Glass marking is an application where the difference between femtosecond and CO2 lasers is clear. The CO2 laser wavelength is absorbed so strongly in glass that the entire interaction happens at the surface. While this is an advantage in some applications where surface marking is desirable (such as head keepers in beer glasses), it means that it is simply impossible to mark below the surface. However, this is not the case with femtosecond lasers, which are able to mark in the bulk of optically transparent materials.
Potential applications include syringe and vial marking for the medical and pharmaceutical industries; sub-surface marking is particularly attractive in this setting, as the codes are indelible and not subject to wear or damage. Very small features can be realised, while the surface of the glass remains intact and free from any process debris.
Our CO2 lasers are routinely used in the production of glass tableware to cut the rims of wine glasses and tumblers.
Rims may be formed by cutting the glass hot or cold. Cutting at the hot end of production gives a rounded, beadless rim. Cold cutting is done using a “crack off” process to remove the excess glass; the laser is used to thermally shock the glass, forcing it to break in a controlled way. Although further grinding and polishing is required, this process produces a rim with a characteristic profile, suitable for the highest quality glassware products.
As laser cutting is done without any physical contact with the glass, tool wear is no longer an issue; productivity is improved as a result. Complex glass shapes can be handled with ease, allowing designers more creative freedom.
CO2 lasers can be used to apply a range of information to glass syringes, vials and tubes for the medical and pharmaceutical industries. Traceability of these products is critical, so the permanent and tamper-proof nature of the laser code is a distinct advantage. Coding directly on the glass means that the information is not lost if the product is separated from its packaging, or if an adhesive label is removed. Our laser markers can apply both human-readable text and 2D Data Matrix codes on the production line, on the fly, and the glass can be marked hot or cold at any stage of the manufacturing process.
CO2 lasers mark glass by making tiny cracks in the surface of the material. The rough texture this produces can mimic a sandblasted effect for decoration, or can serve a practical purpose – for example, a laser mark on the base of a beer glass can keep the bubbles flowing, and the frothy head on your beer! High quality decorative marking is possible; our lasers are used for cosmetics and perfume bottles as well as drinking glasses and crystal glassware.
Marking glass at high temperature allows extremely high quality marks to be produced without cracking. Subtle identification marks, human-readable text and reliable data matrix codes can be applied to glass bottles, jars, vials and other containers at the hot end of production, on the fly. This may be done for traceability or as protection against counterfeiting of products.
The hot glass manufacturing environment is challenging, but the MULTISCAN® HE is engineered to withstand these harsh conditions.