When to Use Conformal Coating Removal Services

If necessary, it is possible to remove unwanted conformal coatings from PCBs. The process can often be accomplished by either the assembly’s original equipment manufacturer (OEM) or an end-user, but the capability to do so does not always exist. For these parties, removing the coating may be beyond the purview of their experience with conformal materials or exceed the capacities of their available removal equipment and supplies.

The need for removing conformal films can arise at any time following PCB completion due to an assortment of causes. Process and product requirements or component replacement issues can significantly diminish a coating’s functional integrity. When these circumstances develop and the removal process is too complicated or inconvenient to complete, it is advisable to seek the assistance of professional conformal coating removal services.

Coating Conditions Leading to Removal

When the coating is beyond repair, removal may be the only way to save the assembly. Conditions that can lead to coating removal include:

• Contaminants: Contaminated substrate surfaces interfere with coating adhesion. If left untreated for too long, removal may become necessary.
• Delamination: Separation of the conformal coating from the substrate produces a finish characterized by torn, unattached and non-conformal coating, defeating the film’s purpose.
• Masking/prep: Poor masking of component surfaces not targeted for coating disrupts their ability to function as designed.
• Outgassing: Gaseous emissions from a processed layer of coating film generates poor coating performance, potentially leading to the need for coating removal.
• Solder joint defects: Depending on their properties and application processes, conformal coatings can increase assembly solder joint fatigue, if the coating material is not suitable to the PCB’s purposes or is improperly applied to the assembly.
• Tin whiskers: These spikey, whisker-like protrusions along the surfaces of metal components are responsible for PCB arcing and short-circuits. Eliminating their presence can require coating removal.
• Vesication: Blister formation between semi-permeable film coatings and another surface material can become severe, rendering the original conformal film dysfunctional.

Skill and Conformance Requirements 

Successful removal of conformal films largely depends on the levels of operator skill and experience. Advanced operator skill levels are necessary for many removal functions. Accurately identifying the coating material is mandatory for successful removal. If recoating is to be completed by the original manufacturer, the specific coating used will be on file. Stripping materials can also be hazardous. Caustic removal materials demand application of highly specialized aptitudes and technical procedures, frequently beyond the means of OEM personnel or end users.

Skilled professionals are better equipped to properly test the film for reliable identification of coating characteristics to more precisely determine appropriate removal procedures. Hence, they can closely duplicate the physical characteristics of the original, within the constraints of such conformance issues as the assembly’s environmental, functional and serviceability requirements.