Belt tension is important to ensure optimal printing. Theoretically, the belts will not need to be retensioned, but after shipping or adjustments, it’s good practice to recheck tension.
Belt on the Y Axis
On the Y axis, move the plate all the way to the back of the machine so that it contacts the Y axis microswitch. Now, flick the belt. You should hear a deep, cello-type frequency.
If the belt is too loose, loosen the 13mm nuts that hold the threaded and smooth rods on the front of the machine. You should loosen a total of four nuts: two on the outermost ends of the rod, and one each on the supports that hold the smooth rods. With the nuts loosened, slide the threaded rod back and tighten the four nuts. Now recheck the tension on the belt and repeat if necessary.
Belt on the X Axis
On the X axis, move the X carriage all the way to the left of the machine so that it contacts the X axis microswitch. Now, flick the X axis belt. Like the Y axis adjustment, you should hear a deep, cello-type frequency. If the belt is too loose, loosen the 13mm nut and bolt on the right X bracket of the machine. With the adjuster loosened, slide the adjuster to tighten the belt and tighten the adjuster (don’t over tighten). Now recheck the tension on the belt and repeat if necessary.
While you are at it with maintenance, take a look at the smooth rods and threaded rods for all axis and grease/lubricate as necessary to ensure optimal performance (graphite lube is preferable for Z axis threaded rods).