Colour 3D Printing. Technology Update.

Posted on Feb 20, 2019

Colour 3D Printing. The State of the art.

February 2019.

Here at 3D-Alchemy our sister business specialises in colour printing CDs and DVDs, so we know a bit about printing colour. We provide print services to some of the UKs leading creative agencies. This blog post is intended to try and align expectations with the capabilities of the current technology

We've always had a colour 3D printing service in our line up, originally offering with the Z-Corp system which is a powder, inkjet and binder technology. It produced nice results with the finished models feeling a little like ceramic.

Our current colour 3d printing is based on the new Stratasys J750 technology, which uses a CMYK (Cyan, Magenta, Yellow and Black) to give pseudo full colour for rigid parts, and a broad pallet of spot colours for flexible parts.

 

Colour Accuracy:

3D Printing in colour is a developing technology with advances to the system coming through all the time. We'd certainly hesitate to describe it as truly colour accurate but it can give you an impressive representation of full colour items, and for some designs and geometeries gives superb results but not all.

Your designs are are 3D printed in Colour from either a 'full colour' .WRL (VMRL) file or STL files to which RGB or HEX colour codes are applied.

In simple terms a .WRL file combines a .STL file with a .Jpeg image which wraps a colour image around the part. When combined with a textured design the results are impressive.

 

Rigid or Flexible parts:

One of the stand out features of the polyjet system is the ability to 3d print Rubber like flexible materials and Rigid materials. Flexible and rigid elements can even be mixed in the same 3D-Print to prototype overmoulded designs.

You can print your rigid design in true 'full colour' based on the .WRL file format. Alternatively you can supply STL files which can be allocated 'spot' colour from RGB or HEX codes.

Your Flexible designs may also be printed in colour, selecting spot colours from a pallet of which depends on the selected Shore A value of the print. 3D-Prints with a low Shore A value (i.e. softer) are paler and less vivid then those with a higher Shore A (i.e. harder).

Flexible and Rigid design elements may be mixed in the same build. 

 

 

Matt or Gloss finishes:

When setting up a polyjet 3D build you have the option of choosing a Matt or Gloss finish. By default we choose Matt as it gives a uniform finish to your part.

The Gloss setting will attempt to give your design a smooth shiny finish, similar to an injection moulding produced part. However the final result depends very much on your design. A fully gloss finish is impossible as some surfaces will always be be Matt, where surfaces are in contact with support material or the base plate.

 

"Off the Machine" and "Post Processing":

That title is a little misleading. 3D prints off the machine always need support material removing so are always subject to a little Post Processing.

For translucent designs or full high gloss finishes, for example automotive light lenses, your designs will require additional hand finishing with fine grades of Wet and Dry and a clear gloss lacquer coat. Translucent designs will need both the inside and outside surfaces polishing and needless to say, the more complex the design the harder and more time consuming this process is.

For some designs Vac Casting can be a good alternative solution.

Where the technology shines:

For 3D printing figures, scans and visualisations in spot or full colour. 3D printed Rubber Like designs in spot colour. Visualisation models.

 

 

Where the technology is still developing:

3D Printed "Off the machine" photography and display models with high gloss, uniform finishes. Models where colour accuracy is critical.  For these applications extra post processing may be required,  assuming an acceptable build is possible to produce with the technology. 

 

 

Don't forget that we also 3d print ABS and ASA materials from a range of colour filaments which offers you lower cost and more durable builds in a spot colour.