Nozzle Dragging on Parts

[Schnupp]

I've noticed that my nozzle has been dragging on my parts. At first I figured my nozzle was too close to my bed but I adjusted it to about 1.5 paper lengths and the problem still persists. My part is not lifting up off my bed either. Here is an example pic:

Any help would be much appreciated

[AbuMaia]

What material are you printing with? It looks like an oozing problem more than a dragging problem. It's not dragging over the circular hole, so it's related to your infill settings.

[Schnupp]

I'm printing with abs at 235 and a heated bed at 110, first layer set for 90

[printbus]

Is that supposed to be the start at a solid layer? Seems too horizontal and too localized to the five infill rows to be random moves.

[Schnupp]

Yes this is the start of a solid layer

[printbus]

Yes this is the start of a solid layer

Ok, then the problem isn't the nozzle dragging across the part. The problem is that the bridging for the solid layer across the infill is collapsing. Help with the scale here - about what is the size of the infill pattern?

[Schnupp]

Im using a .15 fill density. The part is about 5 inches from the far left corner to the far right corner. When that top layer was printing I could hear the nozzle hitting each infill line which is why I stopped the print. During other parts of the print I could hear the nozzle dragging on the part as well but it didnt damage the part at all so I let it go.

[printbus]

Hmm. I always get some dragging, but typically only infrequent. So 5 inches across, roughly 25 infill squares, or 0.2 inches per infill square. That shouldn't be too tough to cover, but I'll let those with more ABS exposure suggest things. Might be interesting to see the gcode to feed it into a viewer for deriving print speeds.

It almost looks like you're not extruding much. Is it the light or is there something brownish down across that one row in the center of the solid layer attempt?

[Schnupp]

Its not the light there is a brownish burnt section which I assume was from the hot end dragging across the part. I double checked my bed leveling and I was actually too close to the bed. I guess 3 small prints somehow threw it off... BUT Im trying to level everything again now and im starting to notice some strange things. I crudely marked up this image to help demonstrate what im experiencing. Im starting to think my 12" heat bed is convex or something because of my measurements.

[printbus]

The thin circuit board heaters aren't all that flat or rigid. Placing a piece of glass (with corners cut off) onto the heater and using binder clips to attach the glass to the heater should straighten things out. You then adjust bed leveling and nozzle clearance to the glass.