All devices for measuring thickness are divided according to the principles of operation, which, in turn, differ, reflecting by this fact the variety of physical processes occurring in nature.
The product in question is a mechanical type of thickness gauges that exist due to high-precision metal processing. An ordinary steel plate with rows of numbers and teeth located along the edges allows you to measure the thickness of the newly applied paintwork with an accuracy of several microns.
How it works
This is how it goes. Tool steel serves as a material for a small quadrangular plate of a fixed thickness of about 1.5 mm with perfectly smooth butt-ends strictly perpendicular to the edges.
Equally deep rectangular grooves are cut at the edges of the product, separated by teeth with a flat top. The resulting picture resembles a meander, except for the slight difference that the height of the teeth is different and smoothly changes from one hollow to another. This is why this type of device is often called a "comb" in the jargon: the edges really resemble a trivial comb.
This feature does wet layer thickness gauges capable perform accurate measurements of the parameters of uncured paints and varnishes. The fact is that the top of each tooth is recessed relative to the surface of the end to a certain, strictly verified depth. This depth grows from tooth to tooth by a discrete amount, gradually increasing.
Thus, each face covers a certain range of recessed depths that are directly used in the measurement process. At the base of each tooth there is a number that serves to read the readings.
The thickness gauge is immersed by one of the measuring faces into a layer of paint, strictly perpendicular to the painted surface, until it comes into close contact with it. Now an "exposure" is needed - for one second the meter is kept motionless in a submerged state. Having removed the plate from the paint, the master can read the readings: some of the teeth will be colored, and some will remain clean. The figure corresponding to the border between them will be the desired thickness of the paintwork. If all the teeth are colored, then you need to use a different face with larger numbers than those written on the current one.
The measurement error, according to typical formulas, will be half a discrete step between adjacent digits. For example, if there are teeth with inscriptions 200 and 225 microns, then the error will be 12.5 microns.
