Coating bend testers – SA564 / SA566

Coating bend testers are instruments designed to assess the behaviour of paints, enamels and coatings when subjected to bending deformation. The coated sample is bent around a mandrel and then inspected to determine whether cracks, flaking or detachment have occurred in the coating.

A bend test is useful when a coating is required to withstand deformation of the substrate without sustaining damage. During production, assembly or service, a painted surface may be exposed to bending or flexing that places stress on the applied film. Therefore, evaluating coating flexibility makes it possible to determine whether the coating maintains its integrity under the expected deformation conditions.

These instruments can be used according to two different assessment criteria: as a pass/fail test, checking that the coating remains undamaged after the specified bend, or to determine the limit at which cracking or detachment begins to occur. The appropriate method depends on the type of inspection, the coating being tested and the applicable standard.

Two configurations are available: the SA564 cylindrical mandrel tester and the SA566 conical mandrel tester. Both are used to evaluate coating resistance to deformation, but use different test principles..

The SA564 is equipped with interchangeable cylindrical mandrels of different diameters. The sample is bent around the selected mandrel and the coating is examined to determine whether it withstands the deformation without cracking or detaching. This configuration is suitable when testing is required at defined diameters or when the minimum diameter tolerated by the coating needs to be progressively determined.

The cylindrical mandrel model is used for tests in accordance with ISO 1519 and ASTM D522 – Method B. The availability of mandrels with different diameters allows the curvature to be selected according to the required inspection, making it possible to compare the behaviour of different paints or coatings at different levels of bending deformation.

The SA566 uses a conical mandrel with a diameter that varies along the length of the test area. When the sample is bent around the cone, the coating is subjected to progressive deformation. This configuration makes it possible to observe where cracks or detachment begin and to identify the bending-resistance limit of the film on a single sample.

The conical mandrel model is used for tests in accordance with ISO 6860 and ASTM D522 – Method A. It is particularly useful where the behaviour of the coating must be evaluated continuously across increasing levels of deformation, without repeating the test on multiple cylindrical mandrels.

The choice between a cylindrical mandrel and a conical mandrel therefore depends on the type of inspection and the applicable standard. The SA564 is suitable for tests at predetermined diameters and for pass/fail assessments based on a specific curvature. The SA566 is more suitable when the point at which cracking or detachment begins during progressive bending needs to be identified.

Coating bend testers are used to inspect paint systems applied to deformable panels and test specimens, particularly where the coated component will undergo subsequent bending, forming or assembly operations. They can be used to assess dried liquid paints, enamels, protective coatings and other coatings that are compatible with panel testing.

Checking coating bend resistance is useful both during the development and comparison of different application systems and in quality-control activities, where it is necessary to verify that the coating behaves properly after substrate deformation.

The SA564 and SA566 coating bend testers therefore provide a practical means of evaluating the flexibility and resistance to cracking of paints and coatings through bending tests, with interchangeable cylindrical mandrels or a conical mandrel selected according to the applicable method and the type of result required.

Applications

• Assessment of paint and coating flexibility by bending
• Inspection for cracks, flaking or detachment after deformation
• Pass/fail testing on coated panels and test specimens
• Identification of the coating resistance limit during bending
• Inspection of paints, enamels and protective coatings on deformable substrates
• Quality-control checks on paint systems intended for bending or forming operations
• Comparison between different coatings or application conditions
• Testing with cylindrical mandrels in accordance with ISO 1519 and ASTM D522 – Method B
• Testing with a conical mandrel in accordance with ISO 6860 and ASTM D522 – Method A

FAQ – Coating bend testers

What are coating bend testers used for?
They are used to assess the ability of a paint or coating to withstand bending deformation without showing cracks, flaking or detachment from the substrate.

How is a coating bend test performed?
The coated sample is bent around a cylindrical or conical mandrel. After deformation, the surface is inspected to check for damage to the applied film.

Does the test provide a numerical flexibility value?
The test can be used as a pass/fail assessment or to identify the bending limit at which the coating begins to show cracks or detachment. The result depends on the method and configuration used.

What is the difference between SA564 and SA566?
SA564 uses interchangeable cylindrical mandrels and allows tests to be performed at defined diameters. SA566 uses a conical mandrel and subjects the sample to progressive deformation, making it possible to identify the point at which the coating begins to fail.

When should the SA564 model with cylindrical mandrels be selected?
SA564 is suitable where coating behaviour must be checked at a predetermined diameter or where progressive tests are required using different mandrel diameters.

When should the SA566 model with a conical mandrel be selected?
SA566 is suitable where the behaviour of the coating must be observed on one sample along increasing deformation and the point at which cracking or detachment begins must be identified.

Which standards apply to the SA564 model?
The SA564 model with cylindrical mandrels is used for tests in accordance with ISO 1519 and ASTM D522 – Method B.

Which standards apply to the SA566 model?
The SA566 model with a conical mandrel is used for tests in accordance with ISO 6860 and ASTM D522 – Method A.

Which coatings can be tested?
The test can be performed on paints, enamels and coatings applied to deformable panels or test specimens compatible with the selected method and instrument configuration.

Why check the flexibility of a paint?
It is useful where the coated substrate may be bent or deformed during processing or use. A coating with unsuitable behaviour may show cracks or detachment after component deformation.