A bit late to this thread but I find if you print on a three layer raft then warping is almost completely gone. Also use 3-4 mm layer expansion for the raft…
I have had issues with large flat parts, when printing ASA on my X1C.
I use Bambu ASA and standard settings.
Inspired by DarkDragonWing:
I am not allowed to link to the youtube video and website, but google
DarkDragonWing and 3d-printer-hot-box
I have had great success with covering my printer with blankets to insulate it, with the purpose of keeping a steady temperature inside the printer of 65-69 degrees C.
I pre-heat the printer by lowering the bed all the way down, setting it to 110C (max setting on my printer) and run the aux fax at 30%. it takes a while to get to 60 degrees C, where i would start printing. Then monitoring the housing temperature, and open the blankets slightly to ensure the temp stays under 70.
I am using “movers blankets” the cheap recycled kind from the hardware store you use for wrapping stuff when moving. I used 5 pcs, folding them so i lay them on top and down one side. ending up with a thick layer on top. And i have taped the top glass edges, but not the door.
The AMS is next to the printer, not on top