3D printers often require bed glue to improve bed adhesion, which is crucial for successful printing. Here are a few reasons why bed glue is used:

1. Prevent Warping and Shifting: Poor bed adhesion can cause the print to warp or shift from its starting position, leading to print failure. Glue helps to keep the print firmly in place.
2. Improve First Layer Adhesion: The first layer is critical for the success of the entire print. Glue ensures that the first layer sticks well to the print bed, providing a solid foundation for the rest of the print.
3. Ease of Use: Glue sticks are easy to apply and remove, making them a convenient option for improving bed adhesion.
4. Compatibility: Glue sticks, especially those made of PVA (Polyvinyl Acetate), are compatible with various print bed surfaces and materials.

By using bed glue, you can achieve better print quality and reduce the chances of print failures due to poor adhesion.