Posted by Robert Kiser on Sat, Mar 14, 2009 @ 04:59 PM
FullCure®850 VeroGray. The new material provides excellent
dimensional stability, great detail visualization and surface quality for rapid prototype models.
Durable parts ideal for engineering simulation and models in transit:
A unique combination of low Water Absorption value (ASTM D570-98 24Hr)
and Heat Deflection Temperature (ASTM D-648) enables VeroGray 3D models to
maintain their dimensional stability in changing environmental
conditions such as transit.
VeroGray also offers excellent Flexural Strength (95 MPa) and Flexural
Modulus along with Tensile Strength of 60 MPa making it ideal for
engineering simulation and structural testing. With the superb surface
quality and detail visualization of the opaque, rigid VeroGray
material, 3D rapid prototype models look and feel like molded plastic parts. This is
valuable whenever plastic simulation is required, such as for toys,
automotive products, consumer goods and electronics, medical equipment,
piping and more.
“Fit and form testing capabilities, are inherent to Objet PolyJet printed parts due to the parts’ smooth surfaces and
fine details. VeroGray further enhances ability to
evaluate designs by enabling rigorous engineering simulation. FullCure®850 VeroGray allows mechanical engineers and designers in various
markets and industries to create functional prototypes requiring the
simulation of plastic.
- Deflection Temperature at 0.46 MPa (Celcius) = 95
- Deflection Temperature at 1.8 MPa (Celcius) = 85
- Melting Point (Celcius) = 130
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.
Posted by Robert Kiser on Mon, Jan 05, 2009 @ 06:51 PM
Rapid prototype systems use Stereolithography files, or STL for short, to replicate the 3-Dimensional computer aided design image into a physical hand held part. Stereolithography files consist of many groups of triangles called "facets". The smoother the surface of the part, the more triangles which make up the part. This is termed "surface resolution". If you were to draw a square box on a piece of paper, then draw a straight line inside the box from one corner to the other, you would see two triangles inside the box. This 2-Dimensional bitmap image you just drew actually now has a resolution in theory. If you were to then draw another line from the other corner to the other, you would see four triangles. You just increased the resolution of your 2D bitmap image. The more triangles, the higher the surface resolution, or "smoothness" of the surface. At the same time, the higher you go in resolution (add more triangles) the larger the file size becomes. There is a point where the surface resolution is okay and the smoothness of the surface doesn't need a rise in the number of triangles as this would only be overkill and harder for the rapid prototype applications software to process, especially during the slicing process. If not enough triangles (or "facets") are present, then the surface appears jagged and resolution must be increased. Most default settings in Computer Aided Design solid modeling packages output smooth surface resolutions, while some do not. Even some of the more expensive software packages output rough surface resolutions by default, which needs to be a thing of the past. The PolyJet 3D printer technology is a printer, so high resolution physical parts are built that are near the actual surface quality of the computer Stereolithography image.
3-Dimensional Stereolithography files are then imported into the rapid prototype system's application software package where a visual simulation of the actual build platform is viewed by the operator. The 3D file is then manipulated inside the simulation and oriented for fastest and most accurate build parameters. Once the platform simulation is finished, the simulation is of course saved and the "build" is started. The next step the application software takes is a process called "slicing". The parts are electronically sliced into 2-Dimensional bitmap images and stored in an area on the computer. When the rapid prototype system is warmed up and ready, one bitmap is shipped into the control electronics, and in the case of the PolyJet 3D printer, this single bitmap is printed down onto the actual system build medium, or "build tray". This first bitmap printed is the very bottom "bitmap slice" of the part/parts on the tray. You may wonder how thick the bitmap slice is. Answer is, in theory it doesn't matter because the PolyJet 3D printer system's mechanical parameters are what control the actual thickness of the bitmap slice to be built, not the application software. Dependent on the thickness of the slice, as determined by the manufacturer of the rapid prototype system, the build tray moves downward after lay down of the first bitmap by the amount of the physical bitmap slice built mechanically on the medium (build tray). Then, in comes the next 2-Dimensional electronic bitmap slice into the electronics and this bitmap slice is laid down on top of the previous and fused together. The build platform then moves down by the manufacturer's specified amount again (called layer thickness), and the next bitmap is laid down on top of the previous. This is basically how rapid prototyping works and is a process called "additive manufacturing". You may hear the term "Direct Digital Manufacturing", but in the end, the term also relates to the final process called "additive manufacturing".