Lasers have been used to mark products in industrial manufacturing for over 25 years. Lasers apply small character codes, like batch numbers, dates, etc.,) to packaged goods in industries such as food, electronics, and pharmaceuticals.
The advantages of laser marking are many: you can permanently add the exact same mark to your product without any contact, reduce the costs of consumables like inks and thermal transfer labels, and easily edit the software to add, delete, or change text, graphics, and barcodes.
If you need to put the same information on your products as they speed by on a production line, then laser marking is likely the way to accomplish the task. Each laser technology has its strengths and limitations depending on your particular need and the materials you use, so you should consider the following:
- Line speed – the pace at which products move across the laser beam influence your choice. High-speed lines require more powerful lasers, for example.
- Substrate – some lasers remove substrate layers to create a mark, and this might not be suitable for certain products.
- Code content – the type and amount of data you need to put on the mark can affect laser choice.
- Environmental conditions – dusty or wet environments may require more preventive maintenance or protective cases over the laser.
A laser (Light Amplification by the Stimulated Emission of Radiation) uses a photon of light to change the surface of a substrate, either by etching or annealing.
Laser etching happens when the heat of the laser beam melts the material’s surface, leaving a raised mark. Etching changes the surface finish of a metal to alter reflectivity and provide more contrast. Etching is a good choice for high-speed marking because the substrate material is almost instantly etched with each laser pulse, letting you set the beam velocity as high as possible and still maintain an acceptable mark.
Laser annealing uses a lower power laser beam to effect a color change without disrupting the material’s surface. Carbon or oxides from the substrate material create the contrasting mark without removing layers. In metals, you can use a lower temperature to anneal the surface and is a good choice for marking finished surfaces. Process speed is lower than laser etching because annealing relies on thermal effects.
Our line of laser marking systems includes CO2, Fiber and Nd:YAG lasers in different power outputs to address a range of substrates and applications. Following is a brief comparison of these different types of lasers.
CO2 lasers are gas lasers based on a carbon dioxide gas mixture that is stimulated electrically. CO2 lasers have a relatively high efficiency and feature a very good beam quality, making them suitable for substrates such as wood, acrylic, glass, paper, or foils and films.
The service life of a CO2 laser is approximately 45,000 laser hours. Their smaller footprint makes them easy to integrate onto existing lines, and they can be mounted in any orientation, and they have a lower initial cost than other lasers.
CO2 lasers have a larger spot size than other lasers, which reduces power density and resolution, and they cannot etch into metals.
Fiber lasers produce a small focal diameter and their intensity is up to 100 times higher than CO2 lasers of the same power. With a very small footprint, fiber lasers can be easily integrated into existing lines and in any orientation. Fiber lasers are suited for annealing metal, etching metal, and for high-contrast marking on plastic. The small spot size, though, might increase mark time.
Fiber lasers are generally maintenance-free and have a long service life.
Nd: YAG Lasers
YAG lasers are diode-pumped crystal lasers that are suited for metals, coated metals and plastics. The small spot size of the laser and short laser pulses produce high peak power to give crisp, clear marks and small characters.
YAG lasers use expensive diodes which do not require maintenance, but wear out after approximately 8,000 to 15,000 laser hours. YAG lasers must be kept in a temperature controlled environment. They have a larger footprint than CO2 or fiber lasers, and must be mounted in a horizontal position.
All laser technologies have key benefits that improve manufacturing capabilities. When deciding on which technology best suits your environment, it’s important to have a partner who can show you exactly what each technology can accomplish.
Talk to us about your laser marking needs so you can be sure to select the right product for your application. Call us at (603) 598-1553.
This labelling news was spotted at Labeling News
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