The replacement bed came with a new plastic bed frame that was straignt. I replaced this as well hoping it would offer more support and straighten the bed.

After a few heat / cool cycles using the calibration process the bed is no longer warped in the middle. I used the auto calibration method and it evened out, but I still had to manually calibrate it to get the head closer to the glass for a reliable print.

The frame support structure has a lot to do with the glass apparently. And as previously posted, it should be made of something that is more tolerant of heat. I imagine that the new plastic bed will warp over time.

mpoffo wrote:

XYZ has said that discoloration is normal and nothing to worry about.  I have it as well and have no issues.

However the fact that uneven heating is evident, the plastic substructure of the bed is warped from that uneven heating and the glass is also being warped by the bed substructure is not normal. If you remove the part of the bed the glass sits in, and put it on a flat surface you will see it is usually warped. This part should be made from aluminum like it is on most other printers and not ABS injection molds.

I mean think about, if the bed is getting hot enough to keep your ABS print slightly hot so it cools evenly and bonds better it only stands to reason that it can get hot enough to warp or stress the ABS support structure as well.

You have no argument from me.  I think that is a very valid point.  I was simple responding to the discoloration comment. 

XYZ has said that discoloration is normal and nothing to worry about.  I have it as well and have no issues.

However the fact that uneven heating is evident, the plastic substructure of the bed is warped from that uneven heating and the glass is also being warped by the bed substructure is not normal. If you remove the part of the bed the glass sits in, and put it on a flat surface you will see it is usually warped. This part should be made from aluminum like it is on most other printers and not ABS injection molds.

I mean think about, if the bed is getting hot enough to keep your ABS print slightly hot so it cools evenly and bonds better it only stands to reason that it can get hot enough to warp or stress the ABS support structure as well.

The warpage in my right rail only affects the front right quarter of the bed. So far even for prints that go into that region it has presented no real issue. It seems once it is hot my bed actual lifts on that side a bit thus closing the gap more.

0.5mm (0.020")?  That's huge warping, much larger than mine.  So you can fit roughly 3x extra sheets of paper between the nozzle and bed, in the furthest-away spots?  Mine is more like 0.2mm (0.008" ~= 1 extra sheet of paper) warp.

Unfortunately, I hadn't tested the clearance in the center of the bed before.  So I don't know if it has changed.  Something odd is going on though, because I was getting really good sticking results, and now builds are warping badly, and can easily be broken loose from the bed.

My printer is only a couple weeks old, and has had some discoloration around the heating elements in the bed, since it was new.  I wonder if those couldn't have led to some failures and uneven heating?  Do others see this in their beds?  (Picture attached.)

If I do the "printer paper" calibration method, when the three areas over the screws just have the paper drag against the nozzle, the center is so tight I can't get the paper in.  It's making it challenging to get prints to stick well across the whole bed.

How do yours compare?  Should I call support?

There is some warpage on the bed. Could also be your linear rods. Mine on the right is slightly bent. When I rotate it I can see the head move away from the bed by .5mm. The best thing to do is just average so you have the proper clearance in your tightest spots. Those could be slightly lower as long as the filament still extrudes.

How do yours compare?  Should I call support?