Previously laser cutting by facture propagation technique has been successfully used in thin glass cutting. In this talk we present use of the technique in cutting of ultra-thin ribbon ceramics. Unlike thin glass, the cutting process is self-initiating due to the presence of grain boundaries in the material. As an example, we used a CO2 laser beam with Gaussian intensity profile to cut zirconia ribbon ceramics with a thickness of about 40 um. Under optimized conditions, the cut cross-section showed no evidence of damage or crystal grain growth. The cutting speed scales with laser power, ranging from tens of millimeters per second to meters per second. We also examined the strength distribution of the cut edge, observing a minimum strength of over 900 MPa. This technique has been similarly applied to ultra-thin ceramics of other compositions, yielding equally excellent performance.

Lasers are an excellent source of directed energy. In this study, we developed a novel cutting method for rein-forced concrete (RC), enabling separation of brittle RC vitrified by ultra-high-power laser ranging from 30 to 60 kW in power. The input laser energy, ranging from 13 to 124 MJ, was initially used to cut RC of 0.5 or 1 m in length without assist gas. Instead of the assist gas, the molten concrete was pulled down by gravity. Vitrification of the RC occurred under all conditions. A 50-kW laser with an energy of 43 MJ successfully penetrated 1-m RC by elevating the laser with focal reciprocation along the optical axis at a travel speed of 6 mm/min. This study validates the potential outdoor application of ultra-high-power lasers, including cutting during the decommissioning of nuclear power plants.

Carbon fibre reinforced plastics (CFRP) are widely used in lightweight applications. The global lack of production capacity for carbon fibres (CF) leads to high production costs. Therefore, semi-finished CF products are expensive. There is also a low resource efficiency that is driven by left-overs from the semi-finished products in CFRP part production.

A laser cutting process for endless-fibre-reinforced semi-finished product left-overs to produce CF-chips was developed. Chips can be used as a basic component for valuable, long-fibre composite parts instead of shredding them for filler material in concrete or incinerate them with energy recovery.

In this investigation, laser factor settings were varied to machine chips of 10, 15, and 20mm edge length. These were used to produce long-fibre reinforced laminates that were cut into coupons and evaluated for mechanical strength.

First results indicate tensile strengths between 75 – 400MPa depending on fibre length of the chips.

Laser cutting of flax fiber reinforced composite (FFRC) is a promising technology as it can avoid typical defects of mechanical cutting like fraying or delamination. However, when cutting with wavelengths in the NIR the high transparency of the matrix coupled with the good absorption of the flax fibers causes an inhomogeneous energy deposition.

To increase the absorbance of the matrix thermoplastic samples and FFRC samples with natural and synthetic absorptive additives were produced . The absorption coefficients at 1064 nm and 532 nm of the modified thermoplastics were measured using a reflectometric setup. Subsequently, the 2 mm thick FFRC samples were cut with a Yb:YAG laser at velocities between 2 – 8 m/min and power levels from 250 – 2000 W. The measured absorption coefficients correlate with the required cutting power, resulting in a power reduction of up to 45% compared to unmodified FFRC.

Advanced materials, like ceramic matrix composites (CMCs) which exhibit superior thermomechanical properties are crucial for addressing 21st century engineering challenges. However, these materials have low machinability and are a challenge to process with state-of-the-art laser or mechanical methods. This study investigates the characteristics of hybrid (sequential) laser-mechanical machining (HLMM) of 6 mm thick alumina oxide (Ox-Ox) based CMC. HLMM involves bulk material removal using high-power continuous wave laser followed by mechanical finishing. Comparisons are made with standalone laser cutting and mechanical machining to assess HLMM's performance in terms of quality, productivity, and future technological progress. Results show a 70% reduction in cutting force and significant increase in productivity compared to standalone mechanical tool cutting; and 74% improvement in surface roughness and full elimination of thermal defects from the material's cut edge compared to standalone laser cutting. HLMM exhibits an overall cutting speed of 560mm/min for 6mm thick Ox-Ox CMC.

In continuous glass manufacturing processes, such as fusion draw, it is essential to cut a glass ribbon into sheets without disruption of the glass flow. This is typically achieved through the use of mechanical or laser cutting apparatuses, which enable the separation process by cross-ribbon scoring followed by bend breaking. This study presents a method for on-draw cutting of hot glass ribbon through localized melting using an infra-red laser beam. Our findings demonstrate that cutting the ribbon, which is already formed but maintains temperature within the annealing range, allows full body ribbon separation through glass melting without generating excessive residual stress. Additionally, this laser-induced process results in the formation of a rounded edge, which might eliminate the need for further finishing in certain applications. An experimental platform, comprising the glass draw, and laser system developed along with a theoretical model of the process are presented.