Attaining Edge Coverage
The problem is that the edges of the bus bars that we are powder coating do not have proper coverage, which is not acceptable to our customer. Is there any solutions we could try? I have wondered if it could be a characteristic of the powder itself.
Q.We powder coat bus bars that are copper and then tin plated. We sandblast the parts before they are powder coated. We apply 3-5 mils of powder, the parts are then cured at 375°F for 20 min. The problem is that the edges do not have proper coverage, which is not acceptable to our customer. Is there any solutions we could try? I have wondered if it could be a characteristic of the powder itself. S. A.
A. You are absolutely correct, it is a function of the powder coating formulation. The powder coating formulative property that you seek is called “Edge Coverage” or sometimes called “Pull Back.” You must discuss this with your powder coating supplier. They will adjust the flow characteristics of the powder coating material to reduce this problem. Be prepared for more orange peel on the surface after the coating has been changed.
This alternative to TGIC-based polyester powder coatings offers similar performance and enhanced transfer efficiencies.
Metal fabricators that laser-cut with oxygen take steps to prepare parts better for powder coating.
A review of available test methods, common applications and innovative instrumentation...