layer • Level of Finish Machining Required • Mandrel design • Material used • Dimensional requirements • Accuracy of spray path More complicated geometries possible through mandrel concept

12. θ2 θ1 Substrate drops off Substrate is flat Case Study: Optimization of Additively Manufactured Structural Mount • Component: Structural mount • Process: Cold spray additive manufacturing • Structural modeling & optimization indicate preferred geometry • Critical factors: • Material properties and layout • Process parameters • Structural performance • Geometric process characteristics… Structural mount Trapezoidal cross section 12

13. Additive Manufacturing Process Dependence Different outcomes by process and properties Design for the cold spray process using removable mandrel Design for direct metal laser sintering (DMLS) powder bed process Design conception for the laser applied powder (LAP) process 13

14. Suitability of Parts for Additive Manufacturing AM makes sense for some, but not all components Redesign may improve the performance independent of cost • Existing clear business case for using AM • Many processing steps, intensive machining • AM saves time, has less raw material waste • No existing business case, but redesign could create one • Current design more expensive with AM • Redesigned part could be more cost effective using additive technique • Consolidation of multi-part assembly into single component • No existing business case, low likelihood that redesign could impact • Low cost conventional processing (e.g., stamping) • Satisfactory performance • High part volumes required

15. Redesign for Additive Manufacturing Parts suited for additive manufacturing may look different than traditional counterparts • Conventional manufacturing • Well-established limits in feature shape and complexity • Casting • Forging • Machining • Higher cost often associated with feature complexity and low weight • Additive manufacturing • New areas of design space • Often no penalty for more complexity • Possible lower cost associated with higher feature complexity and lower weight • Redesign for AM requires creativity and new ways of thinking

16. Additive Manufacturing Technique Selection Laser Powder Bed Electron Beam Powder Bed Laser Applied Powder Deposition Rate Feature Resolution Ultrasonic Fabrication Wire Feed Techniques Cold Spray • Some key considerations • Size of part • Geometric tolerance • Surface finish • Throughput • Geometric complexity • Feature size • Single- or multi-material • Mechanical properties • Microstructure • … • AM technologies are rapidly evolving

17. Thank You