The bursting strength of a material is termed as the strength of the material to resist any type of rupture force that is applied on the material from a uniform direction and can cause the rupture of the material.
Mullen test is used to determine the bursting strength of a sample.
The bursting strength of a material is calculated with the help of a machine called bursting strength tester by applying the maximum amount of hydraulic force that the material can bear.
Bursting factor is a function of bursting strength and the GSM of the sheet and can be termed as the strength per unit GSM of the material.
Burst factor = Burst strength (gf/cm2) / Grammage (grams/m2)
Burst Index = Burst strength (kPa) / Grammage (Kg/m2)
Edge Crush Test
An edge crush test (ECT) is a laboratory test method used to measure the cross-section crushing of corrugated cardboard. This offers the necessary information to determine the ability of a sheet of corrugated cardboard to resist crushing forces.
Nowadays this new standard – the edge crush test – which is directly related to the stacking resistance, is seeing increasing use to test the resistance of corrugated cardboard.
The edge crush test machine can calculate the resistance to compression at the edge of corrugated cardboard. The edge crush test graph therefore shows the resistance in pounds per lineal inch (lb/in), though it is usually expressed as ECT.
The most widespread standard in Europe is the DIN EN ISO 3037, which outlines a paraffin-free method for the edges and applies to all qualities of corrugated cardboard.