A group of researchers have developed a 3D printer that has the capability of printing a part bigger than itself. The ‘Koala 3D’ was developed at the university of Chile and although it isn’t as cute as it’s Australian counterpart it does have the ability to climb, being part climbing robot part 3D printer.
The researcher explain in their paper that traditional manufacturing limits the size of parts being produced. “For example, while a plastic injection molding machine usually occupies various cubic meters, it produces parts that are considerably smaller than itself, somewhere between several cubic centimeters. Similar situations arise with subtractive manufacturing machines, such as mills, lathes, and their CNC counterparts,” the authors write in the paper.
Additive manufacturing on the other hand can produce parts closer to its size, and with the addition of the Koala 3D navigating vertically we are a step closer to creating 3D printers that could fabricate objects much larger than themselves.
The Koala is two major parts: the print head and the climbing robot. The print head does exactly what a print head should do, print. The climbing robot is devised of robotically actuated clamps on the lower part of the machine, and a clamp that can move between the top and bottom of the machine. To enable an infinite range of motion, the researchers ensured that a clamp always remained attached to the beam, while the other clamp proceeded to find a new anchoring point, resulting in a repeated process of ‘printing-reanchoring-printing-reanchoring.’
“The printer can be decomposed into two major subsystems. One is the vertical climbing stage for reanchoring, precise vertical motion during printing, as well as carrying the electronics,” the authors explain. “The other subsystem is the x-y positioning stage for moving the printer extruder. This stage also carries the material impulsion system.”
The team designed the printer to cover a range of motion of 45mm x 45mm on the yx plane with the aim of producing vertical beams with a sectional area of 30mm x 30mm with this motion span. Explaining the reason behind the larger motion span, the researchers state that “The extra motion span (50% larger on every dimension) was intended to allow the extruder to purge outside the printing area as well as potentially introduce some features on the surface of the produced beam.”
The team tested the system by printing 11 vertical beams ranging from 350mm to 850mm to evaluate the printing-reanchoring-printing scheme. Discussing the implications of their successful demonstration, the researchers posit potential future research and applications in construction and product development industries, as well as three problems they encountered in creating the Koala 3D climbing printer: ”The problems are (1) the machine drop after reanchoring, (2) the structural oscillation at high aspect ratios, and (3) the initial alignment between part and base. Addressing these problems will be important in developing autonomous machines that can climb along the same structures they produce.”
Essop, Anas, et al. “Koala 3D: Chilean Researchers Investigate Climbing 3D Printer.” 3D Printing Industry, 30 Mar. 2020, 3dprintingindustry.com/news/koala-3d-chilean-researchers-investigate-climbing-3d-printer-170424/.