D20x22 Series II Navigator HDD
Overview 30-53
A
UTO
D
RILL
In AutoDrill mode, the operator can release the
Thrust/Pullback
and
Rotation Handles
and the drill will
continue to operate.
The AutoDrill may be used in all drilling modes and in combination with both R.A.T.T. modes (Oscillation and
Straight Drilling).
The operator can set one of three constant control operating modes:
•
constant thrust/pullback speed
•
constant thrust/pullback pressure
•
constant rotation pressure
AutoDrill Mode Uses
Constant Thrust/Pullback Speed
mode may be used when drilling pilot holes with a tri-cone rock tool in ground
formation that is not too hard.
Constant Thrust/Pullback Pressure
mode may provide better productivity when drilling or pulling back in hard
conditions.
The
Constant Rotation Pressure
mode may be best suited for pulling back in formations with loose chunk rock
that may move and bind the tool.