Paving the way for technological innovation is the UV laser. Unlike other laser wavelengths, a UV laser does not damage the material surrounding the surface of an object, making it ideal for laser marking particularly delicate materials such as glass.
The Science of UV
UV lasers mark parts using a highly absorptive wavelength of 355nm. UV lasers are commonly known as THG lasers which stands for third-harmonic generation, this is because of the wavelength’s unique characteristics. By passing a standard 1064nm wavelength laser through a non-linear crystal, it reduces it to 532nm, by passing it again through another crystal, it reduces once more to 355nm.
This 35nm wavelength produces significantly less heat than others, so is considered a form of ‘cold marking’, which means materials marked with a UV laser are less prone to damage and heat stress, ideal when the material in question is fragile in its makeup.
Differences Between UV and Sandblasting
So what about sandblasting? Sandblasting is a traditional, incredibly labour-intensive way of marking glass. The process involves directing tiny abrasive particles, with either compressed air or water, onto the surface of glass to form a mark. To begin the process, a template of the design or graphic that is being marked will need to be produced into a self-adhesive stencil.
This stencil effectively protects the area of the glass the user doesn’t want to be affected by the sand stream. Once the stencil is in place, the user can begin the sandblasting process. Using a blast hose, tiny particles of sand (or other abrasive material) are directed over the exposed areas, eroding the glass away and leaving a translucent finish.
Stability is key here and requires the user to keep a firm and steady hand with the blast hose to ensure there are no inconsistencies. Finally, once the long sandblasting process is complete, the user is required to rinse the glass of residue.
Advantages of the UV Laser
One of the biggest advantages of using a UV laser is a reduction in both time and labour compared to this lengthy sandblasting process. With a UV laser the mark to glass is a true ablation process, meaning the result is highly visible no matter the angle, there’s no need for stencils, and there’s nothing to clean up once the mark is complete.
In conclusion, although both methods result in beautifully detailed marks, UV laser marking comes out on top for a few different reasons. Laser marking is contactless, meaning no force is exerted onto the glass, keeping the risk of secondary damage low. This is in stark contrast to sandblasting which can cause damage to the material being blasted and may result in expensive repair work.
Furthermore, sandblasting requires far greater manual labour than laser marking, from the initial application of the stencil to the physical demands of the blast hose, to the cleaning required after marking is complete. Although it produces impressive results, sandblasting simply cannot compete with a UV laser which is an all-round easier and quicker way of marking glass.
