You can make a fixture that will allow you to rotate the board providing
your machine width is enough to handle the board and fixture turned as much
as 45 degrees.  Yes, this can make a big difference( but not always) on
skips but you should be able to eliminate skips by using a good dual wave
system and the right process unless the design layout is really bad and
then nothing will help.  Rotating the board somewhere between say, 5
degrees and 45 degrees will also help to eliminate bridging on connectors
and inline components.  There is however a price to pay in the cost of this
fixtures.

Ride The Wave,

Ken Kirby
Speedline Technologies



 (Embedded
 image moved   "Collins Graham" <[log in to unmask]>
 to file:      01/27/2000 11:44 AM
 pic31419.pcx)




To:   [log in to unmask]
cc:    (bcc: Kenneth Kirby/ElectrovertUS/Cookson)
Subject:  [TN] wave soldering - board rotation




Is the TechNet back up?  Yippee!

Good day TechNet!
Has anyone out in wave soldering land tried using a wave soldering fixture
that allows you to change the rotation of the board so that the edge of the
board isn't parallel to the conveyor?

I'm told that rotating the board slightly (say 5 degrees - not 90 degrees!)
can reduce the
occurrence of solder skips on SMT chips (caps and resistors).  Any
experience out there to confirm or deny this?

Final note: the board design is not suitable for a paste reflow of the SMT
parts followed by use of a partial wave fixture.  Otherwise that would be
my
#1 choice...

regards,

Graham Collins
Process Engineer,
Litton Systems Canada, Atlantic Facility
(902) 873-2000 ext 6215

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