What aspect does layer adhesion in FDM printing depend on?

Layer adhesion in Fused Deposition Modelling (FDM) printing is significantly influenced by the cooling rate of the extruded material. When filament is deposited, it is hot and malleable, enabling good intermolecular interaction with the layer beneath. As the material cools, it solidifies and forms a bond with the previous layer.

If the cooling rate is too fast, the extruded filament may not have sufficient time to bond effectively before it solidifies, leading to weak adhesion between layers. Conversely, a controlled cooling rate allows the layers to adhere properly, providing the mechanical strength required for the final printed part. Proper layer adhesion is critical for achieving a strong, durable, and dimensionally accurate print.

While other factors like printer speed and filament type can impact print quality, they do not directly affect the physical bonding between layers, which is primarily a function of temperature management during the extrusion and cooling phases. The size of the printer is also not relevant to layer adhesion itself, as it pertains more to the build volume and dimensions of the print rather than the quality of the layer interface.