Layer cooling fan duct.

thingiverse

The cooling system of the Makerbot Replicator Original relies on a duct that directs airflow through the layer of melted plastic. The fan that produces this flow must be properly connected to achieve ideal temperatures inside the machine. If this component is faulty or clogged, the extruder may not work efficiently due to excessive heating, potentially causing warping in prints or premature wear and tear. To address these issues, verify that your Makerbot has a functional duct installed and free of any obstructions; clean the area as necessary. Proper setup ensures accurate performance and maintains your 3D printer's quality over time.