The Cornell researchers’ system uses an improved version of a ‘WirePrint’ printer developed in a collaboration between Cornell’s Department of Computer Science and the Hasso Plattner Institute in Potsdam, Germany.
In the WirePrint technique the nozzle extrudes a rope of quick-hardening plastic to create a wire frame that represents the surface, instead of printing the entire solid. The On-the-Fly-Print system builds on that idea by allowing the designer to make refinements while printing is in progress.
The new version of the printer has ‘five degrees of freedom’. The nozzle can only work vertically, but the printer's stage can be rotated to present any face of the model facing up. There is also a cutter to remove parts of the model.
The nozzle has been extended so it can reach through the wire mesh to make changes inside. A removable base aligned by magnets allows the operator to take the model out of the printer to measure or test to see if it fits where it's supposed to go, then replace it in the precise original location to resume printing.
The software designs the wire frame and sends instructions to the printer, allowing for interruptions. The designer can concentrate on the digital model and let the software control the printer. Printing can continue while the designer works on the CAD file, incorporating any changes into the print.
As a demonstration the researchers created a model for a toy airplane (pictured) to fit into a model airport set. This required adding wings, cutting out a cockpit and frequently removing the model to see if the wingspan is right to fit on the runway. According to the researchers, the entire project was completed in 10 minutes.
By creating a “low-fidelity sketch” of what the finished product will look like and allowing the designer to redraw it as it develops, the researchers said: “We believe that this approach has the potential to improve the overall quality of the design process.”
