GT2 Belt tension adjustement

thingiverse

Proper belt tension is a must, and I'll walk you through the method I used on my Geeetech Al Prusa I3. It's surprisingly straightforward due to the idler pulley and adjustment system designed by Geetech for X and Y axes - I swapped out the recommended smooth pulleys for toothed ones. The U-shaped part holding the pulley features a screw in line with the belt, used for both tensioning and adjusting it. This method applies broadly to similar designs. It's astonishing how some designers come up with convoluted solutions for simple components like idler pulleys, often including separate adjustment mechanisms that result in skewed pulleys, belts, and hard-to-adjust tensions. As you can see, I replaced the nut with a butterfly nut and created a hook for the scale using an M3 threaded spacer combined with a piece of threaded rod. To adjust it, simply attach a small electronic scale, pull on it until you reach the desired force, then adjust the nut so that it just touches the frame - easy peasy! A proper tension is approximately 13N for GT2 6mm wide belts, meaning you'll need to adjust for around 26N (about 2.6kgf). If your machine is one of those flimsy acrylic sheet contraptions, be cautious: it may bend or even break, giving you a great excuse to upgrade!