Xometry, an on-demand manufacturing and 3D printing service provider founded in 2014, is advancing manufacturing in the US with its proprietary machine learning-based software platform. This platform, which offers multiple on-demand manufacturing services, from urethane casting and sheet metal fabrication to CNC machining, injection molding, and 3D printing, makes it easy for product engineers to streamline parts ordering, lead times, and manufacturability feedback.
The company also offers dozens of 3D printable polymers, which can be instantly priced on its website once a CAD file has been uploaded. Recently, the company decided to test the strength and durability of several of its polymers in an athletic experiment.
Greg Paulsen, the Director of Applications Engineering at Xometry, asked, “What better way to see how parts perform than putting many together, to the test, under the same environment?”
Sometimes, the best way to test how durable materials are is by throwing them against a wall. A Xometry blog post revealed that the company recently decided to test the durability and impact resistance of some of their materials – nine, to be exact – by pitting them against each other in a “high-velocity impact lacrosse experiment” to see if they would bounce or break apart.
“So we just happen to have a concrete wall outside, and we’re going to honor the spring season of Maryland here by choosing lacrosse as our equipment for testing these parts out,” Paulsen said.
Nine lacrosse balls were 3D printed for the experiment, using three different technologies – selective laser sintering (SLS), fused deposition modeling (FDM), and PolyJet. Paulsen explained that he expected the more rigid materials, like polycarbonate and rigid PolyJet, to chip, and that the ABS-M30 ultralight ball would dent. But he figured the rest would “be able to hold their own.”
SLS was used to make two balls – one was 3D printed using unfilled Nylon 12, dyed green, and hypothesized to stay in one piece, while a white ball was fabricated using glass-filled Nylon 12 which could chip. Both of these balls behaved as expected – due to the strong, tough materials used to 3D print them, the balls both bounced and neither broke.
Five lacrosse balls were 3D printed using FDM technology. Paulsen believed that the blue ABS-M30 with solid infill, the solid black Nylon 12, and the tan, solid Ultem 9085 balls would not break, while, as previously mentioned, the white polycarbonate ball would likely chip and the red ABS-M30 ultralight ball would dent, or even break.
The only difference between the ABS balls was the infill, and while a sparse infill made the ball look the same as the one with a solid infill, the mechanical strength was just not there, and the head of the ball popped clean off because, as Paulsen put it, “energy has to go somewhere.”
The solid Ultem 9085, just like the other high-performance plastics that Xometry offers, is “a beast.”
“It really should survive this, and it definitely did show off that,” Paulsen said when the ball did not break.
The solid polycarbonate ball surprised Paulsen. While he expected it to snap or break, it managed to stay in one piece, even with the high force of the ball’s ricochet off the concrete wall. But the solid Nylon 12, which split in two, surprised him even more, because he figured it would hold up better.
“At some point along the way we must’ve hit it just right at the right angle, right on that lamination, and it split and bounced off in two directions,” he said.
Contours on the inside of the ball were able to confirm that the layers held, so Paulsen theorized that a weak spot in the ball must have caused it to split into pieces.
The final two balls were 3D printed using PolyJet technology – a rigid, gray multi-material one that was expected to chip or shatter, and a gray, rubber-like, Shore A 50 ball, which Paulsen figured would experience some tearing. The multi-material ball endured lots of internal cracking on the first hit, and “broke beautifully” on the second, which was not surprising, as the impact resistance is nowhere near what thermoplastics can offer.
Paulsen referred to the Shore A 50 ball as the wild card, and it impressed him after absorbing the energy from the hit and transforming into a still intact, but “squished egg” type of shape.
“At Xometry we know that your project has unique applications and unique needs,” Paulsen said at the conclusion of the experiment. “That’s why we offer so many different materials, processes, and finishes.”
To watch the full off-the-wall experiment for yourself, check out the video below:
Discuss this and other 3D printing topics at 3DPrintBoard.com or share your thoughts below.[Images/video: Xometry]