How to choose a thickness gauge?

08 Jul.,2024

 

How to choose a thickness gauge?

To choose the correct thickness gauge, you first need to understand several types of thickness gauges currently on the market:

Check now

 1. Magnetic thickness measurement method: the accuracy is relatively high, and it is suitable for measuring the thickness of the non-magnetic layer on the magnetic material. The magnetic material is generally: steel, iron, copper, etc.

 2. Eddy current thickness measurement method: suitable for measuring the thickness of non-conductive layers on conductive metals. But this method has lower accuracy than magnetic thickness measurement method

 3. Ultrasonic thickness measurement method: At present, there is no mature method in China to measure the thickness of the coating layer. Some foreign manufacturers have such instruments, which can not only measure the total coating thickness, but also measure the thickness of multi-layer coatings or more Where neither method can be measured. But the price is relatively expensive.

 4. Electrolytic thickness measurement method: This method is different from the above three methods. It does not belong to non-destructive testing and needs to destroy the coating. But the accuracy is not high, and it is more troublesome to measure

 5. Radiation thickness measurement: This kind of instrument is very expensive (generally above 100,000 RMB), especially for some special occasions.

According to the measurement substrate:

  1. If the measurement substrate is metal, you can choose a magnetic induction thickness gauge or an eddy current thickness gauge. A
    magnetic induction thickness gauge is used to measure the thickness of a non-magnetic layer on a magnetic metal substrate.
    An eddy current thickness gauge is used to measure the thickness of a non-conductive layer on a conductive metal.

  2. The measurement substrate is non-metallic (wood, plastic, glass fiber, etc.), and the ultrasonic thickness gauge is used for measurement

According to the measurement range:

Goto AJR to know more.

The thickness of the general coating is below microns, so the range of the general thickness gauge can meet the requirements. If the precision requirement is high and the coating thickness is thin, then choose an imported brand with a small range; if the coating is relatively thick, you should choose Large range thickness gauge.

According to the measured workpiece:

If the workpiece is relatively small, you should choose a thickness gauge with a micro-probe. The outer diameter of the defelsko micro-probe thickness gauge is only 5 mm, and the measuring part of the probe is smaller, and the area with a diameter of not less than 2 mm is acceptable. For measurement, such as the inner wall of small pipes, etc., you must not only choose a miniature probe, but also a straight probe. For example, it is more appropriate to choose a probe with a 90° or 45° angle. 

How to Choose Dry Film Thickness Gauge?

1. What is a dry film?

Dry film refers to dry paint film (paint film), also known as paint film. A solid continuous film formed by one or more coats of paint applied to a substrate. Generally, the paint film is composed of multiple coats. The amount of coating is determined according to the requirements of the object to be coated. Generally including primer layer, intermediate coating and topcoat layer. It is widely used in the chemical industry. 

2. Why do we measure dry film thickness?

A. The function of dry film or coating

Dry film thickness (DFT) or coating thickness can be said to be an important factor affecting coating performance. With the help of the dry film thickness gauge, the film thickness can be controlled within the error range expected by the paint manufacturer. Appropriate film thickness can ensure the best product performance. Film thickness is an important process parameter that must be measured regularly. The film thickness will affect the appearance of the coating and the protective properties of the coating.

B. The function of fireproof paint and anti-corrosion coating

Taking fireproof paint as an example, if the fireproof paint thickness does not reach the standard, its fireproof performance may be greatly reduced. If the fireproof coating is too thick, it may cause excessive drying time, cracking and peeling of the paint film. Similarly, the anti-corrosion coating thickness is also an important factor affecting the performance of the coating. If the coating is too thin, the anti-corrosion performance of the coating decreases; if the coating is too thick, the anti-corrosion coating may come off. The same is true for other types of coatings.

C. The necessity of controlling dry film thickness

Regular film thickness measurement helps control material costs, manage construction efficiency, maintain paint quality and ensure compliance with contract specifications. Controlling the film thickness in the optimal range helps the coating achieve the best performance. 

D. Dry film thickness measurement method and principle

There are two methods for measuring the coating thickness with a dry film thickness gauge: non-destructive measurement and destructive measurement. Non-destructive measurement will not damage the coating, so most people take the non-destructive measurement method. Non-destructive measurement includes two methods: the magnetic induction measurement principle for the non-magnetic coating thickness measurement on magnetic metal substrate and for the coating thickness measurement on the non-ferrous substrate, we recommend the eddy current measurement principle.

Contact us to discuss your requirements of Thickness Gauge Price. Our experienced sales team can help you identify the options that best suit your needs.