Parylene Coating Blog by Diamond-MT

How to Remove Conformal Coatings

Posted by Sean Horn on Fri, Sep 22, 2017 @ 08:08 AM

Failures of PCBs and similar electronic assemblies can occur despite the protection of conformal coating. Contributing reasons include:

  • Incorrect selection of coating methods/materials related to the assembly’s use.
  • Poor maE_000.jpgnufacture or stresses to the assembly during operation.
  • Challenges to the coating’s integrity – bubbles/voids, inadequate masking, poor adhesion/surface finish, uneven thickness.

As with selecting an appropriate coating pre-application, conformal coating removal requires matching removal methodology with coating type and the component’s function.

Major Removal Methods

Matching the removal method to the coating material, its age, thickness and the PCB’s specific function is an essential first-step to the removal process. Proper identification of the coating material, and its original application method, are also basic to efficient removal. Coating removal is determined by:

  • the type of coating material used,
  • the PCB’s components/their position on the board,
  • the film’s material, its thickness, and
  • effect on the substrate.

Once these have been identified, determination of the appropriate removal method is possible. Major removal methods include:

Industry Standards

Prevailing industry standards provide appropriate process guidelines for conformal coating removal. IPC-7711/7721, Rework, Modification, and Repair of Electronic Assemblies, imparts best-practice procedures for removing conformal films from PCBs. IPC-7711/7721 standards detail coating removal methods determined by their impact on the film, its thickness, and effect on the substrate. IPC-CC-830 defines conformance guidelines for all conformal coatings; film removal is frequently required when IPC-CC-830 requirements for each coating type’s overall quality conformance are unmet during application.

Skill and Conformance Requirements

Operator experience and skill influence film removal. Appropriate material identification is necessary prior to commencing removal. Better-equipped to correctly identify coating characteristics, skilled professionals determine best-method removal procedures with greater accuracy. They can also implement removal procedures within the constraints of conformance issues like the PCB’s environmental, functional, and serviceability requirements, improving the removal process.

To learn more about removing and applying conformal coating, download our whitepaper now:

 Conformal Coating Applications Whitepaper

Tags: conformal coating removal, conformal coating rework, conformal coating removal services