Showing the concept of coefficient of friction.
Coefficient of friction sheet metal.
The determination of the friction coefficient in a sheet metal forming process is a complex procedure because many variables influence the friction mechanisms.
Swathi understanding formability of extra deep drawing steel at elevated temperature.
For glass on glass 0 4.
F f frictional force n lb.
For polished oiled metal surfaces less than 0 1.
The coefficient of static friction typically denoted as μ s is usually higher than the coefficient of kinetic friction.
The coefficient of friction is one of the key parameters in fe simulations of forming processes which can influence the prediction accuracy of these analyses.
For example static friction can prevent an object from sliding down a sloped surface.
The coefficient of friction is the ratio of a force to a force and hence has no units.
Where μ s is the coefficient of static friction and μ k is the coefficient of kinetic friction.
The ratio between the force of friction and the contact force between the two moving objects is represented by a coefficient of friction µ whose value will depend on the tribology system itself and the forming process such as temperature of the sheet ram velocity contact pressure and the strains in the sheet.
In sheet metal forming different friction regimes may occur depending on the lubricant amount and surface topographies of the tool and sheet metal.
However it is possible to find tables in the literature for friction coefficients between various materials.
Typical values for the coefficient of friction when sliding is occurring i e.
Swadesh kumar singh k.
μ static μ s or kinetic μ k frictional coefficient.
Coefficients of friction between materials are best determined through testing.
The aim of this research work is to apply an experimental approach in order to bridge simple benchmark friction experiments with real sheet forming applications.
The value of μ s is generally higher than the value of μ k for a given combination of materials.
The frictional force can be expressed as.
N normal force between the surfaces n lb there are at least two types of friction forces.
Lo valvo a technical note on an experimental device to measure friction coefficient in sheet metal forming journal of materials processing technology 172 2006 16â 21.
Simplified models are given for different conditions of sheet metal forming processes.
Static friction is friction between two or more solid objects that are not moving relative to each other.
The static and kinetic friction coefficient values reference table shown in this article will be helpful for finding the cof values of commonly used materials.
Wilson hsu and huang developed a model for friction in lubricated sheet metal forming which took into account the different lubrication regimes at the sheet tooling interface and coupled to an finite element program.
The friction force is the force exerted by a surface when an object moves across it or makes an effort to move across it.
Static and kinetic coefficient of friction.
F f μ n 1.
