1. Direct Metal Deposition
Unit 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

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

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

5. DMD Process
Focuses CO2 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

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

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

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

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

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

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

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
Overview