odd prints webbing (with pictures) solved

General Software
1

I am having an issue with one of my printers not finishing, it can print the bottom layers fine but after that it always starts to web and I cant figure out why. it does not appear to be jamming because the filament doesn’t get ground up and I think it has something to do with the settings in cura maybe the e-steps or possibly some thing else I don’t really know I’ve never seen prints web up like this before. ps. i have calibrated the steps before so that is why i think it is some thing else. and I have cleaned the nozzle many times.

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2

That looks like filament starvation to me… try a few turns on both idler screws to increase the grip of the hobbed bolt. This will help filament feed into the extruder.

Does that happen all the time or is it this one print? Check that the spool of filament isn’t binding up.

If that’s PLA, then you’re probably experiencing heat creep. The first few layers look good okay… The heat creep will cause the filament to swell in the heat sink portion of the hotend. This increases friction to push the filament through. Try increasing print speed… and/or search forums for ways to combat heat creep. You can also try a little cooking oil on the filament to help it through the hotend…

3

I’m actually printing with cheetah flex its a semi flexible material.The rolls have not seemed to snag or any thing so I’m thinking it is the e-steps or speed, I will tweak both and update you with what happens.

4

Do you have a Flexistruder, or the standard extruder?

If using the standard extruder with Cheetah semi-flex… Tighten the extruder latch a bit, set temperature to the high end of the range (240-245c), and slow down the print speed a lot (like 15mm/sec). Also, take a look at this thing on Thingiverse:
http://www.thingiverse.com/thing:1649544

If that helps with consistent extrusion, you can try lowering the temp (if you are seeing lots of oozing) and increasing the speed a bit.

5

I am using the flexystruder v2 head so I cant really tighten an idler bolt I am already printing at 14 (mm/s) and even trying 10 (mm/s) and having the same kind of success with both printing speeds there a bit hit or miss so I have ruled that out as being the problem I have raised the temp to 248 that seems to be the best temp for me any higher it is oozing any lower It does not print as much. I have made a few more prints and have noticed it prints fine for two prints of this model but then when I go fore printing the third time it will get clogged from over extrusion.

6

Reviewing all this, it does sound like you are clogging or failing to extrude after a few layers of print. I can think of three possibilities:

  1. Loose drive gear set screw.
  2. Heat creep. Shouldn’t be a problem with Cheetah, as long as your heat break fan is running.
  3. Not holding temperature.

#1 is unlikely, as it would likely occur immediately rather than late in the print. But check the set screw, make sure it is on the “flat” of the motor shaft and that it is tight.

For #2… Ensure that the fan cooling your extruder is running and moving air across the fins.

For #3… This one may be difficult to diagnose, particularly if intermittent. At 248c, you shouldn’t have any problem extruding Cheetah, particularly at slow speeds. Is the reported temperature during the print staying close to 248c throughout the print? If there are big drops or long recoveries in the reported temperature, you could have a failing heater or bad heater wire. Although unlikely, you could also have a thermistor reporting 248c when actually at a lower temperature. Unless you have a spare toolhead to swap into place, it might be best to contact Lulzbot support directly regarding how to test/isolate one of these problems.

7

hi, thanks for the help the little fan is broken so I’m going to need to replace that and hopefully that is all that is wrong.

8

If your machine is still under warranty, contact Lulzbot support and they’ll send you a replacement. Otherwise, looks like they have them in stock for $18 + shipping.

I just replaced that fan on my mini a couple weeks ago… Not difficult, especially if you get the fan from Lulzbot because it comes with the right length leads and pins already crimped on the ends. If you source the fan elsewhere, you’ll have to add pins or cut/splice the old wires to use the old pins.

Another alternative is upgrading to a 25 or 40mm fan. You can search the forum and Thingiverse for instructions and designs that adapt the larger fans in place of the little blower. They are particularly helpful if you print a lot of PLA, the additional air flow helps guard against heat creep. But I have never had a problem with any other filament using the standard little blower fan (as long as its running!).

9

fixing the fan did the trick its printing with no problems