Sandvik Coromant Silent tools - How to reduce vibration in metal cutting - Manual (Page 15)

Sandvik Coromant – How to reduce vibration in metal cutting 11
Chip evacuation:
Chip evacuation during boring is critical to performance and the
security of the operation. Relatively short, spiral-shaped chips should be
aimed for with internal turning. These are easy to evacuate and do not
place such large stresses on the cutting edge when chipbreaking occurs.
Hard breaking of the chips, when very short chips are obtained, uses
more power and increases vibration. On the other hand, long chips make
chip evacuation more difficult and present a risk of swarf-clogging. It is
necessary, therefore, to choose an insert geometry which, together with
the chosen machining parameters, fulfil the requirements for good chip
control.
When internal turning is undertaken, the chip flow can be critical –
particularly when deep holes are being machined. The centrifugal force
presses the chips outwards which means, with internal turning, that the
chips remain in the workpiece. The remaining chips can be pressed into the
machined surface or get jammed and damage the tool. It is recommended,
therefore, that internal turning tools should have internal coolant supply.
The chips will then be flushed out of the hole effectively. Compressed air
can be used instead of cutting fluid and by way of through holes, allow the
chips to be blown through the spindle and collected in a container.
Chip evacuation is a critical factor for successful boring.