Reduce PCB assembly defects by up to 60% with ScanCAD

ScanCAD’s multifunctional offline inspection systems are the world leader in SMT templates, emulsion screens and PCBs. But ScanCAD’s capabilities are much higher, helping to change production data to improve processes.

Any process is as good as the data that was used to set it up. Today, most PCB board assembly processes, as well as other multi-stage manufacturing processes, use CAD data to program equipment.

The commonly accepted assumption is that the result of merging all subprocesses fits perfectly with the CAD data. This assumption can be costly, given that each part of a process has a specific tolerance. Taken together, these tolerances can have a dramatic impact on the performance and quality of the finished part.

In reality, there are differences between CAD data and threads. Today’s fully automated equipment is working hard to compensate for these variations by integrating optical inspection systems. They help to apply corrective measures such as the orientation of the template in relation to the PCB board, the placement position of the components, etc., dividing the positioning errors throughout the process.

As the components and their geometries become smaller, these corrections become more and more difficult, if not impossible.

Reasonable would be the “confirmation” that all the physical parts that join do this correctly, BEFORE entering production. This is easier said than done, as stencils can have thousands to millions of openings. A 99.99% inspection is not acceptable because there could be hundreds of potential errors in the one million openings.

A real example of a customer : the adjacent image shows 102 errors in 342,605 apertures on a wafer bump template with 75 µm apertures. This apparently good 99.97% efficiency of openings causes more than 80% of semiconductor integrated circuits to be defective!

ScanCAD systems can analyze each of the parts that come together, first to compare the part with the original CAD data, to see if they fit and are tolerable. After that, we can adjust the CAD data to match the actual components, thus facilitating stricter production, reducing defects and keeping the amount of tolerances as low as possible.

Published studies have shown a 43% decrease in solder paste defects by simply adjusting the data. Thus, correlating the dimensions used to manufacture the SMT template with the batch of components to be used significantly reduces the paste defects, as the actual components do not always fit perfectly with the CAD data.

The same results are recorded when adjusting the automatic placement of components to better match the batches of parts. More accurate placements substantially reduce placement defects, such as the phenomenon of tombstoning, etc. Studies have shown over 60% reductions in the tombstoning phenomenon for the 0201/0402 packages.

Net Digital Service SRL is an authorized distributor for Romania of ScanCAD International products.