If you are experiencing a clogged extruder during a print job and need help, then please have a look at this solution article. This article will focus on the hardware.

With regards to software we recommend doing the following:

  • Make sure the print speed does not exceed 3000mm/min or 50mm/s.
  • Try printing the same model halve the speed and compare the results
  • Try printing with a layer height of .15mm and compare the results
  • Make sure the Extrusion temperature matches the filament specifications

If you wish to receive a Gcode from the Leapfrog Support Team to test your device with, then please open a ticket.
If you are experiencing print quality issues related to a clogged extruder then please follow the Check points below:

Check 1. The filament spool

Check 2. Flushing out the printhead in case different type of filaments have been used.

Check 3. The filament pressure thumbscrew

Check 4. Printhead and hot end

Check 5. Temperature to high in build-chamber

Check 6. Extruder Drive Gear

Check 7. Your filament absorbed to much moisture

Check 1. The Filament spool
Make sure the spool is able to rotate without to much friction. Eventough the PTFE tubes are usually low friction, some filaments can generate a high amount of grip, and the printhead is not capable to pull and extrude filament properly. 
Even a tight bend in the PTFE (between 3rd party filament box and printhead) can make the filament heavy to pull, for the printhead. 


How to check if it’s ok? 
Remove the PTFE tube from the printhead, and try to pull it a little bit, manually as a test. Heavy-to-pull? something is wrong, Easy-to-pull? Then all seems ok!

Check 2. Flushing out the printhead in case different type of filaments have been used.

In case you previously printed a different material, than this could possible cause extrusion issues of a print attempt done afterwards. Especially if the material printed previously requires a higher extrusion temperature.

In order to 'flush-out' those filament remainings, we recommend doing the following.

1. Go to settings / maintenance / head maintenance on your Leapfrog Bolt (PRO)

2. Select the filament previously used, that requires the highest pre-heat temperature. 

3. Press pre-heat

4. Automatically Purge or manually push the filament thru the printhead

5. Unload the filament

6. Automatically Purge or manually insert the filament that you would like to proceed with for your next print.

7. Stop the pre-heat and change the material to the one used in previous step. 

8. Press pre-heat and attempt automatic Purging or manually push the filament thru the printhead

9. Press done and close the maintenance menu. 

Check 3. The filament pressure thumbscrew
Make sure your filament pressure thumbscrew is set to the right amount. The 3D printable gauge (Support / Bolt PRO / 3D Models) can be used to set the right amount. 


3mm = Engineering PLA

3mm = ABS

3mm = HIPS

3mm = PETG              

3mm = Carbon  

3mm = Nylon                 

6mm = TPU / Flex

6mm = PP                 

6mm= PVA / Scaffold    

Check 4. Printhead and hot end
In this step two things are checked at once. Is the inner printhead AND hot end free of any obstructions / filament dirt remainings?

This can easily be checked by going to the maintenance menu and loading PLA thru this printhead to sort of ‘clean’ it out. A steady flow is crucial. In case of doubt u could go to maintenance mode, heat both extruders up, manually feed them both to compare the easy of extrusion.

Also make sure that the PTFE-liner inside the heat break is OK. The PTFE liner should not be dislocated. Please see example below. In case the PTFE liner is dislocated, it is likely that filament leakage has taken place on bottom side of this tube. We recommend replacing this hot end. 

Check 5. Temperature to high in build-chamber
Some filaments can become soft in the temperature range of 50℃ - 80℃. Therefore if the room temperature is within this range, you have a risk of deforming your filament before it enters your hot end. In some cases this may happen at the extruder drive gear / filament pressure mechanism since force is applied on the filament. 
You can either experiment by lowering the build chamber temperature or reducing the filament pressure thumbscrew with increments of 1mm.

In case you are printing a non-toxic filament you could also consider printing with the door open.

Check 6. Extruder drive gear

The extruder drive gear is in direct contact with your filament, and needs to have grip on your filament to be able to move it up and down properly. 

In case your extruder drive gear has been grinding on filament during previous prints, it is possible that dirt has gone stuck in between the teeth. This dirt makes it hard for your extruder drive gear to accurately move your filament up and down during a print job as the grip is reduced.

A quick check that you could perform, is to try and hold the filament string just above the printhead when it is trying to extrude filament. In case the filament is easy very easily to hold on to between your fingers, and the Drive Gear does not grip the filament well, then possible the could be the root cause.    

It is therefore important that the extruder drive gear is cleaned. 

Check 7. Your filament absorbed to much moisture
Different filaments absorb moisture at different rates. But the signs that your filament has absorbed moisture are fairly common.
- Popping/cracking sounds when extruding

- Severly reduced part strength and layer adhesion

- Uneven extrusion lines

- Uncharacteristically severe stringing, blobbing or oozing

- Uncharacteristically textured or "fuzzy" surfaces on prints

If you’re seeing any of the above symptoms, then you could consider to dry out your filament.  Especially hygroscopic materials like nylon, PETG, PVA, and flexibles, symptoms may appear after just one night left out in the open.  Dry out wet filament as soon as you identify it to preserve print strength and quality. Please consult the correct drying conditions on the support page for Filaments.