Selective coating with HumiSeal

Selective coating with HumiSeal conformal coating, developed by Chase Corporation, is an automated process that applies coating only to specific areas of a PCB, rather than covering the entire board. It is widely used in modern PCB Assembly, SMT Assembly, and Turnkey PCB Assembly for precision and efficiency.

How selective coating works

Selective coating systems use programmable equipment to control exactly where the coating is applied:

• CAD data or teaching programs define coating paths
• Robotic valves or spray heads dispense HumiSeal precisely
• The machine avoids connectors, test points, and sensitive areas
• Coating is applied in controlled patterns and thickness

This eliminates the need for extensive manual masking.

Key advantages

High precision

• Coating is applied only where needed
• Protects critical components without affecting connectors

Reduced masking

• Minimal use of tapes or boots
• Saves time and labor in PCB Assembly

Consistent quality

• Uniform coating thickness (typically 25–75 µm)
• High repeatability in SMT Assembly

Material savings

• Less coating waste compared to dip or full spray methods

Faster production

• Ideal for high-volume Turnkey PCB Assembly lines

Typical applications

Selective coating with HumiSeal is used in:

• Automotive electronics
• Industrial control systems
• LED lighting PCBs
• Consumer electronics
• Aerospace and medical devices

These applications require both protection and precision.

Selective coating vs traditional methods

• Selective coating → precise, automated, minimal masking
• Spray coating → broader coverage, requires masking
• Dip coating → full coverage, less control
• Brush coating → manual, used for rework

Selective coating is considered the most advanced method in SMT Assembly.

Important process considerations

• Proper PCB cleaning before coating
• Correct viscosity settings for the machine
• Accurate programming of coating paths
• Post-coating curing (UV, thermal, or moisture)
• Inspection for coverage and defects

Conclusion

Selective coating with HumiSeal is a high-precision, automated method that applies conformal coating only where needed. In PCB Assembly, SMT Assembly, and Turnkey PCB Assembly, it offers superior efficiency, consistency, and cost control compared to traditional coating methods.

We support HumiSeal and equivalent conformal coating solutions for your PCBA projects.

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• Acrylic (AR)
• Silicone (SR)
• Polyurethane (UR)
• UV Curable - UV
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