Mechanical Planetarium - Tuned

prusaprinters

<p>This is an optimized version of the "Mechanical Planetarium" model by Zippitybamba. His original model is on Thingiverse here: <a href="https://www.thingiverse.com/thing:4613061">https://www.thingiverse.com/thing:4613061</a></p> <p>I printed a few parts of the original model on my Prusa I3 MK3S, and I wasn't satisfied with how they fit. This sent me down a rabbit hole of refactoring and tuning the file until I could print it with insanely low tolerances of about 0.12mm on average.</p> <p>The original model is truly excellent and deserves to be on the main page for a long time. I put in a lot of time tuning this, so I thought I should share what I've done.</p> <p>A quick summary of edits:</p> <ul> <li>Combined the base and upper mechanism into one file.</li> <li>Added toggles for rendering each object.</li> <li>Refactored source for ease of reading and editing.</li> <li>Switched to the English fork of "Getriebe.scad" named "Gears.scad". Translated by Chris Spencer. <a href="https://github.com/chrisspen/gears">https://github.com/chrisspen/gears</a></li> <li><p>Added several customizer sliders to:</p> <ul> <li>Compensate for printer Z thickness.</li> <li>Control spacing for meshing of the gears in the base.</li> <li>SCALING! The model is scalable between 50-150% on the X and Y axes only. Object Z heights are controlled separately. Tolerances are corrected so they don't change as you adjust the overall scale. (Scaling to 90% will make it fit on a Prusa Mini)</li> </ul> </li> <li><p>Adjusted the length of the Venus planet arm (by 1mm) so the peg doesn't collide with the idler wheel above it.</p> </li> <li>Tightened everything up so it could be printed on a well calibrated machine with very minimal post-processing. I only needed to smooth out bits on the top layer due to filament retraction.</li> </ul> <p>I also wrote a quick Windows Batch file to generate all 47 files. A word of warning; It will absolutely hammer your processor since it opens a separate copy of OpenSCAD in the background for each file. If you know your way around OpenSCAD, then I'm assuming that you know how to read and use a batch file. "Here be dragons."</p> <p>Update: I identified a small issue with the inner pegs on the Calendar Gear. They were protruding 0.1mm above the center bearing. This would not be an issue for 99% of people printing the model, but I fixed the file and posted an update. If you're printing at anything larger than 100% or a layer height below 0.2mm, take a look at your preview.</p> <p>Update 2: I fixed an issue with non-uniform scaling of the printable planets in the SCAD file.</p> <h3> All credit for this design belongs to Zippitybamba. All I did was clean things up and tweak a bunch of things.</h3> <h3>Print instructions</h3><h3>Print Settings</h3> <p><strong>Printer Brand:</strong> Prusa<br/> <strong>Printer:</strong> I3 MK3S<br/> <strong>Rafts:</strong> No<br/> <strong>Supports:</strong> No<br/> <strong>Resolution:</strong> 0.4mm Nozzle. Layer Varies: 0.2mm and 0.25mm<br/> <strong>Infill:</strong> 15% Grid<br/> <strong>Filament:</strong> Prusament, Mika3D, and Sain Smart PLA</p> <p><strong>Notes:</strong></p> <p>I generally used three perimeters for all objects with the exception of the Mercury Axle. I used five perimeters for that so it would print essentially solid with no fast infill moves. I split the Mercury Axle in half and printed it vertically one piece at a time. I joined the halves using a small piece of aluminum rod that I wedged into the hole in the middle.</p> <p>I also tweaked my perimeter extrusion widths extensively so it would always print full perimeters. In PrusaSlicer it's on the "Advanced" tab under "Print Settings". I adjusted the "Perimeters" and "External Perimeters" while checking the preview until the white "Gap Fill" was replaced with a yellow perimeter.</p> <p>Watch out for Elephant's Foot. If you're using PrusaSlicer, go back into your Advanced Print Settings and adjust the "Elephant foot compensation" until you have a crisp bottom edge.</p> <p>If you use Cura, or some other slicer, poke around in your settings and look for similar options.</p>