What does "accuracy" mean?
The fundamental measure of a coating Thickness Gauge is the accuracy of the reading. This is the difference between the reading and the true coating thickness.
How to test the accuracy of coating Thickness Gauge?
In order to test the accuracy of a particular coating Thickness Gauge, it is important to have a traceable coating thickness standard. The instrument is zeroed on a smooth substrate without any coating and set to a known thickness standard or near At the maximum thickness, measure the standard of medium thickness, and compare the reading with the standard of actual thickness. Error is the difference between the read value and the standard value. This is most conveniently expressed as a percentage of reading.
The Importance of Coating Thickness Gauge Calibration
Calibration is the process by which a manufacturer sets up a coating Thickness Gauge during manufacture to ensure that the required accuracy specifications are met. This process usually requires the thickness of the coating Thickness Gauge to be set to a known value and intermediate thickness values checked. In modern electronic instruments, critical values over the entire coating thickness range are stored in memory as reference points.
Why Do You Need to Calibrate a Coating Thickness Gauge Before Testing?
The calibration of the coating Thickness Gauge will be affected by different materials, shapes and the surface of the metal substrate to be tested. For example, the magnetic properties of steel alloys vary, different aluminum alloys and different non-ferrous metals, copper, brass, stainless steel Conductivity also varies. These variations can affect the linearity of the coating Thickness Gauge. This means that, for example, the instrument is set on mild steel and will read a different reading than it would on high carbon steel of the same thickness. Similar linear effects are seen on thin or curved substrates, especially on shaped substrates such as blast cleaned steel used in structural mills.
To overcome these features that affect most coating thickness gages, it allows you to set the work in progress to maximize reading accuracy.
Adjusting the Coating Thickness Gauge
Adjustable technology allows you to set the coating Thickness Gauge to work in hand. In addition to material differences, shape and surface finish adjustments can be made at elevated temperatures or in the presence of stray magnetic fields. By
adjusting coating Thickness Gauges to these current conditions, the resulting errors are greatly reduced or even eliminated.
The effect of surface roughness, especially on deliberately profiled blast cleaned substrates, either grit or shot peened or mechanically cleaned, is quite significant.
Calibrating Coating Thickness Gauge Using Coating Thickness Standards
There are thickness standards for two basic types of coatings, foil and pre-coated metal.
