Arc bridge and slope for OS-Railway

thingiverse

This page contains both the arc bridge and the slope. This is a massive bridge! it has an 80cm span! :) It uses 4pcs 200mm standard track, which you find on the general track page: http://www.thingiverse.com/thing:2146361 IMPORTANT! Use 100% infill. The arc pieces are already hollowed out. Less than 100% infill will most likely cause structural problems. This is a somewhat more experimental print than my others, and it will require some more sanding and tinkering to get it working. As you can see, the picture prototype version differs somewhat from the STL's. I've tried to fix some issues. For obvious reasons I'm not printing more copies of this one my self but I'm pretty sure I have fixed most issues (I hope) :) On the prototype, I tried 1mm thick walls on some parts but that didn't work, they cracked very easily when I tried to assemble the arc. The pieces with 2mm walls however held together perfect, so I've updated the design so that all pieces have 2mm wall thickness. The arc members all have fastening holes for track supports and the joiner piece. I used only two joiners between the arcs as you might see on the pictures, I include 4pcs in the ready build plates, you can print more if you like but they aren't needed for structural integrity. also if you want to use more supports from the arc down to the track you need to make new ones with adapted lengths. I've included the two lengths that I used in this build, the positions match the track joints where the support is really needed. Things you need to know about the slope The slope parts are designed to be glued. (you can screw the track holder joint and the holder plate but personally I think that's a waste of screws, I used melt glue). The position isn't critical at all, that is why I haven't made any guiding parts on the structure. I tried keeping print time to a minimum. The pillars are already hollowed out! so don't reduce infill, use 100%! Print Settings Printer: Prusa i3 mk2 Rafts: No Supports: Yes Resolution: 0,25mm Infill: 100% Notes: Buildplate 2 and 3 of the bridge will need support for the slide-in-ends. (Support from build plate) All parts designed to be printed with 100% infill. This is important because the material gets really different properties depending on the internal structure. For example, a piece with thin walls and an infill-mesh will be stiff but brittle, it will crack and delaminate easily, while a part which is completely hollow but with thicker solid walls will be much tougher but somewhat flexible. In this application, the latter properties are important for strength. A good example is the track joiners, if you print them with less than 100% infill, they will easily break when you try to disassemble the track layout, but if you print them 100% solid, they can take a lot of twisting and bending. Post-Printing If you have trouble assembing the track, check if there are some edges that sticks out. It's common if you have a squeezed first layer that you might get a tiny edge where that layer is wider. Going over the part with sanding paper or a file (or knife) will fix this. How I Designed This Designed using Fusion 360