Drive Block Versions
This article is only applicable to earlier versions of the drive block. If the lever arm on the top of your drive block is a switch you can flip back and forth, you have the earlier drive block. If you're not sure which drive gear you have, click here for an explanation.
Each drive block includes a spring that puts tension on a bearing inside of the extruder. This bearing pushes the filament against the drive gear, which grips the filament and drives it into the hot end of the extruder. If the bearing is putting too much or too little pressure on the filament, you will see extrusion problems.
How to Adjust Spring Tension
- Unload any filament. To run the script for unloading filament, go to the LCD panel and select Utilities > Filament Options > Unload. The extruder lever arm should be set to the closed position.
- Locate the extruder spring set screw on the extruder that needs adjustment. The set screw is located in a threaded brass insert next to the filament hole in each extruder’s drive block.
- Use the 2 mm hex wrench that came with your MakerBot Replicator 2X to tighten the set screw completely.
- Turn the set screw ½ turn counter-clockwise.
- Test the tension on the spring. Move the extruder lever arm to the open position. You should be able to do this with some difficulty. If you can't move the lever arm, turn the set screw another ½ turn counter-clockwise and test it again.
- Keep loosening the set screw in small increments until you can move the lever arm to the open position.
- Remove the hex wrench and set the extruder lever arm to the closed position. The extruder lever arm should now point towards the opposite extruder.
Adjusting extruder spring tension is part of Maintaining Your MakerBot Replicator 2X.