still not level after using ABL

[adamfilip]

Ive noticed that even with ABL enabled with marlin set to 3 point checks.. so it probes 9 spots in the grid
some parts of the bed are not pressing down as well as others.

wonder what I can do to improve this.

[sniffle]

i've been having this issue on large area prints, but on smaller prints it hasnt really been an issue. part of the problem was my own and i fixed that and it helped(my raise before probign was less than my offset which caused an issue) but even now it still can't print things near the edges.

[misquamacus]

Large print beds are bad about warping. It's a very common problem and gets worse as the bed gets bigger. The simplest solution I'm aware of is using a thick piece of glass that's extra rigid; only clip the glass down on one side. Clipping the glass down on multiple sides just bends it to conform to your already warped heat bed. You'll know you're doing it right if you can see a slight gap between the glass and pcb in several areas. You lose efficient/effective heating but gain a perfectly level build platform. This has worked well for me and it's definitely the simplest/cheapest solution.

[walkercreations]

I have been wondering if a film of thermal paste between the glass and heated bed would help better distribute the heat? That is something I have been considering since my first failed print.

[adamfilip]

Large print beds are bad about warping. It's a very common problem and gets worse as the bed gets bigger. The simplest solution I'm aware of is using a thick piece of glass that's extra rigid; only clip the glass down on one side. Clipping the glass down on multiple sides just bends it to conform to your already warped heat bed. You'll know you're doing it right if you can see a slight gap between the glass and pcb in several areas. You lose efficient/effective heating but gain a perfectly level build platform. This has worked well for me and it's definitely the simplest/cheapest solution.

1 use a 1/4" Borsilicate glass plate. I have 4 clips holding it down to the Heater element. I would be shocked if the clips deformed the glass at all.. its so rigid

[MiniMadRyan]

It's weird you mention this. I've noticed that on larger prints, my first layer is almost always a bit too high, but that it's uniform across the entire print, not just limited to a certain section. Smaller prints though, print perfectly. I was almost wondering if it could be somehow related to the algorithm in the ABL set up, but I haven't had time to experiment with it yet.

[Schnupp]

I've noticed that on large prints in the x and y direction the z axis doesn't move fast enough to compensate for the unlevel bed. This is noticeable when the nozzle moves full speed across the part and scrapes it a bit. Small scraping is common even without abl but I've noticed it more with large abl prints

[TopJimmyCooks]

ABL is awesome but you still want your bed to be basically level in relation to the nozzle. get out a piece of paper or a feeler and level with your nozzle and bed hot and you won't have that problem. Also, the bed material itself has to be flat.