18
2. Allowable maximum rotation speed
In the case of outside diameter gripping, when the chuck is rotated, the gripping force
lowers due to the centrifugal force of the top jaw. Therefore, the rotation speed when the
dynamic gripping force (gripping force during rotation) becomes approximately 1/3 of the
maximum static gripping force is set as the allowable maximum rotation speed. The
centrifugal force is different depending on the mass of the top jaw and the barycentric
position as well as the rotation speed. The allowable maximum rotation speed specified in
the specification is the value under the following conditions:
・
The Kitagawa standard soft jaw is used.
・
Grip the gripping force meter in the center of the jaw stroke, and at this point, the soft
jaw is attached at the position where the periphery side end of the soft jaw and the
chuck periphery are almost lined up.
・
The numerical values are obtained by the Kitagawa gripping force meter. The gripping
position of the gripping force meter is at a position 1/2 of the height of the soft jaw top
surface (height from the chuck surface to the top surface of the jaw).
To avoid serious accidents caused by the chuck or work flying out:
・
Determine the gripping force required for processing by the machine tool
manufacturer or user, and check that the required gripping force is provided
before processing. The gripping force of the chuck must not exceed the
maximum static gripping force.
・
Determine the rotation speed required for processing by the machine tool
manufacturer or user based on the gripping force required for the processing.
The rotation speed at this point must not exceed the allowable maximum
rotation speed.
・
When determining the cutting conditions, refer to pages 19-22.
・
Pay attention since the gripping force is different depending on the state of the oil
supply, grease in use, height of the jaw, performance of the pump and the pressure
reducing valve, piping state, etc.
3. Relationship between gripping force and rotation speed
As the rotation speed becomes higher, the centrifugal force of the jaw increases and the
gripping force lowers. The curves displayed in Fig. 6 shows relationships between the
rotation speed and the centrifugal force when using the standard soft jaw. The centrifugal
Summary of Contents for QB300
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