Technical Support receives a lot of tickets saying that the "printer is not working" or " the printer is causing holes in my print." We need to tell you that the majority of these cases turn out to be nothing wrong with the printer. Instead, we find that the issue is print setting-related OR more specifically print setting-related that turned into a mechanical cause. This is especially true with clogged nozzles/nozzle blocks due to incorrect temperature settings in the 3D slicing software's print settings. 


◄CHECK PRINT SETTINGS►

Even if you think that you're correct you should double check with Technical Support. Here are a few:
TEMPERATURE

ABS
  • Extruder ► 230º-240º 
  • Bed ►70º-80º (100% of the layers)

PLA

  • Extruder ► 210º-220º 
  • Bed ►40º-50º (2% of the layers; some customers even preheat the printer and then run the .GCODE with no temperature setting for the bed.)

PVA (Recommended support filament type for PLA)

  • Extruder ► 195º-200º (**** NEVER USE THE STAND-ALONE PREHEAT OPTION for PVA; these temperatures are very strict****)
  • Bed ►40º-45º (2% of the layers)

HIPS (Recommended support filament type for ABS)

  • Extruder ► 230º-240º 
  • Bed ►70º-80º (100% of the layers)

***If you're using Creatr software, please make sure that you're even checking the profiles that we've sent you as a few of the OEM profiles have come directly from Materialise and not from Leapfrog. For example, there is an OEM ABS that has 260º that we don't recommend using (the Creatr 2.0 version shouldn't have this profile available).

PRINT SPEED/ JUMP SPEED (A.K.A X/Y MOVEMENT SPEED)
Another big cause of "under extrusion" is print speed. Many clients get their new printer that is clocked with being able to print at 300mm/s (18000mm/min) and believe that any model can print at that speed. We hate to break it to you, but the 300mm/s is very hard to achieve: it was possible with a super basic print resulting in just minimum prototype-quality results. Print speed normally needs to be lowered based on the models size, complexity, and layer thickness; if your model has a lot of print head directional changes or needs to lay thinner than average (100 microns or less) layers, then we recommend you slowing the speed down (think about a modified blinder trying to accurately squeeze toothpaste onto a brush - yeah... toothpaste everywhere). Otherwise, you might be experiencing under extrusion due to the high speed. How to test if speed is causing the under extrusion? Try slowing it down to 60mm/s (3600mm/min) and see if you're still getting under extrusion: no issue - speed is the culprit; still an issue - move on to the next section. And we'll tell you now: good luck with successful prints even at that speed if your part is a series of thin spikes, towers, columns, or extra thin walls.


◄CHECK FOR CLOGGED NOZZLE►

However, this article focuses on providing explanations to some of the next things to check on the machine, should you find that all of your print setting temperatures are correct, you should immediately check to see if the extruder is clogged. We recommend that you load either ABS or PLA filament into the questionable extruder, preheat the printer (for ABS, please connect the printer to the PC and preheat to 240º), and manually extrude some filament. In Stand-Alone for PLA, you can simply use the Load Filament command for the corresponding extruder. 

Possible Results:

  • Extruding Normally - that means that something is likely still incorrect in the print profile that you used to slice the .GCODE; request a test .GCODE from Technical Support (specify which extruder and which filament type you're using).
  • Extrudes a Thin Line - Not sure that it's a thin line? Compare it to the attached video called "HS - Normal Extrusion." If it is a thin line, this usually means that you likely have a partially clogged nozzle/nozzle block. Depending on the previously used filament types you may be able to clean and unclog the extruder. Otherwise you'll need to replace it. Here are some helpful solution articles regarding this:
  • Does not Extrude - This likely means that the nozzle is completely clogged. Just to be sure it's the nozzle and not the drive unit, you could do the following:
    • With the extruder still preheated, disconnect the extruders plastic filament guiding bowden tube from the top of the print head.
    • Wait for any extruding command that you may have previously pressed to complete.
    • Then, pull the filament to have roughly 15cm of filament sticking out the end of the filament guiding tube and clip the end of the filament to a point. This should leave you roughly 13cm of filament extending from the end of the tube.
    • Finally, MANUALLY ("caveman style" with your hand, holding the filament only - no the guiding tube) feed the filament through the top of the print head to try and get it to extrude. IF you apply more than about 10kg of force and nothing is extruding out the hot nozzle, then it is clogged. If you have to press fairly hard and it only produces a thin line, then it's a partial clog. Either way see the solution articles listed in "Extrudes a Thin Line" above.
  • Extrudes but at Various Speeds - This is likely drive unit related, which will lead us to our next section.



◄CHECK FOR DRIVE UNIT ALIGNMENT ISSUES►


Here's basically what the drive unit should look like (the image is purposely stripped so as to provide you the best view - top down):

The pressure ring (A) at the back of each filament drive unit controls the pressure that the pinch wheel (B) applies on the filament to the drive gear (C) creating a good alignment and pressure at point D in the image. The orange circle represents the filament.  ****NOTE: This is how the factory ships the printer; this set up is part of the Quality Assurance inspection.


