Thanks for the many useful comments on my question concerning post reflow
cleaning Aplha Metals Fine Line 2000 solder paste. TechNet for president !
I will use this mail to react on some answers from TechNetters & give more
detailed info.

Q  "Why you feel that (any) residue is not acceptable?"
A1 Our core is high-tech militairy assemblies and avionica/space. Residues
   may effect the reliability of our products during its planned (long) 
   lifetime. NOT ACCEPTABLE.
A2 We use conformal coating on all our printed boards. Residues causes
   problems with this coating and humidity tests.
A3 A lot of collegues/customers don't like it for cosmetic reasons.

Q  "Why not use aqueous based paste?"
A1 Because of the high activity of the possible (small but agressive) 
   residues.
A2 I tried some, but the results haven't satisfied me.
A3 A lot of costumers/specs just accept RMA flux (militairy)_.
A4 I have good experience with RMA fluxes in SMT and THT.

Q  "Why do you want to clean No-Clean"
A1 Any residue is not acceptable.
A2 Not wash No-Clean looks evident, but untill now i never doubt the 
   possibilities of good results with washing No-Clean paste. I just 
   neglected the additional materials together with the natural rosin.
   Now that i am wiser i say: 
   "I want to clean RMA based paste, it don't has to be no-clean"

Q  "Buy our product X and machine Y and you'll be happy ever after"
A  Wow! (Not all salesmen have really helped me)

Q  "Look for the best process to achieve a reliable product is the most 
   efficient way"
A  You're right. I was looking from the point of view where i already have a 
   paste in use, a machine which washes THT-boards and a lot of paperwork.
   I hope that i can start from scratch and look for the right combination.


TechNet is really helping me in building "the knowledge".
Thanks again for your reactions.


**********************************
 Ivo de Rooij
 Process Engineer SMT/THT
 Fokker Elmo BV (Fokker Aviation)
 P.O. Box 75
 4630 AB Hoogerheide
 The Netherlands
 phone (+31)(0) 164 - 6 17 000
 fax   (+31)(0) 164 - 6 17 700
 e-mail     [log in to unmask]
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