In the mobile era, almost everyone is inseparable from their mobile phones , and the mobile phone industry is constantly updating and iterating. In addition to the continuous upgrading of system, hardware and other functional configurations, the appearance and essential photography functions of mobile phones have also become battlegrounds for mobile phone manufacturers.
In the innovation of exterior materials, glass has become increasingly popular among mobile phone manufacturers due to its versatility in design, impact resistance, and controllable cost. Applications include front and back covers, and fingerprint sensors. Regarding cameras, the need for advanced imaging technologies such as superior shooting, light sensitivity, and depth focusing has led to the rapid proliferation of triple and quad-camera setups, resulting in a surge in demand for accessories such as camera covers, filters, and prisms. However , despite its numerous advantages, glass's fragility presents significant challenges to manufacturing processes, such as the tendency to crack and develop rough edges. Furthermore, the irregular cutting of components like the earpiece, front camera, and fingerprint sensor places even higher demands on processing techniques.
Glass cutting process comparison
The principles and drawbacks of traditional glass cutting techniques
Traditional glass cutting processes include wheel cutting and CNC grinding cutting. Wheel cutting results in large chipping and rough edges, leading to low yield and low material utilization. It also requires complex post-processing. When cutting irregular shapes, speed and accuracy drop significantly; some irregularly shaped full-screen displays cannot be cut with wheel cutting due to their small corners. CNC cutting offers higher precision than wheel cutting (≤30μm ) and smaller chipping (approximately 40μm) . Its disadvantage is slower speed.
Traditional laser glass cutting uses an ablation mechanism, employing a focused, high-energy-density laser to melt or even vaporize the glass, while a high-pressure assist gas blows away any remaining slag. Because glass is fragile, a high-overlap laser spot can accumulate excessive heat, causing the glass to crack. Therefore, lasers cannot use a high-overlap laser spot for a single cut; instead, a galvanometer is typically used for high-speed scanning, removing the glass layer by layer. The typical cutting speed is less than 1 mm/s .
With the development of laser technology, lasers have also appeared in glass cutting. Laser cutting is fast, precise, produces burr-free cuts that are not limited by shape, and the chipping is generally less than 80μm .
The principle and advantages of ultrafast laser cutting of glass
In recent years, ultrafast lasers (or ultrashort pulse lasers) have made rapid progress, especially in glass cutting applications where they have achieved excellent performance.
The principle behind this is that an ultrafast laser, focused by a focusing head, produces a micron-sized beam with a high peak power density. When this beam acts on a glass material, the intensity at the beam center is lower than at the edges, causing a greater change in the refractive index at the center. The beam's propagation speed at the center is also slower than at the edges, resulting in a nonlinear optical Kerr effect that induces self-focusing (wavefront focusing). This process continues to increase the power density until a certain energy threshold is reached, at which point the material generates low-density plasma, reducing the refractive index at the center and achieving beam defocusing. In actual glass cutting, optimizing the focusing system and focal length allows for repeatable focusing / defocusing processes, resulting in stable perforations.
Filament cutting is a feasible glass cutting process based on this principle. When an ultrafast laser beam propagates through glass material, both Kerr self-focusing and plasma defocusing occur simultaneously. The beam achieves long-distance propagation through a dynamic balance between these two factors, forming micron-sized filaments within the material. These filaments can extend to depths of several millimeters in glass. A linear motor controls the movement of the glass workpiece relative to the laser beam to generate numerous equally spaced filaments. By optimizing the spacing of these filaments, microcracks are created along the diameter direction. Applying a special treatment to the glass containing these microcracks increases the stress at the cracks, causing the glass to fracture along the cracks, thus achieving the cutting purpose.
This is the result of laser-modified glass, which has different properties from the original glass. This processing method also ensures that the surrounding materials in the area are not affected during the process, thus achieving " ultra-precision " processing .
In addition, non-contact processing can avoid problems such as chipping and cracking that are prone to occur in traditional cutting. It has advantages such as high precision, no micro-cracks, breakage or fragmentation, high edge resistance to breakage, and no need for secondary manufacturing costs such as washing, grinding and polishing. It reduces costs while significantly improving workpiece yield and processing efficiency.
National Olympic Pico Infrared Solution
Guoao Ultrafast Laser — High-Difficulty Microfabrication Application Solutions
Guoao Technology's picosecond infrared fully automatic cutting system adopts the new picosecond laser technology, which has advantages over the original laser scanning processing, such as high speed, small edge chipping, and no taper.
The equipment can rapidly cut various optical glasses and brittle materials. The machine features high beam quality, a small focused spot, and minimal power fluctuations, ensuring stable processing quality.
The machine uses German 3D galvanometer processing, which has excellent 3D processing capabilities for products with complex shapes and unique structures, such as curved screens, cones, extended half-planes, and trapezoids . The effect is just as perfect as that of planar laser processing.
Meanwhile, the precise optical path design ensures high-quality laser transmission. Equipped with an automated processing system, it can achieve fully automatic loading and unloading, and automatic focusing laser cutting, reducing labor costs for customers.
Guoao Technology's picosecond infrared fully automated cutting system has been verified by numerous customers on-site, bringing customers a yield improvement of 10-15%, process simplification by 1/3 , personnel reduction of 40% , and process cost reduction of more than 30% . While significantly improving factory profits, it also improves the working environment to a certain extent, and has gained high recognition from customers.
