How to Measure Friction properties
FRICTION is a phenomenon that is part of our daily lives – in one sense, we would find most difficult to survive without it, yet in another it can be most expensive to minimise. It can be simply identified as the resisting force that arises when one surface slides, or tries to slide, over another. It is the textural property commonly measured from packaging materials, shaving gels, cosmetic sponges, etc.
Friction can be a limitation to us; for example, the friction of packaging can be a major limiting factor in the speed of packing machines. Additives are often used to improve the lubricity of surfaces; this is known as 'slip'. Polythene is added to packaging to improve slip characteristics.
We recognise that there are two reactions due to friction that we can define. There is 'static friction' (sometimes shortened to 'stiction') – that is, the resistance to start relative movement; and there is 'kinetic' or 'moving friction' – that is, the resistance to maintain the movement at a specific constant speed. The Texture Analyser can also measure a coefficient of friction, which is an empirical measurement. Rougher surfaces tend to have higher values.
Typical properties that can be obtained from a texture analyser graph:
Stiction, Friction, Coefficient of Friction
Typical Texture Analyser graph with annotated properties of film friction test
Typical Probe/Fixture used for Measurement:
Friction Rigs (single direction and cyclic) >>
The above are only typical examples of friction measurement. We can, of course, design and manufacture probes or fixtures that are bespoke to your sample and its specific measurement.
Once your measurement is performed, our expertise in its graphical interpretation is unparalleled – no-one understands texture analysis like we do. Not only can we develop the most suitable and accurate method for the testing of your sample, but we can prepare analysis procedures that obtain the desired parameters from your curve and drop them into a spreadsheet or report designed around your requirements.
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