What is the purpose of a heated bed in FDM printing?

A heated bed serves a crucial role in Fused Deposition Modeling (FDM) printing by providing a controlled temperature environment that helps prevent warping and ensures better adhesion of the first layer of the print to the bed. When the extruded filament is deposited onto a surface that is too cool, it can contract as it cools, leading to warping or lifting at the corners of the print. This can compromise the overall quality, precision, and structural integrity of the printed object.

By maintaining a higher temperature, a heated bed keeps the first layer of the print warm, which reduces the chances of these issues occurring. It allows for better bonding with the surface, resulting in a successful initial adhesion that is vital for the subsequent layers to build properly on top of it. This is particularly important when working with materials that are prone to warping, such as ABS. Thus, the primary function of a heated bed is to enhance print quality by stabilizing the temperature of the print during the crucial initial phases of the deposition process.