Be sure to let us know what you find. Enquiring Minds want to Know.
Thanks,
Bob K.
-----Original Message-----
From: TechNet <[log in to unmask]> On Behalf Of Christopher Brand
Sent: Wednesday, May 8, 2019 7:45 PM
To: [log in to unmask]
Subject: Re: [TN] Bad Vias - Need help determining the root cause
Hi Richard, Victor, Dennis and All,
I greatly appreciate all the help and insight so far on this.
The boards don't have any selective or wave soldering, just reflow and hand soldering for a few thru-hole connectors. The boards are HASL. The sample of boards in the photos are mostly 2 sided and one that is 4 layer. These are small production runs usually.
In talking with the manager of the board shop, he's sending out samples of their plating tanks to be tested. I've asked him the following questions from input from you folks:
* Air bubbles in the plating tank? The manager says "in the pattern
plating tank we have no air. solution was eductors moving the
solution and swishing of the panels during plating".
* Is their plating current is sufficient? The manager says that they
are "plating the top of the cu scale to be sure". Is there a method
I can tell them to check if their plating current is good?
* They do have a copy of IPC-9121
I am going to look into sending out to get some of the vias microsectioned to get a better look inside them.
Is there anything else I need/should be asking them to check?
Thank you kindly,
Christopher Brand
Ludlum Measurements, Inc.
501 Oak Street
Sweetwater, TX 79556 USA
(325) 235-5494 Phone, ext:3318
On 5/8/2019 9:07 AM, Stadem, Richard D wrote:
> Christopher,
> Having a little more time to look at your pictures this morning, I noticed several pics such as 006 and 010 that show gross open breakout between the via PAD (foil copper) and via BARREL (plated-up copper). There is no evidence of selective or wave soldering on many of these. The breakout is on the TOP side with no evidence of additional solder applied, therefore my only conclusion is that the root cause was purely the plating issues from the fabricator.
> dean
>
> -----Original Message-----
> From: TechNet <[log in to unmask]> On Behalf Of Dennis Fritz
> Sent: Monday, May 6, 2019 2:38 PM
> To: [log in to unmask]
> Subject: Re: [TN] Bad Vias - Need help determining the root cause
>
> Do you have a copy of IPC 9121 - troubleshooting guide? That has a large number of pictures of failed via holes, causes, and remedies.
>
> On Mon, May 6, 2019 at 3:12 PM Christopher Brand <[log in to unmask]> wrote:
>
>> Greetings,
>>
>> I'm having issues with open vias on a couple of runs of PCBAs and was
>> hoping to get some help on finding a root cause or at least point me
>> in the right direction. I know that there is lots of knowledge and
>> experience on this forum and I'm hoping someone will say they've seen
>> this before, as my knowledge is rather limited on this.
>>
>> Here are a few photos of the vias in question.
>>
>> https://ludlums.com/software/BadVias/badvia_01.jpg
>> https://ludlums.com/software/BadVias/badvia_02.jpg
>> https://ludlums.com/software/BadVias/badvia_03.jpg
>> https://ludlums.com/software/BadVias/badvia_04.jpg
>> https://ludlums.com/software/BadVias/badvia_05.jpg
>> https://ludlums.com/software/BadVias/badvia_06.jpg
>> https://ludlums.com/software/BadVias/badvia_07.jpg
>> https://ludlums.com/software/BadVias/badvia_08.jpg
>> https://ludlums.com/software/BadVias/badvia_09.jpg
>> https://ludlums.com/software/BadVias/badvia_10.jpg
>> https://ludlums.com/software/BadVias/badvia_11.jpg
>> https://ludlums.com/software/BadVias/badvia_12.jpg
>>
>> On some, the via barrel has a void in the center and on others the
>> edge of the barrel doesn't connect with the pad, Both issues are
>> causing an open via as you can see in the photos.
>>
>> I know that the board shop recently changed up their plating tanks
>> (new chemical and power supply). Could these bad vias be the result
>> of insufficient current in the plating process or some other process?
>>
>> I'd be much appreciative of any insight this forum could give.
>>
>> --
>> Thank you kindly,
>>
>> Christopher Brand
>> Ludlum Measurements, Inc.
>> 501 Oak Street
>> Sweetwater, TX 79556 USA
>> (325) 235-5494 Phone, ext:3318
>>
>
> --
> Denny Fritz
> Consultant
> 812 584 2687
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