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The Glass Laser Cutting Process

Aug 06, 2020

Glass is an important industrial material, which is used in many industries in the national economy, such as automobile industry, construction industry, medical treatment, display, electronic products, etc. Optical filters as small as a few microns, glass substrates for laptop flat-panel displays, and large-size glass plates used in large-scale manufacturing fields such as the construction industry.

The remarkable characteristic of glass is its hardness and brittleness, which brings great difficulties to processing. Traditional glass cutting methods use cemented carbide or diamond tools, which are widely used in many applications. The cutting process is divided into two steps. First, use a diamond tip or a cemented carbide grinding wheel to cut a crack on the surface of the glass; then use mechanical means to split the glass along the crack line.

There are some defects in scoring and cutting using this method. The removal of material will lead to the generation of debris, fragments and micro-cracks, which will reduce the strength of the cutting edge, which requires another cleaning process. The deep cracks caused by this process are usually not perpendicular to the glass surface, because the dividing line generated by the mechanical force is generally non-vertical. Moreover, the loss of output caused by mechanical force acting on thin glass is also a bad factor.

The development of laser technology has brought solutions to these quality problems.

 

Laser scribing and segmentation

Unlike traditional mechanical cutting tools, the energy of the laser beam cuts glass in a non-contact manner. This energy heats the specified part of the workpiece to a predefined temperature. This rapid heating process is followed by rapid cooling, so that a vertical stress zone is generated inside the glass, and a crack without chips or cracks appears in this direction. Because cracks are only caused by heat, not mechanical reasons, there will be no debris and microcracks. Therefore, the strength of the laser cut edge is not compromised and no further finishing is required.

More importantly, compared to the glass divided by the traditional method, the glass processed by this method has a shatter resistance up to three times. For glass with a thickness between 5mm and 1mm, it is possible to complete the overall cutting in just one step. Dividing and subsequent polishing, grinding, washing and other steps are no longer needed. The strength of the cut edge can be measured by a standardized four-point bending test from DIN-EN 843-1. A piece of glass is fixed on two rollers, and the other two rollers are used to generate the required bending force on the upper surface of the glass, under which the glass can be split into two parts. The test is repeated approximately 100 times to obtain appropriate reliable statistics on the probability of segmentation.

In most cases, laser scribing and cutting is the choice for mass processing. Its advantage lies in high processing speed, high precision, and simple parameter setting. It can be seen that if laser cutting glass is used, it can save time and improve processing quality.

 

Laser cutting glass technology uses

It is not easy to transplant a new and mature technology into a mass production line for processing high-tech products. From the customer's point of view, before implementation, the technology must be an automated and reliable solution, which is not only fully proven, but also economical. In practice, the application of innovative technology is only effective in two situations: the launch of new products requires new production methods to achieve innovative features or reduce production costs by reducing processing steps, or existing production meets economic pressures. Huge improvements in production methods to ease.

In the flat panel display industry, it took five years for the promotion of laser cutting technology to find its place in the production line, provided that thousands of hours of application verification on many processing lines have been experienced. Now it is usually considered for the production of new products with the risk of glass breaking, or for the manufacture of glass-equipped communication mobile products in the electronics industry, or other products that contain thin glass fragile parts, such as sensors and touch panels Or glass enclosure.

Processing is usually carried out in a clean room, just like the biochemical industry, because these are very sensitive to particles generated by traditional cutting or grinding steps. For example, base materials covered with DNA codes (biochemical barcodes) or materials cut into pieces by laser are used for product testing. For laser cutting technology, the next most potential application industries will be the solar energy industry and the automotive industry.

Just like the development of laser technology in the metal processing industry over the years, laser cutting technology for glass processing will continue to develop; this technology will be widely used in the processing of different products, replacing traditional methods. However, the traditional glass processing method will maintain its important position in the processing of most glass products in the future. Generally speaking, the processing quality of the cutting edge is not very high in these applications.

Laser profile cutting is an innovative technology that will find a place in the electronics, automotive or construction industries. In addition to laser cutting glass, there are many other methods of laser processing glass that are in the further development and testing stage, such as drilling, chamfering, and coating removal. These processes require different kinds of lasers, such as green lasers.