Tests for Quality of Corrugated Media

There are several tests that are used to assess the different properties of corrugated boxes. Most of these properties such as bursting strength, puncture resistance, Cobb Value etc are a function of the quality of paper used.

Various types of tests commonly used to measure or determine the properties of the box are given below.  

1. Bursting Strength
   Bursting strength is defined as the hydrostatic pressure required to produce rupture of the material when pressure is applied at a specific controlled increasing rate through a rubber diaphragm to a specific circular area of the material under test.
   
2. Caliper Thickness Gauge Test
   Thickness of paper or paperboard measured under standard test conditions and expressed in millimetres.
   
3. Cobb Value
   The water absorption ability (Cobb value) is the quantity of water in grams absorbed by a surface of one square meter of test specimen on one side only in a specified time, under a specified head of water.
   
4. Compression Strength Test
   The Compression strength is defined as the maximum load a corrugated box can withstand before failure (or specified deformation) under standard test conditions.
   
5. Corrugated Medium Test (CMT)
   In this test, a pre-fluted narrow strip of paper is crushed to flatten the flutes. The force required to crush the flutes is the CMT value of the fluting and is expressed in Newtons
   
6. Crush Test
   In this test, a pre-fluted, narrow strip of paper is inserted in a speciment holder and crushed. The force required is divided by the length of the strip and measured in Kilo Newtons per metre.
   
   There are several types of crush tests:
   
   -  Flat Crush Test (Corrugated Fibreboard): Flat Crush is a measure of the resistance of the flutes in a corrugated board to a crushing force applied perpendicular to the surface of the board.
   -  Edge Crush Test (Corrugated Fibreboard): Measures the edgewise compressive strength, parallel to the flutes, or a short column of combined corrugated fibreboard.
   -  Ring Crush Test (Paper and Paperboard): Measures resistance of paper and paperboard to edgewise compression.
   -  Pin Adhesion test (Ply): A measure of the strength of the bond between the liner and the fluting paper
   
7. Drop Test
   A test for determining the ability of corrugated fibreboard boxes to withstand impact in freefall drops.  This test consists of releasing a filled box from a predetermined height onto a concrete floor or a flat metal plate.
   
8. Puncture Resistance Test
   Puncture resistance is defined as the energy required to force a puncture head of designated size and shape completely through a sample of corrugated fibreboard, i.e. to make the initial puncture and to tear and bend open the board
   
9. Substance Indicator (Grammage) Test
   The grammage or substance is defined as the weight of one square metre of paper or paperboard under standard test conditions and expressed as grams per square metre.
   
10. Vibration Resistance Test
    A measure of resistance of corrugated fibreboard to withstand vibrations under standard test conditions