Dot forming additive manufacturing technology

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Employing Direct Energy Deposition (DED) method, Mitsubishi Electric corporation claims that they have developed a new method to produce high precision parts at high speeds.  This unique dot forming technology combines laser wired DED, Computer Numerical Control (CNC) and Computer Aided Manufacturing (CAM).

Dot forming DED technology ( source :Mitsubishi Electric)

DED is one of the seven additive manufacturing techniques which uses thermal energy to fuse materials together as they are deposited. Mitsubishi claims that they can produce void-free parts of near net shape products for the aircraft and automobile industries using this new dot forming process.

The existing metal additive manufacturing techniques, power bed fusion and DED use continuous energy to melt and fuse either powder or wire to create parts.

Dot forming
Conventional vs Dot forming ( source :Mitsubishi Electric)

Since powder bed fusion uses powder as base material the parts created are porous and could have voids inside complicated shapes, while DED can make very dense parts but with marginally less accuracy.

Dot forming accuracy
Dot forming accuracy

Because of the continuous laser energy and an increase in deposition base temperature, the molten material deposited on top can take longer to solidify, during which time the part could move under its own weight and part geometry might distort affecting the accuracy.

To prevent distortion due to temperature increase, this new dot technology uses a pulsed laser to control and minimize heat input.  As shown in the image below the high temperature is limited to dot like small area reducing the distortion.

Key features

  • High quality with less voids
  • Comparatively high speed
  • Technology combination possible allowing part repairing
  • Common laser welding wire usage
  • Increased accuracy compared to conventional DED
  • Reduced oxidation (20%)

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