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Please check our previous article FDM 3D PRINTING PROBLEMS: Out of Filament
But once you identify the root cause, you can solve each issue. In this article, I’ll discuss potential causes and solutions for a filament not coming out of your nozzle.
1. Nozzle Too Close to Print Bed
Unbelievably, no filament is depositing on the print bed despite the filament being loaded and the print head operating without a hitch.
Causes of Nozzle Too Close to Print Bed?
It’s possible that your nozzle is too close to the print bed. It’s unlikely that the melted filament will have room to escape unless you’ve adjusted your print bed to only a few microns from your nozzle opening. At best, your print won’t have its initial layers and will be more likely to fail once the filament starts to extrude. In the worst case scenario, you’ll create a buildup of melted filament in your hot end, which could result in a blockage.
3D Printing Troubleshooting: Nozzle Too Close to Print Bed
Often, all that is needed is to raise the nozzle’s height slightly. Most 3D printers allow you to set a Z-axis to offset in their system settings. You must increase the offset to a positive value to raise your nozzle above the print bed. This also applies to the reverse, where a negative offset can help with the issue of prints that don’t adhere to your bed.
But be careful—if the offset is too great, it won’t adhere to the platform.
LOWER THE PRINT BED
If your printer supports it, you can also accomplish the same result by lowering your print bed. However, this is the trickier fix because it calls for recalibrating and leveling the bed to ensure even prints.
3D Printing Problem Checklist: Nozzle Too Close to Print Bed
- Z-Axis Offset
- Lower Print Bed
2. Blocked Nozzle
You start a print job, but no matter what you do, nothing prints. It is ineffective to remove the filament and re-insert it.
What’s Causing the Blocked Nozzle?
After switching spools, a small piece of filament was left in the nozzle, frequently because the filament had broken off at the end. When the new filament is loaded, the leftover piece of the old filament in the nozzle prevents the new filament from being pushed through.
Reduce the possibility that issues like a blocked nozzle will affect your extrusions by performing a little printer maintenance. You’ll frequently discover old carbonized filament inside your nozzle before a clog manifests. There will be subtle signs in the caliber of your prints, even though they may sit there for weeks or even months without your knowledge.
Small imperfections in the outer walls, specks of dark filament, or slight variations in print quality between models are signs of a clogged nozzle that are frequently disregarded. People often say that these flaws are just the small differences we’ve expected from 3D printers, but something more sinister could happen. This can be resolved using a cleaning technique called the COLD PULLor Cold Pull, which we describe below.
If you frequently switch from a PLA to ABS, you’ll frequently observe this. A small amount of PLA is left in the nozzle and heated past the point at which it normally melts. That might imply that it will burn and carbonize.
Likewise, if you switch between ABS and Nylon, you’ll see a similar effect. A puff of smoke frequently appears as the new filament is fed through.
3D Printing Troubleshooting: Blocked Nozzle
USE A NEEDLE TO UNBLOCK
If you’re fortunate, unblocking might be a simple and quick process. First, take out the filament. Then, if your printer has a control panel, choose “heat up nozzle” and raise the temperature until the stuck filament melts. The nozzle can also be heated by connecting your printer to a computer running compatible control software. Set the thermostat to 220 °C for PLA. Use a tiny pin to clear the hole after the nozzle has reached the proper temperature (being careful not to burn your fingers). A smaller pin is required if your nozzle is 0.4 mm; an airbrush cleaning kit is ideal.
PUSH OLD FILAMENT THROUGH
You might be able to force the filament through with another piece of filament if you discover that the nozzle is still blocked. Remove the feeder tube from the print head after removing the filament in the same manner as before. To try to force the stuck filament in the nozzle out, heat the hot end to 220 °C for PLA and then use another piece of filament to push it through from the top. Usually, the additional pressure you can apply with your hand might be enough to unblock the printer if the new filament hasn’t been successful. However, avoid pushing too hard, which could result in bent horizontal printer rods.
Use a needle to push through the nozzle once the end has cleared and a brush to remove any extra filament.
DISMANTLE AND REBUILD THE HOT END
If the nozzle is completely blocked, you may need to perform a small operation and disassemble the hot end. Making notes and taking pictures is a good idea if you’ve never done this before, so you’ll know where everything goes when you put it back together. After removing the filament, carefully disassemble the hot end by following your printer’s manual instructions.
The Cold Pull
COLD PULLPART I – CHOOSE A MATERIAL
You can use ABS or Nylon for this, but due to Nylon’s higher melting point, we’ve discovered that it produces the most reliable results over time. Additionally, the filament keeps its shape much better. However, ABS is more widely used, so we’ll use it here.
COLD PULLPART II – REMOVE FILAMENT
Start by removing the current filament in the print head using your printer’s standard procedure. When the time comes, manually feed the filament by removing the Bowden tube or disabling the direct drive.
COLD PULLPART III – INCREASE THE NOZZLE TEMPERATURE
The nozzle temperature should be raised to 240 degrees. We use ABS, but if you use Nylon, check the packaging for the melting point temperature. Let it remain at this temperature for 5 minutes without attempting to push the filament through.
COLD PULLPART IV – PUSH THE FILAMENT THROUGH
Press the filament gently until it begins to emerge from the nozzle. Once it begins to flow from the nozzle, pull it back and push it through again.
COLD PULLPART V – REDUCE THE NOZZLE TEMPERATURE
Reduce the temperature (you’ll need to experiment a little for your filament) to 180 degrees for ABS or 140 degrees for Nylon. For five minutes, let the printer remain at this temperature.
COLD PULLPART VI – EXTRACT THE FILAMENT
Take the filament out of the head. There should be some black carbonized material at the end when you look at it. Continue until everything is clean. Increase the temperature of the hot end slightly if the filament won’t pull from the nozzle.
3D Printing Problem Checklist: Blocked Nozzle
- Clean the nozzle with a needle after heating it.
- Try forcing the filament through with a different piece after removing the feeder tube.
- Check to see if you can remove the filament obstruction by disassembling the hot end.
- Try a COLD PULL(Atomic Pull)
Did you ever try cold pull? What are you doing when filament not coming out of the nozzle?
Let us know in the comments below or on our Facebook page to let us know your ideas, and we would appreciate seeing pictures of your works of art!