It can lead to interesting multi-piece objects you don't need to glue together

Jul 24, 2014 14:51 GMT  ·  By

So far, we haven't heard of any 3D printer that can work on more than one object at a time, or see any form of success if you leave something by mistake on the build plate before you click or press on the so-called start button.

A group of three students from the Massachusetts Institute of Technology decided that something really had to be done about this. And no, they aren't the same students who revealed the Ice Cream 3D printer last week.

The 3D printer we're about to cover was developed by Claudio V. Di Leo, Louise E. van den Heuvel, and Sumant S. Raykar.

They did not just want a 3D printer. They wanted a 3D printing system that could scan objects as well, detecting the placement and orientation of an object already located on the print bed.

This ability would not only allow the printer to print a second object on the first, but also resume a print job after it was interrupted by a power failure or whatever other reason.

They started from a Solidoodle 3D printer but had to create the scanner themselves. Fortunately, they were able to do it with off-the-shelf parts, specifically a line laser and a camera.

Said scanner projects a laser onto the build platform. If the laser becomes distorted, it will tell the printer that there is an object on the platform. The camera then takes a photo of the distortion, which is then used to reconstruct the height of the object at the points where the laser is hitting it.

That done, the printhead (to which the laser is attached) moves the laser to a new location, to make another scan. This repeats until the laser has moved over the whole area of interest, at which point the scan is complete by analyzing all the photos taken during the process. The laser is an Infiniter VLM-650-27, and the camera is a Logitech B905 2MP Webcam.

The hardest part was making sure that the plane formed by the laser was perpendicular to the print bed. If the laser was even slightly tilted, the measurements would have been too inaccurate for the whole “print on top of existing object” goal to be attained.

They did succeed though, by printing a 90 degree laser holder, then taping it to the print head (which always remains parallel to the print bed).

The best part about this invention is that it can be applied to many 3D printers, not just Solidoodle's, with a bit of tinkering. All for under $60 / €44 ($26 / €19.3 for the laser, $30 / €22 for the camera).

To prove that everything works, the MIT students printed a block of plastic over an incomplete pyramid. The processing was done in Matlab though, so you will need to acquire it if you want to give your own 3D printer this capability.

Finally, besides printing on top of existing objects, the scanner could be used to periodically inspect print jobs, calibrate the 3D printer for different things (homing the z-coordinate, leveling the print bed) and even embed electronic of functional parts into a print (though this would need engineers to develop tool paths that would avoid collision with the foreign object).

Scanner enhances Solidoodle 3D Printer (6 Images)

Solidoodle 3D printer gains extra skills
Solidoodle 3D printer gains extra skillsSolidoodle 3D printer gains extra skills
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