Painting vs. Dyeing: Which Coloring Method to Choose for 3D Printing?

A wide variety of technologies can be found in the field of additive manufacturing including those able to directly 3D print parts in color. However, this is not the cast for all and most of them tend to create parts in a standard color and then color must be applied during post-processing. In fact, in many industries and applications, such as consumer goods, having colored parts can be an essential feature of final products. Therefore, implementing post-processing techniques that can apply color to newly printed models can greatly facilitate manufacturing processes. Two of the most widely used methods in 3D printing are painting and dyeing.

Although at first glance they may seem very similar, the truth is that, depending on the additive manufacturing technology used, materials and end uses, it will be more appropriate to use one or the other. It is worth mentioning again that there are some 3D printing technologies that allow you to create multicolor parts directly in the manufacturing process. These methods include material jetting (injection of material in the form of resin), binder jetting (injection of colored binder), and filament multiextrusion (printers with two heads that exchange materials). For all other polymer technologies, additional steps will be required to apply color to the final parts. To better understand the differences between dyeing and coating, here is a comparison of the two processes, with a focus on polymeric materials.

Painting (left) and dyeing (right) are common ways to color parts in post-processing for 3D printing

How Do Painting and Dyeing Compare?

Painting

Painting refers to the coloring of parts by applying acrylic paints or enamels. Depending on the final application of the part to be painted, one will opt for manual or automated painting. In any case, the process involves several steps, which take over in the last post-processing stage: application of a primer to prepare the surface, base coat (color) and finally clear coat (clear enamel) to protect the finished part. As for the manual process, although painting with brushes is possible, the most popular, even at the professional level, is spray painting since it allows for more uniform coloring.