Raft top bottom layers separating

[timskloss]

I'm trying rafts for the first time to print some large diameter (200mm) parts. I'm using 1 bottom layer and 2 top layers with 100% infill for the raft, but raft top layers are not adhering to the thick, bottom layers. It is as if the top layers are being printed too high above the bottom layers. The extrusion amount seems correct, but there is no adhesion. I think this is a bug in the software.

Inspecting the Gcode for a 1 bottom, 2 top layer raft:
; useRaft,1
; raftExtruder,0
; raftTopLayers,2
; raftBaseLayers,1
; raftOffset,5
; raftSeparationDistance,0.15
; raftTopInfill,100

Layer 1 (bottom) is printing at at height of 0.600 mm
Layer 2 (top 1of2) is printing at a height of 0.822 mm (thick 0.222)
Layer 3 (top 2of2) is printing at height 1.044 (thick 0.200) **why is this smaller than the previous layer? Bug???
Layer 4 (part first layer) 1.394 mm (thick 0.350, which is 0.2 layer thick plus 0.15 separation)
Layer 5 (part second layer) 1.594 mm (thick 0.200, which is correct for the print)


Unfortunately S3D doesn't allow us to control the top and bottom printing parameters like Cura, they are fixed an hidden. The only controls we have are number of layers, printing speed and temperature.

[aerodan]

Was there an answer to this question? Same problem here. The Raft Top Layer always come unglued.

[airscapes]

I have used rafts while printing D&D miniatures and have had no issues using the settings listed below.

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[aerodan]

Airscapes, at what speed are your raft top layers printing - and is it unique from the other layers in your print? For me, the issue is that I have to manually modify the gcode to get slower printing raft top layers, without also effecting any other speeds. With PETG, the raft top layers won't stick unless I can slow down the print speed - but I don't want to slow down the whole print.

[airscapes]

The 2 settings you would want to alter (no idea what they are now) is Separation distance and Above Raft speed (first layer of part)
The speed is a % of some speed all of which start with over all speed. So if you are printing a 60mms you may want to make 2 processes and have the first print to the 3rd layer at 30mms then switch tho your 60mms..

[aerodan]

Ah two processes! I’ll try that. Thank you.