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BBT tool holder for CNC Milling Machines

BBT tool holder system is becoming popular between the application engineers. The application of BBT holders in manufacturing process results in remarkable improvement of rigidity, accuracy, speed and performance.

BBT tool holders
Fig.1. BBT tool holders

BBT tool holders with simultaneous fit of taper and flange to spindle face contact.

The main idea behind the BBT tool holders design is a simultaneous contact of tool holders' taper flange and spindle face.

BBT holders are interchangeable with BT spindles.

BBT is a Simultaneous Dual Contact Spindle System interchangeably compatible with existing machines and tool holders. Machines equipped with standard BT-30 and BT-40 tool holders, there is a gap between the machine spindle face and the tool holder flange of 2.0 mm. In case of BT-50 taper this gap is 3.0 mm. BBT holders have thicker flange which eliminates a half of the gap. If a machine also has a BBT spindle nose, the other half of this gap will be eliminated by the spindle face and therefore provide taper and face simultaneous dual contact. This results in remarkable improvement of rigidity and performance.

The radial deflection, vibration, deviation, runout all are significantly reduced since BBT holders have better rigidity values than standard BT holders. With BBT holders this deflection is from 60 to 100 micron, while standard BT holders' radial deflection is about 400 to 600 micron. In addition, the runout defined by BBT tool holders' standard is under 2.5 micron, while with standard BT holders the runout of the taper is about 5-10micron. This shows that BBT tool holders are more accurate than tools with the regular BT interface. Utilizing of BBT holders gives better surface quality, longer tool life, improves productivity and reduced cycle time. BBT holders also allow higher cutting power transmission.

BBT tool holders
Fig.1. BBT vs BT

Elimination of Z-Axial shift

BBT face double contact tool holders always have face contact, which prevents an unwanted slip of the tool holders into the spindle at high RPM. At high RPMs spindle nose will widen due to law of inertia, and the taper will slightly move into the spindle. This will cause the loss of the Z-axis accuracy. This variation can be from 0.02 to 0.06 mm. The face contact of BBT spindle, in contrast, will prevent the tool holder from being drawn back into the machine spindle. BBT tools provide maximum machining accuracy and superior finish due to tight contact between tool holder and spindle compared to standard BT holders.

I.M.T.E. Inc. offers a wide range of BBT holders. For more information on our BBT holders please contact us today.

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