Abstract: A control apparatus for a drilling machine and a drilling method capable of quick adaptation to drilling by drills of various diameters, especially drills of small diameters, and of improving cutting efficiency. The control apparatus includes a cutting condition setting unit for setting the cutting conditions in accordance with the depth of the hole being drilled and a control unit for controlling the rotary speed and movement position of the drill. The cutting condition setting unit defines the regions of the beginning part, the inner part, and the penetration part from the side close to the drill of the workpiece toward the depth direction of the hole of the workpiece in accordance with the depth of the hole when drilling a throughhole.

Abstract: Backlash compensation for a numerical control apparatus. Backlash compensation is intelligently applied based on a judgment as to a change in direction or velocity commanded for a cutting tool, table, or the like. Backlash compensation data is stored into a memory of a numerical control apparatus. A judgement is made as to the necessity of backlash compensation, based on velocity data of the feed mechanism, and deciding whether the feed mechanism is being stopped or reversed. Compensation data is output to a servo drive unit.