Surface treatments permit manufacturers to change or modify important surface characteristics of metal work pieces. Typically performed during finishing, these industrial processes, such as burr removal, burnishing, nitriding, galvanizing, grinding and powder coating, often impact a part in important ways.
For instance, some surface treatments ultimately contribute to the marketability of components by enhancing their aesthetic properties or improving modifying electrical conductivity. Laser engraving and laser marking constitute important finishing operations in the production of many types of manufactured parts. Laser engraving physically removes some portion of material from the surface; laser marking by contrast changes the appearance of a surface area indelibly, without causing any diminishment.
The Laser Marking Process
Laser marking systems all rely upon lasers to alter surface properties. However, depending upon the manufacturer's objectives, this technology may require the use of specific types of lasers. For instance, some manufacturers utilize industrial fiber lasers for both part engraving and part marking; in other cases, a manufacturer will employ different lasers to perform these operations. Laser marking usually causes a permanent discoloration on a portion of the part's surface. Depending upon the type of laser employed and the substrate, this process may involve the formation of surface oxidation. This change enables manufacturers to mark parts without impacting other properties of the metal work piece.
Types of Laser Marking
Manufacturers today draw upon a variety of proprietary laser marking systems and products. Some types of laser marking technologies include annealing laser marking, carbon migration laser marking, foaming laser marking, and coloration laser marking.
Annealing Laser Marking
This form of laser marking will transform the appearance of carbon-rich metal substrates. A laser produces color changes on a metal surface as a result of generating heat. Depending upon the metal substrate, manufacturers can produce a variety of different colors by heating the surface to specific temperatures. However, they must exercise care to simply heat the surface and not cause the metal to enter a gaseous state. Manufacturers can use annealing laser marking to produce indelible black marks on stainless steel. The process of annealing laser marking often requires more time to complete than some other types of laser marking. It sometimes contributes to the marking of medical instruments by manufacturers, for instance.
Carbon Migration Laser Marking
At least one manufacturers has developed a proprietary carbon migration laser marking system. The firm indicates its equipment will produce indelible black marks on stainless steel, steel, iron and titanium by causing carbon to migrate to the surface of the metal part. The application of a laser beam then produces a chemical reaction on the surface which results in a permanent black color change over the affected surface area.
Foaming Laser Marking
This laser marking process will transform the surface of plastic parts, but will not work effectively on metal substrates. Essentially the application of a laser beam to the surface of the plastic work piece raises the temperature of the plastic sufficiently to cause the degradation of some polymer constituents in the plastic. The release of gases from the hot surface produce foam-like changes, indelibly altering the appearance of the work piece.
Coloration Laser Marking
Several technologies exist for affecting metal and plastic product color through the use of laser marking. In some cases, a manufacturer first treats the surface of a metal work piece with a proprietary coating. Chemical changes occurring during laser marking on coated metal surfaces produce permanent discoloration. Some systems produce variable colors (depending upon the surface temperature achieved by the metal substrate).
Materials And Applications
Laser marking today relies upon some high tech materials. Numerous applications exist for this technology:
Laser marking systems in manufacturing settings typically involve the use of computerized and automated processes. Laser marking machines may use fiber lasers, carbon dioxide lasers, or other types of specialized lasers, depending upon the specific system and substrate involved. While many laser marking systems mark plastic, glass, wood and fiberglass products, some marking technologies label specific metal substrates. Popular materials which sometimes undergo the laser marking process include copper, brass, stainless steel, steel alloys, aluminum, gold and silver.
Popular applications for laser marking include ensuring finished metal parts carry clear product labels. Many manufacturers use this process to clearly designate product codes on the exteriors of metal components, for instance. Some metal parts fabricators apply permanent bar codes to metal components using laser marking tools. Manufacturers may choose to laser mark designs, logos, brand names and a variety of other types of information. Laser marking systems have found wide utility in diverse economic sectors. Medical, electronic, automotive, consumer goods, and aerospace components manufacturers have discovered numerous uses for laser marking systems.
Laser Marking Advantages
The use of laser marking systems benefits metal parts manufacturers in a variety of ways.
- By indelibly changing the surface appearance of a portion of a metal part without altering the part's other properties, manufacturers can more effectively track components. Permanently applying a bar code or serial number permits easier identification of constituent components during machinery assembly, for instance.
- The use of automated laser technology promotes greater duplicability and uniformity. A laser marking system which relies on computer number control processes can label industrial parts consistently without the marking mistakes which sometimes result from human error.
- Laser marking in modern manufacturing settings occurs rapidly. It conserves production time. Laser marking systems may eliminate expenses associated with alternative labeling systems.
- Manufacturers utilize some laser marking systems to mark a variety of different surfaces. The versatility and flexibility of this process may hold production advantages.