In laser drilling, a short laser pulse with high power density feeds energy into the workpiece extremely quickly, causing the material to melt and vaporize. The greater the pulse energy is, the more material is melted and vaporized. Vaporization causes the material volume in the drilled hole to increase suddenly, creating high pressure. The vapor pressure expels the molten material from the hole.
Over the years, several drilling processes have developed from the basic method: