April 11, 2014

This proof-of-concept logo was 3D printed using a new additive manufacturing process, light-directed electrophoretic deposition (EPD). A layer of tungsten nanoparticles (dark brown) was first deposited on areas illuminated through a laser cut aluminum mask. The mask was then changed, along with the solution of nanoparticles, to deposit alumina ceramic material (white). In the future, the masks will be replaced by a digitally projected mask for a completely automated deposition system.

 

Electrophoretic deposition (EPD) has been gaining increasing interest as an economical and versatile processing technique for the production of novel coatings on metal or conductive parts. The biggest use for this process is as a first coat primer for automotive cars. The body of the car is positively charged while the liquid primer in the dunk tank is negatively charged, forcing the attraction of the primer to the metal surface.

A wide range of materials can be used in the electrophoretic deposition process, including ceramics, metals, polymers and even living cells. However EPD has also its limitation: it can only deposit material across the entire surface and not in specific, predetermined locations, until now.

Researchers at Lawrence Livermore National Laboratory have created a technique called light-directed electrophoretic deposition, which uses photoconductive electrodes and DC electrical fields to dynamically pattern the surface material. This allows the buildup of material in targeted areas where the light comes in contact with the photoconductor's surface. This enables the creation of arbitrarily patterned 3D multimaterial composites over large areas with fine resolution.

Researchers used light-directed EPD to produce an alumina ceramic-tungsten nanoparticle composite. Initially, the tungsten nanoparticles were deposited across the photoconductive surface, then illuminated through a laser cut aluminum mask. A different shaped mask was then substituted along with the new material, to deposit the ceramic material. In the future, the aluminum masks will be replaced by a digitally projected mask, similar to those found in DLP televisions, for a completely automated deposition system.

Light-directed electrophoretic deposition has the potential to elevate traditional EPD from a single layer, single material coating process to a true additive manufacturing technique that allows for unique composites to be formed. For example, void areas can be precisely created in a part to control polymer material behaviors for energy absorption or within cellular material for the creation of veins or blood vessels for manufactured organs.

"We have presented a novel electrophoretic deposition technique based on using light to pattern materials on a photoconductive layer. This represents a large step in advancing electrophoretic deposition as a method of fabricating complex 3D patterned composites," said Andrew Pascall, research engineer and lead author.

The research "Light-Directed Electrophoretic Deposition: A New Additive Manufacturing Technique for Arbitrarily Patterned 3D Composites," is published in Advanced Materials.

 

Posted in 3D Printing Technology

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AMnerd wrote at 4/14/2014 10:14:46 AM:

Soooo is this atomic layed deposition and not additive manufacturing then?



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