Dear all,

I am trying to gather some industrial experiences on the double sided 
reflow soldering.  Please take a minute or two to fill up the following 
questionaire.  After compiling the results, I am willing to share the final 
results to those of you who respond to it.  

Would you care to reply, please send to [log in to unmask]

Thank you very much.

Best regards,

Victor



TN++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++

Questionaire for double sided reflow soldering
==============================================

Type of oven used : (  ) IR conventional
                    (  ) Forced Air
                    (  ) Forced Air with Nitrogen
                    (  ) Others, pls. specify _____________

Brand Name of the oven : ______________________

How often does your shop floor perform double sided reflow process?
(   ) 75 % of the time, or above
(   ) 50 < x < 75 % of the time
(   ) 25 < x < 50 % of the time
(   ) less than 25 % of the time

What is the length of the PCB commonly used in double sided reflow process?
(   ) 200 mm or above
(   ) 100 < x < 200 mm
(   ) 100 mm or less

Which connecting medium do you use in the double sided reflow process?
 (   ) conductive adhesive + solder paste (melting pt. 183 C)     
 (   ) the same kind of solder paste 
 (   ) high temp. solder paste + solder paste (melting pt. 183 C)
 (   ) low temp. solder paste + solder paste (melting pt. 183 C)
 (   ) Others : ____________________________________________________
                ____________________________________________________

Do you find this process difficult to control?  Why?
____________________________________________________________________________
____________________________________________________________________________
____________________________________________________________________________


When doing the second pass, how often did the components on the bottom side 
fall off? 
(   ) 1.  Never happen
(   ) 2.  0 < x < 20% of the time
(   ) 3.  20< x < 40% of the time
(   ) 4.  40< x < 60% of the time
(   ) 5.  60< x < 80% of the time
(   ) 6.  80% or above

If you answer 2. to 6. please list the components which caused problems :
(   )  BGA, # of pins : _____   Size: _____ mm x _____ mm
(   )  PLCC # of pins : _____   Size: _____ mm x _____ mm
(   )  QFP  # of pins : _____   Size: _____ mm x _____ mm
(   ) Others(Pls. specify) : Type _______ # of pins _____ Size: ____mm x ____mm
                           : Type _______ # of pins _____ Size: ____mm x ____mm


What might be the suspected reasons for the fallen components?
__________________________________________________________________________
__________________________________________________________________________
__________________________________________________________________________


Thank you very much for your time.




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