- Due to excessive extruder temperature
When using PLA, ideal temperatures are between 160 and 220 degrees Celsius. Extruding too low of a temperature will result in no extrusion at all or print issues, too high of a temperature your filament could vitrify (To change or make into glass or a glassy substance, especially through heat fusion.) in your extruder and clog it.
- Due to dust accumulating in the hot end
Dust and debris can stick to the inner walls of your extruder and restrict the flow of plastic eventually leading to a clog.
- Pull out any remaining filament from the hotend
- Heat your extruder to the optimal temperature
- Use a drill bit < 0.35 mm or .33mm guitar string to clean out the residues with a sweeping motion
Note, hold the drill bit in our hands, a drill is not required.
Software controlling the printer calculates the extrusion volume based on the filament diameter, the diameter of your extruder nozzle and the extrusion speed (flow rate – in mm/s).
The printer controls the volume of plastic that is pushed out of the nozzle by turning the extruder wheel and pushing a certain length of filament down the hot end.
- Irregular Diameter Filament or Variance Too High = Inconsistent Extrusion
With irregular diameter, the volume of extruded plastic varies and the software can’t adjust the extrusion length to compensate for the variation. = Inconsistent Extrusion’.
Tolerance of a filament (variation in diameter) ± 0.03 mm for high quality filament. ± 0.05 is industry standard. Anything greater is poor quality and should not be used with our printers.
With filament with higher variance extruder failure is typical (extruder fails= no plastic makes it to the hot end). If your filament suddenly becomes too thin for the tensioning mechanism and there is insufficient pressure gripping the filament. Another effect of a decrease in filament diameter is that back flow could occur in the hot end (hindering plastic delivery to the head).
When filament diameter is too wide the extruder motor cannot push it through the top of the extruder, springs can help accommodate slight variances, but if it is too large it may not fit into the hot end opening at all. The extruder gear may also shred the surface of the plastic leaving nothing to grip and can also cause a stall in the extruder.
- Solution: Purchase filament with a maximum tolerance of ± 0.03 mm. Use a micrometer to measure the diameter at several places and insure that it meets the advertised tolerance.
Filament Roundness Tolerance
Filament will compress somewhat due to the extruder wheel gripping the plastic. This reduces the roundness of the filament but is consistent across the entire spool so will not affect the print. Inconsistent roundness (filament that suddenly loses its perfect round shape and becomes oval) can lead to extruder failure in the same way that increasing or decreasing filament diameter can.
- Solution: Purchase filament with ± 0.03 mm roundness tolerance.
Moisture will create small water bubbles in the filament itself. When heated at the tip of your extruder, water boils and explodes which can affect the print quality.
- Solution: Store your 3D printing filament in bags with desiccants or use a plastic bin with a lid. Place a small open bucket inside with uncooked rice.
Filament Jamming in the Spool
Filament can become jammed before it leaves the spool, due to how the spool was wound from the manufacturer. Being present will allow you to catch the situation and pull the filament clear. However if you don’t notice or are not present the print will skip layers until the filament becomes free, if at all.
- Solution: A filament guide placed at a point where it forces the filament free from the spool first can eliminate this. To reduce the friction against the PLA guide you can use a guide that incorporates a oil-soaked piece of felt to reduce the friction. Use 3-in-1 oil, since it’s has a higher smoke point than canola (you don’t want it burning in the extruder). We are working on a design in the mean time, here is another groups design http://www.thingiverse.com/thing:103729