What is Glass Laser Etching?
Laser etching glass (also referred to as laser engraving or marking) is an increasingly popular solution for printing on glass products and glazing. Laser etching machines allow permanent high-resolution codes and symbols to be etched onto nearly any colour or type of glass.
When an etching laser hits glass, the glass fractures. Natural grains and crystalline structures in the surface of the glass, when heated very quickly, will separate a microscopic sized “chip” from the surface as the hot piece expands rapidly relative to its surroundings. In this way, lasers are used to etch or engrave onto glass bottles, vials, glazing and other glass products. If the power, speed and focus are all well controlled, excellent results can be achieved.
What is the difference between Laser Etching and Engraving Glass?
The main difference between laser etching and laser engraving is the depth to which the laser penetrates the glass surface, and the depth of the resulting mark. Typically, all other factors being equal, a higher powered laser will be required to engrave glass versus to etch it.
Advantages of Laser Etching Glass
By irreversibly altering the surface of the glass, laser etching leaves a mark more permanent than any inkjet printed one. Inkjet marking on glass can sometimes be altered due to a wet bottle surface at the time of printing, it can also be washed away during processing or damaged by abrasion during handling.
Using laser etching, glass bottles, vials, jars and glazing panels can be marked with serial numbers, internal tracking codes, quality marks and alphanumeric traceability information on both clear and coloured glass. This is especially important for manufacturing lines where a great deal of moisture is present that can dissolve inks or loosen labels, or where product handling can abrade or smear printed codes. The permanent laser etched marks protect codes from tampering and help protect against fraud, and the high quality marks that result enable clear coding that helps instil brand confidence among customers.
The glass ablation produced by the laser process produces visual consistency for alphanumeric codes, but cannot be relied on for consistency over the larger areas required for more complex figures such as 2D codes. It is also essential that an extraction system be in place to remove glass chips as they are flaked off during etching, to ensure they do not interfere with the laser beam as it creates subsequent characters.
Glass Laser Engraving and Etching Solutions
Laser marking systems like the Videojet 3640 CO2 laser and Videojet 7810 UV laser produce micro cracks that etch into the glass surface to produce serial numbers, internal tracking numbers, and traceability information on clear and coloured glass.
A good example of how laser glass etching technology has been adopted into an industry norm is the production line. In this particular setup, the laser beam is directed towards a rotating or vibrating mirror. The mirror moves in a manner that traces out numbers and letters onto the surface being marked. This is particularly useful for printing dates, expiry codes, and lot numbering of products travelling along a production line in (for example) a pharmaceutical, food or beverage bottling line. Laser etching allows the glass bottles to be marked “on the move.” The location where the marking takes place is called a “marking laser station,” an entity often found in packaging and bottling plants. The speed of laser etching systems has largely led to them replacing older, slower technologies such as the hot stamping and pad printing of marks on glass as production line speeds have increased.
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