I ordered my X1C January 31, 2023. I first began to read about warped bed issues a week later, so that was one of the first things I checked when my X1C arrived February 17.
Tested with a steel rule and a feeler gauge, the bed showed no gap anywhere parallel to the y axis. Any measurement parallel to the x axis showed a central dip, 0.76 mm lower than the edges. The curve was pretty smooth, the same front to rear, and symmetric about the middle, but a little steeper near the edges. I was not certain that this was a significant problem, and the comments here suggested that Bambu did not have a real solution at the time, so I just used the printer and waited to see what happened.
Most of my initial prints were small items and the curved plate had no real effect. Then I began to print larger items (150 mm wide) that would rock because their bottoms were not flat. Replacement beds were still being sent out with a warp. I placed my models with the long dimension front to rear, and waited.
Around the end of May, I began seeing reports here that users were receiving greatly improved replacement beds. I printed a thin test piece covering the entire usable bed, and submitted a detailed ticket, including the log.
The initial responses from Bambu support were just a stock answers that did not really address the problem. Manual tramming (which I had done before) cannot make melted plastic become flat on a curved surface, but I did it again anyway. They said my cold measurements were invalid because the bed flattens when warm (what about PLA on the cold plate?), so I did it again with the bed at 95°C. The dip became worse, 0.86 mm lower in the center. I sent them a video of the measurement. Indicator zeroed in the center:
They asked me to print a small cube so they could see a recent bed level mesh - I referred them to the log I had already submitted with the ticket. After a couple days for “engineering” to evaluate the log, they made arrangements to send me a new bed.
Bed replacement took me a couple hours, mostly because I was taking my time, and taking pictures as I took things apart so I could put them back correctly. I printed pictures from the wiki and glued them onto cardboard (see below). With holes punched by an awl, I put each screw in the cardboard at the correct spot as they came out of the printer, so every screw could go back into the same hole where it started. The 1.5mm hex wrench that comes with the printer lasted for about three screws before the ball end was worn out, you can grind it flat or use a better wrench of harder steel. The bed replacement is not a difficult job, just takes time and attention to details.
The new bed is not absolutely perfect. There is still a slight curve left to right, but the center dip is now only 0.07 mm, and I can live with that.
These two images can be printed on letter sized paper (ignore the duplicated screw position image)
