Desktop 3D printing has contributed to the rapid growth of many industries, but until recently, 3D printed objects were limited to monochrome.
At Ultimaker, we strive to push the boundaries of desktop 3D printing applications: in collaboration with Delft University of Technology,
one of our engineers has developed a technique for grayscale printing using the Ultimaker 3. This method allows users to print objects with two
colors and varying shades.
Linear Halftoning
Tim Kuipers has used a technique called linear halftoning to generate 3D objects with full grayscale images. The principle of halftoning is not a new concept
; it actually dates back to the 17th century.
The effect is shown in the image below:
Mellan's "The Sudarium" was hand-drawn using the hatching technique.
In his co-authored research paper, Kuipers explains linear halftoning as "creating the sensation of continuous tones by printing small patterns of discrete colors."
Following the principle of hatching, linear halftoning is used to create black and white lines with varying thickness, giving the viewer the appearance of grayscale imagery, while in fact,
the object consists of simple black and white lines.
Leveraging the dual extrusion capabilities of the Ultimaker 3, Kuipers was able to create the black and white lines that resulted in grayscale objects.
He further explains: "Full layers are printed with either white or black filament, and at every layer, the printer alternates between printing black and white filament. The apparent grayscale tone
is achieved by exposing more or less of the black filament relative to the white filament, making the black more prominent, which makes the 3D print appear darker in that area, while white
makes it lighter.
Applications
This grayscale printing technique has applications in several areas.In prototyping, linear halftoning can be used as a design feature in developing conceptual models, as it is not limited
to printing using a discrete set of colors.Alternatively, for manufacturing, it can be used to communicate technical details on the printed object.
For instance, it can be used to identify how fragile different areas of a fabricated tool are by showing various intensities of blackness.
Grayscale can Grayscale rod
As a design feature, grayscale printing can be used to allow for more variation, as there is no limitation to printing in two colors only. Grayscale printing can be used to visualize technical information on a printed object, e.g.
,which parts are more fragile than others.
There are also more artistic applications: compared to single-color printing, objects printed in grayscale can enhance depth, definition, and realism.
Users combining 3D scanning with 3D printing can create physical models of scanned people or objects.
A grayscale print of Tim Kuipers' bust. Large patches of similar colors show This method enables small, high-contrast details, which are particularly effective for sculptures and models.
the functionality of this method.
In addition to precise X/Y axis calibration, the Ultimaker 3 used for the experiment did not require any hardware modification to achieve these results. The grayscale printing time
also increased by a moderate amount, up to 20%, compared to single-color printing.
Full-Color Printing?
In the future, if more than two extruders are used to print dark blue, red, and yellow alongside black and white filaments, it may be possible to create full-color prints similar to the 3D hatching
technique.
At Ultimaker, we plan to directly add halftoning functionality to Cura so that users can input pre-colored files and create their own grayscale objects.
Article source: https://ultimaker.com/en/blog/49783-3d-hatching-grayscale-printing-on-the-ultimaker-3