laser engineered net shaping

8/13/2019 Laser Engineered Net Shaping

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LENS


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LASER ENGINEERED NET SHAPING


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ANOTHER RAPID PROTOTYPINGPROCESS!

Net-shape = Final shape

Uses metal powder

Powder is supplied coaxiallyalong with laser


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UNBEATABLE WHEN IT COMES TOREPAIR

Gear with broken tooth

Mass

Gear with tooth by LENS


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COMPONENTSSANDIA LABS-OPTOMEC

Nd:YAG laser with sixinch focal length planoconvex lens

Hermetically sealedglass enclosure ,backfilled with argon,operating at a nominaloxygen level of 2-3parts per million.

Base plate with 3-axiscomputer controlledpositioning system

Powderfeed unit


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PROCEDURE

High power laser melts site of deposition

Powder deposited by nozzle into hot-spot

Laser builds cross-section in raster-scan fashion

Table lowered by layer thickness

New layer constructed on top of previous layer

Repeat process till build is complete

Melt pool protected by inert gases


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APPLICATIONS

Metal components made of state-of-the-art materials such astitanium and Inconel

Medical implants

Material discovery-Aluminide composites, Tic

Hybrid manufacturing- product enhancement


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DIAGNOSTICS Laser Doppler velocimetry for powder flow and relative density of the

powder

Time resolved infrared imaging for thermal characteristics

High magnification, high speed digital imaging and standard videoimaging

Material build-up height, the melt depth into the previous layer

Component velocityLaser irradianceZ-axis increment (thickness of layer)Powder volumetric flow rate.

PROCESS VARIABLES


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POWDER SIZE

Particles do not become molten until they are actually injectedinto the melted metal puddle in the deposition region

For smaller particle sizes , the melt puddle appeared to be stableand well behaved.

For larger particle size distributions, the molten puddle was veryenergetic and unstable

Directing the larger particles into the molten deposition regioncauses a larger displacement of the liquid metal thus adding moreenergy to the oscillations of the melt pool

Surface finish of 12-25 micrometre


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MATERIAL PROPERTIES

Tests revealed properties to be as good or even better thancasted/wrought parts

Textured growth of the deposited material occurred across thedeposition layer boundary in nearly all cases for thin-walled parts

Little inter-granular melting in the substrate region The absence of equilibrium and metastable phases in the

microstructures suggest the very high cooling rates associatedwith LENS process


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SOME FACTS

Roughly eight feet long, eight feet highand 3.5 feet wide.

$350,000 to $500,000

Dimensions in the X-Y plane could bemaintained to less than 0.002

inches(0.02 mm).

The dimension in the Z or growthdirection could only be maintainedwithin 0.015 inches.

laser engineered net shaping

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