A tip from a newbie on large print base warping....

Have you tried just using a ceramic tile ? it has heaps more thermal mass than glass or the alu-bed..  I found that I have 0 warpage on tile.. due to its far slower cool-down abilities, it tends to maintain a constant temp over the life of a print..

I agree this is a good trick.  Thanks for posting it.

That said, isn't the warping ultimately caused by upper layers cooling faster than bottom layers and so - depending on the amount of infill - pulling the bottom during that contraction?   That has led me to think that keeping the ambient environment at a warm consistent temperature was probably just as important as futzing with the stickiness of the print surface.

I guess I was starting think that ability to stick and ability to resist warping might be two different things, even if at some level having a high level of "stick" prevents warping with low-rise objects.

I'd be interested in others' thoughts or a pointer to what I'm missing.

Matt

Doesn't even need to be upper layers vs lower layers.. just delta's in the temp across the part versus the ratio of cooling plastic... a long, flat, thin piece is far less likely to warp or lift compared to the same piece but doubled in thickness - because the plastic 'inside' is going to be molten still compared to the cooling exterior, which will now contract (shrink) as it cools.. but its overall volume is constrained by the still molten liquid.. so it warps...

This is why its often those thick 'chunky' pieces that warp but a relatively 'light' piece will print just fine... and punching circles (holes) in planes helps resolve the problem as the contraction will occur around the circular cutouts and not at the 'usual' points of strain (like say, a vertex).  This is also why you only ever see warping from a vertex, not mid-plane. (And all of this is different from small footprint objects which as you observed can 'lift' due to the contraction having a higher force vector than the adhesion to the buildplate.. simple matter of increasing surface area to the buildplate using Brim to win this battle.. and why it also helps with warping overall sometimes...)

A heated build area reduces the occurence of this, because it slows the overall rate of contraction of the exterior vs the interior. Likewise a hotter buildplate, because it slows the entire process down to a rate that is generally speaking, more uniform.

So yes - having a uniform ambient will assist matters.. but then you'll have fun and games with other areas that are 'assisted' by rapid cooling (such as bridging ). You gain some, you loose some...

Of course, opinions differ on this - and I'm no expert either, but unfortunately when luck combines with empirical evidence, you end up with a multitude of 'solutions' ...