Ovals Instead of Circles

[Don_FG]

I've been printer for about 6 months and most things I can figure out. Replaced the extruder end this week because I had a severe clog. In replacing the hot end I found that the top end was starting to break in areas. So I print a new top end and there lies the issue. Picture one is how it set on the bed.

The hole from the top to the bottom (vertical) is circular which is good.

Holes on the sides, picture 2, is oval, not good considering that is where the hot end goes.

Also it seems compressed by about 1/4 inch from top to bottem.

So my question is, what the heck is going on?
1.jpg2.jpg

[Sebastian Finke]

Belts loose?

[Roxy]

Are you getting the edges curling up? Especially when the printer is trying to go outwards for an over-hang? Because that will result in extra material being put down and work to fill in the hole to make a less than perfect circle.

There are several reason why that happens. If the edge is curling up, when it gets pushed down it fills the circle hole more than is desired. But also, the fact it is curling up means the nozzle is rubbing against the edge and any extra material available gets put down on the print at that point. (like some extra hot plastic that is smeared near the extruder hole).

[Don_FG]

Verticals hwve screw drives so no slipping. No curls on the edges, I'm using petg so no heated bed. Thought it was shrinkage but that would not explain the perfect holes from top to bottem
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Gonna reset the firmware today and have another go at it. I'll share results.