What is the Difference Between Bursting & Crush Strength of the Fiberboard

Bursting strength and crush strength are two factors that you can see printed on the seals of a corrugated box. What’s also printed is a box compression certificate, that will describe the board's strength, size, and weight. An emphasis is laid on both properties, as they are most successful in the corrugated industry in choosing the right box type for an objective. Both are super capable of determining the strength and durability of both the board and the resulting box. 

However, both tests are conducted on different instruments. Let us understand how these tests are varied and what instruments accurately measure them.

What is a Bursting Strength Test?

A bursting test, performed on a high-quality bursting machine, is the measure of the pressure/force required to puncture the fiberboard. This test determines the board’s ability to withstand the rupturing forces during transportation and safeguard the contents. It indirectly relates to the box’s ability to resist both internal and external forces and protect the products. 

The bursting strength is calculated in lbs per square inch. To perform the test, the user places the sample on the testing platen. A bursting pressure is then applied on the board sample and continues till the sample is ruptured. The digital display panel displays the bursting pressure and the burst factor at the time of rupture. These average readings are the calculated numbers of the test. 

What is a Crush Strength Test?

The crush strength test, performed on a ring crush tester, measures the edgewise compression/crush strength of the box. It directly relates to the stacking strength of the corrugated box. The crush strength is expressed as an ECT value but calculated in lbs per square inch. 

To perform the edgewise crush test, the user places the small sample of fiberboard between 2 plates, standing perpendicular to the flute’s direction. The compression load is applied to the sample by these platens and continues until a peak load is created.  

The Difference

The basic difference between the above two tests is that under the bursting strength test, the user must have a minimum GSM of board required. Therefore, he first has to enter the GSM of the test sample in the bursting machine. 

The crush test, on the other hand, doesn’t require the board of a certain minimum GSM. Hence, a board of lighter GSM can also be tested on a ring crush tester. A board measured on this machine can definitely weigh less but can have equivalent strength to the one measured on the crush tester. 

Conclusion 

So, these were the differences between the crush and bursting strength tests. To know more about these tests, connect with the experts at UEC, a leading manufacturer of paper testing machines. Visit the website www.uecin.com today.