Open Source, Powder-Based 3-D Printer Has Full-Color Potential

PWDR is an open source, inkjet-based 3-D printer that has the potential to bring a Wizard of Oz-like range of color to the previously black and white world of additive fabrication.
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PWDR doesn't look fancy, but it could be the first technicolor tool for 3-D printing.

PWDR is an open source, inkjet-based 3-D printer that has the potential to bring a *Wizard of Oz-*like range of color to the previously black and white world of additive fabrication.

Unlike the MakerBot and RepRap printers that build objects by melting plastic, or the Form 1 that uses a laser to cure resin, PWDR works just like a desktop printer. An HP inkjet deposits a liquid binder, mixed with ink, onto a layer of white gypsum powder. After the printhead passes, a roller bar drags a thin layer of powder across the surface and the process repeats a couple hundred, or thousand, times.

When completed, the printer looks like a fish tank full of baby powder and the model needs to be carefully removed, dusted off, and dipped in clear glue that infiltrates the part and solidifies it. This process is essentially the same as what ZCorp 3-D printers offer and opens the potential for hobbyists to create models featuring thousands of colors using a CMYK process, not the two or three offered by newer home user systems.

PWDR was developed by Alex Budding, a mechanical engineering student at the University of Twente in Singapore. "There were quite a few open source 3-D printers around, but a powder-based process was missing from the line," says Budding. "And there was a specific application for the machine in the area of ceramic materials."

The $1,400 printer is long on potential, but is currently short on polychromatic goodness. The code on Github is only capable of controlling a single color cartridge. "Full color printing needs a full color head." says Budding. "But the control of more modern, color heads is unknown and have to be reverse engineered. And for me, this is a research project, so the color is no concern." In short, if someone wants to print a full color version of their Minecraft model on the cheap, there will be a little hacking required.

While it lacks full color capabilities out of the box, the machine's mechanical stats are solid:

  • Maximum build size: 125mm x 125mm x 125mm (117 cubic inches compared to 156 for the Form 1 and 410 for the Replicator 2)
  • Minimum vertical step size: 50 microns (25 microns for the Form 1 and 100 microns for the Replicator 2)
  • Speed: ±1 minute per layer, but varies based on complexity
  • Print resolution: 96 DPI

Also, a word of warning to entrepreneurial readers: Budding claims that the core patents on this technology expired in 2010, but 3D Systems, ZCorp's parent company, has recently flexed its legal muscles to defend other disputed patents, so perhaps consult a patent attorney before putting a model on Kickstarter.

For the really adventurous the machine has another option – replacing the inkjet with a laser turns the system into a selective laser sintering (SLS) tool. "A whole new range of materials become available for experimenting with open-source rapid-prototyping; for example, when using the 3-D printing process: gypsum, ceramics, concrete, sugar, etc," says Budding. "And when the SLS process is fully supported, plastic materials like ABS, Polypropylene, Nylon and metals become available as building material." This mod will require a lot of work both in finding materials and tuning a laser, but could dramatically alter the world of 3-D printing.

PWDR is just the beginning and Budding urges potential contributors to the project to look beyond its plain acrylic enclosure and think about the big, multicolor picture. "I don't think tinkering on the machine is the important bit," says Budding. "Sure, there is always something to improve; a better inkjet head, trays for excess powder or a nice LED display. All pretty nice, but the main reason to release the project open source is to enable other to use the machine for research purposes. New materials, new printing algorithms, new applications for printed product."