Final curvature

  • deviation from the straight
  • deviation
  • find curvature
  • level condition
  • objective
  • out of straightness
  • permissible deviation
  • quality criterion
  • run-out curvature
  • spring back
  • straight-axis condition
  • winding
  • wire bend
  • wire curvature

The result of a straightening process is expressed e.g. by the final curvature of the product to be straightened. Basically there can be two objectives: to create a straight product, i.e. a final curvature of zero within the set tolerances, or to produce a defined final curvature other than zero. Which of these two objectives applies will largely depend on the process which follows the straightening.

To guarantee final products of constant positive quality it is important to produce a final curvature that is as constant as possible. A changing final curvature goes hand in hand with varying process transitions and ultimately leads to final products of fluctuating quality. 


  • friction
  • frictional coefficient
  • frictional force

External friction is the inhibition of relative movement between touching bodies. In the case of solid bodies, friction is mainly based on microscopic unevenness. The frictional values of different materials relative to each requires special attention in this connection. Internal friction is the friction between parts of the same body. In liquids this friction is called viscosity.

During the straightening process, friction occurs mainly in the straightening rolls. It consists of the following components, which together add up to the total running resistance: rolling and sliding friction of the rolling elements and cages relative to each other, lubricant friction and seal friction. The aim must be to keep the friction as low as possible by ensuring an acceptable bearing load and optimal lubrication.

Friction leads to “losses”, i.e. kinetic energy is converted into frictional energy. This energy fraction is therefore no longer available for use in the production process.