New Problem - Curling Edges

[RayLivingston 1]

I'm doing some large prints, and have a new problem - the edges of the first few parallel perimeter layers are curling up, rather than adhering to the bed.  This means what should be a square cornder in the cross-section ends up becoming a rather large radius fillet.  The center "in-fill" layers are adhering just fine, and I don't have this problem on smaller prints I've done.  The rest of the print, which is 1/2" thick, prints absolutely perfectly.  One difference that may be a factor - I've set the Shell->Wall Thickness to 3mm.  Could that be the problem?

 

Regards,

Ray L.

[PaulK 14]

You don't say what printer or material, but here is a completely random possibility when this started happening to me recently when normally I am fighting to get PLA off the bed.

I had dual extruder set up, one PLA, one ABS. I was printing something *entirely* in PLA, but because the ABS extruder wasn't disabled, Cura heated the bed up to ABS temp (Cura, please don't do this!). Turns out PLA will adhere to a bed this hot (I think it was 85 or something), but it is reaaaal soft and tends to curl up and corners.

 

Of course, there about a zillion other reasons too.

[RayLivingston 1]

The printer is a modified Tevo Tarantula, and I'm printing with PLA.  Only one extruder, and using the same termperiatures I've used for many other smaller parts.  This has happened on two different larger parts, so it is a consistent problem.  Smaller parts do not exhibit this problem.

 

Regards,

Ray L.

 

[PaulK 14]

Larger parts exert a LOT more force on the corners/edges. It sounds like just a bed adhesion problem, where you have enough for smaller parts but the big ones are getting you. The usual solutions -- brims, adhesion help, more squished first layers, etc. will probably do the trick. You can get pretty big with PLA and survive it if you can get the adhesion.

[RayLivingston 1]

That makes sense.  I did not print a brim, as it was not necessary for the smaller parts.  I'll try one of these big ones again with a brim.

 

Thanks!

 

Regards,

Ray L.