Laser bonding is a marking technique that uses

laser A laser is a device that emits light through a process of optical amplification based on the stimulated emission of electromagnetic radiation. The word ''laser'' originated as an acronym for light amplification by stimulated emission of radi ...

s to bond an additive marking substance to a

substrate Substrate may refer to: Physical layers *Substrate (biology), the natural environment in which an organism lives, or the surface or medium on which an organism grows or is attached ** Substrate (aquatic environment), the earthy material that exi ...

. First invented in the mid 1990s by Essilor International, this patented method produces permanent marks on metal, glass, ceramic and plastic parts for a diverse range of industrial and artistic applications, ranging from aerospace and medical to the awards and engraving industries. It differs from the more widely known techniques of

laser engraving Laser engraving is the practice of using lasers to engrave an object. The engraving process renders a design by physically cutting into the object to remove material. The technique does not involve the use of inks or tool bits that contact th ...

and

laser ablation Laser ablation or photoablation (also called laser blasting) is the process of removing material from a solid (or occasionally liquid) surface by irradiating it with a laser beam. At low laser flux, the material is heated by the absorbed laser ...

in that it is an additive process, adding material to the substrate surface instead of removing it. Laser bonding has been achieved by Nd:YAG, CO₂ laser,

Fiber laser A fiber laser (or fibre laser in Commonwealth English) is a laser in which the active gain medium is an optical fiber doped with rare-earth elements such as erbium, ytterbium, neodymium, dysprosium, praseodymium, thulium and holmium. They ar ...

and

Diode-pumped solid-state laser A diode-pumped solid-state laser (DPSSL) is a solid-state laser made by pumping a solid gain medium, for example, a ruby or a neodymium-doped YAG crystal, with a laser diode. DPSSLs have advantages in compactness and efficiency over other type ...

and can be accomplished using other forms of

radiant energy In physics, and in particular as measured by radiometry, radiant energy is the energy of electromagnetic radiation, electromagnetic and gravitational radiation. As energy, its SI unit is the joule (J). The quantity of radiant energy may be calcul ...

The laser bonding process

Mark quality depends on a variety of factors, including the substrate used, marking speed, laser spot size, beam overlap, materials thickness, and laser parameters. Laser bonding materials may be applied by various methods, including a brush on technique, spraying, pad printing, screen printing, roll coating, tape, and others. The marking process generally comprises three steps: 1. Application of the marking material. 2. Irradiating the marking material with a laser in the form of the desired mark. 3. Removal of excess, unbonded material. The resulting marking is permanently bonded to the substrate, and in most cases it is as durable as the substrate itself.

The durability of laser bonded markings

Markings placed on stainless steel are extremely durable and have survived such testing as abrasion resistance, chemical resistance, outdoor exposure, extreme heat, extreme cold, acids, bases and various organic solvents. Marks on glass have been tested for resistance to acids, bases and scratching. NASA's International Space Station, or ISS, was home to aluminum squares laser marked with CerMark® marking material for almost four years. These squares were part of the Material International Space Station Experiment, or MISSE. In this experiment test markings were applied to coupons made of materials commonly used in the construction of the external components used on space transportation vehicles, satellites and space stations. Markings applied using a wide range of different methods and techniques, including laser bonding. The material test coupons were then affixed to spaces provided on test panels, which were then installed onto trays which were attached to the ISS during a space walk conducted during the STS-105 Mission flown on August 10, 2001. The trays were positioned on the ISS so that they could expect to receive the maximum amount of impact damage and exposure to a high degree of atomic oxygen and UV radiation. The experiment was recovered on July 30, 2005 during STS-114 and returned to earth on August 9, 2005. The markings,

DataMatrix A Data Matrix is a two-dimensional code consisting of black and white "cells" or dots arranged in either a square (geometry), square or rectangle, rectangular pattern, also known as a matrix (mathematics), matrix. The information to be encoded c ...

two dimensional bar codes, were evaluated and found to be readable and visually looked as good as the day they were placed in orbit. The laser bonding process is outlined and specified in both military and NASA NASA HDBK-6003 NASA Marking Handbook, Laser Bonding Section 5.1.5, p.15 marking specifications and standards. Laser bonding is also a preferred technique for use in the United States Department of Defense "Item Unique Identification" system (IUID).

References

{{Lasers Bonding Laser applications

The laser bonding process

The durability of laser bonded markings

See also

References