Packages from carton blanks are finished by adhesively joining two board sides. Before packages can leave the manufacturer, the joints are tested through peel tests. As manual peeling does not provide measurable information, several methods have been developed: for example, the T-peel test (Fig. 1) or the angle-peel test (Fig. 2).
Both methods show some disadvantages:
* The joint of a T-peel specimen is not fixed during the test, which leads to a significant test result scatter.
* The specimen preparation and its insertion into the test rig are time consuming.
AssiDomän decided to use the Y-peel test, where the specimen ist held by a 3-clamp arrangement (Fig. 3).
Together with an especially designed test program, the test is very simple to perform:
* Place the 2 individual specimen legs into the locked lower clamps. Specimen stops ensure a constant free length.
* Place the glued legs into the gimbal-mounted upper clamp.
* Unlock the lower clamps so that they can rotate around the mid-point of the jaws.
* Start the test.
The test program calculates all the required results and displays them in the graph. A key result is the plastic energy consumed by the glued joint until its maximum force.
Using this configuration, AssiDomän profited from valuable features:
* Fast and easy handling simplifies the machine operator´s work and avoids errors.
* Deduction of all elastic energy from the consumed total energy means that only the joint's characteristics are considered.
* Significant reduction of the result scatter compared to the T-peel test makes the test results and the packaging more reliable. |
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