Baseplate extremely uneven

[atomic field]

I have a VCore-4 500 CoreXY without an enclosure that I've been using for over a year, generally with great prints (all PLA). I recently added an enclosure to the printer and have started printing ABS with a much higher bed temp (110C). The prints are coming out great, with one exception - the bed shape is crazy. An adaptive mesh shows a maximum variance of 0.8mm, but the prints are coming out with a crazy hump. I measured one at 3.8mm!

Any clue what's going on? It seems odd that the prints are coming out that distorted when the printer's mesh doesn't seem to be that far out. Bed adhesion isn't an issue, and I'm leaving the print to cool on the bed.

The photo is of a part of my V-Chonk build, one of the skirts. As you might guess, it's supposed to be flat!

[willow hound]

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[oblique ore]

When the gantry gets hot it flexes and that is what the bed looks warped. If you are not running RatOS RC4 I would highly recommend it. It has an adaptive heat soak that will help with first layer issues and will deal with any gantry flexing.

I suspect the print warping is just the ABS contracting. The bottom layer is lot more structure vs the top layers and it’s just pulling like that.

[atomic field]

Thanks - yeah, I'm beginning to suspect it's contraction because the print bed doesn't seem that far out if I put a flat steel level on it, even at 110C, which explains why the heatmap looks acceptable even when the prints don't. The weird thing is that it's happening to so many prints. I'm going to try changing some of the default slicer settings and see what happens

[limber rapids]

Also, are you letting the plate cool completely prior to pulling the piece off? I've had warping issues when pulling pieces off too soon.

[oblique ore]

ABS is a lot more prone to warping than PLA

[atomic field]

So I'm finding out! I was expecting it to corners lifting, etc rather than this. I might try putting the parts on the bed, cranking the temperature neck up to 110 and leaving it for an hour or so, then quickly clamping the parts between two flat plates to see if they'll straighten out a bit as they cool. I'll not at all confident that it'll work, but it's worth a go

[oblique ore]

I print polymaker ABS and print the first layer at 100c and then lower down to 90c. I think the lower temp helps with some of my warping issues

[atomic field]

Thanks, I'll give that a go! I've been printing with the bed at 110C, perhaps that extra heat isn't helping either. The more the part cools, the worse it's going to be

Are you using the parts fan?

[oblique ore]

thats always been my thought and it works for my setup. Yes I run the fan but only at 25%

[atomic field]

The default profile has the fan at 40%, which seems high for ABS

[oblique ore]

I started with the rat rig profiles for Orca and tuned from there