| 摘要 |
A method of forming a void 14 with a circular cross section in a substrate 16 comprising the steps of causing a laser cutter 10 to traverse in an arc 12a to an intended circumference 14a of the void and traversing the intended circumference of the void at least once, wherein the lead in from the arc to the circumference comprises a radius. The start point of the laser cutting may be the centre 13 of the intended void circumference and the laser may further finish cutting back at the centre point. The path traversed to the circumference from the start point may be a spiral (12c fig 1b) and the outer circumference 12 may preferably be traversed between 1 and 4 times. The substrate material may be ceramic, polymer or composite material, preferably aluminium nitride and the laser is preferably a Carbon Dioxide laser. The formed hole preferably is frustoconical in shape. |
