Fiber Jam Troubleshooting for Markforged Industrial & Desktop 3D Printers

Knowledge Base Article | September 3, 2024

Introduction

The following is a guide to troubleshooting the following error:

Content

Troubleshooting A Fiber Jam
Enable / Disable Fiber Jam Detection
Detect and Debug fiber Jams

Supplies

5 mm hex key
Tweezers
10mm torque wrench
Replacement PTFE tube
Anti-seize

Note: All supplies listed above can be found in the Markforged Accessory Bag, which is included with every printer purchase.

Note: The printhead is factory-calibrated. Do NOT adjust or disassemble unless instructed to do so by Markforged Support or Markforged Partner. If a printhead has been adjusted, disassembled, or modified without instructions, it will not be honored under warranty.

Troubleshooting a Fiber Jam

The following are the most common causes of a fiber jam.

1 Extruder Jam

An extruder jam is most common when printing with Kevlar. If there is a high volume of Kevlar in the part, the likelihood of an extruder jam is increased due to the repeated use of the fiber cutter. Due to Kevlar’s flexibility, it tends to bend or break and can get caught in the extruder.

2 Nozzle Jam as a Result of Incorrect Fiber Nozzle Height

If the fiber nozzle is set to an incorrect height, it can lead to a nozzle jam. A fiber jam due to improper leveling is common when printing with Carbon Fiber because it is thicker than the other fibers. When printing with Carbon Fiber, level your fiber nozzle with extra care.

Enable / Disable Fiber Jam Detection

Automatic fiber jam detection is enabled by default and is recommended to stay enabled. This allows the printer to notify the user when a fiber jam occurs.

1. Select Menu > Settings > System info

2. Select the gear icon at the bottom of the screen.

3. Enable or disable automatic jam detection by toggling the Fiber Jam Detection switch.

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Detect and Debug Fiber Jams

If the printer suspects a fiber jam, it will pause the print and prompt you with troubleshooting steps. Follow the instructions on the screen to diagnose and resolve the issue. Once the fiber jam is resolved, you can resume the print.

1. Press Troubleshoot on the screen.

Note: If you choose to skip, it is recommended that you unload and reload the fiber before resuming your print.

2. Verify that the area below the print bed is clear, then press Next.

3. If your fiber is already unloaded, select Next.

For more details on how to unload the fiber, see Load Or Unload Fiber Filament (Desktop and Industrial).

4. Disconnect the fiber Bowden tube from the printhead and check if any fiber is left inside the Bowden tube.

If there is fiber present, press Yes and continue to step 5. If not, press No and skip to step 6.

5. Remove the remaining fiber from the fiber Bowden tube and load tube.

6. Unscrew and remove the fiber nozzle from the printhead using the 10mm nozzle wrench.

Check if there are any obstructions inside the nozzle (it may be helpful to hold the nozzle up to a light to see if there is anything inside the nozzle). If there is an obstruction in the fiber nozzle, press Yes and continue to Step 7. If not, Press No, and skip to Step 9.

7. Remove the PTFE tube from the fiber nozzle, then check if the obstruction is inside the nozzle.

If there is no obstruction in the fiber nozzle, press No and continue to step 8. If there is an obstruction in the fiber nozzle, that nozzle is no longer usable. Cancel your print job and install a new fiber nozzle.

Note: Once the new fiber nozzle is installed, a nozzle height adjustment must be performed before restarting your print.

8. Check the PTFE you removed from the nozzle for obstruction.

If there is an obstruction, press Yes. If not, press No.

9. Looking at the face of the fiber nozzle, examine the wear indicator notches on the size of the nozzle.

If the nozzle looks like the image with the red X, the nozzle is worn through and must be replaced. Cancel your print, install a new fiber nozzle, and perform Fiber Nozzle Height Adjustment before restarting your print. If the nozzle looks like the image with the green checkmark, the nozzle is still usable. Press No and continue to Step 10.

10. Prepare your fiber nozzle by inserting a new PTFE tube into the nozzle and applying a thin layer of Anti-Seize to the nozzle’s thread.

Then press Next.

Note: Even if there were no obstructions in the PTFE tube, it is recommended to install a new one as the used PTFE tube may have crimps or dents from the removal process which can lead to future fiber jams. Additionally, be careful not to get any Anti-Seize inside of the nozzle.

11. Screw the new nozzle halfway into the printhead using the nozzle wrench. Unscrew the nozzle and then screw it in all the way; this helps distribute the Anti-seize over all the threads.

Once the fiber nozzle is installed, press Next.

12. Allow the fiber nozzle to heat up.

After heating the nozzle, use the nozzle wrench to tighten the fiber nozzle until the wrench clicks. Then press Next.

13. Reinstall the fiber Bowden tube back into the print head.

Check that both fiber Bowden tube and feed tube are reinstalled correctly. Then, press Load Fiber and reload your continuous fiber.

14. Once the fiber is reloaded, verify that the fiber successfully extruded from the print head.

If it did not, please contact your Markforged Partner. If fiber was extruded, you have successfully cleared the fiber jam. Press Yes and continue.

Note: When contacting your Markforged Partner, please provide your machine ID, printer logs, and any photos of the obstructions you may have.

15. Follow the prompts on the screen to navigate back to the print job progress screen. If you have successfully cleared your fiber jam and wish to resume your print, hit Resume.