{"id":5153,"date":"2026-04-13T15:46:34","date_gmt":"2026-04-13T07:46:34","guid":{"rendered":"https:\/\/txjpcba.com\/?p=5153"},"modified":"2026-04-13T15:46:34","modified_gmt":"2026-04-13T07:46:34","slug":"how-to-avoid-bubbles-in-conformal-coating","status":"publish","type":"post","link":"https:\/\/txjpcba.com\/ar\/how-to-avoid-bubbles-in-conformal-coating\/","title":{"rendered":"How to avoid bubbles in conformal coating?"},"content":{"rendered":"

Bubbles in conformal coating<\/h3>\n

Bubbles in \u0627\u0644\u0637\u0644\u0627\u0621 \u0627\u0644\u0645\u0637\u0627\u0628\u0642<\/strong> are a common defect that can compromise protection, insulation, and long-term reliability. In \u062a\u062c\u0645\u064a\u0639 \u062b\u0646\u0627\u0626\u064a \u0627\u0644\u0641\u064a\u0646\u064a\u0644 \u0645\u062a\u0639\u062f\u062f \u0627\u0644\u0643\u0644\u0648\u0631<\/strong>, \u062a\u062c\u0645\u064a\u0639 \u0627\u0644\u0646\u0645\u0648\u0630\u062c \u0627\u0644\u0623\u0648\u0644\u064a \u0644\u062b\u0646\u0627\u0626\u064a \u0627\u0644\u0641\u064a\u0646\u064a\u0644 \u0645\u062a\u0639\u062f\u062f \u0627\u0644\u0643\u0644\u0648\u0631<\/strong>, \u0648 \u062a\u062c\u0645\u064a\u0639 SMT<\/strong>, bubbles may create weak points where moisture, contaminants, or air can penetrate, leading to corrosion or electrical failure. Preventing bubbles requires proper material handling, surface preparation, and process control.<\/p>\n

\"How
How to avoid bubbles in conformal coating<\/figcaption><\/figure>\n

Ensure proper PCB cleaning<\/strong>
One of the main causes of bubbles is contamination such as flux residue, oil, or dust. Before coating in \u062a\u062c\u0645\u064a\u0639 \u062b\u0646\u0627\u0626\u064a \u0627\u0644\u0641\u064a\u0646\u064a\u0644 \u0645\u062a\u0639\u062f\u062f \u0627\u0644\u0643\u0644\u0648\u0631<\/strong><\/a>, the board must be thoroughly cleaned and dried. Residual solvents or moisture can outgas during curing, forming bubbles under the coating.<\/p>\n

Control moisture and humidity<\/strong>
Moisture trapped in components or the PCB can vaporize during coating or curing. In \u062a\u062c\u0645\u064a\u0639 SMT<\/strong>, it\u2019s important to store boards in controlled environments and, if necessary, pre-bake them to remove absorbed moisture before applying \u0627\u0644\u0637\u0644\u0627\u0621 \u0627\u0644\u0645\u0637\u0627\u0628\u0642<\/strong>.<\/p>\n

Use correct coating viscosity<\/strong>
If the coating is too thick, it may trap air during application. Proper dilution (if allowed by the manufacturer) and maintaining the recommended viscosity help the coating flow smoothly and release trapped air.<\/p>\n

Apply coating evenly and at the right speed<\/strong>
Application method matters. Whether spraying, dipping, or brushing, applying the coating too quickly can introduce air bubbles. In automated \u062a\u062c\u0645\u064a\u0639 SMT<\/strong><\/a> lines, parameters such as spray pressure, nozzle distance, and flow rate should be optimized to ensure smooth, even coverage.<\/p>\n

Avoid excessive coating thickness<\/strong>
Applying overly thick layers increases the risk of bubble formation and solvent entrapment. It is better to apply multiple thin layers rather than one heavy coat in \u062a\u062c\u0645\u064a\u0639 \u062b\u0646\u0627\u0626\u064a \u0627\u0644\u0641\u064a\u0646\u064a\u0644 \u0645\u062a\u0639\u062f\u062f \u0627\u0644\u0643\u0644\u0648\u0631<\/strong> \u0627\u0644\u0639\u0645\u0644\u064a\u0627\u062a.<\/p>\n

Degas the coating material<\/strong>
Before use, some coatings can be degassed (removing dissolved air) to prevent bubble formation. This is especially useful in \u062a\u062c\u0645\u064a\u0639 \u0627\u0644\u0646\u0645\u0648\u0630\u062c \u0627\u0644\u0623\u0648\u0644\u064a \u0644\u062b\u0646\u0627\u0626\u064a \u0627\u0644\u0641\u064a\u0646\u064a\u0644 \u0645\u062a\u0639\u062f\u062f \u0627\u0644\u0643\u0644\u0648\u0631<\/strong><\/a>, where process optimization is being tested.<\/p>\n

Allow proper flash-off time<\/strong>
After application, giving the coating time for solvents to evaporate (flash-off) before full curing helps prevent bubbles. Rushing the curing process can trap solvent vapors inside the coating.<\/p>\n

Optimize curing conditions<\/strong>
Curing too quickly or at too high a temperature can cause rapid solvent evaporation, leading to bubbling. Controlled curing\u2014whether thermal or UV\u2014ensures a smooth, defect-free finish.<\/p>\n

Inspect and adjust process<\/strong>
\u0641\u064a \u062a\u062c\u0645\u064a\u0639 \u0627\u0644\u0646\u0645\u0648\u0630\u062c \u0627\u0644\u0623\u0648\u0644\u064a \u0644\u062b\u0646\u0627\u0626\u064a \u0627\u0644\u0641\u064a\u0646\u064a\u0644 \u0645\u062a\u0639\u062f\u062f \u0627\u0644\u0643\u0644\u0648\u0631<\/strong>, visual inspection (often with UV light) helps identify bubble issues early. Process parameters can then be fine-tuned before moving to mass production.<\/p>\n

In conclusion, avoiding bubbles in \u0627\u0644\u0637\u0644\u0627\u0621 \u0627\u0644\u0645\u0637\u0627\u0628\u0642<\/strong><\/a> requires attention to cleaning, moisture control, application technique, and curing conditions. By optimizing these factors in \u062a\u062c\u0645\u064a\u0639 \u062b\u0646\u0627\u0626\u064a \u0627\u0644\u0641\u064a\u0646\u064a\u0644 \u0645\u062a\u0639\u062f\u062f \u0627\u0644\u0643\u0644\u0648\u0631<\/strong>, \u062a\u062c\u0645\u064a\u0639 SMT<\/strong>, \u0648 \u062a\u062c\u0645\u064a\u0639 \u0627\u0644\u0646\u0645\u0648\u0630\u062c \u0627\u0644\u0623\u0648\u0644\u064a \u0644\u062b\u0646\u0627\u0626\u064a \u0627\u0644\u0641\u064a\u0646\u064a\u0644 \u0645\u062a\u0639\u062f\u062f \u0627\u0644\u0643\u0644\u0648\u0631<\/strong>, manufacturers can achieve a smooth, uniform coating that delivers reliable protection.<\/p>\n

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