Reposted rom our LinkedIn group.
We're currently producing these by hand using formers around a mandrel from small cut pieces of stainless steel. However the process is very labour intensive and the end result is far from perfect or uniform. I'm reasonably happy with the stainless steel cold working process as it produces really hard tube (required).
The tube is produced flared on one end so that it can be encapsulated in plastic, open split tube (not welded), 3.0mm ID, 0.3mm wall, 30mm long from flat ribbon stainless steel shim.
We have abandoned the idea of drawing or using a series of rollers as they would then need to be cut to length and deburred - not easy supporting a 3mm open/unwelded tube.
I guess we are looking to design some sort of pliers/former type tool and appreciate it may be a multi-stage process;
1. strips cut from stock formed longitudinally into a dished shaped 'U'
2. simultaneously side + downward pressed around a mandrel
3. Flared end