Общий каталог Kemmler 2017 - 2018 - страница 671

Balancing limits In accordance with DIN ISO 1940 the balance grade is denoted with G as well as the units gmm/kg or µm respectively and is relative to the number of revolutions. At a speed of 15,000 rev./min and a weight of 1 kg, G 6.3 corresponds with a permissible center deviation between rotational axis and center of gravity axis of the spindle of 4 µm. At twice the speed of 30,000 rev./min it would be 2 µm. If the tool holder was only half the weight, i.e. 0.5 kg, the permissible counter balancing tolerance is also halved. Aim of counter balancing is to fi nd a compromise between the technically feasible and the economically effi cient. Because the radial inter- change accuracy for a brand-new HSK holder can be 2 to 3 µm and for an ISO taper shank holder can be 5 to 10 µm, it means an initial quality limit of G 2.5 or G 6.3 respectively at 10,000 rev./min. The following diagram shows the quality grades to DIN ISO 1940-1, i.e. the permissible rest imbalance in relation to the balance body mass for different counter balance qualities G relative to the maximum operating speed. Fine-balanced with Pre-balanced with Pre-balanced with balancing bores in the fl ange balancing bores at the collar balancing fl at at the tool body 13 KEMMLER 13.36