Rich,

Just a thought - I've experienced a similar problem here, with a 
double-sided SMT board and the root cause was the JOT loader/destacker. 
There are components close to the edge of the board, and when the 2nd side 
was loaded into the printer, the board would hit on a support rail made of 
steel.  Components were actually being damaged from this support rail.  We 
fixed the problem with custom plastic sleeves. 

Howard Watson
SMT Manufacturing Engineer
AMETEK/Dixson




Rich Lasko <[log in to unmask]>
Sent by: TechNet <[log in to unmask]>
02/24/03 10:42 AM
Please respond to "TechNet E-Mail Forum."; Please respond to Rich Lasko

 
        To:     [log in to unmask]
        cc: 
        Subject:        [TN] Handling Damage of SMT Components


Good morning everyone,
 
I am encountering a random problem with damage (components being cracked 
and sometimes broken off) to some SMT components on the secondary side of 
the board.  (Most of the damage is to the SOT-23's and chip 
resistors/capacitors (0805).  
 
Here is the summary:
 
I have a double-sided SMT board with Thru-hole components on the primary 
(top) side.  Board thickness is approx. 0.093".  The board is approx. 16" 
long and 12" wide.  I believe I have isolated the root cause to be the 
in-line wash system that this board is sent through.  (Electrovert Aquapak 
544 - And yes I know it's old - Ha!)  The operator lays the board on the 
stainless steel "mesh" primary side up.  This can not be good for the SMT 
components on the bottom side.  (Argggg)  Has anyone else encountered 
something similar to this.  If so, what changes were made to help protect 
the board during the cleaning process?  I am concerned that any "bouncing 
around" that happens during the wash cycle is cracking/damaging these SMT 
parts.  Thoughts... 
 
Any help would be appreciated.
 
Rich Lasko
Badger Electronics
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