Single traverse of the gun over the surface, which lays down a thin layer, often 10 to 25 micrometers. Total thickness is controlled by counting passes, and the step between adjacent strokes, called the index, sets the overlap. Thickness per pass, overlap and time between passes all affect heat input, residual stress and banding.
We're getting a thou per pass, so it's twelve passes to hit 0.012, then measure.
Thin passes with cooling time between them leave less stress than a few heavy ones, even at the same total thickness.
Also heard as
- spray pass
- stroke
- sweep
Related terms
Surface speed
How fast the part surface moves past the gun, set by part rotation and robot traverse.
Striping
Visible bands or ridges across a coating caused by uneven overlap between passes.
Residual stress
Stress locked into a coating and substrate after spraying, from splat shrinkage, cooling and impact.
Mil
One thousandth of an inch (25.4 micrometers), the usual North American unit for coating thickness.