inconsistent extrusion rate

[Manny1 0]

Hi guys.

I just printed something and the density of the object does not seem to be very consistent. It appears as though there has been some under extrusion in a part of the print, but then it returns to the correct extrusion rate later on. I'm not sure how or why this happened, since i did not play around with the printer while it was printing.

I printed this in PLA at 210C at 50mm/s, with a layer height of 0.1mm, a shell thickness of 0.8mm, retraction enabled, 25% fill density and cooling fans on. I had support under the top bar, which is where the print seems to go back to normal.

I've attached links to some photos of the print, including the lines where you can see the extrusion rate change.

Thanks for any help!

[Dim3nsioneer 557]

I guess you had a lot of stringing before you cleaned the print. That was a serious material loss which caused the underextrusion. Try to print more slowly and cooler if not for the whole print then for this section. You may use the TweakAtZ plugin for that purpose.

[gr5 2,167]

You definitely have some underextrusion on those side bars. I'd also print slower. Don't print any cooler than 210 if you are going at 50mm/sec. I'd stick with current temp (or even raise it to 220C but 210C is usually fine if your temp sensor is accurate) and slow it down to 25mm/sec for either the whole print or at least the problem area.

There is a speed/quality tradeoff. I you want better quality then go for slower printing.

[Manny1 0]

thanks for the replies. My main concern with this is that I usually print with these settings and have never had a problem before. The only thing that has changed is that this is a new reel of PLA and it feels rather gritty. Not sure how much of a difference that makes to the print.

And yes, there was a lot of stringing!

[gr5 2,167]

PLA and it feels rather gritty.

Hmm. Maybe the filament was getting a bit stuck in the bowden tube?

If there's lots of stringing I tend to lower the temperature to fix this. Try 200C next time. In fact when you are printing something that is stringing worse than usual, just go right to the TUNE menu and drop it by 10C but don't go below 190C.

[gr5 2,167]

And whenever you see underextrusion like this try raising the temp (woah - contradicting advice!) and/or slow it down in the TUNE menu.

[Manny1 0]

LOL thanks. I'll give it a shot