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The Elcometer 456 is a precision digital thickness gauge designed to measure the thickness of paint and coating films on metals. It can be used on both ferrous and non-ferrous surfaces and is ideal for the paint, automotive, industrial inspection and quality control industries.
The Elcometer 456 Dry Film Thickness Gauge, also known as the Paint Thickness Meter, is available in three different models. Each model offers more advanced features and capabilities, from the basic Model B to the most advanced Model T.
The Integral models are ideal for one-handed operation due to their integrated design and the large contact area of the Bigfoot™ internal probe. This design increases stability during measurement and provides consistent, repeatable and accurate dry film thickness results.
Dry film thickness can be measured on magnetic steel surfaces or non-magnetic metals such as stainless steel and aluminum, using a digital thickness gauge.
For non-magnetic coatings on magnetic substrates (such as paint on steel), the principle of electromagnetic induction is used.
For non-conductive coatings on non-ferrous metals (such as aluminum), the principle of eddy current is used.
In this type of device, a permanent magnet is mounted on a balanced arm. The force required to separate the magnet from the coating surface is a measure of the coating thickness.
The force is applied by a coil spring connected to the balanced arm and a graduated wheel. By rotating the scale, the applied force is gradually increased until the magnet is separated from the surface. Instead of showing force, the scale of the device is graduated directly in units of thickness, and the coating thickness is read from a pointer on the body of the device.
| Measurement Range | 0 to 500 µm (standard model), Up to 30 mm (special model) |
|---|---|
| Measurement Accuracy | ±1 to ±3% depending on model |
| Reading Rate | Up to 140 readings per minute (Scan Mode) |
| Power Supply | Replaceable AA battery |
| Connections | Bluetooth, USB |
| Standards | AS, ASTM, BS, ISO, SSPC |
Electronic thickness gauges used for magnetic substrates operate on the principle of electromagnetic induction. In this system, a three-coil probe is used:
The central coil is powered by the device.
The two side coils detect the magnetic field created.
The signal produced by the device is sinusoidal and creates an alternating magnetic field around the central coil.
If there is no magnetic material near the probe, the magnetic field passes through both side coils in a balanced manner. However, as the probe approaches the uncoated substrate, the field becomes unbalanced and the field strength in the closer coil is greater than in the more distant coil. This difference creates a net voltage between the two coils that is proportional to the distance to the substrate (and therefore the thickness of the coating).
In the eddy current method, a single-coil probe with a high frequency (several megahertz) is used to create an alternating field in the non-ferrous metal under the coating.
This field induces eddy currents in the substrate, which themselves have associated magnetic fields. These fields affect the probe of the device and cause a change in the electrical impedance of the coil. The magnitude of these changes is directly related to the thickness of the coating.
One of the most important criteria for selecting the right thickness gauge is the level of accuracy required in the measurement. Among the different types of devices, there is a range from medium to very high accuracy, which is usually directly related to the price of the device; the higher the accuracy, the higher the cost of the device.
In addition, the coating application process, surface conditions and operator skill also affect the variability of measurement results.
The accuracy of the device is the difference between the number displayed by the device and the actual coating thickness. The smaller this difference, the more accurate the device is.
To check the accuracy of an instrument, it is essential to use traceable reference standards.
First, the instrument is zeroed on a flat, uncoated substrate. The instrument is then calibrated using a standard of known thickness (close to the maximum measuring range of the instrument). Intermediate thicknesses are then measured and compared with the actual standard values.
The difference between the reading and the actual standard value is the measurement error. This error is usually expressed as a percentage of the reading.
To check the accuracy of an instrument, it is essential to use traceable reference standards.
First, the instrument is zeroed on a flat, uncoated substrate. The instrument is then calibrated using a standard of known thickness (close to the maximum measuring range of the instrument). Intermediate thicknesses are then measured and compared with the actual standard values.
The difference between the reading and the actual standard value is the measurement error. This error is usually expressed as a percentage of the reading.
Fast, high-accuracy measurement
(up to 140 readings per minute)
Color display with backlight
Ergonomic design with automatic calibration capability
Automatic data storage and Bluetooth connection for data transfer
Available in Integral and Separate Probe versions
Suitable for use in rugged environments
