Tag: troubleshooting

Sometimes prints will have issues only at a specific height. The symptoms may be poor fill at a specific height, layer shift that always occurs at a certain Z, or something else that seems to consistently occur at a certain height.

When this happens, I start looking at, and around, the lead screws for Z. I look at the motors, the screws themselves, and the bearings. When I inspect the lead screws, I make sure there are no physical issues, such as nicks or dings in the screw itself and that the lead screw isn’t bent in that location.

If the sides of a calibration cube are a little bowed, there are a couple of things that I would look at.

  • e-steps/rotation distance (Klipper): if your extruder is extruding too much material, the material has to go somewhere.
  • calibrate Z: same thing as above, if your z steps are off, you might not be moving up as much as you think you are. The extruder is calibrated to extrude a certain amount of material. If you end up extruding more material, it needs to go somewhere
  • pressure advance: your nozzle may be oozing a little bit and causing your sides to become bowed

I’ve printed parts in the past that end up looking like something was dragged across the surface while it was printing. In reality, something may have been dragging across the surface. The first thing that I check when this happens is to make sure that the nozzle is clear. This is a typical sign that the nozzle may be clogged.

If it does turn out to be clogged, I do a “cold pull.” Heat the nozzle up 20 – 25 degrees past what you use it at during printing. Then let it cool completely. The idea is that any debris will collect into the filament. Once it is cool, heat it up again but tug on it from the extruder end. It will break loose from the nozzle at a much lower temp than what you print at. Hopefully, any debris that was clogging the nozzle comes with it. Just cut the end of the filament off and feed it back in.

Sometimes I print parts that have a top surface that look like a riverbed. There are valleys and branches going all across the surface of the part. This is usually a result of the nozzle being too close to the bed. Mechanically, there is too much filament coming out of the nozzle for the amount of space between the bed and the nozzle. When this happens the filament flows into other areas of the print and creates these valleys.

In short, your nozzle is too close to the bed if you have this. Adjust the height or redo your bed level.

These issues are easiest to identify on square parts. If you have mysterious blobbing on organic shapes, maybe try a cube test print to see if your printer has one of these issues on the corners. If you do end up with issues on your corners, and your printer has no other problems with printing, pressure advance (Klipper firmware) or linear advance (Marlin firmware) may solve your issue. Although they accomplish the task in different ways, both solutions solve the problem of issues with corners in 3d printing.

As a side note, when I am attempting to determine how accurate my machine is or to calibrate it, I first print a cube that I designed that has very large corner radii so that corner issues won’t bias my calibration.

Some 3d printers end up with rough top layers. One thing that you can check if this happens to you is the rate of filament flow. Filament flow is affected by a couple of things, the most common issues are:

  • Flow rate setting in slicer. I normally set my flow rate to 105% – 110% for the first few layers, then turn it down to 100%. If this is set too high then your printer is adding more filament than you might need, resulting in a rough surface.
  • Extruder calibration. Run a simple extruder calibration to double check that you are extruding the amount that you think you are. If you are overextruding, you might be causing problems for yourself.

After a while, things wear out on your printer. One item that is often overlooked is the connection on either end of a Bowden tube. If the teeth that hold the tube in place aren’t doing their job correctly, the tube can move back and forth as the extruder extrudes and retracts filament. The result of this is that you can end up with zits and voids in your final print.

To fix this, replace the fittings on either end first. If it still happens, replace the tube too.

There are a lot of potential causes for stringing, or spider webs. Some of the most common are poor retraction settings, poor temperature settings, and an improperly calibrated extruder.

Also, keep in mind that ambient temperature can affect stringing if you don’t have an enclosure.

The first thing that I do if I find that my printer is stringing is print a retraction tower, a temperature tower, and recalibrate my extruder. This takes 30 minutes and saves tons of time.

I read a user’s help request in an online forum that was interesting because it illustrates what can happen from time to time. The symptom that the user was experiencing was that there was way too much squish in their first layer of printing. It was almost non-existant.

They were stumped for a while as to what the cause was. In reading through their comments and the things that they tried, it turned out that they had a BLTouch. Basically, what had happened was that they had set up a mesh bed level manually, and then they allowed the BLTouch to override that stored level. A misconfigured BLTouch was the culprit, in this case. It was going through the motions, but it was storing an inadequate bed level, which was overriding the valid mesh bed level that they had stored previously.

This is probably the most difficult thing to troubleshoot, and I had it happen to me a while ago. After checking everything that I could think of, I tried a test print. It worked, ah, what a relief. I tried a few more prints. So far so good. Now to go ahead and try the overnight print. It failed at around hour 12 or 13. Ugh. Back to the drawing board. After going through several logs, I found a T0 error. Ah, something to look into.

In my case, it turns out that my temperature sensor wire was frayed. A $12 replacement fixed it, probably something that I should have done to begin with.

Live and learn.