Most laser marking techniques involve either engraving the mark into metal or plastic components, or ablating a surface layer to reveal a contrasting material underneath. Both processes usually require high energy pulsed laser systems and of course involve process debris.
Fiber lasers are now a robust industrial tool with a unique series of capabilities that enable a wide range of precision materials processing manufacturing methods. Fiber lasers offer low running costs, a fast ROI, a small footprint and exceptional reliability, and are thus enjoy a growing acceptance within the laser-assisted manufacturing industry as a cost-effective alternative to conventional laser design.
Laser marking is able to generate high contrast, easily readable and durable identification on a wide variety of components for industrial use or consumer products. Computer generated vector or bitmap patterns (logos, barcodes or text) can be engraved or etched using a non-contact process onto metallic and nonmetallic materials, including metals, plastics, glass, electronics, PCBs, wafers, medical devices, sporting goods and packaging.
A combination of a reliable industrial laser, fast and accurate galvanometric imaging systems and convenient computer control provides manufacturers with a unique combination of speed, permanence and versatility that cannot be matched by any other marking technique.
Laser marking processes
Traditionally, laser marking involves either engraving a physical mark onto a surface just as for traditional engraving methods, generating a simple color change in surface, or etching of a surface layer of material to reveal another, highly contrasting layer underneath. Either technique can be used on a broad spectrum of materials, and in addition to generating identifying marks can also form part of an industrial process, for example in electronics manufacture.
The advantages of laser marking include speed, flexibility and the non-contact marking process, meaning that components parts are not stressed by the marking process. The non-contact nature of the process also contributes to low maintenance schedules, as tools do not need to be replaced. Additionally laser marking is also highly repeatable and easily readable (even machine readable).
Stringent Quality Control
A laser engraving process is often used for marking metal surfaces as it is swift, non contact and extremely durable, but is however also responsible for the production of debris - fine metallic particles removed from the surface as part of the engraving process.
Naturally for bearing manufacture there are stringent requirements for process debris. The marking of bearing housings using a laser has thus traditionally combined a "minimal" engraving process with an induced change in surface color. CMS had until recently accomplished this using Nd:YAG lasers, but customer demand was looking for a way around the cost, maintenance, lifetime and reliability issues associated with the Nd:YAG design.
For this application CMS engineers have pioneered the use of a fiber laser from SPI Lasers plc of Southampton, UK - more specifically a 100 W cw/modulated fiber laser usually used for welding and cutting tasks. SPI has been developing fiber lasers for the industrial market for several years, primarily for materials processing applications such as microwelding and microcutting, but also for marking applications.
Switching to the new fiber laser means generating the same thermally induced high contrast mark on the bearing housing, but doing so with less production of debris, at reduced raised recast, and at much greater convenience to the end-user - meaning almost no maintenance, increased lifetime and exceptional reliability.
The 100W fiber laser used in this application typifies the flexibility of fiber lasers as a tool for a wide variety of applications - marking applications are traditionally an application for high energy pulsed lasers, but the performance envelope provided by fiber laser technology allows systems integrators like CMS to redefine these domains.
Advantages of fiber lasers
Many different laser designs have found their way into materials processing applications. Fiber lasers are however revolutionizing many of these applications through a combination of improved optical performance, better system flexibility, high component yield, long up-time and exceptional reliability.
Critical to many marking applications, they do not exhibit the shortcomings in spot size performance found in other laser designs - at all power levels, across all pulse sequences and during the entire lifetime of the laser, the spot size remains small, predictable and consistent.
The small spot size and high beam quality also mean high irradiance at the focus, so manufacturing tools equipped with fiber lasers can produce better results faster and at lower power levels. The focused beam consistently treats only a very small area of material, with the benefit that very little heat is generated in the surrounding area. High quality precision marking, welding and cutting can be performed close (0.1 mm) to the most complicated and intricate component parts.
Factoring in the reliable operation and power modulation flexibility, fiber laser technology is now frequently chosen as an upgrade over conventional flash-lamp pumped solid state, or even DPSS laser technology in many other laser-assisted industrial manufacture segments. The consistent and improved marking performance means reduced maintenance costs, longer up-times and improved production quality with less scrap. Fiber lasers are also exceptionally physically robust and thus suitable for the most challenging of industrial environments.
All of these factors equate to a plug-:%$-play, maintenance-free architecture for systems integrators looking to cut development, production and servicing costs, with the added benefit of being able to provide the end user with a better, more flexible product. Last but not least, the end user will be able to focus on their business demands rather than having to become laser maintenance experts.
Advantages for industrial manufacturers
In general, the choice of tooling for any application comes down to determining the required performance followed by a trade-off between initial outlay, component yield, uptime and maintenance.
Not only are component assemblies becoming increasingly more complex but, at the same time, more and more demands are being placed on their quality and functionality. The deployment of manufacturing tools equipped with fiber lasers to enhance process control can thus bring important financial advantages for any manufacturer. Coupled with the small footprint, such tools can also open up processes that were previously out of reach for some manufacturers.
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