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AlexHaysler

Underextrusion Help!!

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Hi,

Have been printing with my UM2 Extended for a month and a half now, had a problem today with motor slip though! Once that was sorted, went through material change process, cleared nozzle and went to print and after ejecting filament as normal at the start of the print it just started to print the model with dots of material! :(

Does anyone know why this is? Looking forward to some awesome advice :)

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The rotation is very small - did you feel the feeder motor for an entire minute of printing to make sure? It's possible that your flow rate is set to 1 (1%) and it is moving 100X slower than it's supposed to. This would be a Cura setting if your cura machine settings specify "rep rap" mode (not default, not likely, and not recommended) or that could be your material settings on the UM2 (that should be where your flow settings are). In the later case you can just check in the TUNE menu after it starts printing.

A video of the first minute of printing that shows the head moving then pan the camera to the feeder for a while then the last few seconds back to showing the whole printer. That might help us narrow down the issue.

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Just before you check any other think. Get the extruder metal prt cleaned with a brush. Sometimes it's just that. There are also chances that the filament it's bigger than 3mm. Or just the tension spring etcetc.

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Don't know how it would do filament changes, but can you check if the set screw that holds the knurled sleeve is still secured?

Maybe the motor is rotating freely inside that sleeve.

(just like in the image, but yours probably isn't missing, just loose)

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Thanks for your fast responses guys!

Manually fed in filament quite a few times until came out clear, then re-run it and seemed to work fine again! Will monitor over the next few prints, and post photos as on closer inspection of old prints there is some very minor underextrusion.

Bowden tube also wasn't pushed all the way in, what a dope! :p

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If the Bowden tube is not ALL the way down into the Teflon piece, the filament has a great chance (50-100%) of crashing into the top of the teflon, and is not fed through the teflon and into the head at all.

This is a total stop, and the knurled drive will inside 1 second carve a bump in the filament and then make almost no noise, slowly and happily purring away at thin air.

Nothing happens!

Fix: Make Bowden fix inside Teflon top. Then Manually extrude filament WHILE you help it a lot by pushing from behind so the drive can overcome the bump in the filament!

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