The Z axis chain has a pretty wicked backward curve going on, but so far doesn't seem to have caused any problems.
3D Solutech pla
Printing with 100% infill was causing lots of problems, so I switched to 80% infill which seemed to work a lot better, and doesn't sacrifice much in the strength department.. I printed all 20 chain links simultaneously which took somewhere around 11 hours. Probably my longest successful print to date (haven't had a printer for very long).