When I tried printing the original ball and socket links, the socket pieces would snap off when assembled. So I made this stronger version which prints on its side. The friction fit is nice and tight. I did have one piece split lengthwise when assembled though, so this still isn't perfect.

I used ASA for my print, so I'm not sure if this will work with the more rigid PLA.

Prusa

Prusa Mk2

No

Yes

0.2mm

20%

In Slic3r PE, I used "support on build plate only" and set the contact Z distance to 0. This is required, otherwise the lower layers of the ball will curl up at the edges and get caught on the nozzle. After printing the support residue can be sanded off.