Why do circuit boards fail due to poor conformal coating application?

Conformal coating defect on PCB leading to poor coverage

When considering the long term reliability of Printed circuit boards (PCBs), it is important to understand that they can fail due to being exposed to harsh or extreme environments such as airborne contamination, salt spray, moisture, fungus, dust and corrosion.

By definition conformal coating is a protective non conductive dielectric layer that is applied onto the printed circuit board assembly to protect the electronic assembly from this damage. The coating when applied well gives added protection. So, if the conformal coating is poorly applied to the PCB then the circuit board is more likely to fail in the long-term.

Looking specifically at the application of the coating there are several defects that can occur during processing that can fundamentally impair the performance of the conformal coating. This can lead to reduced long-term reliability of the PCB. These defects can include Capillary Flow, De-wetting, De-lamination, Cracking, Orange Peel, Pin holes, Bubbles & Foam.

Logically, it is wise to avoid these effects in the process which can potentially improve the lifetime of the circuit board and limit problems in the field.

For further information click conformal coating defects and long-term reliability or contact us NOW at  +44 1226 249019 or email sales@schservices.com

How does corrosion occur even when I am using a conformal coating to protect my printed circuit board?

In conformal coating, there are several mechanisms that cause failure of printed circuit boards (PCBs). One of these failure mechanisms is corrosion.  This is defined as the chemical or electrochemical reaction between a material, usually a metal, and its environment that produces a deterioration of the material and its properties.

To learn more click Conformal Coating failure mechanisms Corrosion to find out more.

What is the conformal coating failure mechanism “orange peel” and why does it occur?

In conformal coating, there are several mechanisms that cause failure of printed circuit boards (PCBs). One of these failure mechanisms is Orange Peel.  This is defined as an uneven textured surface, often appearing dull, which looks like the skin of the orange.

To learn more click Conformal Coating failure mechanisms Orange Peel to find out more.

Why do bubbles occur in my conformal coating?

In conformal coating processing and failure mechanisms bubbles are trapped pockets of air under coating, pin holes are burst bubbles that reach to the surface of the PCB and foam is extreme bubbling.

To learn more click Conformal Coating failure mechanisms Pin holes Bubbles and Foam to find out more.