Boring bar for lathe – selecting based on L/D ratio
Boring bar for lathe: As the L/D ratio of the bore (and hence the boring bar) increases, vibrations tend to increase. To counter this you can use lower cutting parameters, but beyond a point this strategy becomes unviable because of the increase in cycle time.
The alternative is to use boring bars that are more resistant to vibrations.
The shank of a normal boring bar is made of hardened steel, but as the L/D ratio increases, you can switch to a material that reduces the vibrations. Like solid Tungsten Carbide bars. The ability to resist deflection increases as the coefficient of elasticity increases, and Tungsten Carbide has 3 times the coefficient of elasticity of steel. There is also carbide reinforced steel, which is a metal matrix composite (MMC). This is steel with Titanium Carbide (TiC) particles embedded in it. A damped boring bar is a hollow bar with a vibration damping mechanism in it.
Pics. and text source for Boring bar for lathe: Cadem NCyclopedia multimedia CNC training software.
