Open Cable Chain - reliable print springs

thingiverse

This is a redraw for the spring retainers used on Claghorn's open cable chain, which you can find here: https://www.thingiverse.com/thing:611593/comments The original design is awesome, however I had a lot of issues with 1st layer failures when printing a bunch of springs in ABS with my printer (borosilicate+PVA bed, heated enclosure... prints ABS really well normally). I discovered the reason is the original had some thickened square portions along the S shaped parts. When sliced these thick areas become 3 tiny little dots (~0.4x2mm) on the plate, which get individually printed before the nozzle runs a perimeter around them. With ABS on my printer, tiny isolated dots like that often don't stick and curl up on the nozzle. Often one of those tiny dots would lift and spoil the print before it even finished the 1st layer. So I redrew the springs from scratch in Freecad, using a uniform thickness on the S portion. Now my printer is chruning out an average of 75 good ABS springs out of a plate of 80. Of course, no brim was used (you'd have to be insane LOL). I printed mine in 0.3mm res with an 0.4mm nozzle, 0.45mm line width. No infill will be used, no supports needed, no brim (trust me, you don't want to get in to post processing a ton of these springs... much easier to fix bed adhesion some other way for these parts).