CONFORMAL COATING

What is Conformal Coating?

Conformal coating is protective chemical material coating applied after the final SMT PCB assembly or through-hole assembly process. Coatings are comprised of 5 different types, Acrylic, Epoxy, Urethane, Silicone and Parylene resins. Applying the coatings to a PCB board assembly can be done by hand spray, robotic spray, brush or dipping. The coating acts as an additional dielectric layer that provides protection due to environmental and mechanical stresses, such as thermal extremes, chemicals, dust, salt fog, abrasions, and moisture. In a PCB assembly that has close spacing of conductive pathways or close spacing of components the coating will help minimize dendrite growth over a period of time that causes shorting.

Robotic Spray vs Traditional applications:

The method of application will depend on the customer requirements of the turnkey pcb assembly, but PNC prefers spray method for consistency in overall coating thickness. There are often select components on a pcb board assembly that will not be required to be coated. The traditional way is to block out or mask the selected components with tape. This is time consuming, costly and a possibility that the component can be damaged on the SMT assembly when removing. The robotic method can be programmed accurately to spray around the parts thus ensuring no component damage from masking and maintain a repeatable coating thickness.

When choosing a conformal coating for your turnkey pcb assembly, there are many manufacturers to choose from. The following are a few that we work with, Dymax, HumiSeal, Dow Corning, Hysol, Loctite, and Huntsman. Based on your application and environment of your PCB assembly, choose the Type of coating that fits the PCB board assembly, by visiting their web pages to find the strengths and weaknesses.

IPC J-STD-001D Conformal Coating thickness requirements

Type AR Acrylic Resin 0.03 – 0.13 mm (0.00118 – 0.00512 in)
Type ER Epoxy Resin 0.03 – 0.13 mm (0.00118 – 0.00512 in)
Type UR Urethane Resin 0.03 – 0.13 mm (0.00118 – 0.00512 in)
Type SR Silicone Resin 0.05 – 0.21 mm (0.00197 – 0.00827 in)
Type XY Parylene Resin 0.01 – 0.05 mm (0.000394 – 0.00197 in)

Written by Sam Sangani

Sam Sangani is the President & CEO of PNC Inc., a Nutley, NJ based Printed Circuit Board manufacturer. Sam graduated from L. D. Engineering College with a BS Degree in Mechanical Engineering. He also continued his education and graduated from Steven’s Institute of Technology where he acquired a Master’s degree in Computer Science.

After completion of his BS, Sam worked as a QC Manager, for Xerox, Romania and London. He was responsible for the Quality Control of Cable and Wire Harness imports from Romania. After completing his Master’s Degree, he worked as a Senior Programmer with IBM, Tucson, Arizona. Sam was responsible for leading the Mainframe System Programming Team.

In 1997, Sam acquired PNC INC., a Nutley, NJ based PC Board fabrication Shop. From 1997-2013, Sam has made tremendous improvements and changes within PNC INC., as he added many new Products and Technologies in PNC’s portfolio. With his proven track record and leadership, PNC has never had an unprofitable year and has continued its growth yearly since 1997.

His current responsibilities are Strategic Planning, Corporate Management, New Business Ventures, Sales & Marketing, Trade Shows, Professional Services and leading productive teams to achieve peak potential. He has also utilized Lean Management techniques which have built a foundation for PNC’s high-paced growth. Sam also enjoys real-estate investing, web design & SEO, trading stocks, options, futures and Forex markets.