Laser technology challenges thin and brittle non-metallic materials, and subtleties make the universe

Processing challenges of thin and brittle materials

In the field of non-metal processing, laser processing of thin and brittle materials has attracted much attention. With the continuous development and iteration of consumer electronic products such as smartphones, LED lighting, tablet computers, and wearable devices, materials such as glass, sapphire, and ceramics have been widely used due to their unique high-quality properties, such as hard tempering Glass is used as a display screen for smartphones; hard and chemically stable ceramics are used to make electronic component substrates and insulating materials; hard scratch-resistant sapphire is used for LED substrates, mobile phone camera protective glass, smartphone displays, Cover glass for smart watches, etc.

Materials such as glass, sapphire or ceramics used in these applications are typically thin in thickness, increasingly hard and very brittle. In terms of processing requirements, the above-mentioned applications usually require very precise cutting, drilling and even grooving processing processes on these fragile and fragile materials, which makes the traditional machining processes such as milling, drilling, and grinding face great challenges. Because the material is extremely thin and brittle, any stress applied to the material due to contact during processing can cause the material to shatter and ultimately be scrapped.

However, the challenges faced by traditional machining methods have brought more opportunities for non-contact laser processing.

Ultrafast lasers meet machining challenges

Precision machining of thin and brittle non-metallic materials such as glass, ceramics, and sapphire usually uses ultrafast lasers. The ultrafast laser pulse duration is extremely short, at the nanosecond, picosecond or even femtosecond level, moderate laser energy is applied to the surface of the material, and the material is removed by breaking the chemical bonds of the material. In this process, the laser energy The machining process is over before it can be transferred around the machining area, so the heat generated is almost negligible and the material is not thermally damaged.

With the increasing application of these brittle materials in LEDs, smartphones, wearable devices and other products, the number of lasers, laser systems and related scientific research institutions dedicated to the processing of such brittle materials has also increased, and their efforts have also promoted Laser technology continues to make breakthroughs in the field of brittle material processing.

(1) Thin-film glass drilling scheme in Hannover Center

At the beginning of December 2016, the Laser Center Hannover (LZH) and the Laser Center Bavaria (BLZ) jointly held a seminar with the theme "Laser Processing of Glass Materials", which mainly discussed the latest developments and trends in the field of laser glass processing.

At present, the field of laser glass processing is developing rapidly, and some innovative processing processes and systems are making continuous progress in the processing of thin, flat and tubular glass products.

At the symposium, a research team at the Hannover Laser Center led by Philipp von Witzendorff introduced a novel thin-film glass drilling scheme that combines a single pulse with different pulse durations and successfully avoids drilling holes in the glass during drilling. Fragments appear on the edges, and the processed surface is very smooth, which can successfully chemically strengthen the drilling of thin sheet glass, such as the strengthened glass used in mobile phone screens.

The newly developed glass drilling process at the Hannover Laser Center is more cost-effective than the water jet method and can also process glass with a thickness of 4 mm. Innovations in glass processing at the Hannover Laser Center provide a valuable impetus for products such as consumer electronics.

(2) IceFyre, a picosecond hybrid fiber laser that can change the rules of the industry?

In terms of glass/sapphire processing, the Spectra-Physics business unit of MKS Instruments is very strong in this regard. As early as December 2015, Spectra Physics launched the ClearShape femtosecond laser for fast and high-quality cutting applications of chemically strengthened glass, non-strengthened glass and sapphire, which can achieve a cutting speed of 1m/s and has no burrs on the cutting edge. Chips, edge roughness Ra <0.1μm.

The IceFyre, a compact high-power industrial picosecond hybrid fiber laser debuted by Spectra-Physics in February this year, is a game-changer – combining high power, ultrashort pulses, unprecedented versatility, and tunable repetition rate , Programmable and flexible adjustment of pulse width, pulse can be triggered on demand and many other functions and cost advantages. Delivering >50W average power and up to >200μJ pulse energy at 1064nm, the IceFyre is an ideal light source for precision machining of sapphire, glass, ceramics, plastics and other materials with adjustable pulse repetition rates from single shot to 8MHz.

Is IceFyre a game-changer in the industrial micromachining laser market with its performance, cost, size and reliability performance? We will wait and see.