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Laser engraving, a subset of laser marking, is a process where the laser beam physically removes the surface of the material to expose a cavity that reveals an image at eye level. The laser creates high heat during the engraving process, which causes the material to vaporize.

The emitted laser beam allows the controller, typically a computer, to trace patterns onto the surface and to manage the direction, intensity, speed of movement, and spread of the laser beam aimed at the surface.

What surfaces can be engraved? Wood, leather, and glass are suitable materials. Standard cast acrylic plastic, acrylic plastic sheet, and other cast resins generally laser very well, as do anodized aluminum and other coated metals.

What’s the process? Select a material and a desired design, which will be created in a graphic program on a computer and sent to the laser. The design is engraved after the material is placed in the engraving machine.

The technology has a multitude of applications, from marking industrial parts for identification and traceability to makerspace and DIY uses.

Depending on the design, the laser medium can consist of a gas mixture (CO2 laser), a crystal body (yttrium aluminum garnet laser), or glass fibers (fiber laser). When energy is fed to the laser medium through a pump source, it emits energy in the form of radiation.

The CO2 laser is the most widely used due to its relatively high efficiency and good beam quality. With a wavelength of 10.6 μm, they are mainly suited for working on a wide variety of non-metallic materials and on most plastics.

With a wavelength of 1.064 μm, fiber lasers aren’t typically used for organic materials; however, they are the laser of choice for direct metal and engineered plastic marking.

Crystal lasers have the same wavelength as fiber lasers and are also suited for marking metals and plastics. The equipment includes relatively expensive pump diodes, which must be replaced after about 15,000 laser hours. The crystal itself also has a shorter service life than a fiber laser.

Different patterns can be engraved by programming the controller to traverse a particular path for the laser beam over time. The trace of the laser beam is carefully regulated to achieve a consistent removal depth of material. The speed at which the beam moves across the material is also considered in creating engraving patterns. Changing the intensity and spread of the beam allows more flexibility in the design. For example, by changing the duty-cycle, or proportion of time the laser is turned on during each pulse, the power delivered to the engraving surface can be controlled appropriately for the material.