Hi Snow

It generall is a result of paste + reflow but can also come from the PCB if the finish is solder coating of bare board.

What is the PCB surcae finish in this case?

If NOT  solder coating (ie, OSP, ENIG, immersion silver, immersion tin, etc) then it CANNOT be from the bare PCB.

To solve this usually you might experiment with flux and reflow parameters.

Regards,

C.B. Katzko
VP, Research + Development
TTM Meadville Asia Pacific
Email [log in to unmask]
Mobile +86 13817362590
Tel +86 21 37747528
Fax +86 21 37747590


----- Original Message -----
From: Snow Fu [[log in to unmask]]
Sent: 04/13/2011 01:39 PM ZE8
To: <[log in to unmask]>
Subject: Re: [TGAsia] Solder Ball



Hi, Justin,
More question for clearly understand the nonconforming.
What’s the process caused the solder ball?
Is it come from PCB producing process?
Or is it come from PCBA SMT process / wave process?

Best Regards
Snow Fu
________________________________
From: TGAsia [mailto:[log in to unmask]] On Behalf Of Justin Wu
Sent: 2011年4月13日 12:09
To: [log in to unmask]
Subject: Re: [TGAsia] Solder Ball

Hi All,

We have found some solder balls inside TH on the PCB (See below photo), however there is no exact matching of the defect mentioned in IPC, but according to IPC-A-610 Clause 5.2.7.1, the solder ball is accepted if it is embedded in the solder resist. So, would you please share your experience in such case with me?
 [cid:[log in to unmask]]
Thanks in advance!

Best regards,
Justin Wu
Utilux South China Ltd
Phone: +86-755-2850 7521
Fax:    +86-755-2850 0927
E-mail Address: [log in to unmask]<mailto:[log in to unmask]>




__________ Information from ESET NOD32 Antivirus, version of virus signature database 6037 (20110412) __________

The message was checked by ESET NOD32 Antivirus.

http://www.eset.com

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

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

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