Каталог оснастка Dormer Pramet 2016 - страница 261

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EFFECTS OF IMBALANCE ON MACHINE SPINDLES, TOOLHOLDERS AND TOOLS Imbalance An imbalance produces a centrifugal force during the The centrifugal force (F) increases linearly with the rotation of the spindle impeding the smooth running imbalance (U) and squared with the number of DIN 69871 of the tool. This imbalance influences the working revolutions according to the formula below. process and the life span of the spindle bearings. Counter balancing ISO 60 To compensate for unwanted centrifugal forces, the have compensation holes or areas which assist in symmetrical distribution of mass must be restored directing the total amount of all centrifugal forces with the aim of eliminating any centrifugal forces influencing the axis towards zero (see DIN ISO 1940). influencing the spindle bearing. Tool holders generally MA S 403 BT Eccentricity of center of gravity The imbalance of a spindle causes its center of rest-eccentricity (e) or eccentricity of center of gravity. gravity to deviate a certain distance from the rotating The heavier the weight of the balance body mass (m), axis in direction of the imbalance. This distance is called the greater the rest-imbalance (U) permissible. DIN 2080 HSK-A Calculation imbalance VDI 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: MORSE U =  m × r U = imbalance in gmm r = eccentricity of center of gravity in μm m = mass in kg 260