3D printing is a relatively slow process. The “rapid” part of “rapid prototyping” comes from the speed at which users can start print jobs. Traditional manufacturing methods, like injection molding, require huge time and money investments to setup. But one can start a 3D print within a few minutes of finishing a CAD model and that makes the printing process — which can take several hours or even days — worthwhile. Even so, the 3D printing community would benefit from advancements that improve print speed. This new multi-nozzle 3D printing technique developed by engineers from Rutgers University promises to dramatically increase print throughput.
3D printing enthusiasts know that multi-extruder FFF (fused-filament fabrication) printers already exist. Those utilize two or more “print heads” to print in multiple materials or duplicate parts. From a speed standpoint, their ability to print two parts simultaneously is very attractive. But even IDEX (independent dual extruder) models have a serious limitation: the two print heads ride on the same rail (usually the X axis). Because they can’t move independently in the Y axis, they are really only suitable for printing duplicate or mirrored parts. Printing two unique parts would defeat the purpose, as each print head would have to work consecutively instead of simultaneously.
This new process uses sophisticated g-code generation algorithms to solve that problem. The printer’s gantry contains several small hot end nozzles and those do not move independently. Instead, they move as a group while only extruding when necessary. That is efficient because the slicer software orients the parts and toolpaths to combine movements as much as possible. For example, two parts might both have long straight surfaces. In that case, the slicer software would line those surfaces up so that two nozzles could print those surfaces simultaneously.
By applying that concept to the several parts and several nozzles, the slicer software is able to create efficient toolpaths that keep as many nozzles simultaneously extruding as possible. This doesn’t speed up the print time for any individual part—a single part takes longer than it would on a traditional 3D printer. But it does dramatically improve throughput. Because this process can produce several parts at once, the average per-part print time is very short.
Of course, MSLA (masked stereolithography) resin 3D printers already achieve something similar. They cure the entire layer at once and the per-layer time stays the same no matter how much area the layer covers. An MSLA 3D printer completes 10 parts of equal height in the same amount of time as a single part.
The advantage of this new process from Rutgers is that it works with standard thermoplastic filament. MSLA printers can only work with UV-curable resin, which isn’t ideal for every application. This new process works with any filament, which means that users could take advantage of the wide range of available materials.