SUND Knowledge: the thickness test

21 February 2022

Stress test from all sides

The series "SUND Knowledge" takes you through the laboratory: Quality assurance is a fundamental part of the SUND Group. For this purpose, various machines are used with which the products can be accurately tested. Lab manager Gabi Krügel explains the test equipment. Part 4: the thickness gauge.

To test the quality of a garbage bag, Gabi Krügel uses, among other things, a thickness gauge: "The device measures the thickness of the film of the garbage bag in the complete circumference in the transverse direction. If you were only measuring the longitudinal direction and you had a thin or thicker spot, which can happen, then this would falsify the measured values," she explains. By measuring a large strip, average values can be calculated that paint a more realistic picture of film thickness.

"I enter the parameters and clamp this strip here and press the start button," Krügel says. On the first pass, the device calibrates itself. At the same time, the device measures the thickness of the film strip at 99 points, thereby determining the average value.

With a whirring and buzzing sound reminiscent of an old printer, the device begins the measurement. The test strip is clamped to nine rollers that keep the film taut while allowing it to pass smoothly. The measurement is mechanical, and the data is transferred directly to a connected computer.

The average film thickness is determined in the analysis.  However, the deviation of the maximum tolerances from the determined average value is particularly decisive. The smaller the deviation, the better the quality. "A bag is only as good as its weakest/thinnest point." explains Gabi Krügel