The PosiTector® 200 Coating Thickness Gauge non-destructively measures the thickness of coated non-metals including paints on wood, concrete, plastics, composites and more using proven ultrasonic technology. With the new Maximum Thickness Mode, the PosiTector 200 is easier than ever to use.
Measuring principle
The PosiTector 200 probe emits ultrasonic sound pulses that travel to coatings and reflect/echo from any interface that differs in density eg substrate. It measures the time for an acoustic pulse to travel from the probe to the coating/substrate interface and back. By multiplying this travel time by the speed of sound through the coating (which is similar for most polymer coatings), the thickness of the coating can be calculated.
Although density variations are almost always present at the coating-substrate interface that the PosiTector 200 can detect, density variations between coatings can also be identified. The PosiTector 200 Advanced model can often detect interfaces between layers of different or identical coatings, as long as the initial layer is allowed to fully cure before subsequent layers are applied. Typically, the loudest ultrasonic echoes represent the coating-substrate interface, and smaller echoes represent individual layer thicknesses.
default mode
The PosiTector 200's default measurement mode has been used successfully for decades to measure coating thickness on a wide variety of coatings and substrates. The PosiTector 200 searches for the loudest ultrasonic echo within its measurement range and reports this as the coating thickness. In multilayer mode, the thicknesses associated with maximum echogenicity (depending on the number of layers selected) are reported as individual layer thicknesses. For most measurement applications, especially when measuring smooth polymer coatings, this method provides accurate readings of the total coating thickness and individual layers without setup or adjustment.
Applications measuring surface roughness or many large echoes near the coating surface on the PosiTector 200 can sometimes be challenging because these conditions produce loud, unwanted echoes that are often larger than the desired echoes that form the coating-substrate interface bigger or louder. While increasing the instrument's Lo Range can ignore these unwanted echoes, it is time consuming and it is sometimes difficult to make adjustments to ignore unwanted surface echoes while still measuring thinner coating areas.
Maximum Thickness Mode
NEW Max Thick Mode is suitable when increasing the Lo value range requires adjusting the adjustment value too close to the expected coating thickness, or if the user does not want to adjust the range at all.
When Max Thick mode is enabled, the PosiTector 200 searches for the deepest significant echo, not the loudest echo. This means that any large echoes near the surface (usually caused by surface roughness or a "noisy" coating system) will be ignored. This mode is generally more effective in reporting the total coating thickness at the substrate interface and eliminates the need to adjust the instrument's preset Lo range. Since some small echoes are unavoidable inside the substrate, only echoes above the preset loudness are reported. On PosiTector 200 Advanced models, this threshold can be adjusted from the graph display mode.
While Max Thick mode is enabled, and when multiple slices are selected (PosiTector 200 Advanced only), the slice thickness associated with the deepest ultrasound echo is reported.
Note: Maximum Thickness Mode is not recommended for thin metal substrates or composite materials such as carbon fiber or fiberglass.
in conclusion
The PosiTector 200 Ultrasonic Coating Thickness Gauge measures the thickness of coatings on non-metals including wood, concrete, plastics and more. For most applications, the new Maximum Thickness mode will provide accurate readings while ignoring incident surface reflections without having to adjust the Lo range.
A simple gage update can add this capability to existing PosiTector Standard (serial numbers 795,375+) and Advanced (serial numbers 784,000+) models.
