Apparatus and method for minimizing elongation in drilled holes

A drilling apparatus configured for drilling holes into a composite workpiece, the drilling apparatus comprising:

• an end effector including:
• an end effector housing,
• a drill bit attachment extending outward from the end effector housing,
• a rotation actuator coupled with the drill bit attachment and configured for actuating rotation of the drill bit attachment, and
• a linear motion actuator configured to actuate linear motion of the drill bit attachment toward and away from the workpiece;
• a drill bit attached to the drill bit attachment, wherein the drill bit includes a forward end, an aftward end opposite the forward end, a tip formed at the forward end, a widest portion aftward of the tip, and a narrow flute portion aftward of the widest portion, wherein the flute portion extends between the widest portion and the end effector, wherein the flute portion has a smaller diameter than the widest portion, wherein the widest portion has a smaller length than the narrow flute portion;
• and
• a control system configured to send control signals to the end effector commanding the end effector to rotate the drill bit and commanding the end effector to move laterally outward and inward, wherein the control system commands the end effector to move laterally outward toward the workpiece at a first speed and commands the end effector to move laterally back inward away from the workpiece at a second speed, wherein the second speed is faster than the first speed.

A method of drilling holes into a composite workpiece with a drilling apparatus, the method comprising:

• actuating rotation of a drill bit attachment with a drill bit attached therein;
• actuating the drill bit attachment linearly toward the composite workpiece at a first speed, thereby forming a hole through the composite workpiece;
• and
• actuating the drill bit attachment linearly away from the composite workpiece at a second speed, wherein the second speed is greater than the first speed to limit an amount of time that a relatively wider portion of the drill bit contacts the workpiece during withdrawal of the drill bit from the composite workpiece.