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First | Initial Layer flow  

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Gatze
(@gatze)
Active Member
First | Initial Layer flow

Is it possible to set the flow of the first layer independently of the main flow higher ? To get a bit more adhesion. In Cura it is called 'Initial Layer Flow'

The only thing I could find is this:

https://forum.prusa3d.com/forum/prusaslicer/prusaslicer-initial-layer-flow/

So only in G-code possible ?

Posted : 24/12/2021 5:41 pm
Neophyl
(@neophyl)
Illustrious Member
RE: First | Initial Layer flow

There are a couple of ways that spring to mind but adding a couple of lines to your printers start gcode is the simplest and least effort solution.  You could slice and use the layer slider to insert custom gcode at whatever layer you want.  Thats a pain and you would have to do it for every model though so I wouldn't recommend that method.  In the start gcode of your printer profile is best.

Just a few days ago in this very forum someone was trying to do something very similar https://forum.prusa3d.com/forum/prusaslicer/how-to-do-arithmetic-inside-a-condition/

They ended up using this in their start gcode
{if layer_num==0}M221 S75{endif}
{if layer_num==1}M221 S{100 * extrusion_multiplier[0]}{endif}

as they wanted a lower extrusion on the first layer  and it reset back to the value set in the filament settings on layer 1.  You can do the same but set a higher value first the first entry.

Don't know what printer you have but the usual advice on adhesion is - clean bed, get the z height right so the first layer is properly squished and then it doesn't come loose.  Simple as that.  Then use elephants foot compensation to remove the first layer spread.  However that advice while always applicable to a prusa printer might not necessarily be applicable to another depending on the print bed in use.  If it is a prusa though then sort that out before messing around with flow and multipliers and all the other crutches.

Posted : 24/12/2021 6:16 pm
taviens
(@taviens)
New Member
RE: First | Initial Layer flow

Hello,

 

I tried to set that gcode piece at start gcode and prusaslicer keeps sending an error:

start_gcode
Parsing error at line 19: Not a variable name
{if layer_num==0}M221 S105{endif}
    ^
Posted : 23/01/2022 11:34 pm
Neophyl
(@neophyl)
Illustrious Member
RE: First | Initial Layer flow

That is because you cant use it in the START gcode field.  The example thread you took the lines from is using them in the custom layer change gcode sections.  Same tab but different sections.

Also you cant just add that line in as it will set the flow to 105% and then it will stay at that value.  Which is why you need to add BOTH lines from that post

{if layer_num==0}M221 S105{endif}
{if layer_num==1}M221 S100{endif}

As the first one will set the flow for the first layer to 105 and the second will set it to 100 on the second layer.  Alter for whatever values you want.

Also if you are doing this to improve layer adhesion on the first layer its not really the right solution.  You would normally adjust your bed levelling first, then use a slicker thicker first layer height is you have problems with an uneven print surface.  After that its increasing the first layer extrusion width.  Increasing flow to fix a fundamental underlying problem is like hitting things with a hammer.

Posted : 24/01/2022 9:18 am
taviens
(@taviens)
New Member
RE: First | Initial Layer flow

Thank you very much!.

It is not related with adhesion, my pla sticks pretty good at default settings. Its because small gaps of, what I think, underextrusion, in the first layer:

underextrusion gaps first layer

 

In my previous artillery genius printer, I used this "technique" to avoid those gaps.

Posted : 24/01/2022 12:26 pm
KP GRAFIX
(@kp-grafix)
Member
RE: First | Initial Layer flow

@taviens have you sorted this out? I too have no adhesion problems, perimeters are ok, but I'm getting those infill gaps like in your photo... sometimes at random places too

Posted : 20/08/2023 3:11 am
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