by Laurie Barcaskey This article was originaly written for the NTMA newsletter If you are considering adding or upgrading your marking process, laser technology might serve you well. However, the investment requires doing some homework to ensure the system you choose will optimize your capabilities and allow room to grow. Whether looking for a dedicated workstation or integrating the marking into a production line, identifying the primary features to fit your budget need consideration. Finding the best partner to provide the solution becomes important. What one machine shop finds suitable for them does not always prove the best for another shop. Laser marking offers more flexible technology over chemical etching, which it most commonly replaces. Programming through the software provides the ability to quickly change marking details without having to print a mask specific to each marking file. Upgrading from dot peen can prove beneficial, however for applications where stress fractures might be a concern, you may want to think again. Understanding Marking Areas Within the laser marking solutions you will find different power sources that are specific to the types of materials you need to mark. Fiber sources are most suited for metals and some plastics, while CO2 sources best serve organic materials like wood, leather, and glass, along with some other plastics. Applications where heat may impact the product, or high contrast is needed there are other specialized laser sources such as UV, Green, Mopa and Solid State. When referring to laser marking systems, the "marking area" is the maximum surface area on which the laser can engrave, etch, or mark at one time. This area is crucial for determining the size of the designs or texts that can be applied without repositioning the material. The size of this marking area is largely determined by the lens that is used in the laser system. Standard Marking Area The industry standard for a marking area is often cited as 4 inches by 4 inches (approximately 102mm x 102mm). This size is suitable for a wide range of applications, offering a good balance between size and precision for many products and components. However, specific requirements can vary, and so laser systems are equipped with lenses that can offer both smaller and larger marking areas. Role of the Lens The lens in a laser marking system functions similarly to a lens in a camera or a magnifying glass. It focuses the laser beam to a precise point on the material's surface. The characteristics of the lens, including its focal length, determine the size of the marking area and how finely the laser can focus.
Impact on Focal Distance The focal distance is the distance between the lens and the material being marked. It is critical for achieving clear, precise marks:
Advantages of Laser Technology Having the ability to achieve different mark results based on program settings makes laser technology attractive. Ranging from a light surface etch to deep engraving, and annealed marking for contrast you can meet the demands of identification for a multitude of applications with one system – a job shops dream come true. There are quite a number of advantage of using laser technology:
Software and Usability Many of today’s lasers include user-friendly intuitive software that includes common navigation allowing beginners to get started quickly. This may include preloaded settings based on the type of material, preferred type of mark, and batch size. Typical marking details such as alpha/numeric characters and symbols are available in standard True Type fonts. The ability for marking bar codes increases to include 1D and 2D codes in a variety of formats, where programmable dot peen systems only allow for 2D codes. For more experienced laser programmers, the ability to access the background tools for deeper dives into the software may be the key factor when evaluating the software capabilities. Logo Importing and Data Entry Importing logos is a frequent request. Most lasers will accept standard formats such as .jpeg, .bitmap and .eps, however some software platforms may require files be converted to a specific format. Job shops looking to expand through contract marking may face time spent converting file formats from what customers provide to what the laser will accept. Entering the data into the software becomes important when the data changes often. To optimize the accuracy bar code scanning information from work orders removes transposing characters or placing data in the incorrect fields. Most software platforms will also allow entering data from spreadsheets optimizing throughput of items with multiple fields such as nameplates. Yet other times, interfacing with a host computer for data entry streamlines the data entry real-time. Workstation Types and Safety
This leads to the types of workstations to consider, and safety is a key factor. For the sake of this article the focus is on a Galvo arrangement. A Galvo arrangement, short for "galvanometer arrangement," in the context of laser marking and engraving, refers to a system that utilizes galvanometer scanners to steer the laser beam across the target material's surface. These scanners contain mirrors that rapidly oscillate to reflect the laser beam in precise patterns, enabling the laser to etch, mark, or engrave with high speed and accuracy. This system contrasts with other types of laser positioning systems, such as gantry systems, which move the laser head or the workpiece mechanically over a fixed path. Sometimes Gantry style laser systems are more favorable for large batches of small parts. In Galvo arrangements Class I enclosed workstations meet OSHA standards for light-tight environments protecting the operators and area workers from stray beams. Laser providers typically offer a standard enclosure, and some can build a customized cabinet. Third-party automation organizations can also assist with custom enclosures and installations. Some key features of the enclosures to consider include the size and weight of parts being presented to the workstation, along with the access to the internal chamber. Manually operated, motorized and programmable doors are options with most laser suppliers. The ability to mark larger parts may require looking closely at the Z-axis, which is especially important to consider for proper focal distance. Options to automate the Z-axis are invaluable when part sizes change frequently and insure quick setup with accurate settings. While fixture requirements differ from impact marking, the tooling in laser applications assist with proper placement of the part for the marking process. Stability of the part during the marking process is more important than having it securely held. When available, T-slot bases offer the most flexibility for quick changeovers. Some shops choose to work without the enclosure in a Class IV arrangement. While these workstations offer greater flexibility with part sizes, they present the need for extra attention to safety in the area the laser is set up. The operator should be equipped with safety lens to suit the wavelength of the laser source. Preferably Class IV arrangements are placed in an area enclosed with laser safety barriers, if not in a room dedicated to laser marking. Maintenance and Partner Selection Another favorable feature of laser marking is the minimal maintenance requirements. By keeping the lens clean and the internal chamber of the enclosure free of debris and fumes from the marking process clear, legible mark results can be achieved consistently. A good air filtration system aids in this maintenance process. As you consider the partner for your project you want to explore the depth of their marking experience. Some partners are specific to laser marking, while others have a broader background in direct-part marking applications. The size of the organization will provide some indication of their ability to meet delivery and support post-sale issues. During the exploration period you will want to have test marking done on your materials and spend some time to be acquainted with their software. There are a lot of companies offering laser marking solutions, and like machine shops, they are not all the same. Choose wisely.
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