Printed Circuit Board Assembly & PCB Design SMT Electronics Assembly Manufacturing Forum

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Conformal coating over No-clean

Chris Jackson

#15339

Conformal coating over No-clean | 19 June, 1998

We are in the process of validating Silicon 1C55 (thermal cure) conformal coating over Alpha LR725 solder paste. I am looking for anyone who may be using this process, or has been exposed to someone who is doing this process. Our concern is with the remaining residue (oh, by the way did I mention that we hope to do this with NO cleaning process) after reflow may undergo a 2nd reflow, or softening, in the thermal cure for the Silicon (we are reaching approx. 125 to 130 c for 12 to 15 minutes). If this occurs then we have a concern with the crosslinking of the coating with the board around areas where the residue remains. We feel that solder balls will not be an issue since the Silicon is 100% solids and will not tend to shift the solder balls. I would appreciate anyone who might be able to shed light on this subject. Thanks My phone # 864-638-3601 ext 4500

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Alan Brewin

#15340

Re: Conformal coating over No-clean | 25 June, 1998

HumiSeal 1C55 is used by several of our customers over NO-clean pastes with success. Have you seen anything to cause concern?

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