First Layer Speed Modifier Doesn't Change Anything  

RE: First Layer Speed Modifier Doesn't Change Anything

30% of what though ?

please save your project file as a 3mf, zip it up into an archive and then attach it here. Must be zipped for the forum to accept the file. 
With the 3mf project we can then see all your settings so we can slice it with exactly the same as you are using and see what may be effecting things.  It’s the best way to debug issues like this as there are so many interacting options. 

RE: First Layer Speed Modifier Doesn't Change Anything

Suction Cup

The regular speed is between 45 and 80 mm/s. I don't think that that's particularly fast, and 30% is quite small. So I doubt that it's maxed out even with the modifier. 

RE: First Layer Speed Modifier Doesn't Change Anything

@thedasman - Are you using Simplify 3D as your slicer by any chance? To know what the 30% represents, we'd need to know your basline printing speed.

RE: First Layer Speed Modifier Doesn't Change Anything

I'm using Prusaslicer 2.1.1. 

All speeds are in mm/s

Perimeters: 45

Small perimeters: 25

External Perimeters: 25

Infill: 80

Solid infill: 80

Top solid infill: 40

Support material: 50

Bridges: 30

Gap fill: 40

RE: First Layer Speed Modifier Doesn't Change Anything

@thedasman

try this

In Prusaslicer 2.1.1. select your PETG profile, make sure everything is set back to default for that profile, then go to Filament settings/advanced, and look at the (Max volumetric speed) in the Print speed override window, my guess is its going to say 8 mm³/s (now do the math, you want 30% of that speed) 30% of 8 is 2.4 so set your Max Volumetric Speed to 2.4 and re-slice.

when you see this on the LCD display it's still going to read 100% because the 2.4 represents 100% of your speed for this slice/print

Good luck

RE: First Layer Speed Modifier Doesn't Change Anything

@thedasman

apologies, I missed the part about only wanting the first layer speed, it's been one of those days. 

So, try this instead

In Prusaslicer 2.1.1. select your PETG profile, make sure everything is set back to default for that profile, then go to Print Settings/Speed/ Modifiers window, and look at the First layer speed (I think it's something like 20 by default) so you want it 30% slower so do the math 30% of 20 is 6, so enter 6 in your first layer speed, that should cause your first layer to print at 30% of it's default speed.

there are two ways to do this I used the absolute value.

RE: First Layer Speed Modifier Doesn't Change Anything

Everything looks normal and correct from your 3mf.  You have first layer set to 30%.  Your first layer has perimeters and Infill on it as expected.  Your perimeters speed is set to 45mm/s and your external perimeter speed is set to 25mm/s the same as your small perimeter speed.  Your infill speed is set to 80mm/s.

Slicing the file as it is and looking at the preview and changing to the speed view your perimeters are being printed at around 7.5mm/s and your first layer infill at around 20-24mm/s (the colour coding isn't the most precise).  Well 30% of 80mm/s is 24mm/s so the infill is correct for speed.  30% of 25mm/s is also 7.5 so it also looks like your outer  perimeter speed is also correct and the inner perimeters are a slightly different colour so without going too far out on a limb Id say they are also going to be correct for 30% of the 45mm/s that your default perimeter uses.

So what is the actual issue ?  The slicer is slicing it correctly.

RE: First Layer Speed Modifier Doesn't Change Anything

The slicer is working correctly, but when I actually run the gcode on my printer, the first layer prints at the same speed as the rest.

RE: First Layer Speed Modifier Doesn't Change Anything

How are you measuring the actual speed when printing? 

RE: First Layer Speed Modifier Doesn't Change Anything

If anyone is wondering, I tried just setting the first layer speed to the equivalent in mm/s and it works fine. So maybe the slicer doesn't like using a percent? ¯\_(ツ)_/¯