Fiber laser engraving machines work by focusing a high-power laser beam onto a specific point on the material being engraved. The intense heat of the focused beam causes the material's surface to melt or vaporize, creating a permanent mark or design. The laser beam is moved across the material, following a pre-designed pattern to create the desired engraving. This process is highly precise and can be used to engrave a wide range of materials, including metals, plastics, and ceramics.