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WAVE
DYNAMICS
With
rosin fluxes and organic acid fluxes, oxides resulting from the cleaning
action of the flux were encapsulated in the flux bodies and were removed
during the cleaning process. Because IF2005Mz does not contain any
of these bodies, the oxides must be removed using proper wave dynamics.
The
solder wave should be adjusted so as to have a dead zone at least
1" from the back adjustment plate of the solder nozzle. The
solder in the dead zone should have little to no movement in either
direction.
Next
check the immersion depth of the board in the wave. To insure
correct heat transfer from the bottom to the top, the board should be
immersed in the solder wave as deeply as possible without flooding the
topside of the board. Next take a 4 inch spatula and try to block
the front flow of the solder wave. Preferably, you should have to
exert pressure to accomplish the blocking. Front flow pressure of
the solder wave is important. The front flow pressure is the force
of the solder wave moving in opposite direction of the board.
As
the PWA makes contact with the wave, the top layer of solder should stop
flowing reverse to the travel of the board. The oxides in the dead
zone should begin to move in the same direction of travel as the board
and at the same speed. If you stop the board on the wave, the
oxides should also stop moving. Once you have established these
dynamics, your board will exit the solder wave in the dead zone and this
will reduce the possibility of solder shorts. Next check these
dynamics with a glass plate or level check. Always flux the glass
plate prior the checking the wave dynamics.
Dwell
time in the solder wave should be at least 4 seconds @ 500°F to provide proper
heat transfer to the topside of the board. A quick check is to
place some IF2005Mz on the topside of the board. Observe the board
as it exits the wave. If you have proper heat transfer, the white
residue will volatize as the board exits the solder wave.
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