What is the purpose of using a raft in FDM printing?

In Fused Deposition Modelling (FDM) printing, the use of a raft serves a crucial function by providing a stable base for the model and improving adhesion to the build platform. A raft is a layered structure that is printed beneath the actual model. Its primary purpose is to create a level surface that helps counteract any warping or adhesion issues that might occur due to uneven surfaces or temperature variations of the printing surface.

By increasing the contact area between the model and the print bed, the raft enhances the bonding capacity, ensuring that the model remains securely attached throughout the printing process. This is particularly beneficial for models with smaller footprints or those made from materials that tend to warp as they cool. The raft also helps to mitigate problems related to the first layer of the print, which is critical for overall print success. Once printing is complete, the raft can be easily removed, leaving behind a cleaner model base without affecting the quality of the printed object.