Каталог оснастка Dormer Pramet 2016 - страница 261

Предыдущая страница Следующая страница

Навигация

EFFECTS OF IMBALANCE ON MACHINE SPINDLES, TOOLHOLDERS AND TOOLS

Imbalance

An imbalance produces a centrifugal force during theThe centrifugal force (F) increases linearly with the
rotation of the spindle impeding the smooth runningimbalance (U) and squared with the number of
of the tool. This imbalance influences the workingrevolutions according to the formula below.
process and the life span of the spindle bearings.
Counter balancing
To compensate for unwanted centrifugal forces, thehave compensation holes or areas which assist in
symmetrical distribution of mass must be restoreddirecting the total amount of all centrifugal forces
with the aim of eliminating any centrifugal forcesinfluencing the axis towards zero (see DIN ISO 1940).
influencing the spindle bearing. Tool holders generally
Eccentricity of center of gravity
The imbalance of a spindle causes its center ofrest-eccentricity (e) or eccentricity of center of gravity.
gravity to deviate a certain distance from the rotatingThe heavier the weight of the balance body mass (m),
axis in direction of the imbalance. This distance is calledthe greater the rest-imbalance (U) permissible.

Calculation imbalance

Imbalance is a measure, specifying how much measure of distance „e“ determines the distance of unsymmetrical distributed mass deviates radially from the center of gravity of an element to the rotating the rotating axis. Imbalance is measured in gmm. The axis. Imbalance is calculated as follows: U = m × r U = imbalance in gmm r = eccentricity of center of gravity in μm m = mass in kg