Thomson Linear Motion Optmized
Ball Screws - Screw Critical Speed
Sizing
For background discussion on this topic see the earlier section on critical speed. link
Screw critical speed (maximum RPM) calculation
A screw assembly has a maximum RPM which it should operate. For Inch screws the critical speed can be calculated using the following formula:
nc = Cs x 4.76 x 106 x dr/L2
Where
nc = Critical speed [RPM]
dr = Root diameter of the screw [in]
L = Unsupported length or length between the bearings [in]
Cs = End Fixity Factor. See table below
It is recommended to operate below 80% of the screw critical speed.
End fixity factor - critical speed
