Making this kind of paper pulp mold will require variation in porosity of a print. I need to make the top surface with slight gaps to let water be drawn through but not the pulp.
The key step in what the Stratasys does seems to be this: “Designers can easily maximize air flow and minimize clogging by altering the raster gaps in the FDM toolpath.”
I’m not sure what setting to use in Cura to alter something equivalent to the “raster density”. The way I imagine it, I would build up a normal support structure and then sort of crosshatch the top layer leaving a small gap between each filament pass. I would end up with a fine screen that could let water through but not paper pulp fibers. By adjusting the gaps I could find the optimum screen porosity for the process.
I started 3D printing paper pulp molds a couple of months ago. To draw the parts you need to “cut” your mold into three or more parts using something like Fusion 360. Then stack the parts in Cura, using +z offset as needed.
In Cura can set custom settings for each part on the build plate, so for sections of your mold that pass vacuum, set wall thickness, top layers, and bottom layers to zero. Then you just have infill, which you can adjust by changing the infill density.
The part of the mold that forms the parts will have fine square infill. The part in the middle will have less infill (I found triangle infill works well here), and the part closest to the vacuum port will have very wide infill (also triangle). I wrote a blog about how to make 3D Printed paper pulp molds here. 69 It goes way more in-depth and links to other things you need. I hope this can become more of an open source project.
