The goal of this chain mail design was to simplify each loop as much as possible so the pattern can be shrunk to a minimum printable size while still maintaining good strength and flexibility. Each loop links 3 of other loops which I think is more flexible (most designs found on Thingiverse link 4). The natural shape for a 3-link loop is a hexagon but I distorted it to a more triangular shape so each link crosses at 90 degrees. This allows the printed gap between loops to be more controllable (so they don't get printed together) and it helps to keep the links from getting tangled.

The finished pattern has good drape and does not tend to get tangled up. You can pretty much roll it into a ball and then throw it on a table and it will lay flat again after a few flicks. My intent was to make a useful fabric but, for now, it is finding much more use as a toy to play around with.

Please see my improved version of chain mail at: https://www.thingiverse.com/thing:2611564 . It has smoother surfaces and drapes a little better and is much more customizable.

RepRap

Reprapguru

No

No

0.2mm

see notes

This design is not the easiest thing to print since the goal was to optimize everything else. Do not try to use rafts or brims or you will have to trim the 540 pads one by one. Your printer must be well calibrated and the bed must be flat over the entire area. I had to buy a new Pyrex plate because the original one was warped 0.2mm. Here is the recipe that worked repeatedly for me:
Material: PLA, Bed temperature: 55C. Extruder temperature 210C
Bed coating: blue tape
Infill: none, but make shell thickness 2mm (or 3 lines) so you get 100% fill.
First layer speed: 15 mm/s. This gives the PLA a chance to stick.

You may need to add a z-hop of 0.2mm for long travels in case the extruder is wacking into surfaces it has already printed. This slows things down though and wears on the z axis bearings.
Do a test run with the included test stl file which has only 8 loops.
Keep an eye on the printer during the first layer since this is where most of the problems occur. If one pad comes loose it will make a mess of the rest of the print.