Detecting Process Defects


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Over the last 30 years I have seen process problems in soldering, PCB manufacture, component failures and investigating product failures worldwide. In many cases, the same process problems or failure modes just go round and round and will return if the true cause of failure is not detected.

The causes can be highly complex or very simple. The examples in this article show typical failures of boards and solder joints, the solutions for which are all online if you care to search. Some people say that when we went to lead-free, all the problems changed; actually, many remained the same and looked different, but now there are new ones to solve.

The following resources provided by National Physical Laboratory (NPL) and IPC may help you solve your process problems in the coming years. In the second part of this article, I will illustrate some process problems and their root causes. First let’s look at the Defect Database Live and then our “Defect of the Month Video” from IPC.

Defect Database Live

The National Physical Laboratory has created an Industry Defects Database that allows engineers to search through a range of defects covering components, printed circuit boards and assembly problems. The aim is to add more defects and via submissions from the industry each month. The defects database allows engineers to submit defects online with full details and solutions to current problems or requests for advice and possible solutions to the process issues or failures.

The database is unique in the industry as there is no other managed resource of its type with the added scope of having defects added via requests for defect examples from the industry.

IPC Defect of the Month

I was invited by IPC to produce a Defect of the Month video clip, to be featured on their website. Each month, we focus on a different defect type and provide photographic examples or videos showing the defects happening in real time. You can visit the IPC website or my YouTube channel to see many of the 40 clips produced showing solder balling, dendrite formation, popcorning, PCB delamination and headin- pillow failures. There are also some technical book review clips included that may be a useful reference source.

Selected Process Defects from the Industry

Now let’s look at some of the most common process issues faced in the industry and some typical examples. However, it’s worth looking at what actual industry experiences. The following three graphs show the results of short online surveys from engineers attending online webinars regarding the most common problems or process issues with PCBs and assembly.

Read The Full Article Here

Editor's Note: This article originally appeared in the August 2015 issue of SMT Magazine.

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