Max. thickness (ferrous met.)
The maximum coating thickness that the instrument can detect when measuring on ferrous metals such as steel. With a larger coating thickness, the thickness gauge sensor simply cannot “catch” on the metal surface under the paint, and effective measurement will not be possible. This parameter is indicated in micrometers — thousandths of a millimetre; the larger it is, the more versatile the device is, the wider the possibilities for its use. On the other hand, a large maximum measurement thickness can adversely affect the accuracy when measuring small values.
For modern thickness gauges, the maximum thickness
up to 1000 microns is considered small,
from 1000 to 1500 microns — small,
from 1500 to 2000 microns — medium,
more than 2000 microns — significant. In the most advanced professional-level models, this figure can reach 20 – 30 cm.
Max. thickness (non-ferrous met.)
The maximum coating thickness that the instrument can detect when measuring non-ferrous metals such as aluminium alloys. With a larger coating thickness, the thickness gauge sensor simply cannot “catch” on the metal surface under the paint, and effective measurement will not be possible. This parameter is indicated in micrometers — thousandths of a millimetre; the larger it is, the more versatile the device is, the wider the possibilities for its use. On the other hand, a large maximum measurement thickness can adversely affect the accuracy when measuring small values.
For modern thickness gauges, the maximum thickness
up to 1000 microns is considered small,
from 1000 to 1500 microns — small,
from 1500 to 2000 microns — medium,
more than 2000 microns — significant. In the most advanced professional-level models, this figure can reach 20 – 30 cm.
Max. error
The maximum measurement error provided by the device, in other words, the largest deviation from the real value of the measured value that may occur during the measurement process. The smaller this indicator, the more accurate the device, the smaller the error it gives in the measurement process; on the other hand, high accuracy has a corresponding effect on cost.
Specifically, in thickness gauges, an accuracy of 10% is considered low, 5% is average, 3% is good, and less than 3% is excellent.
Continuous measurement
Support of the device of a mode of
continuous measurement.
In this mode, the user does not need to press the button every time to take measurements — the device constantly scans the space and automatically displays the measurement results on each subsequent contact with the painted surface. This format is very convenient for large-scale work — for example, for a comprehensive check of the car body.
Auto switch-off
The presence in the device of the
automatic shutdown function: the device turns off on its own if the user has not performed any actions with it for some time. The response time for this function is usually a few minutes.
Auto-off saves battery power; it is especially useful if the user forgets to turn off the instrument manually.
Power source
All power sources can be divided into two categories: replaceable batteries in a standard size and
built-in batteries. The former are convenient in that a dead battery can be quickly replaced with a fresh one, while the original battery will have to be charged — and this takes time and an external power source. In addition, batteries can be selected at your discretion by type (disposable/rechargeable) and capacity. Batteries, in turn, can be made more compact and at the same time capacious, besides, they do not need to constantly spend money on fresh batteries.
The main characteristic of a replaceable battery is its size; The most popular sizes found in thickness gauges are as follows:
—
AAA. Elements, also known as "mini-finger" or "little finger". They have a cylindrical shape with a diameter of 11 mm and a length of 44 mm. Usually used in 2 or 3 pieces. They can be made in the form of batteries.
—
AA. Elements, also known as "finger". They have a cylindrical shape with a diameter of 13.5–14.5 mm and a length of 50.5 mm. Usually used in 2 pieces. They can be made in the form of batteries.
—
PP3. Batteries of a characteristic rectangular shape, with a pair of contacts on one of the ends. They have a nominal voltage of 9 V. They can be made rechargeable, however, for a number of reasons, this op
...tion has not received distribution; disposable “PP3” are used much more often.
— CR2032. One of the most popular sizes of "tablet" batteries. They have the shape of a disk 3.2 mm thick and 20 mm in diameter. They are used in the most miniature devices, where compactness is crucial. They are only made disposable.
— LIR2032. A rechargeable version of the CR2032 batteries described above, made using lithium-ion technology.
— A23. Cylindrical batteries with a diameter of 10 mm and a length of 29 mm. They are distinguished by a rather high voltage — 12 V. They are usually made disposable.
As for batteries, the key parameter for them is the technology by which the battery is made:
— Li-Ion. Lithium-ion technology allows you to create batteries with a good charge density — that is, compact and at the same time capacious. In addition, they are not subject to the “memory effect” (reduction in capacity when charging to full discharge) and charge quickly enough. Of the shortcomings of such elements, one can only note the likelihood of overheating and fire in case of malfunctions, however, subject to the operating rules and the use of serviceable chargers, the probability of this is almost zero.
— Li-pol. An improved version of the lithium-ion batteries described above, providing even greater charge density, but at a slightly higher cost.Operating temperature
The temperature range at which the thickness gauge can normally perform its functions. If you go beyond this range, the device may not break down immediately, but you won’t have to talk about accurate measurements. Note that you have to pay attention to this parameter mainly in cases where the device is planned to be used outdoors. So, for use in winter, it is worth making sure that the device is able to operate at
temperatures below zero, and for hot climates, it is desirable that the upper limit of the range is
+40 °C and above.