Color 3D Printing

Posted by LGM | Wednesday, May 21st

Color 3D Printing

LGM offers the option to 3D print a given part in full CMYK color using a Zcorp 650 additive powder printer.  (Now renamed the 3D Systems Projet 660Pro).  The addition of color and the ability to use texture maps, opens up a world of possibilities to designers from in house form reviews to sales and marketing.  Color 3D printing can be a cost effective way to add an extra level of detail when leveraging your existing 3D CAD data.

As ground breaking as it can be, color 3D printing carries with it some caveats.  It is important to understand where color 3D Printing excels and where it falls short in order to get the full and best use of color.

Within architectural modeling (at the time of writing this) it is our opinion that color 3D printing will not be able to replace laser-cut, hand-painted and assembled  textured plastic when it comes to producing a photo-realistic model.  That said, color 3D printing is much faster and often less expensive, so it does have a place within our product offerings.  

Where color 3D powder printing is at its best:  

     1) There are no other viable true full color 3D printing processes that exist.  Period.  Many machines can print in a single color and some can even use multiple single spot colors, but none function the same way or produce the same gradients or color blends that we have come to expect form inkjet printers.  

     2) Color 3D printing works best when used to explain things diagrammatically.  For example, if you want to highlight, within a development project, what is residential versus commercial, color 3D printing would be a good choice.  If you have a sales presentation, and want to illustrate a difference in materials used, a color 3D print would be a cost effective way to add this level of information to the project.  If you have a working part and want to help display various functions within that static piece, adding color to the 3D print would be a great way to convey that concept.

     3) Color 3D printing also offers semi-custom, low quantity, manufacturing possibilities that are not available through other means.  For example, if you have a colored 3D CAD model of a figurine, it is possible to 3D print a low number run it a much more cost effective way that having it prepared for mass manufacturing (molding, casting, painting, etc.).

What to be aware of when considering color 3D printing:

     1) Manage your expectations!  Keep in mind that color 3D printing is still somewhat of a fledgling process.  Print resolution is in the 150 DPI range, so the final models won't be as crisp as a standard high resolution 300 DPI paper or vinyl 2D prints.  The fact is, this process is still intended for prototyping, so the parts will not be the same quality as a colored, injection molded, plastic piece.

     2) Color variations:  There is still a disconnect between colors in the CAD model and final 3D printed part; meaning, what you see on the screen is not what will ultimately print on the model.  It is nearly impossible to match a specified spot color.  For example, if your dictate that a given section on your 3D model needs to be a certain PMS color, we would not be able to match that perfectly.
The best way to get as close as possible to specific colors is to run sample tiles and/or palettes.  The printed colors can then be reassigned to the digital 3D to get the desired colors to print on the final part.
This also applies to texture maps.  The image that is shown on screen will often have a variation from what actually prints.  Our best practice is to run a sample tile with the texture map applied.  Once we have seen what the print looks like, we can adjust the color balance accordingly.
Even between different prints of the same parts, we see some minor variations in color.  There are a number of variables that go into the machine set up that can result in variations, however, LGM only uses brand new 3D systems powder and binder for their color printing to help eliminate these differences.  
The orientation of the part within the build envelope can produce slight color variations.  Not only how it sits, but what part it sits next to can change how it looks.  One phenomenon known to occur is referred to as "ghosting," by which a neighboring part or shape can slightly change the color.

     3) Level of finish: Color 3D printed models will not typically have a plastic-like smooth surface finish.  Just like other additive powder manufacturing, the surface will have a slight, usually somewhat rough and striped texture to it.  This effect can be reduced through the use of outer coatings.  
You cannot have different surface finishes or material qualities with color 3D printing.  Metal will not be smooth, shiny and reflective. Glass will not be transparent or reflective.   While you can produce a fully colored part in one fell swoop, you cannot get the level of textures seen and felt in the real world material.

     4) Color longevity:  Because the technology is derived from industrial design, where physical prototype models are used in an abbreviated design cycle, color 3D prints are intended to have a relatively short shelf life. 3D Systems colored inks are not UV stable.  Exposure to sunlight or UV radiation will degrade the color over time.  This effect is not immediate so you can feel free to display the model, but displaying the model in direct sunlight for a prolonged period (in a window unit of your sales center) is not advised.
To increase the vibrancy and depth of the color on a 3D printed piece, LGM infiltrates the part with a water thin cyanoacrylate adhesive.  This is followed by a UV-resistant clear coat.  These two steps help to insure that our color parts not only look the best and brightest, but also increases the durability and longevity due to environmental variables.



Links to:

3D systems  to discuss/show the difference in color printing (no true full color)

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