I’ve had my Taz 4 for a few months, and I’m generally happy with it.
However, I noticed recently that my print bed isn’t flat. I can level it just fine at the corners, and verify that it’s level, but I’ll have portions of the bed higher than the corners. Is this normal?
I’d really like to print using the whole print bed, but I don’t feel confident doing that when the center of the bed is significantly higher than the corners (nozzle crashes in center while corners are a little on the low side).
Is this a faulty glass plate? Is there something I can do about this?
It would be very, very strange to have the glass not perfectly flat, that is one reason glass (borosilicate float glass) is used.
If you are absolutely sure it’s not flat then contact support for a replacement. If you have a steel ruler, you can use the edge to verify if it’s flat, just lay the edge across the glass at different angles and see if there is a gap anywhere between the edge and the glass.
Also check out the proper bed leveling video by Lulzbot on Youtube just in case you missed a step.
I haven’t tried it yet, but that sounds like good advice. I currently can’t print large parts (even 6" long), because of the difference in level between the edges and the center.
How do I set the z height in the center of the bed after leveling? With the end stop?
Yes, the Z end stop knob. You want it to just slide a single sheet of paper under it and if you move the paper it should have a slight amount of friction between the nozzle and bed.