Metal fabricators using a laser to cut metal often encounter an oxide residue on the surface of the metal, forming an oxide residue because of the high heat generated during laser cutting.
Not removing this residue weakens the bond in powder coating, which applies a dry powder to the metal surface, then cures to form a hard, durable finish.
The residue prevents the powder coating from bonding properly to the metal surface, leading to adhesion problems and weaker finishes. Metal fabricators must remove the oxide residue before applying powder coating to avoid this issue.
The following is quoted directly from our sister site, Schuette Metals:
Scratching And Flaking The Surface: Laser Oxide Scale
A laser oxide scale is a film formed on metal surfaces after laser cutting metal from the combination of extreme temperatures and oxygen. The scale is found near the area laser cut and has a shiny bluish finish. Most importantly, the oxide scale prevents powder coating or paint from sticking to the metal substrate.
Sounds innocuous enough, right?
Unfortunately, it’s not. Companies pay fabricators sizeable sums of money to create functionally attractive components. That layer of oxide becomes the Achilles Heel for steel parts; any finish easily chips or flakes off, exposing the substrate to the elements and defeating the purpose of those protective metal coatings.
Removing Laser Oxide Scale
Removing the oxide scale becomes essential during the metal fabrication process. Fortunately, there are a couple of easy solutions.
In a pre-wash system, typically multi-stage, one of the first stations is an acid or chemical shower removing the oxide scale. This simple step removes the potentially destructive element of air and moisture exposure to a steel substrate.
Blasting the substrate with abrasive particles physically removes the residue from the metal’s surface.
Choosing the right method is important based on the metal type and the project’s specific requirements. For example, abrasive blasting may not be suitable for delicate or thin metals, while chemical cleaners may not be effective in many oxide residues.
Removing the laser oxide scale ensures optimal adhesion and a longer lifespan for powder coating. Some crucial benefits of removing the laser oxide scale include:
- Improved Corrosion Resistance
- Increased Durability
- Better Overall Finish