However, here are some issues that we've seen that can cause under extrusion:





Pressure Ring Too Loose

Here, you see where the pressure ring is too loose causing a gap (D) between the pinch wheel (B) and the drive gear (C). The result of this will be that the filament slips, causing a very noticeable clicking sound when trying to extrude. The filament moves around fairly easily in this case.


To resolve this, please hand-tighten (NEVER USE TOOLS, as this can bend the shaft between the pressure ring and the pinch wheel) the pressure ring (A) until you only see about one or two screw threads at point A.1.


This will create more pressure between the pinch wheel and the drive gear, pressing the filament against the teeth of the drive gear.


We've attached a video showing how you can test to see if the pressure ring might be too loose; the video shows that someone can easily cause the filament to feed back into drive unit by applying resistance.


See also "Drive Gear is Misaligned" below, as the symptoms can be similar.








Pressure Ring is Too Tight

In the image to the right, you see that the pressure ring (A) is screwed almost completely to the back of the printer causing the gap (D) to close too tightly damaging the filament. This small distance between the pinch wheel (B) and the drive gear (C) can actually cause under extrusion by damaging the filament itself. 


The slicing software and firmware are set for a 1.75mm filament to be fed through the machine. However, if you send filament that has gashes and pieces missing though the extruder, it's going to under extrude as the filament is no longer 1.75mm.


In addition, we've seen filament with certain gashes that have actually caused the filament to get stuck in the drive unit - mainly where it feeds through the filament glad at the top of the drive unit.


Finally, the filament residue left in the drive gear's teeth has been known to cause filament to slip, since the drive gear's teeth no longer can grip the filament to feed it through.


To resolve this, loosen the pressure ring (A) and cut out any damaged filament.



(Gashes in the filament.)


NOTE: Though the pressure can be too much or too little, there is a little bit of play in the "perfect" pressure (meaning it doesn't have to be exact). The reason why this is even adjustable is to help provide customers a bit more ease when using the quick release knob when loading and unloading filament. This is the reason why you may have received a printer with it not set perfectly; it may have been adjusted when doing the QA check at the factory.





Drive Gear is Misaligned

To the left, you see an issue where the pressure ring (A) and threads (A.1) look good, but the filament is slipping - usually at irregular intervals - because the drive gear (C) is not lined up with the pinch wheel (B).


This causes an random speed loss of extrusion and can cause the filament to actually be driven out of the side of the drive unit through the side-gap created (D).


Again, you may hear the clicking sound of the filament skipping, even if the pressure ring is perfect set. The symptoms can be similar to those of the pressure ring being too loose.


To resolve this issue, use a number two allen/hex key/driver to loosen the drive gear's grub screw (the small black circle on the drive gear (C) in the image to the left), and center the drive gear. If the pressure on the pinch wheel is strong enough, the loose drive gear can be slid and you'll feel the corners of the pinch wheel bump; find the happy medium. Finally, hold the drive gear in place and tighten the grub screw back.


You can see more information on this in Step 4 of the following solution article:

How to Clean the Drive Units of My Creatr HS 3D Printer 





Damaged Extruder Motor Axle

[EXTREAMLY RARE]

Though this is not a common issue, you may find that the pressure ring (A) and thread (A.1) are causing the pinch wheel (B) to create good pressure on the drive gear (C), but you're still having issues where extrusion is coming and going in what seems like regular waves.


We have noticed in some cases where the motor axle on the extruder's stepper motor is bent or damaged causing it to wobble when rotating. This slow wobbling causing the filament to skip in regular intervals. It may not even skip but simply extrude a bit less at some points and not others.


This may be hard to detect by a jog control extrusion or Load Filament command. It is often seen in the first layer of large first layer prints where the print (see image below).


The best way to confirm this is is to remove the drive unit from the printer and rotate the motor axle with your fingers (observing the axle for any wobble).


See: How to Replace the Filament Drive Units on the Creatr HS



If you see this, make a video of the wobble send it in a new ticket for Technical Support; the only resolution is to replace the motor. If the video file is larger than 15MB, the entire message won't send. Instead, use a free file sharing website and send us the download link in the ticket.

(A bent/broken motor axle usually print in strips that seem fairly evenly spaced.)



◄OTHER CAUSES►


There of course may be other causes not mentioned here. If you get to this point and can't figure out the cause, please open a new technical Support Ticket and let us know what all you have checked. We will want to know which filament types you've ran though the extruder (past and present) and roughly at what temperatures. We'll certainly ask you which 3D slicing software program you used on your PC to create the .GCODE file and if the issue is occurring with just one certain .GCODE file, or if the issue occurs with any .GCODE file that you run. We look forward to assisting you further, so don't be shy - open a new ticket.