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supermerill / SuperSlicer

G-code generator for 3D printers (Prusa, Voron, Creality, etc.)
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Extrusion Multiplier only works for 1 and .95 values, ignores other #2455

Open ModMike opened 2 years ago

ModMike commented 2 years ago

What happened?

When printing an Ellis flow tile test with values from .90 to 1.0, only the .95 an 1.0 tiles are different. I redid the test with the wall thickness technique, and same result.

Project file & How to reproduce

Extrusion Multiplier.3mf.zip

Alternatively, print a 4 perimeter cube with no top or bottom at .90 and another at .99. Measure wall thickness. You will see that it does not scale flow as expected, so walls are nearly same thickness.

Version

2.3.57.11

Operating system

No response

Printer model

Ender 3 but Voron users also reporting issue in discord.

supermerill commented 2 years ago

I don't understand.

ModMike commented 2 years ago

When setting the extrusion multiplier to anything other than 1 or .95, there is very little effect because there is a math error in the Slic3R library.

In order to get the extrusion multiplier to somewhat work, I needed to set it to .95 and then set default line width to 111%. This is a hack that is going around in the Voron community to get it to work. This has been verified by a few people, notably Martin whom I believe contacted you about it, as well as Yukie, and Methos.

supermerill commented 2 years ago

If I set the extrusion_multiplier to 2, I have 2 times the length of filament used in the gcode file. So by reading "Extrusion Multiplier only works for 1 and .95 values, ignores other", I clearly have a problem understanding what you really means by that.

ModMike commented 2 years ago

When I set the extrusion multiplier to .98 I get a VERY small change as compared to .90. So small that it is next to useless. Apparently the math is wrong in the Libslic3r which causes the extrusion multiplier to not scale properly.

I know this goes back to the defunct Slic3r, so not sure if it can be or will be ever fixed.

ModMike commented 2 years ago

I updated the the first to make it easier to understand and reproduce.

supermerill commented 2 years ago

can't replicate image

ModMike commented 2 years ago

You have to print to replicate. I will upload pics later today.

Thank you for taking the time to look at this!

legend069 commented 2 years ago

You have to print to replicate. I will upload pics later today.

Thank you for taking the time to look at this!

providing the sliced g code will be fine, as we can see the output values for each extrusion, if you have problems with it printing it could be several other things.

please provide the sliced g code file for extrusion multiplier set to 1.0, 1.05, 0.95 or the specific values you think are causing problems.

supermerill commented 2 years ago

Also "Measure wall thickness" is an unreliable metric.

ModMike commented 2 years ago

I gave up on this seeing as Sli3r and Prusa said they would look at it. By the looks of it there was a new build that specifically addresses this, not sure if it's the issue I was originally referring to. By the way, the latest Mac nightly build is corrupt for some reason.