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Blobby extrusion

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Howdy!

I'm getting spotty feeds on my U2 - using both ABS & PLA. Tried gluing the surface and change the bed distance to see if it was too close / far away, but with no difference. When feeding manually it extrudes without problem, but once it starts printing it only produces small blobs. I'm thinking that it might be something with the temp sensor or heater block being off - I lent it to a friend and the he had the sensor replaced as it broke, could that be related?

IMG_20150820_112300.jpg

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It could be the sensor.  I've tested about 20 sensors and they vary by a surprising amount.  Try this temperature test.  Also consider getting an Olsson block (just google it) both so that you are testing with a fresh nozzle and so that it's much easier to clean the nozzle in the future.

 

Also switching between abs and pla often is very very problematic for about 3 critical reasons.  For example ABS doesn't come out of the nozzle easily when switching to PLA and it can line the inside of your nozzle making the effective nozzle diameter quite a bit less than the expected .4mm and making it hard for filament to come out.  Or it can cause a full clog of course.  ABS pretty easily cooks to a gunk that acts more like a hard wax than the properties of honey needed to get through the nozzle.

I recommend sticking to one plastic (either one) for at least 100 consecutive prints.

Edited by Guest

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Thanks for the fast reply!

I haven't tried the temp test yet, but I did feed through more PLA until it was clear. Did a test-print but with same result.

Video: http://kkvgbg.se/dremelfuge_fail.m4v

dremelfuge_fail.jpg

Thanks for the suggesting the Olsson block - I'll look into getting one if this doesn't clear up. Will also do the heat test to see if I need to pick it apart and reset the sensor or heater.

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First do a few Atomics to clear out the crud in your hotend. Since you've mixed ABS and PLA there's a good chance there's some leftover ABS in there like gr5 mentions:

http://support.3dverkstan.se/article/10-the

Then re-level your bed a little bit closer to your nozzle and try again. Alternatively you can manually loosen the three thumbscrews under the bed during the print. You can also try simply pushing the bed upwards a little bit with your finger to see if things look better during the first layer.

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IRobertI has good advice - I wouldn't re-run the leveling procedure but definitely try unscrewing the 3 thumbscrews by about a half turn to see if that fixes it - this is what it looks like when the bed is just a little too far from the nozzle. But your other photo I think still had issues on the second layer so I didn't mention this.

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Thanks for the input all. I ended up doing the atomic a couple of times, still no dice. I picked apart the head and cleaned out the nozzle and checked all wires, reassembled and still no good.

Might be electronic fault somehow - I'm thinking that the heating block or sensor is tripping a fuse if there is one. I just heated up the head through the menu and it jumped to 200°C with no problems, but then started to cool down again. A quick restart of the UM2 showed the residual temp - still cooling - but it wouldn't go up again. The wires going to the board (temp1 & temp3) look OK, and I've tried resetting the firmware in case that was at fault.

So I'm thinking either a faulty heating cartridge or something on the board acting up.

I shot a video of the rising / falling temp as well as the exposed heating block: Video

(The rattling noise is the loose back fan)

Also, while taking the heater block apart the grub screw is all worn out - any suggestions for where to get replacements? Looking to get an Olsson block, but need to see how much repairing this will cost me…

Cheers!

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I'm not sure that grub screw is even necessary.

Did you uncover the electronics board under the printer?  Usually if there is a problem with the heater itself (not the sensor) then it's most often right there.  There is a "terminal block" where 6 wires can connect (for the 3 heaters).  The one you care about is the first one (heater 1).

If there is blackness/brownness or charring in the area then it's probably not a good connection.  The screw or clam that holds the wire in place is probably not holding it in place.

Edited by Guest

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I checked the connections to the board, they were slightly loose so I retightened. No scorching as far as I can tell.

Heating the head up worked as previously, but as soon as it reached the manually set temperature it would start to drop again. Restarting the machine didn't help, the head refused to heat up now.

I updated the firmware, reassembled the head and everything else, and it heated up fine and stayed at the assigned temperature, and I could increase / decrease the temp. I did a small test print which started out fine (it didn't stick to the bed though, so I aborted)

On the second print the print starts coming out blobby again and after a minute the printer stops with:

 

Error - StoppedHeater Error

 

On the support page Ultimaker.com/support I've checked the suggested check 1&2 for the error, so will see if the head is touching the fan assembly (#3). Suggestion 4 doesn't apply, so unless it's touching the fan assembly I'll have to open a ticket...

As a side note: The grup screw is what keeps the sensor and heater in the block, right? At least I can't remove them until I loosen the grub, so figure it ought to be tight.

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The board and head cooled down enough to check, and the nozzle isn't touching the fan assembly. Off to create a support ticket!

Thanks for the help all, I'll post any solutions I get. Should you get suggestions I'm still interested though!

Cheers

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heater error means the PID controller for the nozzle was at 100% for 30 seconds and the nozzle did not heat by at least 10C. So for example if you were in the stage where you were heating the nozzle it should be at 100% for more than 30 seconds but the temp should increase. Or if you are almost at goal temp but a bit low (say 1C low) for a very long time (say a minute) then the I term in PID will try to keep increasing the heater power until it's at 100% - if it's at 100% for an additional 30 seconds and the nozzle just won't get up to goal temp then you get heater error in this case also.

It is most often caused if the heater or the temp sensor fall out of the print head - meaning they are no longer coupled (sending power to heater doesn't heat the sensor) or if the heater just isn't getting power. If the sensor has a bad connection then the temp should read something completely wrong (e.g. 0C or 300C) when at room temperature.

It of course can also be caused if the fan shroud is touching the nozzle block as you mentioned.

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I would love to use this image and your initial one in an educational book, with your permission. I would also need high-res versions from you.

Please send me a direct message for more information.

Thank you!

Anne

 

Thanks for the fast reply!

I haven't tried the temp test yet, but I did feed through more PLA until it was clear. Did a test-print but with same result.

Video: http://kkvgbg.se/dremelfuge_fail.m4v

dremelfuge_fail.jpg

Thanks for the suggesting the Olsson block - I'll look into getting one if this doesn't clear up. Will also do the heat test to see if I need to pick it apart and reset the sensor or heater.

 

Edited by SandervG

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