Help: do I have bowed axes?

[atelles 0]

I finished levelling the bed, and corners seen ok, but then I printed a test and got this:

The perimeters of the bed seen ok, but the middle of the bed is way too close, and the nozzle is blocked, unable to deposit plastic.

This creates pressure on the nozzle, and when the head moves away from the middle you can see overextrusion.

What could cause this?

My guess is that somehow my axes are bowed in the middle.

But is it the 6mm axes that support the print head? Or is it the XY axes?

 

[phanc60844 0]

either you bent the rods that support the extruder or the bed is bent. fix a glass sheet to the bed and use a piece of paper to gauge the nozzle height across the full extent of the bed. it cant be the x,y axes as they would move the extruder up/down every revolution, more likely one of the extruder support rods is out. you could remove them and roll them over the glass that you checked the bed with.

Paul

 

[gr5 2,189]

It's probably the plastic is bowed. If you just keep printing it will probably be fine by the 3rd layer. How thick was the first layer? I think the default cura is .3mm to account for this kind of thing.

 

[atelles 0]

Hey, thanks Paul and gr5.

I examined the bed and it was indeed bowed. But I only flipped it over, since the other side is much better.

This fixed the issue, but now I suppose I have to check my belts, it looks like I have a bad case of backlash: