Method and system for making holes in composite materials
View Patent ↗A method of making a hole in a composite material comprising the steps of providing an elongate cutting tool having a cutting portion in the form of a tubular cylinder; and advancing the cutting tool in a direction parallel to a longitudinal axis of the cutting tool whilst rotating the cutting tool about said axis and vibrating the cutting tool along said axis.
1. A method of drilling a hole in a composite material comprising the steps of:
providing an elongate cutting tool having a cutting portion in the form of a tubular cylinder; and
advancing the cutting tool in a direction parallel to a longitudinal axis of the cutting tool whilst rotating the cutting tool about said axis and vibrating the cutting tool along said axis, wherein the cutting tool is advanced at a first feed rate over an initial and a final portion of the drilling of said hole and is advanced at a second feed rate over an intermediate portion of the drilling of said hole, the second feed rate being greater than the first feed rate.
2. The method of claim 1 , wherein the frequency of the vibration applied to the cutting tool is in the range of 18 KHz to 24 KHz.
3. The method of claim 1 , wherein the cutting tool is advanced at a feed rate of up to 100 mm/min.
4. The method of claim 1 , wherein the speed of rotation of the cutting tool is no greater than 3400 rpm.
5. The method of claim 1 , wherein the cutting tool is retracted by a first distance for every second distance the cutting tool is advanced.
6. The method of claim 5 , wherein the cutting tool is retracted by 0.5 mm for every 1 mm advanced.
7. The method of claim 1 , wherein at least a portion of the cutting tool is coated with an abrasive grit.
8. The method of claim 7 , wherein the abrasive grit comprises diamond grit.
9. A method of drilling carbon fibre composite material according to the method of claim 1 .
10. A drilling system for making a hole in a composite material comprising:
a elongate cutting tool having a cutting portion comprising a tubular cylinder; and
a drive mechanism configured to simultaneously rotate the cutting tool about a longitudinal axis of the cutting tool and vibrate the cutting tool along said axis; and configured to advance the cutting tool in a direction parallel to the axis at a first feed rate over an initial and a final portion of the drilling of said hole and is advanced at a second feed rate over an intermediate portion of the drilling of said hole, the second feed rate being greater than the first feed rate.