If I had to guess I would suggest air bubbles in the holes during plating. Some bubbles were down I the holes and other bubbles pushed up to the end of the hole. Bob K. -----Original Message----- From: TechNet <[log in to unmask]> On Behalf Of Dwight Mattix Sent: Monday, May 6, 2019 3:18 PM To: [log in to unmask] Subject: Re: [TN] Bad Vias - Need help determining the root cause Looked at the first 5-6 images... Are those images all after reflow? Or wavesolder? -----Original Message----- From: TechNet <[log in to unmask]> On Behalf Of Christopher Brand Sent: Monday, May 6, 2019 12:11 PM To: [log in to unmask] Subject: [EXT] [TN] Bad Vias - Need help determining the root cause 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
