Page 352 - Carbide drills I Thread cutting tools 2023

Technical notes regarding use of deep hole drills

FRAISA SA recommends the following drilling strategy to increase both service life
and reliability:

Step 1 Pilot hole = 1.5 x d.
e.g. Supradrill® U 3xd. B62011.
The pilot hole must be free of chips prior to insertion of the
deep-hole drill!
1.5 x d

Step 2 off Insert the tool into the hole at max. 300 1/min
and v f = 1000mm/min.
Without cooling up to 1 mm from the bottom of the pilot hole.
1.5 x d

on
Step 3 Coolant supply on.
Drill using recommended cutting data and without chip
breaking. When drilling through-holes, reduce the feed rate
by at least 25% before retracting from the hole.

Step 4 Retract the deep-hole drill with double the feed rate (=2 x v f ) –
until 1.5 x d after entering the hole. Position as stated in Step 2.

1.5 x d

off
Step 5 Next reduce the spindle speed to max. 300 1/min.
Coolant feed is switched off.
Withdraw the drill from the drilled hole. (max. 1000 mm/min).

SAFETY NOTE
Outside of the drill hole, long deep-hole drills may only turn at a low speed (max. 300 1/min).
Higher spindle speeds can cause such tools to vibrate, leading to spontaneous failure.

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