I have extensively searched the forums and tutorials for an answer to my specific problem and have found no solutions.
I am having tremendous problems with getting dense support in a water-soluble material (PVA, scaffold etc) to A) stick to its underlying PLA support column, and B) provide a decent undersurface quality. I think the solution is to print the dense support VERY SLOW, but as far as I can tell, there is no way to specifically do this in Simplify3D. I use a dual extruder setup with second extruder printing soluble dense support and the first extruder printing PLA for the model and support columns.
Some background: I am printing large parts (> 30 cm^3), with complex organic shapes that require many supported areas involving almost all layers of the print. The parts are mostly empty space, which means that most of my print time and material is spent printing support columns.
Some ideas that I have tried based on other forum suggestions that don't seem to work are:
1) Slow down the print speed for supports using the support structure underspeed setting in the speed tab. This doesn't work because it slows down the speed for all of the support, not just the dense layer. Most of my model is support columns, and this slows down the print to the point it is unacceptably slow (> a week). I only want to print the dense layers slow. I want the support columns to print fast.
2) Print with different processes on different layers zones as described at the link below. This doesn't work because my dense layers are scattered throughout the print and almost every layer is going to intersect with some dense support. There aren't any layers that are only model and
http://support.lpfrg.com/support/soluti ... nt-quality
3) horst.w suggested creating a separate process specifically for supports in the post linked to below, then printing both processes simultaneously (and ignoring the warning about double printing in the same volume). I created two identical processes except for one small change. Process 1 - model + support with 3 layer separation between, and Process 2 - model + support + dense support (extruder 2) with 3 layer dense support and no separation. When both processes were printed together, the dense layers were missing.
To give you an idea of the type of geometries I am working with, here is a picture.
Interestingly, Cura has the ability to set a separate speed for dense support (they call it support interface speed, see link). If I can't get this issue resolved in Simplify3D, I may have to switch to Cura, which would be unfortunate since I have invested months in optimizing my printing using S3D.
Thanks in advance for any help you can offer!