Initial layer printing slower with increased flow

Snapmaker Luban
1

I did some test prints using Recreus Filaflex 70A. Due to lacking flow I increased the flow in the material properties up to 180%. The higher the flow, the lower the speed is used for the initial layer. Second and following layers print at correct speed.
Luban 3.15.1

1 Like
2

As for the flow rate and the work speed. Users can reduce the flow rate by 5% and print a calibration cube to check that the filament is extruding correctly and eliminates the issue. Normally, the work speed of the first layer should lower than the one of higher layers.

For Snapmaker Luban, the default first layer work speed is 18mm/s.

image
image945×635 27.7 KB

3

Good day Snapmaker-Edwin

I reduced the speed for the initial layer to 15 mm/s and set Flow to 100%. This shows in the GCode file as:
;LAYER:0
M107
G0 F900 X145.794 Y160.377 Z0.2
;TYPE:SKIRT
G1 X146.218 Y160.017 E0.0259

Setting the Flow to 180% without any other changes generates the following GCode:
;LAYER:0
M107
G0 F900 X145.794 Y160.377 Z0.2
;TYPE:SKIRT
G1 X146.218 Y160.017 E0.0259

So there is no difference to the G0 F900 instruction.

Observing the process the speed of 15 mm/s is correct for 100% flow. But for the 180% flow the actually observed speed is closer to 5 or even 3 mm/s.

I think it is not a problem of the GCode but of the realtime movement generation in the controller.

Regards
Pete

4

Update: the reduced speed on the initial layer can only be observed on the second and subsequent items to be printed. After power up the first item prints with correct speed.