What are Different Parameters of Corrugated Fiberboard

Corrugated fiberboards are widely used in packaging industry. They are sturdy and stand against moisture to a certain level. Corrugated fiberboards are made up of the pulp of paper. Every layer is made up of different grades of paper. Since it is layered and has fluted sandwich structure in between, it possesses a tendency to bear shocks. Therefore, it is a favourite among packaging material manufacturers, and users. Apart from their strength, CFB’s ability to get recycled easily is a plus point which makes it more popular.

Different types of crushing tests to check the durability to CFB

There are three different types of tests that can be conducted on CFB from different sides. And to check the load bearing capacity a different test is performed.

Edge crush test. This test determines the compression strength of the test sample. The sample is placed on the testing plate, standing on its edge. Edge crush tester applies a load from the top to a level where the sample gets deformed. The pressure applied is measured in Kg/m  (load/unit length) and the peak value is stored. The higher the value, the stronger is the CFB.

Ring crush test. This test is extended form of edge crush test. In this test, the sample is cut and fixed on the plate in the form of a ring, like a cylinder. An axial pressure is applied on this cylinder to check at what point it gets deformed. In this test, the tendency of CFB to bear the load increases as the pressure distributes uniformly throughout the wall/circumference. The importance of performing this test is to determine how corrugated fiberboard would behave if used in cylindrical packing e.g. yarn packing; whether the sample is suitable for such packings or not.

Flat crush test. This test determines the pressure bearing tendency of corrugators. The fluted layer of paper between two flat layers of paper are called corrugators. The sample is placed flat on the testing plate and using another plate, force from the top is applied until the CFB flattens. The test results largely depend on heights of the corrugators. Higher the flutes, earlier they collapse. Some CFBs have very small flutes which do not collapse easily and has the tendency to withstand up to 10kN This force applied is measured as the standard for that sample.

Sometimes edge crush tester is used for all the three types of testing.

Bursting strength test. This test determines the strength of CFB to bear the pressure applied against the wall. The testing instrument applies hydraulic  pressure through a rubber diaphragm on the sample to a level until it gets ruptured. The value of peak force is measured on the display. Higher the bursting strength of sample, better is the quality.