TECHNET Archives

August 2014

TechNet@IPC.ORG

Options: Use Monospaced Font
Show Text Part by Default
Show All Mail Headers

Message: [<< First] [< Prev] [Next >] [Last >>]
Topic: [<< First] [< Prev] [Next >] [Last >>]
Author: [<< First] [< Prev] [Next >] [Last >>]

Print Reply
Subject:
From:
Victor Hernandez <[log in to unmask]>
Reply To:
TechNet E-Mail Forum <[log in to unmask]>, [log in to unmask]
Date:
Thu, 21 Aug 2014 05:26:38 -0500
Content-Type:
text/plain
Parts/Attachments:
text/plain (54 lines)
What is the size of the coupon, how many PTHS were within that 1 square inch area, how many 10 seconds floats, what is the thickness of the coupon and temperature of solder.

Victor,

-----Original Message-----
From: TechNet [mailto:[log in to unmask]] On Behalf Of Nagaraj U
Sent: Wednesday, August 20, 2014 10:14 PM
To: [log in to unmask]
Subject: Re: [TN] Query on Copper dissolution

Hi,

We took an "A" coupon and covered 1 PTH using thermal resistant tape to prevent the solder coming in contact with the hole and did a solder float on the remaining 2 holes. Although this may not be exact verification of the thickness, the difference in plating thickness within the 3 PTHs in an A coupons is <1microns.

Thanks!
U.Nagaraj
________________________________________
From: Louis Hart [[log in to unmask]]
Sent: Tuesday, August 19, 2014 7:57 PM
To: TechNet E-Mail Forum; Nagaraj U
Subject: RE: Query on Copper dissolution

My apologies for answering your question with a question, but how do you know the reduction is 20-25 microns? I presume a measurement before the floats is not possible. I'm interested to see what the experts have to say. Louis Hart

-----Original Message-----
From: TechNet [mailto:[log in to unmask]] On Behalf Of Nagaraj U
Sent: Tuesday, August 19, 2014 1:59 AM
To: [log in to unmask]
Subject: [TN] Query on Copper dissolution

Hi All,

We have a few customers asking for 6x solder float at 288°C, 10 seconds (IPC-TM-650, 2.6.8, Condition A). After completion of 6x solder float (using SnPb 63/37 solder) we typically see reduction of Copper in PTH (due to copper dissolution) in the range of 20 to 25µm. The reduction in Cu thickness is maximum at the PTH knee area.

Can I have some inputs if this level of copper dissolution is normal?
If it is not normal, how do we reduce this?

Thanks in advance!

Best Regards,
U.Nagaraj
MICROPACK, India.
[Logo]
[Logo]

______________________________________________________________________
This email has been scanned by the Symantec Email Security.cloud service.
For more information please contact helpdesk at x2960 or [log in to unmask] ______________________________________________________________________

______________________________________________________________________
This email has been scanned by the Symantec Email Security.cloud service.
For more information please contact helpdesk at x2960 or [log in to unmask] 
______________________________________________________________________

ATOM RSS1 RSS2