Desktop 3D printing has fostered many rapidly growing industries, but until recently, 3D printed objects were limited to monochrome.
At Ultimaker, we strive to push the limits 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 different 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 below:
Mellan's "The Sudarium" was hand-drawn using hatching techniques.
In his co-authored research paper, Kuipers explains about linear halftoning: "by printing small patterns of discrete colors to create the perception of continuous tones."
Following the principle of hatching, linear halftoning creates both black and white lines of varying thickness, giving the viewer the appearance of a grayscale image, 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 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 in comparison to the white, making the black more prominent and the 3D print appear darker in that area, while the white
makes it brighter.
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 of printing in only two colors. 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 who combine 3D scanning with 3D printing can create physical models of scanned people or objects.
Printed grayscale bust of Tim Kuipers. Large patches of similar colors show This method can achieve small, high-contrast details, which is particularly effective for sculptures and models.
the functionality of this method.
Aside from precise X/Y axis calibration, the Ultimaker 3 used for the experiment did not require any hardware modifications to achieve these results. Compared to monochrome printing, the grayscale printing time also increased by a moderate amount, up to 20%.
Full-color printing?
In the future, if more than two extruders are used to print dark blue, red, and yellow alongside black and white filament, it may be possible to create full-color prints similar to the 3D hatching technique.
At Ultimaker, we plan to add halftoning functionality directly 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