Voronoi Cup 3D Print with PETG

When one gets into 3D printing, it’s hard to miss the Voronoi style prints, as they are interesting looking and make you wonder how the hell would one go about printing something like that. Naturally, I had to give it a go, and at the same time learn how to make the models. In the process, I found that there are several ways to go about it.

There’s a plugin for Maya called Voronoi Mesh Generator. Seems awesome, but let’s see if there are any free tools. Sure enough, there’s a website voronator.com that will allow the upload of the model to be converted to Voronoi mesh, and it offers several options for the size of the holes and thickness of generated geometry.

I made a basic cup of 14 sides, and modeled in the 7 areas that will house the mesh. Then, I extracted the polygon faces to be used for Voronoi mesh generation, uploaded them to voronator website, and brought the downloaded mesh into the scene with the cup. I used zBrush feature DynaMesh at pretty high resolution to combine the Voronoi mesh pieces with the rest of the cup so as to not have any intersecting geometry. Then I decimated the mesh to more manageable polycount, and at that point, the model was ready for the slicer.

I use Ultimaker Cura, and for this print I wanted to try Zyltech’s purple PETG filament which was waiting unopened for perfect opportunity to shine. The reason for using PETG is that it seems to have absolutely no issues with adhesion – it will stick firmly to the masking tape used to prevent damage to the glass bed when 3D print is removed. Another reason is that it seems to best handle the overhangs, and it’s stronger than PLA.

I initially thought I must have supports, and when searching for tips regarding printing supports for Voronoi meshes, I found that Autodesk’s MeshMixer will create tree supports that may use less filament than standard Cura auto-generated supports. MeshMixer can also create Voronoi patterns, and it is a free software. After trying to generate tree supports in MeshMixer, which took a very long time and resulted in several crashes, I thought that those supports would be impossible to remove, since PETG is so very sticky. Hmm, what to do… So I checked Voronoi models on Thingieverse, because usually the use of supports was noted, and I found that most often supports were not used. Alright then, no supports it is!

So I sliced the model and sent the .gcode to the printer. It took over 12 hours to print and around 67g of filament. The resulting cup was very hard to remove. There was a lot of thin stringy filament connecting the mesh cells all around the cup, which was normal. Bed temperature was at 90°C and extruder was at 235°C.

“Do not use power tools on your prints!” This is the warning often found in 3D printing how-to articles and videos. The stated reason is that the friction will generate enough heat to melt or deform the print. But I wasn’t quite sure that is so after I watched an artist use dremel to sculpt his piece created with 3D pen, which uses same filaments as 3D printer. I figured that PETG would be perfect for this experiment because it is stronger and has higher melting point than PLA. It would take hours to clean up the print any other way. So here’s my first attempt at using a rotary tool to clean up the PETG 3D print. It worked like a charm in removing the stringy bits and pieces of drooping filament that didn’t have anything underneath to stick to during the printing process. No cell walls were destroyed in the process. I didn’t record from beginning, so this is only a second pass where most of the strings were already removed, making it a little hard to see the difference. However, the process is the same as in the beginning.

You can grab the .stl file for this cup at Thingieverse.

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