Inspecting conformal coatings of electronic assemblies

Paul Boughton

Transparent protective conformal coating protects electronics assemblies against damage from moisture and wetness.

The new Viscom S3088 Conformal Coating Inspection (CCI) system inspects coatings quickly and reliably for typical defects such as cracks, bad spots, layers that are too thin or too thick, smearing, impurities, or splashes.

Transparent protective coatings contain UV fluorescent indicators that emit visible light, allowing automatic optical inspection. The Viscom S3088 CCI system features an 8M camera technology with four orthogonal cameras and also is equipped with UV LEDs. The S3088 CCI system is immediately available worldwide.

Electronics manufacturers use the Viscom S3088 CCI at the end of the process chain after lacquering and drying.

“The new inspection system that inspects the conformal coating is an integral part of the Viscom product family. The S3088 CCI works with the Viscom SI inspection software, thus offering the same user interface and programming strategy,” said Detlef Beer, responsible for product development at Viscom. “This basis makes it possible to implement traceability concepts, special tests such as reading labels with a data matrix code (DMC) and other features. As a result, the system also can be integrated in production control systems, making it a Manufacturing Execution System (MES).”

Technologically, the S3088 CCI is based on the successful Viscom S3088 system. It works with UV LEDs, which contrasts the UV-reactive conformal coating with the background material, clearly detecting the contours of the lacquer.

“With a resolution of 11.7 or 23.5 µm/pixel, even the smallest bad areas, contaminations or splashes are clearly visible. These then are classified either as defects or as providing valuable indicators to further optimise the coating process,” Beer continued.

In this way, the Viscom S3088 CCI ensures that electronics manufacturers reliably comply with the IPC-CC-830 directive for the qualification and performance of electrical insulating compounds for printed circuit boards.

As a result of flexible algorithms, the system can be quickly adapted to different conformal coating methods. Simple inspection programmes can be created in only a few minutes.

Additionally, it features a good price/performance ratio: An S3088 CCI system is more economical than a classic AOI system. The inspection system is thus intended for electronics manufacturers who apply conformal coatings to large- and medium-sized quantities of electronics assemblies in fields such as automotive engineering, aerospace, industrial electronics and medical technology, among others.

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