Transcript bending of stiff hybrid tails

Stiff tail troubles
• The new stiffer hybrid tail
flexes the interconnect
card on the rod by about 1
to 1.5 mm
• Some tilt in the connector
as well
• Force needed to push
board flat ~ 250g
• Rod tested fine at room
temperature, but not in the
cold (could be open
connectors)
Old, softer tail in the same
position
• Some flexing of the
PCB board
• No tilt in the
connector
• Force needed to push
board flat ~ 80g
New bends to the tail
• Pos. 3 on the rod (smallest
gap between module and
interconnect card)
• Tail bent in situ on the rod
• Bends are close to c-fiber
than before
• Some improvement, but
still deflection of the PCB
New bends to the tail
• Same bend moved to
pos 5 (larger gap)
• No deflection of the
PCB
• But: Highest point of
tail is ~1.5mm above
stay-clear, not
acceptable
New bends to the tail
• Tail bent like original (soft
tail)
• Added “kinks” with
tweezers, while module
was on the rod
•Less deflection of the PCB (~
100g)
•Also works in pos. 5
•The 2 modules used for these tests
showed no opens in the tail after
extensive bending
The tail tale continues
• The goal is to bend the
tails only on the vacuum
fixture, not on the rod, to
avoid putting stress on the
connector
• Try out new bending tools
(the tweezers used
previously crease the tail
dramatically):
– non-tapered rounded
tweezers
– Modified sur-clip pliers
Bending with the new tools
• Was not able to repeat the tail bend shape
previously developed (see slide 5) by
bending on the vacuum fixture with either
tool
• Try different shapes
• Tweezers work better than surclip pliers
Best bend so far
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Small radius on top, large radius on bottom
Use new tweezers to make the small radius bend at the connector end, and
bend tail back over the module frame by hand to make bottom part more
rounded
Board deflection ~80g
This seems to be as good as it can get without bending the tail while the
module is on the rod
A SS6 rod was assembled using this bend on all modules, still needs to be
electrically tested in the cold