Gerard O'Brien
President
S T and S Testing and Analysis
Gerald O'Brien is Chairman of ANSI J-STD 003, and Co Chairman of IPC 4-14 Surface Finish Plating Committee. He is a key member of ANSI J-STD 002 and 311 G Committees Expert in Surface finish, Solderability issues and Failure analysis in the PWA, PWB and component fields.
Gerard O'Brien has submitted responses to the following questions.
Pad Missing ENIG Plating
As the co-chairman of the committee responsible for ENIG, rework of the boards post nickel plating is NOT allowed and ...
Tarnished OSP Circuit Boards
Changing colors of the Cu on OSP coated boards and associated soldering issues is a good indication of an issue ...
OA Flux Turning Blue
I am assuming you are talking about flux in the fluxer and not in its original container - most likely ...
Solution for Warped PCBAs
Sorry but you will not be able to flatten these assemblies. You would have to take the PWB above its ...
Recommended Fiducial Shape
This defect is not the result of the fiducial shape. All fiducial designs work fine with a normal HASL process. ...
Old Components and Blow Holes
Blow holes are primarily the result of poor hole wall generation of the PWB and defective or insufficient plating thickness. ...
Out-gassing and Cleaning
Due to the nature of the materials you are using, there will be outgassing under vacuum, although you did not ...
Gold Plating and Embrittlement
Goldembrittlement occurs at 5 wt.% in the solder joint although the industryusually defaults to 3 wt.%. You can calculate easily ...
Via Wall Thickness Test
There are a number of copper plating thickness"meters" where by you insert a probe into a plated through hole and ...
A Generic Reflow Profile
The only way that a single profile could be usedfor all board designs would be if the rate of rise ...
What Causes Black Pad?
Blackpad occurs during the immersion gold deposit and not during assembly which isresponsible only for revealing the defect. The primary ...
Deionized Water Sample Testing
Exposure to atmosphere will definitely impact the resistance of thewater as will the container you are using -- but this ...
BGA Die and Pry Testing
The amount of dye penetration looks too extensive for Kirkendall voids.Are the images showing ball separation from the chip? ...
Mixing Different SAC305 Solders
Providedthe new material meets the requirements of the appropriate JSTD, I would see noissues in mixing the SAME alloy from ...
Gold Plated Hole Defects
Thefirst question is how many layers of interconnect are there in these holestypically? When you say exposed gold, do you ...
HASL vs. Immersion Gold
Ifyou are leaving exposed pads or test points that will be susceptible toatmospheric attack then there have been a number ...
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