What Is Over-Extrusion and How Can It Be Avoided?

Additive manufacturing enables the creation of intricate and detailed structures, offering unparalleled design freedom to users. According to the latest Hubs Report for 2023, FDM printing technology, also known as fusion layering, stands out as the most popular 3D printing process due to its ease of use and user-friendly nature. However, like any printing method, errors can occur during the fusion layering process, resulting in unaesthetic or unusable prints. We have previously discussed issues such as elephant foot, stringing, and warping. Now, we would like to address another common problem that may arise during FDM printing: over-extrusion.

Over-extrusion happens when the 3D printer’s extruder deposits an excessive amount of material, often leading to bulging and swelling at the edges of printed parts. Additionally, the individual layers may have inconsistent thicknesses, resulting in uneven and unappealing surfaces. Over time, this excessive material flow can even cause nozzle clogging. In the following sections, we will examine the causes of over-extrusion and provide you with potential solutions to avoid this error in future prints.

Over-extrusion manifests itself in over-swelling edges and a lack of precision and detail (photo credits: Creality)

In most cases, over-extrusion can be attributed to excessive printing temperature. When the temperature setting on the 3D printer is too high, the filament melts too quickly, and the extruder loses control over the flow rate. Consequently, higher temperature settings result in a more fluid material for extrusion. In such cases, the cooling fan fails to rapidly cool down the filament, leading to uncontrolled and excessive material flow through the nozzle. Another contributing factor to over-extrusion is the diameter of the filament used. If the filament has a smaller diameter than the nozzle, it can pass through too quickly, causing over-extrusion. Similarly, incorrect filament diameter settings in the slicer software can also lead to incorrect flow rates and over-extrusion. Additionally, improper calibration of the flow rate (known as the extrusion multiplier in slicer software) can contribute to over-extrusion.