Hegner Scroll Saw Bellows

thingiverse

Replacement bellows for Hegner scroll saws. These typically fail (crack) due to the original material hardening over time. Hopefully this model will allow to you to make a fast/cheap repair to your saw using flexible filament (TPU). Files: - hegner_bellows.scad - simplistic OpenSCAD model to create the shape. Tweak top and bottom openings as needed to match your saw. All slopes are at 50 degrees (measured from horizontal) to avoid the need for support. Defaults are 28mm/84mm openings in the bellows and 1mm sidewall thickness (provides room for 2 perimeters with a typical nozzle). - hegner_bellows_28_84_1mm.stl - STL model built with OpenSCAD defaults. - assorted photos showing original (failed) part, rendered model, printed part, and installation. Instructions: - (Optional) Tweak the OpenSCAD file to change settings to match your Hegner saw if you need something different than defaults and generate a new STL. - Slice (my settings below). Goal is to have 2 touching perimeters for the main body of the bellows (all but the handful of layers at the top and bottom where the "lip") - 2 perimeters - 250u layer height - solid (100%) concentric infill (need for the "lips") - forced cooling on all but the first layer (for TPU) - 15mm/sec speed (for TPU) - enable gap fill if your slicer supports it - add a brim if you need additional adhesion to the bed - Print with a flexible TPU (I had great success with Ninjaflex with a225C hotend and a 40C GeckoTek bed -- really good adhesion) - After printing, "fold" the upper 3 sections of the bellows in to itself (see attached photos showing the folding progression). - Stretch/slide the upper opening of the bellows on to the lower scroll saw arm. If needed, you can reach through the lower opening of the bellows to help slide the bellows onto the lower saw arm. - Stretch/slide the lower opening of the bellows over the bellows mounting plate on the base of the saw. Good luck.