I'm using Cura 4.6.1, trying to print PLA + PVA combination.
It was very hard to stick the first PVA layer(support layer) to Raft so I took a look at my gcode, and I found those starting layer of support is too fast.
'Raft Print Speed' controls those speed of raft layers.
'Initial Layer Speed' controls the first layer of real printing part.
And 'Number of Slower Layers' controls those a few layers after the first layer.
But the first two layers of support is between raft and the first layer, so it's not affected by raft speed or initial layer speed, and always print with the 'Support Speed'
I think the first two layers of support is put into between raft and real print to adjust gaps regardless the airgap/z overlap values, and it works brilliant in the aspect of z height.
But it always run with 'Support Speed', not 'Initial Layer Speed' so it is very hard to stick to raft especially if 'Support Speed' is high.
I couldn't find the way to control the speed of first layers of support. But if there is, Anyone knows about that, please let me know.