The speed of additive manufacturing (3D printing) may be accelerated thanks to MIT engineers, who have developed a new desktop 3D printer which is up to 10 times faster than existing commercial versions.
Most common 3D printers are able to fabricate at a rate of about 20 cubic centimetres in an hour, but the new MIT-engineered unit is able to print similarly-sized objects in just a few minutes.
The team managed to accelerate 3D printing thanks to innovations in the printer’s compact printhead, which incorporates two new, speed-enhancing components. Firstly, they added a screw mechanism that feeds polymer material through a nozzle at high force. Secondly, the printhead integrates a laser which rapidly heats and melts the material, letting it flow faster through the nozzle.
The team demonstrated the new 3D printer by printing various detailed, handheld 3D objects, including small eyeglasses frames and a bevel gear. The printer was able to complete the prints within several minutes.
According to Anastasios John Hart, associate professor of mechanical engineering at MIT, this development opens up the door for 3D printing to become a more viable production technique, especially for applications that require more than a few copies of parts, or for product engineers looking to iterate designs quickly.
“If I can get a prototype part, maybe a bracket or a gear, in five to 10 minutes rather than an hour, or a bigger part over my lunch break rather than the next day, I can engineer, build, and test faster,” Professor Hart explained.
Similarly repair technicians may install fast 3D printers in their vehicles, allowing them to 3D print a repair part on-demand, on-site, rather than having to source parts from a warehouse.
The MIT advancements originated from previous work, where the researchers identified the underlying causes limiting the speed of the most common desktop 3D printers, which extrude plastic, layer by layer. They found the printers were limited in speed due to the speed of the printhead, the amount of force the printhead is able to apply to push material through the nozzle, and the speed with which the printhead can transfer heat to melt a material and make it flow.
In most desktop 3-D printers, plastic is fed through a nozzle via a “pinch-wheel” mechanism, where the plastic filament is advanced between two small rotating wheels. While this works well at relatively slow speeds, increasing the force and speed causes the wheels to lose their grip on the material, an inherent engineering limitation on the speed with which the plastic can be pushed through.
The MIT researchers replaced the pinch-wheel mechanism with a screw mechanism that turns within the printhead. The screw turns and grips onto the plastic filament’s textured surface, feeding it through the nozzle at higher forces and speeds.
Downstream from the screw mechanism, a laser heats and melts the filament before it passes through the nozzle. With a laser, the plastic is more quickly and thoroughly melted, compared with conventional 3D printers, which use conduction to heat the walls of the nozzle to melt the extruding plastic. The heating can also be adjusted by tweaking the laser’s power.
Finally, a high-speed gantry system connected to a motion stage that holds the printhead allows the printhead to move nimbly between multiple positions and planes, thus allowing the printhead to move fast enough to keep up with the faster plastic feed.