Dear all,
     
I am doing a survey on the double sided assembly.  Please take a few 
minutes to complete the following questions.  I will be grateful to inform 
you the result once I have finished compiling.
     
If you have filled this before, please ignore it.
     
Would you care to reply, please email to [log in to unmask]
     
Thank you very much.
     
Best regards,
Victor
     
TN3-------------------------------------------------------
     
Questionaire for double sided reflow soldering 
==============================================
     
Type of oven used : (  ) IR conventional
                    ( x ) Forced Air
                    (  ) Forced Air with Nitrogen
                    (  ) Others, pls. specify _____________
     
Brand Name of the oven : __HELLER____________________
     
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
( X  ) less than 25 % of the time
     
What is the length of the PCB commonly used in double sided reflow process? 
( X  ) 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)     
 ( X  ) 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? NO BUT IT SHOULD PAY 
ATTENTION TO THE HEAT PROFILE ,WHICH HAS A BIG DEPENDENCE ON THE CHIP'S 
DIMENTIONS._________________________________________________________________
________ 
____________________________________________________________________________ 
____________________________________________________________________________
     
     
When doing the second pass, how often did the components on the bottom side 
fall off? 
( X  ) 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? __RATIO OF 
THE WEIGHT AND THE NUMBER OF LEADS 
________________________________________________________________________ 
__________________________________________________________________________ 
__________________________________________________________________________
     
     
Thank you very much for your time.
     
     
     
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