Filament getting stuck

[BalajiHari 0]

I have a colido 3.0 3d printer, using cura for slicing and printing. 

Last few weeks have faced this problem of filament getting stuck and not printing. 

Do let me know how to resolve it ? 

Thanks in advance 😄

[GregValiant 1,344]

I don't know that printer but there are a couple of things that are common to all bowden tube printers.

• If a gap forms between the bottom of the bowden tube and the back end of the nozzle - hot plastic can be pulled into the gap making a little "O-ring" that can impede the new plastic coming in.
  • Pull the filament out.  Carefully trim back the end of the bowden tube by 5 or 6mm with a razor blade taking care to make an exact 90° cut.
  • Push the bowden back into the hot end ensuring that it is flush against the back of the nozzle and then install the locking clip onto the holding fitting.
• As the machine goes back and forth in the "X" it will cause the bowden tube to rotate in the hot end fitting.  No way around that.  Additionally, every retraction pushes the pulls the bowden into those little knives.  Over time, the little knives in the fitting will work down into the plastic of the tube allowing it to move up away from the back of the nozzle causing the gap.  This is the reason that bowden tubes are considered to be an expendable part as they get shorter every time they are trimmed.
• Make sure your retraction distance isn't overly long.  On most bowden printers a retraction distance of 6.5 is OK but the "max retraction length" is something that can be specific to each printer model.  Long retractions will pull molten plastic up into the heat break causing a partial blockage.
• Heat Creep
  • Make sure the hot end fan is working whenever the machine is printing.
  • Take the hot end cover off and inspect the fan blades and the fins on the heat sink.  They can collect strings of filament and won't work as well as when they are clean.  That allows the heat from the heater block to move up into the heat break (between the block and the heat sink) causing the filament to soften and fold.  That appears to be what is going on with your filament pull.
• Smashed filament
  • If you have an adjustable spring tensioner on the extruder arm, and if the spring is putting a lot of pressure on the filament it can cause the filament to deform and get wider than it should be.  Constant retractions across the same spot of filament will make it worse.  That makes in harder and harder to push the filament through the bowden tube.  When you pull the filament it has a characteristic "accordion" look.  Loosen the spring tension.
• Cooking the filament can happen if the filament is sitting in the nozzle for a while and you are printing very hot (for that material).  The filament can char and little pieces of char can break free and clog the nozzle.  The nozzle would need to be removed and cleaned out.

Those are the main things.  Now you have something to do today.