Laser Glass Cutting
Laser cutting of glass in not a novel technique, excellent results have already been achieved by various research institutes. There are several patents concerned with controlled cutting of glass with zero width and other brittle materials in a straight line using CO2 laser beam. Laser glass cutting produces a high quality cut edge with minimal microcracking. This is achieved using a controlled cleaving of glass through a combination of heating and cooling. Laser separation of glass with zero width can be summarised by the following steps:
• The glass surface is heated by laser beam
• Compressive stress builds up in surface layers, but there no surface damage
• When a coolant is applied, this cools surface on cutting line
• Steep temperature gradient generates high tensile stress on the glass surface.
• This causes propagation of incipient crack in the glass sheet
Today various types of glass varieties are in use in a range of applications. This can be anything from small optical filters in micrometer to 19 inches glass substrates for flat panels e.g. for notebook, also even to bigger size glass for automotive or architectural industry in a mass productions. The glass industry can be categorised into five groupings.
The most common type of glass is soda- lime glass, also known as alkali- glass, which is used for automotive and architectural/ home appliances. The common glass thickness ranges from 1.6mm to 10mm. Glass plates that are 1 mm thick or less are referred to borosilicate glass and are mainly used for flat panel displays (FPDs) and electronics products.
Image: Glass Cutting Laser (SLC150SD) and typical beam profile
Laser zero width cutting methods surpass the traditional glass cutting/separating methods. With the right combination of heat and cold the laser beam precisely heats a specific line on the glass followed by a cold jet of air or an air/liquid mixture. These thermally induced tensions cause a precise fissuring of the glass. The result is a cut edge of the highest quality. The main advantages of this process are:
• High precision
• No micro-cracks, fragmentation or chipping
• Glass edges have a high resistance to breakage
• Glass edges virtually achieve optical quality
• Cost-effective production by reducing the need for washing, grinding, polishing and breaking machines
• Can be integrated in clean-rooms
• No loss of material
You can find our White Paper on Zero Width Glass Cutting with Co2 Laser for further reading.