Selecting the proper wavelength for an application is extremely complex, requiring knowledge gained through years of marking experience. All materials absorb or reflect light energy of certain wavelengths. The material’s ability to absorb or reflect a given wavelength determines the effectiveness of that wavelength for marking. Additionally, other factors influence the selection of the wavelength (and laser system): the size of the character to be marked, the desired marking speed, desired line width, the type of mark, the physical properties of the material, the color of the material, the power of the laser, the pulse frequency, etc. These factors interact with each other in a dynamic manner making the selection process very complicated. The only method to ensure the application is marked using the best wavelength (and laser system) is to run test samples varying the factors accordingly. The final selection should be made only after samples have been successfully marked.
The most popular lasing medium is neodymium doped Yttriuum Aluminum Garnet (Nd: YAG). YAG lasers are most often used as the base platform to produce different wavelengths when properly configured. The most versatile wavelength is infrared (1064nm). This wavelength is used to mark a variety of materials including metals, ceramics, composites, and some plastics.
Other industrial wavelengths include green (532nm), ideal for composites and some plastics, and ultraviolet (355nm) ideal for glass and some plastics.
Another popular laser type is the gas operated CO2 (10,640nm). CO2 lasers are popular for marking organic material such as wood, paper, and rubber as well as some painted or anodized metals.
Often, a material can be marked using more than one wavelength. As mentioned earlier, a material’s absorption rate effects cycle times and quality of the mark. Only by test marking a sample with various wavelengths can the optimal laser system be determined for your application. Control Laser Corporation operates one of the largest marking development centers in the country.
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