A 3D printing system that allows designs to be altered after the printing process has already begun could improve the prototyping process for designers.
3D printing is commonly used for ‘rapid prototyping’ by quickly creating a physical copy of a proposed design, eschewing the need for processes normally only found in industrial facilities.
The new 3D printing system uses an improved version of an innovative ‘WirePrint’ printer developed at the Hasso Platner Institute in Potsdam, Germany.
In conventional 3D printing, a nozzle scans across a stage depositing drops of plastic, rising slightly after each pass to build an object in a series of layers.
The WirePrint technique uses the nozzle to extrude a rope of quick-hardening plastic to create a wire frame that represents the surface of the solid object described in a computer-aided design (CAD) file.
WirePrint aimed to speed prototyping by creating a model of the shape of an object instead of printing the entire solid. The on-the-fly-print system further builds on that idea by allowing the designer to make refinements while printing is in progress.
The printer has ‘five degrees of freedom’ with the nozzle able to work vertically, and the ability to rotate what has already been printed to present any face of the model facing up.
This could allow an aeroplane fuselage to be turned on its side to add a wing for example. There is also a cutter to remove parts of the model, such as to give the aircraft a cockpit.
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.
Researchers from Cornell University in New York have further adapted WirePrint to allow for an interactive prototyping system that prints what you are designing as you design it.
The designer can pause anywhere in the process to test, measure and, if necessary, make changes that will be added to the physical model still in the printer.
The software, a plug-in to a popular CAD program, 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, but will resume when that work is done, incorporating the changes into the print.
As a demonstration the researchers created a model for a toy aeroplane to fit into a Lego airport set. This required adding wings, cutting out a cockpit for a Lego pilot and frequently removing the model to see if the wingspan is right to fit on the runway. The entire project was completed in just 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."
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