Software and multiple nozzles bring down cost of 3D printed parts

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Large and complex 3D printed parts can be produced at a fraction of the cost of current methods with a new approach developed by engineers at Rutgers University.

Parts printed with the MF3 prototype using a 0.4mm diameter nozzle
Parts printed with the MF3 prototype using a 0.4mm diameter nozzle - Rutgers University

The new approach - Multiplexed Fused Filament Fabrication (MF3) - uses a single gantry to print individual or multiple parts simultaneously. By programming their prototype to move in efficient patterns, and by using a series of small nozzles to deposit molten material, the researchers were able to increase printing resolution and size as well as significantly decrease printing time.

“MF3 will change how thermo-plastic printing is done,” said Jeremy Cleeman, a graduate student researcher at the Rutgers School of Engineering and the lead author of the study. The team has applied for a US patent for their technology, which is detailed in Additive Manufacturing.

According to Rutgers, the 3D-printing industry has struggled with throughput-resolution trade-off, which is the speed at which 3D printers deposit material versus the resolution of the finished product. Larger-diameter nozzles are faster than smaller ones but generate more ridges and contours that must be smoothed out later, adding post-production costs.

By contrast, smaller nozzles deposit material with greater resolution, but current methods with conventional software are too slow to be cost effective.

To program a 3D printer, engineers use a slicer, which is computer code that maps an object into the virtual ‘slices,’ or layers, that will be printed.

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Rutgers researchers wrote slicer software that optimised the gantry arm’s movement and determined when the nozzles should be turned on and off to achieve the highest efficiency. MF3’s new toolpath strategy makes it possible to ‘concurrently print multiple, geometrically distinct, non-contiguous parts of varying sizes’ using a single printer, the researchers wrote in their study.

Cleeman said he sees numerous benefits to this technology; the hardware used in MF3 can be purchased off the shelf and does not need to be customised. Additionally, because the nozzles can be turned on and off independently, an MF3 printer has built-in resiliency, making it less prone to costly downtime, Cleeman said. When a nozzle fails in a conventional printer, the printing process must be halted but in MF3 printing, the work of a malfunctioning nozzle can be assumed by another nozzle on the same arm.

As 3D printing increases – for manufacturing and particularly for the prototyping of new products – resolving the throughput-resolution trade-off is essential, said Cleeman, adding that MF3 is a major contribution to this effort.

“We have more tests to run to understand the strength and geometric potential of the parts we can make, but as long as those elements are there, we believe this could be a game changer for the industry,” said Cleeman.