Now that 3D printers and the process itself are becoming more standard, researchers are searching for ways to fine-tune the intricacies of how this type of printing works.
Improving speed is one key area of focus--and the subject of new research from scientists at MIT, who have developed a new desktop 3D printer that performs up to 10 times faster than existing commercial counterparts.
Key to the printer’s design—by a team in MIT’s Laboratory for Manufacturing and Productivity—is a compact printer head that enhances speed in common processes. As a point of comparison, the machine can print a few Lego-sized bricks in a few minutes, a fraction of the time conventional printers would take, according to researchers.
A collection of objects and test samples printed on a new, ultra-fast 3D printer recently developed at MIT, including a miniature chair, simplified model of Building 10 at MIT, eyeglasses frames, a spiral cup, and a helical bevel gear. Researchers there developed the printer, which is 10 times faster than typical 3D printers in use today. (Source: Chelsea Turner)
This type of speed will change the game for how useful 3D printing can be for a design and production, and on its overall adoption commercially, said Anastasios John Hart, associate professor of mechanical engineering at MIT.
“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,” Hart, who also is director for the lab as well as MIT’s Mechanosynthesis Group, said. “If I’m a repair technician and I could have a fast 3D printer in my vehicle, I could 3D-print a repair part on-demand after I figure out what’s broken. I don’t have to go to a warehouse and take it out of inventory.”
Researchers published a paper on their work in the journal Additive Manufacturing.
While researchers at the University of Michigan used an algorithm targeting the stability of the printing process to help speed it up, MIT researchers focused on something else—the design of a compact print head, they said.
The design allowed for the inclusion of two new, speed-enhancing components: a screw mechanism that feeds polymer material through a nozzle at high force, and a laser built into the print head that rapidly heats and melts the material, allowing it to flow faster through the nozzle.
The team based its design on previous research identifying several factors limiting the speed of current 3D printers: how fast a printer can move its print head, how much force that part can apply to a material to push it through the nozzle, and how quickly the print head can transfer heat to melt a material and make it flow.
“Then, given our understanding of what limits those three variables, we asked how do we design a new printer ourselves that can improve all three in one system,” Hart explained. “And now we’ve built it, and it works quite well.”
The new printer eliminates the common way plastic is fed through a nozzle in typical 3D printers, which is through a “pinch-wheel” system. The system is comprised of two small wheels within the print head that rotate and push the plastic, or filament, forward.
While this works well at slower speeds, a faster process eventually would cause the wheels to lose their grip on the material, thus creating a “mechanical disadvantage” limiting how fast the print head can push material through, Hart said.
With the screw mechanism that turns within the print head Hart and his team included in the new design, the printer can feed plastic through the nozzle at higher forces and speeds.
“We have a lot more contact area with the threaded texture on the filament,” he said. “Therefore, we can get a much higher driving force, easily 10 times greater force.”
The laser—which the team added in the design downstream of the screw mechanism--heats and melts the filament before it passes through the nozzle. In this way, it more quickly and thoroughly melts the plastic compared with conventional 3-D printers.
There is one key glitch in the design, however, which the team discovered during testing. Because the plastic is fed through the nozzle at such high forces and temperatures, a printed layer can still be slightly molten by the time the printer is extruding a second layer.
“We found that when you finish one layer and go back to begin the next layer, the previous layer is still a little too hot,” Hart explained. “So, we have to cool the part actively as it prints, to retain the shape of the part so it doesn’t get distorted or soften.”
Researchers are attempting to fix this problem as well as explore other types of materials aside from plastic they can use with the machine, he added.
Elizabeth Montalbano is a freelance writer who has written about technology and culture for more than 15 years.