Why is the first layer critical in FDM printing?

The first layer in Fused Deposition Modelling (FDM) printing is critical primarily because it is essential for adhesion. During the printing process, this initial layer must firmly attach to the print bed to ensure stability throughout the printing of the entire model. Good adhesion prevents issues such as warping, shifting, or even complete failure of the print job. If the first layer does not adhere well, it can lead to defects, misalignment, or the print coming loose and ruining the overall project.

In many cases, enthusiasts and professionals alike focus significant attention on the calibration of this first layer, adjusting factors like height, temperature, and speed to optimize adhesion. This foundational layer serves as the building block for the rest of the print, affecting the quality and success of the final product. The importance of achieving an ideal first layer cannot be overstated, as it sets the tone for the subsequent layers that follow.