How to Select a Laser for Cutting Applications?

1 Answer
Can you answer this question?

- GoPhotonics

Jan 23, 2024

Laser cutting is a precise and versatile manufacturing process that utilizes a focused laser beam to cut or engrave various materials with high accuracy. Various laser cutting processes are designed for specific applications, encompassing different types of laser cutting machines. The main types of lasers used for cutting are CO2, Nd-YAG (Neodymium Yttrium-Aluminum-Garnet), and Nd:YVO4 (Neodymium-doped yttrium orthovanadate), as well as fiber-optic lasers. These lasers differ in the materials used to generate the laser beam.

CO2 Laser Cutting

In CO2 laser cutting, laser amplification occurs through a CO2 gas discharge, combining CO2, Nitrogen, Hydrogen, Xenon, and Helium. Two gas options are available: Oxygen, preferred for cutting thicker materials, and Nitrogen, favored for thin sheets. The use of Oxygen results in the formation of an oxide layer on the cut surface that necessitates pre-treatment processes like blasting to prevent material breakage. Notably, Oxygen burns the material, while Nitrogen melts it. 

In Nitrogen laser cutting, it produces a clean cutting surface without an oxide film. However, cutting with nitrogen may lead to less smooth cutting surfaces and occasional slight burring. Additionally, the amount of spatter on the inside of the product tends to be higher compared to cutting with oxygen.

Fiber Laser Cutting

Fiber laser cutting employs optical fiber for light amplification instead of traditional gas discharge. Laser diode-emitted light passes through the optical fiber which generates a powerful beam capable of melting stainless steel up to 1 cm thick. An accompanying strong airflow system aids in pushing away molten material for a clean cut, with fiber optics incorporating elements like Ytterbium, Neodymium, Erbium, and Dysprosium.

Fiber laser cutters offer a faster and more efficient solution for trimming objects with a depth of less than 5 mm when compared to CO2 laser cutters. A fiber laser typically has a long operational life of 25,000 laser hours without the need for servicing, that enable the creation of powerful and stable rays. This longevity sets fiber laser cutters apart from other laser types. Although they share a similar average output with CO2 lasers, fiber lasers can achieve levels that are 100 times greater.

Operating in constant, quasi-continuous beam, or pulsed modes, fiber lasers exhibit versatile functionality. They demonstrate exceptional performance in materials such as:

  • Metals, particularly stainless steel, copper, aluminum, and brass.
  • Ceramics, where intricate patterns and designs are crafted.
  • Carbon-fiber-reinforced Polymers, utilized for specialized industrial applications.

Nd:YAG Laser Cutting

Crystal laser cutting processes can utilize Nd:YAG (neodymium-doped yttrium aluminium garnet); however, a more common choice is Nd:YVO (neodymium-doped yttrium ortho-vanadate, YVO4) crystals. These devices enable exceptionally high cutting power; however, the drawback is that they have a lifespan of 8,000 to 15,000 hours, with Nd:YVO4 typically having a lower one.

These lasers are compatible with both metals (coated and non-coated) and non-metals, including plastics. In specific circumstances, they can even process certain ceramics. The Nd:YVO4 crystal, when combined with high NLO coefficient crystals (LBO, BBO, or KTP), can frequency-shift the output from near-infrared to green, blue, or UV, providing a variety of functions.

Nd:YAG utilizes crystals for laser beam amplification, distinguishing itself from gas discharge or fiber methods. These lasers demonstrate proficiency in both continuous and pulsed laser beams.

Excimer Laser Cutting

Excimer laser cutting is a precision cutting process that uses an ultraviolet laser beam. The term "Excimer" is short for "Excited Dimer." These lasers are known for their ability to produce short-wavelength, high-energy ultraviolet light, making them effective for precise material removal in applications that demand extreme accuracy. The ultraviolet wavelength used in excimer laser cutting allows for focused and controlled ablation of materials, making it suitable for intricate and delicate cutting tasks. This type of laser cutting finds applications in various fields, including eye surgery, microelectronics, and semiconductor cutting.

Direct Diode Laser Cutting

Direct Diode Laser (DDL) relies on laser beams directly from diodes, eliminating amplification mediums like gas discharge or fiber. The diodes generate a potent laser beam, contributing to the process's high efficiency.

Direct Diode Lasers provide a blend of speed and compactness, which excels particularly in the processing of metals, especially thin sheets of steel and aluminum. This makes them highly effective in sheet metal fabrication applications. Additionally, when it comes to non-metal materials, Direct Diode Lasers are well-suited for working with plastics such as Polymethylmethacrylate (PMMA) and polycarbonate (PC). These materials are commonly employed in various manufacturing and construction processes.

Click here to learn more about Laser Cutting.