Arjun

Check the timing on your spray fluxer.
        If the leading and trailing edge have the most problems, the spray 
on/off timing could need improvement.

        To do this, use a glass slide with heaters and wave off. Run the slide 
through the fluxer and look at the pattern.

        An alternate method is to wrap an unstuffed panel with colored paper 
towels and observe the color change where it is wet by the flux thinner.

        You may also be striping the panel with uneven coverage. This test can 
detect that, also.

Aric Parr

______________________________ Reply Separator _________________________________
Subject: ASSY:Wave Solder 
Author:  [log in to unmask] at INTERNET
Date:    7/11/97 2:45 PM

     Hello Fellow Internetters,
     I work for ERG telecommunications, in Perth, Australia.
     We have been seeing problems  with the wave solder process,with two 
     defect types ie. Bridging (approx 12%) and solder balling(Approx 2%). 
     Bridging has the higher rate of the two problems.
     The location that the bridging problem occurs is mainly at the front 
     of the boards as they pass the wave machine.  Also bridging is mainly 
     the trailing edge type but, there are instances when it bridges 
     across the board.. 
     The machine that is used, has the capability of spray and foam 
     fluxing. Alternating between these two fluxing types, I observed that 
     the foam fluxing gives better results, in most cases at 0% defect 
     rate. My concern with changing to foam fluxing is that the residual 
     contamination left after such a process is high( i am yet to test some 
     boards with a Ionic contamination tester). The flux that is used is 
     halide free Multicore X32-10i. 
     
     Does anyone have any suggestions to reduce such wave solder problems ?
     
     Regards
     Arjun Murthy 
     
     [log in to unmask]

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