Ive been printing for a while now and all is good
However how level should the bed actually be? as i want to do some extensive modifications now and the setting will be crucial
ie not a level as possible, but an actual tolerance like 0.1 to 0.3mm or less than 0.2mm etc
Thankyou
Level enough that your print sticks at all points and the first layer doesn’t get torn up by the second layer.
As you ask for a tolerance, I’d say about 0.05 is acceptable with a 0.5 mm nozzle.
The ideal distance imo is 0.25 mm to print with 0.2mm layers and a ‘0.3 mm’ first layer.
Ive set the bed to within 0.05mm and the nozzle 0.1mm away from the bed at its zero point
Prints perfectly every time.
I just have to remember to clean the bed with acetone before each print.
However the next problem is that the parts stick so well they have to be tapped off with a small hammer 
0.1 mm might be too close and explain why your pieces are sticking so much. Try 0.2 mm.
What i don’t understand is :
0.1mm nozzle distance + 0.25mm first layer => 0.35mm nozzle distance printing first layer.
Should’nt this normally reduce the adhesion? Or do the slicers internally subtract the nozzle distance from first layer height?
If so, which value would they use for subtraction?
cheers,
Christian
Indeed you would expect that but practically it’s not what you get (at least not what I get).
Indeed you would expect that but practically it’s not what you get (at least not what I get).[/quote]
sure enough, but, WHY? ~:|
cheers,
Christian
Perhaps it works like this :
The nozzle is lifted by layer height setting, let’s say 0.2mm (layer height setting) also for the first layer.
By setting a different first layer height the printer “thinks” is should use extrusion for, let’s say 0.3mm (first layer height setting)
and thus thus “overextrudes” like a 0.3mm layer while actually lifting the nozzle only 0.2mm, thus filling the approx 0.1mm nozzle distance gap.
This would mean, first layer height = layer height + nozzle distance.
Can anyone confirm this?
Would be a reasonable explanation at least …
cheers,
Christian
I think that nozzle height with everything at running temperature should ideally be zero.
That’s practically very difficult to achieve, so a gap is used and extra material extruded for the first layer, whatever the first layer height used (slicer default is 200%).
[quote=“Paul Compton”]I think that nozzle height with everything at running temperature should ideally be zero.
That’s practically very difficult to achieve, so a gap is used and extra material extruded for the first layer, whatever the first layer height used (slicer default is 200%).[/quote]
Thanks Paul, exactly how i thought.
But how does Cura engine do this? Only by the flow rate setting for first layer?
cheers,
Christian
Hi,
I think that the distance thing is because we check bed to nozzle clearance cold, when everything heats up expansion takes place and reduces the bed to nozzle clearance.
I just experimented a bit and found out that if i set extrusion rate to 150% via G-gode befor first and back to 100% before second layer
the prints have way better bed adhesion. My nozzle distance is about 0.1 to 0.15mm.
Layer height setting was 0.2mm for first and 0.2mm for rest of the layers.
Unfortunately curaenginge has no parameter to set the flow rate for first layer, so i had to do this manually by inserting M221 S150 / M221 S100 into the g-code after slicing.
But it works very well.
cheers,
Christian
A bit of research reveals that there is an “initial layer line width (%)” option in advanced settings on recent versions.
You mean in cura engine settings?
If so, it only spreads the first layer lines wider.
I changed that to 200 getting 20mm brim with gaps instead of 10mm brim with gaps.
So, not very helpful. The Flyby info states that it will increase the extrusion witdth and adjust the line width accordingly.
So it doesn’t change the flow in the way you need.
The Slic3r setting directly increases the flow rate, withot changing anything other.
So that would work as expected.
But i mostly use cura for faster and mostly “better” slicing.
cheers,
Christian