What are the advantages and disadvantages of single-mode and multi-mode cleaning

The mode of a laser usually refers to the energy distribution state of the laser in the plane perpendicular to the direction of propagation, which can be divided into single-mode and multi-mode. Single-mode refers to the situation where a laser generates only one mode of laser output during operation. The energy intensity of a single-mode gradually weakens from the center to the outer edge, and its energy distribution form is a Gaussian curve. Its beam is called a fundamental mode Gaussian beam. The laser beam output in single-mode features high beam quality, small beam diameter, small divergence Angle, and energy distribution close to the ideal Gaussian curve. In addition, single-mode has good focusing characteristics, with a small focused spot and strong mode stability, making it suitable for cleaning scenarios that require strong removal, such as rust.
The spot output by a multimode laser is often composed of multiple modes. The energy distribution within the spot is relatively uniform, and the more modes there are, the more uniform the energy distribution becomes. Its beam is also called a flat-top beam. Compared with single-mode lasers, multimode lasers have poorer beam quality, larger divergence angles, require optical systems with larger aperture for transmission, and have a larger focused spot than single-mode lasers. However, multi-mode is easier to achieve large single-pulse energy, peak power and high average power output, and the energy distribution is uniform. It has more advantages in cleaning scenarios that require less damage and high efficiency, such as molds. What are the advantages and disadvantages of single-mode and multi-mode laser cleaning
Single-mode lasers, due to their excellent beam quality, small focused spot and high energy density, are suitable for removing strongly adhering contaminants such as blue rust, and are also applicable for cleaning thin materials and precision parts that are sensitive to heat input. However, due to the excessive concentration of single-mode energy, it may cause certain damage to the base material during cleaning.
For scenarios such as molds where the substrate is required to remain undamaged after cleaning, multimode lasers must be selected. Multimode beams have uniform energy distribution and high peak power, which can control the peak power density to be higher than the damage threshold of contaminants but lower than that of the substrate. Therefore, during cleaning, contaminants can be effectively removed without damaging the surface structure of the material. In addition, the focused light spot of multi-mode is larger. For scenarios where single-mode and multi-mode can achieve the same cleaning effect, the cleaning efficiency of multi-mode is usually higher. However, for strongly adherent contaminants, multimode laser cleaning may be inadequate.
Based on the respective advantages and disadvantages of single-mode and multi-mode cleaning lasers, the application scenarios they are suitable for are also different.
The main application scenarios of single-mode
Metal rust removal: The high energy density of single-mode lasers makes them an ideal choice for metal rust removal. They can efficiently remove the rust layer on the metal surface. The higher the laser power, the stronger the rust spot removal ability and the higher the efficiency. The 1000W high-power single-mode pulsed laser, with QBH output, is easy to integrate and features strong cleaning ability and high efficiency.
Weld seam oxide cleaning: During the welding process, due to the high processing temperature, oxides and material precipitates are prone to form around the weld seam, affecting the welding quality and appearance. A 200-500W single-mode laser can precisely remove oxides, ensuring the appearance and quality after welding.
Precision component cleaning: 100-200W single-mode laser, QCS output, strong cleaning ability, low heat output, small material deformation after cleaning, and minimal thermal impact.
The main application scenarios of multi-mode
Mold cleaning: During the use of molds, residues such as plastic, metal fragments, and dust may accumulate. These residues can affect the surface quality of the products and cause product defects. Regular cleaning of molds can prevent corrosion and wear, thereby extending the service life of the molds. Due to the significant differences in the characteristics of the mold base material and contaminants, the use of flat-top beams can effectively remove contaminants without damaging the mold. 500-1000W square spot multimode laser, with high efficiency in cleaning molds and no damage to the substrate.
Perovskite solar cell edge cleaning: It refers to cleaning the film layer at the edge of the thin-film solar cell to create an insulating area, which is conducive to subsequent packaging work. The YFPN-1000-GMC-H50-F laser features a square spot output with uniform energy distribution and high peak power. It can thoroughly remove the film layer at one time without damaging the glass and has high efficiency.
Laser roughening: By using laser to roughen the surface of materials, the adhesion of the material surface can be significantly enhanced. According to different roughening roughness requirements, multimode lasers with different single-pulse energies of 5mJ, 15mJ and 50mJ are used to ensure roughening efficiency while meeting different roughness requirements.