Belts are a very important component of all FDM 3D printers. Belts are the main drive mechanism that moves the print head along the X and Y axes. When you have the correct 3D printer belt tension, they ensure smooth, consistent movement of the print head.

When belts are worn, too loose, or too tight, they can cause print defects and print failures.

Overtight belts generally do not cause print defects. But increased tension can lead to increased wear and shorten the life of the belt.

Problems with Too Tight Belts

Most belts are made of a mix of rubber and wire rope (usually steel) for reinforcement. The wire rope increases tensile strength and creates a more reliable part.

If a belt is tied too tight, the belt can stretch. Stretched belts cannot be repaired. Once a belt is stretched, it cannot return to its original shape.

Any stretching can cause the belt to misalign with the gears, causing slippage.

In extreme cases, an overtight belt can break like a rubber band. Not only can this damage the printer, it can also cause injury.