Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display. PowerPoint to accompany Krar Gill Smid Technology of Machine Tools 6 th Edition Direct Metal Deposition Unit 91

91-2 Objectives Describe DMD and be able to compare it with conventional rapid prototyping processes Explain what is meant by “The Big Three of Manufacturing” Discuss how the DMD process is used in various industrial applications

91-3 Direct Metal Deposition (DMD) Form of rapid tooling Makes parts/molds from metal powder, melted by laser to computer-aided design of part, and then solidified Rate of solidification dependent on heat- affected zone of laser and metallurgical properties of powder Allows production of molds/dies in end material

91-4 DMD Technology Blending of five common technologies –Lasers –Computer-aided design (CAD) –Computer-aided manufacturing (CAM) –Sensors –Powder metallurgy

91-5 DMD Process Focuses CO 2 laser beam onto flat tool-steel workpiece to create molten pool of metal Small stream powdered tool steel injected into melt pool Move laser beam back and forth (CNC control) tracing out pattern (CAD design) Solid metal part built, line by line, one layer at a time No material waste

91-6 DMD Creates consistent, fine microstructures that yield superior quality and tool strength Allows creation of mixture of graded metallic compositions that have never been available Provides closer tolerances Lower tooling costs Improved productivity

91-7 From CAD to Steel Customer posts CAD files Engineers download and edit CAD files Updated CAD model sliced, toolpaths created Data post-processed and embeds laser and powder commands Information downloaded to 3-axis machine DMD process Hard faces applied within argon filled box

91-8 DMD Materials Variety of metal powders and metal matrix composite materials Tool-steel alloys Stainless steel Copper Stellite alloys Inconel Tungsten carbide Titanium diboride Fast solidification rate results in very-fine- grain part microstructure

91-9 Big Three of Manufacturing Speed –Faster product to market Economy –Lower tooling costs due to factors including reduction of labor and capital equipment costs Quality –Parts produced are generally.001 in. oversized –Quick clean-up and ready for use

91-10 DMD Applications Die repair and refurbishment Thermal management Creation of thermal model to locate hot spots Direct metal prototypes instead of plastic models Surface modification and coatings Aerospace and aircraft component repair

91-11 From Prototype to Production Time saved - deposition begins when CAD file ready First-stage tooling (create prototype) Design change flexibility –Material added to tooling without interface boundary Suitability for complex designs –Work same without regard for size or complexity

91-12 Overview DMD process among most promising metalworking advances in decades Benefits directly impact manufacturers' bottom line –Reduce time to market –Die repair and refurbishment –Direct metal prototyping –Thermal management –Strength improvements –Reduce environmental waste