Cylindrical Mandrel Bend Tester QTY-32, 13 Mandrels 2-32mm, for Paint Film | FMFPAX

QTY-32 Paint Film Bending Tester for Coating Flexibility Checks

The QTY-32 is a cylindrical mandrel bend tester for checking the flexibility of paint, varnish, and related coating films on metal panels. A coated sample is bent 180 degrees around a selected mandrel, then inspected for cracking or peeling from the metal substrate.

Use it when a coating quality control workflow needs a repeatable paint film flexibility test with known mandrel diameters. This model uses 13 cylindrical mandrels from 2 to 32 mm and follows the GB6742 reference listed for the QTY-32 manual.

Applications and Standards

• Suitable for coating test work in laboratories and in the automotive, paint and coating, and metal industries.
• Used to assess the flexibility of paint and clear varnish films, providing a practical reference for evaluating coating performance.
• Standards stated in the supplied product material: GB/T 6742 and ISO 1519.

Durable Construction

The supplied product material describes the tester as made from quality materials for durable service, with stable and accurate operation during long-term use.

When to Use It

• Checking paint and varnish film flexibility on coated metal panels.
• Comparing whether a coating cracks or peels after cylindrical mandrel bending.
• Recording the first mandrel diameter that causes coating damage, or confirming the smallest diameter that leaves the film intact.
• Running a controlled 180 degree bend test with a selected mandrel diameter.

How the Test Works

Coatings behave differently as the bend radius becomes smaller. The operator tests from larger to smaller mandrels, checks the coating condition immediately after bending, and records the diameter where cracking or peeling first appears.

Key Specifications

Operating Sequence

1. Prepare the sample according to the relevant product standard: sample, coat, dry, and measure film thickness before testing.
2. Place the tester securely near the edge of a laboratory bench so the adjustment handle can move freely and the sample can be inserted.
3. Select a suitable mandrel, install it between the tester base and the mandrel hole, and tighten it by hand.
4. Lower the support plate. Insert the panel with the coated side facing down between the mandrel and the adjustment handle, then clamp it with the fastening screw and pressure strip.
5. Raise the support plate so the test panel sits tightly against the mandrel.
6. Lower the adjustment handle to the lowest position, then adjust the pressure roller knob so the pressure roller fits closely against the panel.
7. Lift the adjustment handle smoothly over 1-2 seconds until the panel bends 180 degrees around the mandrel.
8. Lower the support plate and release the panel from the mandrel for inspection.

Reading the Result

• Inspect the panel immediately after bending.
• Check whether the coating has cracked or peeled from the substrate. Coating within 10 mm of the panel edge is not counted.
• If a 10x magnifier is used, state this in the test result to avoid confusion with normal visual inspection.
• Test from larger to smaller mandrels until coating damage first appears. Repeat the same mandrel diameter on a fresh panel to confirm the result.
• Record the first mandrel diameter that causes cracking or peeling. If the smallest mandrel does not damage the film, record that the film remains intact at that smallest mandrel diameter.

Panel and Handling Notes

• For aluminum panels, keep the long edge of the sample parallel to the rolling direction.
• To help prevent coating damage during the bending operation, a thin sheet of paper may be placed on the coated side of the panel before testing.
• For consistent judgement, perform the test at 23 +/- 2 degrees C and 50 +/- 5% relative humidity.

Maintenance

• If the QTY-32 tester will not be used for a long time, coat all mandrels with anhydrous Vaseline.
• Keep the mandrels and clamping surfaces clean so particles do not mark the test panel during bending.

FAQ

Is the QTY-32 a cylindrical mandrel bend tester?

Yes. It bends coated metal panels around cylindrical mandrels so the operator can check paint or varnish film flexibility.

What does the QTY-32 tester measure?

It checks coating flexibility by showing whether the paint or varnish film cracks or peels after bending around a selected mandrel.

How many mandrel diameters are listed?

The QTY-32 uses 13 mandrel diameters: 2, 3, 4, 5, 6, 8, 10, 12, 16, 18, 20, 25, and 32 mm.

What sample size is recommended?

The listed test panel is 120 x 50 x 0.3 mm tinplate. For 1.0 mm special-thickness panels, a separately made fixture or equipment arrangement is required.

How should the final result be recorded?

Record the mandrel diameter at which the coating first cracks or peels. If no damage occurs even on the smallest mandrel, record that the coating remains intact at that smallest diameter.