We need some  basic information on application of ultrasonic vibrators for
vertical , racks operated PTH line . We are plating 0.25 , 0.30 and 0.35 mm
via holes . Desmear process is applied off PTH line . In some of small via
holes we found round , circular voids in the center of the hole . It looks
like typical void created by air bubble . We have allready pneumatic
vibratotrs in the PTH line , but we intend to install ultrasonic vibrators
in the conditioner , which is the first solution in the line . The questions
are :
1 ) Power ( watts ) per plated area ?  Does it depends on hole size and
board thickness ?
2 ) Recommended frequencies ?
3 ) What is the recommended distance between the transducer and the boards?
4 )  What percentage  of the energy actually reach the center of the hole ?
How distance between the transducer and the board affect the amount of
ultrasonic energy that actually reach the board ?
All practical recommendations will be appreciated !
Edward Szpruch
Eltek Ltd - Israel
Tel  972 3 9395050
Fax 972 3 9309581
E-mail :  [log in to unmask]

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