Engraving on metal requires the material to melt and evaporate. This process can be explained by the fact that the average laser power is used to melt the material and the peak power is used to evaporate the material. A key point in achieving the best engraving rate is that there is just enough molten material to be evaporated at the effective peak power. If too much material has been melted, it will result in a decrease in engraving rate and excessive recast material and burrs. If the molten material is insufficient and the peak power is sufficient, the engraving rate is lowered. Precision high-contrast marks can be produced on some ceramics and plastics only at high peak powers.