Ultimate Prusa Casing MK4 - Drawers/FuzzySkin

Loved the aesthetics of the Ultimate Prusa Casing so much that I absolutely did not want it to be ruined by visible layer lines. The fuzzy skin option in PrusaSlicer does an excellent job of hiding layer lines, but until paintable fuzzy skin is added, it does not play well with parts that require dimensional accuracy such as this casing. Fortunately I was able to use Blender and modifiers as a workaround. Skip to the end for the workaround to apply fuzzy skin to certain surfaces on your own parts.

The attached .3mf files should have all the correct settings and modifiers applied already. Feel free to change the fuzzy skin point distance and fuzzy skin thickness. I used FSPD 0.4mm and FST 0.3 mm for my print.

If you do use this with the default MMU3 buffer attachment, you will need to reprint the buffer holder that attaches to the frame with about 10mm sliced off the top so that it doesn't interfere with the operation of the drawers.

The LCD cover and screen cover were printed in two colors of PETG with PLA supports. The PLA basically acts as soluble support because PETG/PLA adhesion is so poor, improving the surface finish of the parts above the supports. However, due to the bad adhesion the first layer after the support must be slowed down significantly. The attached .3mf files should have all the necessary settings embedded. The parts were printed face-down on a textured plate to get a similar finish to the fuzzy skin on the rest of the parts.

The hex inlays should be printed with an open side facing down toward the build plate. I used superglue to attach the hex inlays after finally printing them. There are a lot of files and I struggled with stringing problems while trying to print multiples of the hex inlays together. I finally gave up and printed them individually with 5mm brims at 0.6mm brim separation gap. These settings resulted in a good first layer with strong adhesion to the build sheet and a brim that peeled off easily. Different printers might require slightly different settings to get the desired result. You might also experiment with sequential printing to reduce the number of prints.

https://help.prusa3d.com/article/sequential-printing_124589

Fuzzy Skin Workaround

1. Open the STL in Blender
2. Switch from object to edit mode and delete all the triangles in the STL that you DON'T want to apply fuzzy skin to. Using the select linked flat faces command should speed this significantly. It also might be quicker to select the faces you DO want to apply fuzzy skin to and invert the selection before deleting.
3. Apply a solidify modifier to thicken the remaining surfaces back into a volumetric object. Use a thickness slightly more than the nozzle thickness you expect to print with. I used 0.5mm for my 0.4mm nozzle. Make sure the extrusion is in the correct direction, the outer faces must remain in the same location.
4. Export the new STL with a different name than the original STL. Make sure that the apply modifiers box is checked.
5. Open the original STL in PrusaSlicer.
6. Add the STL you exported from Blender as a modifier to the original STL. The location should already be right, but if it's not change XYZ location of the modifier STL until all the faces align correctly.
7. Apply fuzzy skin setting to the new modifier STL, change the FS point distance and FS thickness as you see fit.