# Purpose Of Performing Co-Efficient Of Friction Test

Co-Efficient of Friction test is the best test that helps to measure the stacking ability of the plastic films. It contributes to preventing the accidents that usually occur due to friction in packaging, transportation, loading, materials, etc. There may be variation in the friction due to uneven thickness of the films, which may also lead to uneven strength of films. The COF of the plastic films can be tested easily with the help of a testing machine i.e.co-efficient of friction tester. It is widely used to verify foils, papers, plastic films and other related material. For finding dynamic and static friction, users can also adjust the speed of packages by testing the coefficient of friction.

The coefficient of friction is also known as COF can be evaluated easily by providing or sliding the facade of two materials against each other. The dimensional value of the coefficient of friction is actually measured as the ratio of the force required to slide the material façade to the force which is perpendicular to the surfaces. The lower friction of co- efficient shows that the surfaces are slicker that means the material is less resistant to the sliding motion. Co-efficient of frictional value is directly related to the slipping properties of the films.

Difference between Static Friction and Kinetic Friction

The different between both the types of frictions is known as the “Slip-Stick.” The static COF is measured at the point of incipient motion whereas the dynamic COP is measured at a constant velocity.

Static Coefficient of Friction is denoted by (µs)

It is defined as the Coefficient of Friction for the instant motion between the start surfaces

Kinetic Coefficient of Friction is denoted by ((µk)

It is defined as the Coefficient of Friction for motion between surfaces is established.

How to Calculate the Coefficient of Static Friction?

The static coefficient of friction is calculated by the given formula.

(µs) = As / B

Whereas,

A = Reading on the load monitor at the instant the block slips on the plane and,

B = Weight of the block.

One can test the coefficient of friction according to the requirement of test and according to the type of sample.  3 types of test can be performed with the instrument.

1. Sample to sample
2. Sample to glass
3. Sample to metal

How to perform the test with COF Tester?

COF test can be performed easily only by sliding a plane under a dead weight. The instrument is designed as per various standard test methods that are provided by different standardization authorities like ASTM D1894, ASTM D202, ASTM D4918, ISO 8295 and TAPPI T815. As per the standards, the sample of a film is attached firmly to the base of the block.   This block is connected to a load cell, and it helps to measure the frictional force between the block and plane.

Best Solution for COF Test

Presto Stantest manufacture premium quality of Coefficient Of Friction Tester. The device is designed as per the guidelines provided in various standards. It is declared as the appropriate testing device that can measure the stacking ability of the plastic films.

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