-----Original Message-----
From: Stadem, Richard D. 
Sent: Thursday, February 06, 2014 8:44 AM
To: 'Lars Wallin'
Cc: Steve Gregory
Subject: RE: SOLDERING PROBLEM

I would suggest a solution consisting of B, with the addition of Arathane 5753 mixed 1:5 with 5% by weight of Cabosil (M5) added around the outside perimeter/base of the component prior to moulding the whole board. The Arathane will reduce/eliminate any shock or stress on the solder joints from vibration or handling, and will spread any Tc mismatch out also. I would think that the Arathane would be fully compatible with the polyurethane potting, but the folks at Huntsman can confirm that for you. Having the epoxy under the part might not be a good idea, as it can expand and cause the stress to be applied directly to the SJs. So having a perimeter seal of Arathane around the part before the entire CCA is overmolded will both support the component and keep the polyurethane overmolding out from under the part.
This would provide you with a low-outgassing solution for a high-rel application, if it is.

-----Original Message-----
From: Lars Wallin [mailto:[log in to unmask]] 
Sent: Thursday, February 06, 2014 8:19 AM
To: Stadem, Richard D.
Cc: Steve Gregory
Subject: SOLDERING PROBLEM
Importance: Low

Hello Steve and Richard,

Many thanks for your service in this matter.

Hope that now will be able to open the attachments.

Best Regards
Lars Wallin
IPC European Representative
Location: Stockholm, Sweden
Phone:  +46 8 26 10 07
Mobile: +46 70 212 74 39
Email: [log in to unmask]<mailto:[log in to unmask]>

________________________________
Fr?n: Lars Wallin
Skickat: den 6 februari 2014 07:14
Till: Technet
?mne: VB: L?dproblem + bild

Hello Technet,

Please check the attach sketch.
It involves soldering a large capacitor (20 x 30 x 40 mm see enclosed picture) and then mould in the whole board with a warm polyuretan mould mass. The requirement is that the solder joint should withstand 300 cycles (from-40C to +85 C).

Figure A, can not cope with the requirement of 300 cycles. a =  polyurethane mass.

Which of the figures B-E do you think would be a better solution? Or would you suggest any other solution?

Looking forward to your answer.

Best Regards
Lars Wallin
IPC European Representative
Location: Stockholm, Sweden
Phone:  +46 8 26 10 07
Mobile: +46 70 212 74 39
Email: [log in to unmask]<mailto:[log in to unmask]>


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