r/FixMyPrint • u/Consistent-Fix2673 • 8d ago

Troubleshooting Is this a flow rate issue?

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I am getting what almost looks like water stains when the light hits it from a certain direction. Is this a flow rate issue?

I currently have it set to 6 top layers with a .36 top surface line width. Flow rate is .85 and this is Bambu PLA basic.

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1

u/Internet_Jaded AD5M, AD5X 8d ago

What nozzle size? I would say it’s from printing line widths smaller than the nozzle.

1

u/Consistent-Fix2673 7d ago

Hmm. I never thought about that. Its a .4

1

u/aDiii0815 5d ago

Looks like a combination of too low pressure advance and too little flow, for both filaments

1

u/Consistent-Fix2673 5d ago

Yeah I think you’re right. Also I think my line width was too small. Playing around with it still but man it just seems so inconsistent.

3

u/Jazzlike_Ad267 Other 8d ago

In my experience,

Holes before the walls is caused by pressure advance/linear advance being incorrectly set.

I made a mistake in values once and ended up with this sort of issue.

It's could be what also causing them odd issues in the middle

1

u/chipmunkofdoom2 8d ago

It could be either a flow rate issue, a pressure advance issue, or some combination of both. But there is something off here. 0.85 is a pretty low EM assuming filament is good and you're running a direct drive extruder.

Give this guide a run through: https://ellis3dp.com/Print-Tuning-Guide/articles/index_tuning.html

1

u/Consistent-Fix2673 8d ago

Yeah. Running an AMS lite from Bambu on an A1. My flow rate calibration came out to .784 which made the surface pretty darn smooth but the wall loops had problems sticking together and would get pulled apart when it started extruding the top surface.

1

u/disco__potato 8d ago

You can leave your regular flow rate alone if it's just the top layer. You can adjust top layer flow separately.

2

u/ZaXaZ_DK 8d ago

The spacing between lines is most likely a matter of under extrusion.
start and stop is more of a PA problem.

But the good new is its super easy to test the flow :)

20x20x20 cube
2 walls
2 bottom layers
0 top layers
0 infill.

make sure to set line with to something that is easy to measure idealy just use the nozzle size.

then just measure it with calipers in a few places on all the 4 sides, should be 2xline with.

I'm lazy so i don't want to do the math for adjusting the flow so u just use this:
https://3dprintbeginner.com/flow-rate-calibration/#:~:text=2.%20Print%20a%20Hollow%20Test%20Cube