Simplify3d now offers the „dense support“ feature in version 4.0.0, i.e. you can just print the last 2-3 layers below the model with PVA, while printing the rest of the support structure in PLA...
… at least this is how it works in theory. In reality, I myself can't get a print with the „dense support“ feature and PVA on PLA to work . The PVA-layers (90% dense infill) just won't stick a bit to the PLA support and everything crumbles together at the nozzle.
Nevertheless adding the following two features could perhaps solve the problems I face:
1.) Add a configuration parameter for including a number of dense infill support layers on top of the normal support. These layers would still be printed with the choosen support extruder, i.e. PLA (extruder 1), and therefore the first PVA dense infill layer (extruder 2) would have more contact area to the PLA support and therefore will stick a lot better to the PLA. Here is an example of how the configuration tab could look like:
2.) Add a configuration parameter for the default print speed of the second extruder, which is independent of the default speed of the first extruder. PVA seems to be better printable at low speeds. Right now there is only a parameter „support underspeed“, but lowering that one would unnecessarily slow down the printing of the PLA support as well, which just isn't necessary and is very time consuming.
And a third request:
3.) While using the prime pillar function, I did ask myself, why the prime pillar is printed with 100% infill even when no extruder change takes place in one of the layers nearby. Wouldn't it save material if the prime tower infill is normally like 15% and only 1-2 layers before and after a tool change a dense infill layers is printed? (The effect would be especially high for prints with large z dimensions and only few material changes). This feature should be choosable for extruder 1, extruder 2 or both extruders, because I wouldn't like my PVA layers to be just with 15% infill