Predetermining the thickness of a coating
A method for predetermining a thickness of a coating which is to be arranged on a substrate is provided. A spray spot is arranged on a surface of the substrate or a test substrate. The volume of the spray spot is determined, and based on the determined volume, the thickness of a layer which is to be applied is worked out. An arrangement for predetermining the thickness of a coating is further provided.
1. A method for spraying a coating material onto a substrate, the method comprising:
spraying, by a spray gun connected to a gas container and a gas heater, a spot of coating material onto only a portion of the substrate, in a fixed time span, wherein, during the spraying, the spray gun moves at a speed, v, relative to a surface of the substrate, along parallel tracks having a track offset, p, that guides the spray gun during the spraying;
detecting, by a device, a volume of the spot applied to the portion of the substrate;
calculating, by a controller coupled to the spray gun and the device, a layer thickness of a complete coating that is to be later applied to the substrate by the spray gun, based on the volume of the spot as detected by the device, wherein the layer thickness is determined by the equation:
h layer =1/( v*p )*Δ V spot /Δt
where h layer is the layer thickness, v is the speed, p is the track offset defining a spacing between the parallel tracks, ΔV spot is the volume of the spot, and Δt is the fixed time span; and
in response to the calculating the layer thickness by the control device, applying, by the spray gun, the complete coating of coating material to the substrate at the layer thickness, wherein, during the applying the complete coating of coating material at the layer thickness, the spray gun moves at the speed, v, along parallel tracks having the track offset, p.
2. The method as claimed in claim 1 , wherein the substrate is a test substrate.
3. The method as claimed in claim 1 , wherein the substrate is a gas turbine component.
4. The method as claimed in claim 1 , wherein the volume of the applied spray spot is determined by tactile profilometry.
5. The method as claimed in claim 1 , wherein the volume of the applied spray spot is determined by optical profilometry.
6. The method as claimed in claim 1 , wherein the volume of the applied spray spot is determined by an optical 3-D scanning technique.
7. The method as claimed in claim 6 , wherein the optical 3-D scanning technique performed is a structured light scan.