Ultimaker first layer a bit messy (previously working model)

[gadgetfreak 7]

Hi,

I got a picture from misbehaving UM2 at a friend yesterday night.

I'll troubleshoot on site today but since I'll be short on time once there I thought I'd ask for some fellow input here first.

This is what I know before looking at the unit first-hand:

The machine has printed fine everyday for a week.

This same model has also printed fine on this machine with the same roll of filament.

Now the first layer gets really messy, like this:

 

Bed leveling has been re-done twice and still the same issue.

They tried with two different rolls of PLA.

 

I was thinking it looks to be too hot/over-extrusion so I will check the used filament profile for temp/bed temp/diameter/flow etc.

 

Also cleaning the bed as it looks a bit messy.

 

If that doesn't help I'm thinking of trying AtomicBobs cleaning process like documented here (by another nice forum contributor) to rule out strangeness in the nozzle:

http://www.fablab-regensburg.de/wp-content/uploads/2013/12/Ultimaker-2-Nozzle.pdf

 

Any other input from you guys?

Thanks.

 

 

[illuminarti 18]

Definitely wouldn't hurt to clean the bed. The glue should be virtually invisible when it's applied right.

Maybe also adjust the bed leveling screws during the start of the print if needed toake sure the first layer is properly squashed down - it's a bit hard to tell in the photo, looking at it on my phone.

[illuminarti 18]

Also check the outside of the nozzle - maybe if it has gunk on it, it might be catching/pulling up freshly laid plastic.

[gadgetfreak 7]

Thanks Simon, good pointers

 

[jonask 0]

Hi,

i also try to figure out how to avoid those "messy" first layer lines. If i print large first layers i got the same problem.

As you can see on your picture, only the large lines look really messy. The outer lines, where the head don´t travel so far until it lays the next line right beside look pretty ok.

Sometimes i`m able to avoid this, by leveling the bed while it prints the first layer like Simon sad. Just restart the Print when you think its OK.

 

[SandervG 1,521]

I would also double check the bedleveling.

Perhaps there is glue in the nozzle because too much was used?

Other models behave the same?

He has no problem with extruding in mid air? (move material) ?

 

[gadgetfreak 7]

The problem has been solved!

I was never on site, but apperently there was gunk built up around the nozzle that was the root cause.

Good troubleshooting feeling Simon

Thanks for the help guys!

 

[jonask 0]

witch speed do you guys use for your first layer? I`m using 5mm/s right now but it takes a looooong time if you print large first layers.

 

[SandervG 1,521]

20mm/s should be alright for a first layer.

Unless you are printing something very delicate like a chainmail, you may want to go 10/15mm/s i guess.

 

[illuminarti 18]

I generally do 30mm/s on the first layer on the UM2. On tape, for the UM1, I print first layers at 75mm/s.