Getting a colourful end result with your next FDM part

FDM lends itself very well to colour printing, as there are wide range of coloured filaments available to choose from. This means that for single-colour prints, it’s usually just a question of picking a filament in the right colour, with the desired mechanical properties.

But what if you want something more sophisticated? Perhaps your design is an attractive display piece, and you’d like to accurately capture the colours of your 3D model in the printed version. Perhaps it’s a functional prototype where you’d like to colour-code the individual components for demonstration purposes. Regardless, there’s good news: recent advances in FDM printing means that there are several options for achieving eye-catching, multi-colour results. Let’s look at those options in detail…

Printing in full colour vs. post-processing

If you’re aiming for a striking, multi-colour FDM print, you should decide at the beginning of your project whether to colour your part during the post-processing stage, or to take advantage of new technology that allows for actual printing in full colour. While the latter certainly represents an attractive time-saver, full-colour FDM is still a relatively new technology that will require a specialist printer, or outsourcing the project to a specialist. If this will not prove practical, you might consider printing each colour as a separate component, then gluing them together, although this will mean factoring another post-processing stage into your project timelines.

If you are looking to blend your colours, a specialist printer — such as 3D Systems’ Pro-Cube C — will be required. However, for really sophisticated colouring applications like this, it’s still hard to beat finishing by hand.

Painting your part by hand

Most of the painting approaches used for other 3D printing technologies can be applied to FDM prints relatively easily. To begin with, make sure your part has been properly cleaned and finished before priming to ensure a good result.

We would recommend investing in an airbrush for painting FDM prints, as this will ensure a smooth, even finish. Even if you have sanded, bead-blasted or tumbled your part to remove any visible layers, it’s possible that painting will cause them to become visible, particularly if your paints are too thin. Airbrushing helps avoid this. Use acrylic paints, and build up your colours in several thin layers, letting each one dry for 30 minutes before applying the next.

Once your paints have fully dried, a layer of epoxy will keep them looking bright and new for longer (although you may wish to factor this last layer into your part dimensions, if they need the be completely precise).

The perfect time to explore coloured FDM printing

If you have ever considered creating full-colour parts, whether it’s for prototyping or production, but dismissed the idea as too time-consuming or expensive, now is the perfect time to revisit it. With the range of techniques and technologies now available, it’s more straightforward than ever to create a unique, attractive result for your next print.