Failed at third layer

Hi everybody,

I really can not get my head around this. Everytime when I print larger objects with PLA I have to warm my sanded kapton hotbed to 110 degrees to make it stick for the whole print.
And after laying down a base layer at 200 degrees I continue with a second layer at 185 degrees which goes well but the third layer constantly fails somehow. It does not seem to have enough grip on the previous layer (as visible in the image). Anyone experienced this as well?

What I'm also wondering, what temperature set up do you use for larger PLA objects? I'm using:

HB first 110, then from 8mm height to 12mm height 110 -> 60
Nozzle first layer 200 and the rest 185

Thank you in advance!

Wesley

Looks like you are printing on a raft (which is isn't necessary on heated Kapton) and your flow rate is too low for the object so it doesn't stick to itself.

Also you don't need Kapton for PLA although it should work. Also I find sanded kapton sticks less well than not sanded. Plain glass is much better for PLA.

Have you tried printing with with the latest Skienforge settings provided?

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[www.hydraraptor.blogspot.com]

Is your bed properly levelled?

I print PLA on glass (with PVA juice) at 185/85 and have trouble getting my prints off the bed sometimes...

your first layer should be very flat and completely filled. I slice my first layer in slic3r with 150% flow....

post a picture of the first layer....

Tnx guys for the quick responses!

@ Nophead I actually print on sanded Kapton tape with a raft because all the print got loose when I printed on the plain glass. But I will try it again on plain glass haven't done that yet with the new settings.
@ Traveltrousers Checked my HB and it is leveled. If the plain glass doesn't work I will try PVA juice on plain glass. I will post a picture on monday when I'm back at the printer

By the way, Could it be that the reason for the prints not sticking to the HB is that I live in a house where the room temperature is not very high and there is a chance of a constant small draft? If so, is it adviced to build a cage for the printer?

Edited 1 time(s). Last edit at 11/15/2013 08:45AM by Wesslie.

A cold room with a draft will not help but it looks like the main reason it does not stick to the bed or itself is that the flow rate is low so you are laying down cylindrical filaments that only touch tangentially instead of a squashed bead. I.e. it doesn't look like whatever you sliced it with is set up correctly.

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[www.hydraraptor.blogspot.com]

What layer height are you using? If you need to use a value 0.3mm.or less.

@Nophead, I will set the flow rate higher and make sure the HB is leveled or maybe even lower the nozzle in SF, thank you!
@RyanMark, I am using the 0.3mm PLA settings in SF from Nophead, that should work, thanks!

Get right down and watch the first layer come out of the nozzle, it should be literally being smeared across the bed. if it's falling or round the extruder is too high and you need to either relevel, set the Z-height in firmware or both.

Check out my bed levelling test I put on thingiverse

[www.thingiverse.com]

if that doesn't stick to the bed, there's your problem...

Thanks!
I tried the bed leveling tool and now the bed is perfectly leveled and I don't need a raft or anything it sticks very nice! Finally I can print again!

Nice! 450 tail fin?

Yeah, it's a RC helicopter tail fin for my nephew