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Filament Jam Troubleshooting

Filament Jam Troubleshooting

Updated on Dec 10, 2024

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Symptoms

It is possible that errors in the setup of the S1 can cause filament to get stuck during initial filament loading or automatic reloads. This will be indicated by one of the following symptoms.

  • S1 goes into sleep mode while actively printing indicating that filament is not moving. (Shown by a blue state light).
  • The printer runs out of filament when a reload should have occurred.



Types of Filament Jams

Wedged Filament

Indicated by the 3D printer extruder skipping, grinding filament, or slipping. The printer will run out of filament but no runout will be detected via the printer runout switch if enabled.

  • Only occurs during automatic reloads.
  • Filament ends are able to slip past each other and are wedged together.



Filament Catching 

Indicated by filament runout, or failure to load filament. Filament runout will be detected by the printer if the sensor is enabled.

  • Occurs during initial filament loading or automatic reloads.
  • Filament getting stuck on a sharp edge in filament path.



Identify Jamming Locations

Step 1: Recreate Filament Jam

In order to identify the location where the filament is getting stuck in the loading or reloading process. The error must be recreated.

 

Step 2: Turn off S1 and Pause Print If Necessary

If it is necessary for your 3D printer to be printing in order to recreate the failure, pause the print after the failure occurs. Once the print is paused, turn off the S1 so that the filament will not move if it is dislodged from the sticking point. This will help you accurately identify where the filament is getting stuck.



Step 3: Disconnect Tubes Near End of the Filament

If the filament does not exit the S1 before getting stuck, refer to the last section of this document called “S1 Catching Points”.

If the jam occurs near the printer’s extruder, disassembly the setup around where the filament is catching. This may involve disconnecting Bowden tubes or connectors. 



Step 4: Identify Type of Jam and Location

Measuring how far the filament sticks out of the bowden tube can help you figure out how far into the extruder the filament is getting caught.

Note: Because the unloading levers are spring loaded, the filament will stick out about 2mm further than where it got stuck.



Preventing Wedged Filament

Filament can jam in locations where the filament is not properly constrained by a tube or other containment method. Filament jams occur when the ends of the filament strands are able to slip past each other and get wedged together by the geometry of the filament path.

Wedged Filament Fixes

  • Find or design a 3D printed adapter that guides the filament into the printer via a tighter path
    • Hint: many adapter fitting designs for MMU’s are available to download and 3D print for free online.
  • Find or design extruder modifications to better guide the filament.
    • Hint: modifications made to print TPU and other flexible filaments usually provide more filament support.
  • For more help, check out our compatibility guide.
  • Ensure that the path of the filament is never more than 3mm wide.
  • Cut filament at 90 degrees before inserting it into the S1.



Eliminating Catching Points

Any sharp edges in the filament path can create catching points, preventing the S1 from smoothly reloading filament.

Catching Point Fixes

  • Find or design a 3D printed adapter that gradually guides the filament into the printer.
    • Hint: many adapter fitting designs for MMU’s are available to download and 3D print for free online. Check out sites like Printables, Thingiverse, and MakerWorld
  • Find or design extruder modifications to better guide the filament. Ensure there are no sharp overhangs or edges in the filament path.
  • Chamfer any sharp edges to guide the filament through its path. 
    • Hint: small center drills work great for adding chamfers in tight spots
  • For more help, check out our compatibility guide.

 

Best Practices

  • Chamfer all transition points between parts in the filament path.
  • Ensure the filament is properly guided all the way into the extruder.
  • Transition points in the filament path should always go from smaller diameter to larger diameter to eliminate catching points.



S1 Catching Points

The most likely catching point of the S1 is at the exit of the filament Junction as the filament enters the bowden tube. Follow the steps below to verify this.

Verifying the problem

Step 1: Turn the S1 on and allow the filament to jam.

Step 2: Remove the bowden tube at the exit of the S1 by pushing down on the Blue fitting and pulling. The Filament should start moving when this tube is removed. Use the unloading lever to back up the filament and turn off the S1.

 

Preventing S1 Catching Points

First, ensure that the end of the tube is cut square. If not, use a razor blade, utility knife, or bowden tube cutter to square up the end of the tube. Reinstall the tube. The tube should push into the S1 about 4mm.

 

If the problem persists, use a small center drill or similar tool to chamfer the inside of the Bowden tube. 

 

Things to Keep In Mind

  • Always ensure all Bowden tubes are cut clean and square. You can use a 3D printed cutting jig like this for best results.
  • Use a sharp center drill or chamfer bit to chamfer the inside of the Bowden tube.