Posted by Robert Kiser on Tue, Jan 20, 2009 @ 10:35 AM
PolyJet 3D printing technology has two build styles, "Matte" and "Full Glossy". Unlike other rapid prototyping technologies, the PolyJet 3D model printed on the aluminum build tray must be supported as it is grown by a gel-like support material. If the main model walls were not supported, the walls would begin to collapse, the part could separate from the build tray, and damage could occur to the system. The soluable gel-like support structure is easily removed via a water jet spray system. Once removed, the support leaves behind a clean model wall that has a slight Matte finish to the part if the 3D model was printed using the Matte feature.
Some PolyJet 3D models can be created using the "Full Glossy" feature of the Objet Studio software. Full Glossy is a mode feature where no gel-like support encompasses the part. The only support material needing to be removed is the very bottom of the 3D model where a pad of support is used to anchor the model to the tray. Full Glossy mode is reserved for parts generally .787" (20mm) or less in height because collapse of model walls can occur above this height, quality will suffer, and damage can occur. If a part is "dome shaped", then a taller height model can be produced without wall collapse because the wall is supporting itself and no liquid resin runoff can occur. If you have a model cylinder standing on end and there is (for example) a hole running perpendicular through the cylinder, then the inside of the hole must be supported or the hole would collapse in on itself. In this Full Glossy case, there is support added in the part.
"Full Glossy" 3D models look impressive, but there are limitations and risks involved. Also, dimensional tolerances will differ between a PolyJet 3D model printed in Matte versus Full Glossy. If a "ball" shaped part is produced in Full Glossy mode, then half the ball will be Matte finish because the bottom half of the part requires support during the build process. For guaranteed model accuracy and functionality, "Matte" selection is default for the hard acrylics, TangoPlus FullCure930 rubber elastomer, and the DurusWhite FullCure430 polypropylene like resin.
