Tensile Testing, or Tension Testing, falls in the core domain of mechanical engineering and material science. It is a destructive engineering process in which a paper sample subjected to a controlled and predetermined tension. Often, the capability and endurance of the paper sample are tested to the extent to which it doesn’t get damaged. A tensile strength testing machine evaluates the tensile strength of paper or paperboard by stretching it till the time it breaks.
Tensile testing and durable paper products go hand in hand. This form of testing is used to determine the vulnerability and forms a vital determinant of the quality of the paper. Through this test, the yield strength, ductility, tensile strength, Young’s Modulus, Poisson’s Ratio, and strain bearing capabilities of a paper are observed.
What is Tensile Strength?
The tensile strength of a paper is dependent on its fibre orientation, which flows in two directions. Tensile testing evaluates the mechanical and material properties of a paper by determining its stress-strain relationship in both directions. As the first step, one selects a sheet of paper. Strips, also known as ‘Paper Sample’, are cut from the sheet of paper in two perpendicular directions. The first being Machine Direction and the second, Cross Machine Direction. Machine Direction refers to the normal direction of the paper, and Cross Machine Direction refers to the orthogonal direction of the paper, during the manufacturing process. The tensile strength of paper is more in Machine Direction than in Cross Machine Direction and demonstrated as N/m.
Tensile Testing – Equipment
1. Sample Strip Cutter (Guillotine Type)
The Guillotine type Strip Cutter consists of hardened steel blades which enables precision cutting of a variety of items like paper, paperboard, plastics and foils. It can cut strips in 15mm x 300mm or 25mm x 300mm strips. Unlike hand trimmers, the Guillotine type automatic Strip Cutter produces sharp edges and correctly measured strips accurately. The production of test strips is under the BS EN ISO 6892-1 and ASTM E8M guidelines.
2. Sample Strip Cutter (Punch & Die Type)
The Punch & Die type cutters are industry favourites for producing most accurate samples for tensile strength tests, folding endurance tests, ring crush tests, water absorbency tests, and the likes. Broadly, paper, plastic, textile, or paperboard is cut in 15 x 300mm, 25 x 300mm, 50 x 300mm, and 12.7 x 152 mm strips, but can also be customized as per a customer’s needs.
3. Electro-Mechanical Tensile Strength Tester
The Tensile Strength Tester evaluates the tensile force of a sample before breaking and the typical elongation during rupture. A calibrated potentiometer, with load ranges between 0-50 N or 0-300 N, regulates pulling rate through DC variable speed drive and delivers accurate results. It precisely determines the tensile strength of paper, paperboard, plastics, textile, and metal foils.
Tensile testing is a must-do evaluation technique for determining the ability of a material to perform in different situations and forces. It serves as a proof of concept for all new launches. Tensile testing also allows a business house to be entirely sure about the strength of the material used in the product.