Каталог Widia инструментальная оснастка - страница 1089

Balancing

The balance quality is usually specified by the balance grade G, according to IS0 1940-1 and ANSI S2.19 standards. The balance quality grade (G) was derived from practical experience, which is expressed in millimeters per second (mm/s) and ranges from 0,16–4000. For rotating tooling and general machinery parts, it is usually specified to be G 2.5 or G 6.3. A lower number designates better balance quality.

The permissible residual unbalance can be calculated by the following equation:

9549 x G x M

U per =

n

Where: Example:

n = operating speed in rotations per minute (RPM) U = 9549 x 6.3 x 2 per = 12 gmm 10,000

The same value can be obtained from the chart on the following page. It gives the permissible specific unbalance in gram millimeters (gmm) as a function of the rotational speed and the balance quality (G). For the example above, at 10,000 RPM and for grade G 6.3, the maximum residual unbalance would be 6 gmm/kg. The toolholder assembly (including the tool) has a mass equal to 2 kg, the permissible unbalance is [(6 gmm/kg) x 2 kg], which equals 12 gmm.

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