3D-printed Benchy – After experimenting for two years, Jan Roetz has pushed a 3D printer to produce a Benchy—normally used for calibration—within 59 seconds. The breakthrough came from removing inertia bottlenecks, boosting extrusion and cooling capacity, and redesigning the moti
In 2024, Jan Roetz started with a simple dare: could a 3D printer make a Benchy— the boat-shaped calibration benchmark— in less than one minute? Two years of experiments followed, and on the final push, he finally broke the one-minute mark.
The project’s constraints were clear from the start: the speed of extrusion, how quickly the printed plastic could cool, and how fast the motion system could move without falling apart. Roetz narrowed the hard limits down to three primary factors, then attacked the last one first.
On the extrusion side. his hotend combines four strands of filament in one hotend and can extrude about 400 cubic millimeters of plastic per second. For cooling, an air duct around the nozzle could deliver about 400 liters of air per minute. With those targets in place, the motion system became the bottleneck.
Roetz’s original setup used a print bed mounted on an air bearing on top of a granite base. The bed’s movement was controlled using cords connected to stepper motors, and the friction was extremely low. The problem wasn’t resistance—it was inertia. To fix it, he replaced the build plate with a lighter carbon-fiber frame.
The swap changed how the bed traveled. Instead of riding on an air bearing, the lighter carbon-fiber frame slid between the base granite slab and a glass plate above it. Above the portion used as a build plate, there was an opening to accommodate the new arrangement.
Even with the lighter frame, the motion system wasn’t done. The metal pulleys used on the stepper motors carried too much inertia, so Roetz replaced them with smaller, semi-circular plastic pulleys.
Before committing to speed, he ran a sub-60-second dry test to make sure nothing would break. That test pointed to a practical, high-stakes detail: cable guides. Without them, cables were whipping around—especially under the acceleration of 225 G.
Once those guides were in place, Roetz moved from testing to production. He was able to successfully print several successive 59-second Benchies. The results weren’t pretty—he described the prints as not photogenic—but they were mechanically sound and dimensionally correct.
He also found a ceiling. Going faster would have been possible, but it degraded print quality too much.
Roetz’s accomplishment lands as the end of a long arc. The same project was previously covered when he was aiming for parallelization instead of speed. In the final under-minute Benchy, that earlier parallelization experiment wasn’t used. Still, the work didn’t stop at mechanical changes; he also experimented with dynamic temperature control.
A video recording of the final result is available through the embedded link, showing what it looks like when every constraint is forced to give—until the clock finally dips under a minute.
3D printing Benchy printer speed extrusion flow rate cooling air duct air bearing carbon-fiber frame stepper motors dynamic temperature control over-minute print