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May 2014

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From:
"Gumpert, Ben" <[log in to unmask]>
Reply To:
TechNet E-Mail Forum <[log in to unmask]>, Gumpert, Ben
Date:
Wed, 28 May 2014 20:20:46 +0000
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I assume that the concern is for voids in the solder joint, which the dimples tend to cause. Which indicates that printing solder paste does not fill the dimple. I would expect that solder jetting to better fill a dimple since it flows better, but I don't have any experience with it.

But voids are not necessarily a defect, especially when design induced (see J-STD-001 Table 7-14 Note 1) so I would be hesitant to add a requirement to your vendor (and likely cost to your product) without understanding why the assembler is asking for this.

Ben

-----Original Message-----
From: TechNet [mailto:[log in to unmask]] On Behalf Of Guy Ramsey
Sent: Tuesday, May 27, 2014 7:43 AM
To: [log in to unmask]
Subject: EXTERNAL: Re: [TN] Dimples - Bumps - SolderJetting

Interesting, printing would fill the dimple. I had not considered that problem. Dispensing would be an issue too. 
Those are pretty significant tolerances. Maybe the committee that writes that standard should revisit. Looks like  you are going to need a note on your drawing. For most BGAs the majority of solder comes from the Ball, but you must have enough paste to get good contact with the ball. How deep is your deposit? 

Guy

-----Original Message-----
From: TechNet [mailto:[log in to unmask]] On Behalf Of Roland Jaquet
Sent: Friday, May 23, 2014 11:48 AM
To: [log in to unmask]
Subject: [TN] Dimples - Bumps - SolderJetting

Dear Technetters,

 

We have an issue with BGA and vias in pad and the usual flatness required for assembly and Solderjetting.

The IPC-6012C for Class 3, says it is acceptable for Dimples up to 75µm and bumps up to 50µm .

 

At the assembly line, they do not want Bumps and almost no Dimples (max
25µm) 

 

Do we have any Pro/Con experiences as to where to lead and define boundaries for it?

Is there some more specs in regard of SolderJetting ?

 

Thank you for your help

 

Best Regards

Roland

 

 

 

 


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