MobiPrint Hits the Ground Printing

What do you get when you cross a 3D printer with a robotic vacuum? Believe it or not, that is not the lead-in to a joke, but is actually more or less an accurate description of a real, mobile fabrication platform called MobiPrint. Developed by researchers at the University of Washington, MobiPrint is a robot that can autonomously map out a room, then it fabricates 3D-printed objects in place, as directed via a companion web app.

But why in the world would anyone want a 3D printer that drives itself around? Well, think about the limitations of existing printers. They have print beds of a fixed size, which means that the print volume is restricted. Larger prints need to be broken into pieces, which then require post assembly steps — or alternatively, one must purchase a more expensive printer. Moreover, as prints are moved from the print bed to their desired locations in the environment, it may turn out that their size or shape is not quite right. In these cases, multiple iterations of a design may need to be printed. A mobile fabrication platform like MobiPrint has the potential to overcome these challenges.

MobiPrint is built around a Roborock S5 vacuum robot that had the cleaning components removed. The team rooted the robot (naughty, naughty!) and installed open-source firmware called Valetudo as a replacement. This gave them control over the onboard LiDAR scanner, as well as the ability to read the robot’s state and send control signals to trigger movement.

A Prusa Mini+ 3D printer was mounted on top of the robot to add its fabrication capabilities. The mechanical structure of the robot was altered such that it could extend away from the robot, and also reach down to the level of the floor. The stock control board was replaced by the Duet3 Mini 5+ Wi-Fi-enabled control board that can run on battery power. Finally, a 12 volt 7 amp-hour rechargeable battery was added to the device to enable three to four hours of operation.

To highlight the versatility of the system, the team showed how it can be used for a number of real-world applications. In the area of accessibility, MobiPrint can streamline the production and integration of tactile surface indicators, which help people who are blind or have low vision navigate spaces safely by signaling hazards like stairs or guiding them towards entranceways. Traditional methods to install these indicators can be costly and complex, often involving embedding or casting materials directly into cement.

In home furnishing, MobiPrint may prove useful for creating custom household items tailored to fit specific spaces and needs. For instance, an ergonomic footrest can be printed at an exact height under a work desk, or a pet feeding bowl can be adjusted in size as the pet grows. This capability to fabricate items on demand, precisely where they are needed, minimizes the need for measurements and manual placement.

The mobility of MobiPrint does come at a price, however. It is not as stable as a fixed-position printer, so some vibrations will be experienced during the print, which decreases the quality and accuracy of the objects it produces. This issue may be fixed in the future by adding reinforcements to the device. But even with that fix, the printer will still be limited in the types of materials it can work with — since it prints directly on the floor, a heated bed is not available. MobiPrint will not be the right tool for every job, but in the right situations, it could offer up a lot of convenience.