We do have several solution to produce jump rings.
The simplest solution is
This machine is fast and reliable on the condition that wire temper is soft and wire size thin.
The wire is wrapped onto the pin and cut afterward by a little blade which is installed on the pin itself, therefore the proportion between the pin and the wire diameter has to be proper…the pin diameter must be at least two times bigger than wire diameter.
According to the technology involved, obtaining a flush cut is not possible by this machine.
In fact the cut is always V shaped…see reference picture on the web link above.
The main difference between the 2 machines is that Ezlink was born to allow the assembling operation (even if it could work in continuous way too without stop in order to produce loose links).
While the NK20 is capable to produce different parts having different shapes (changing the tooling) but it doesn’t support the assembling.
Both the machines are suitable for flush cut.