Common Methods and Techniques for Metal Engraving

Laser Engraving

Metal laser engraving typically relies on the principle of sublimation. Sublimation refers to the process by which a substance transitions directly from a solid to a gaseous state, bypassing the liquid phase. This differs from evaporation, in which a substance first changes from a solid to a liquid, and then from a liquid to a gas.

During the metal engraving process, the laser beam delivers extremely high energy to the irradiated area, rapidly heating the metal surface to high temperatures. Since metals require higher temperatures to undergo a phase transition, the energy from the laser beam causes the surface layer to transition directly from a solid to a gaseous state or vapor, resulting in the instantaneous vaporization and removal of material. This creates the desired text, patterns, or markings on the surface.

Laser engraving ensures that parts remain clearly identifiable over the long term. Compared to laser etching and laser marking, metal laser engraving is faster, more durable, and offers greater engraving depth, making it suitable for engraving barcodes, logos, serial numbers, part numbers, and QR codes.

Laser Engraving Materials

Manufacturers apply laser engraving technology to a variety of materials, such as:

● Metals—Laser engraving is suitable for a wide range of metal materials. Aluminum is lightweight, highly thermally conductive, and offers high processing efficiency, making it particularly well-suited for applications requiring speed and high-volume production. Additionally, aluminum is highly responsive to laser wavelengths, enabling high-contrast, high-precision engraving results. In contrast, while stainless steel is harder, composed of various alloys, and more challenging to process, its corrosion resistance and high-temperature tolerance give it an advantage in high-standard applications requiring permanent marking. Laser engraving can produce clear, durable text, patterns, and serial numbers on stainless steel surfaces.

● Coated Metals—Laser engraving is equally effective on coated metals. This unique technology facilitates marking on coated metals by removing the coating or finishing layer. Laser engraving works on low-carbon steel, powder-coated stainless steel, coated aluminum, and other types of coated metals.

● Plastics — The temperature required for laser engraving typically varies by material. It depends on the absorption spectrum of the plastic used and the additives incorporated during manufacturing. Plastics suitable for laser engraving include ABS, polycarbonate (PC), PET, polypropylene (PP), acrylic, and others.

‌Laser Engraving vs. Laser Etching

Some people tend to use the terms “laser etching” and “laser engraving” interchangeably. However, although their purposes are similar, these two processes are actually distinct methods.

Laser engraving involves using a laser beam to physically remove certain portions of a metal’s surface. It creates a cavity on the metal surface that can be touched and seen. In contrast, laser etching of metal requires heating the metal surface with a laser beam to melt specific areas of the surface. The heat generated by the laser beam melts the metal surface, causing the material to stretch or expand. This process creates a visible and tactile raised mark.

The key difference between laser engraving and laser etching lies in the effect or transformation they produce on the metal surface. The laser etching process does not involve any form of material removal. It does not leave deep marks like laser engraving does. The depth of patterns produced by etching is typically 0.001 inches or less.

Similarly, laser etching metal requires lower temperatures than laser engraving. Although laser etching is faster because it does not involve material removal, laser engraving leaves a more durable and long-lasting mark. Laser-etched metal is prone to wear, whereas laser-engraved metal is not.

Laser Engraving vs. Laser Marking

Laser engraving refers to the process of imprinting information onto a part’s surface by penetrating the material’s surface significantly. Laser marking, on the other hand, refers to imprinting clear information onto a part’s surface with little or no penetration.

When laser engraving metal materials, material is removed from the metal’s surface, thereby altering its surface structure. In this way, the technology produces durable, high-contrast marks that are easily recognizable. In contrast, laser marking uses a focused laser beam to alter the surface of the workpiece. Four common laser marking methods include foaming, coloring, carbon migration, and annealing.

Many manufacturers use galvo or fiber laser systems to mark bare metals and reinforced plastics. These lasers operate at wavelengths different from those of CO₂ lasers, allowing them to mark raw metals using metal markers. Although manufacturers often use the terms “laser engraving” and “laser marking” interchangeably, there are distinct differences between the two.