The first laser in the world was created in 1960 by American scientist Theodore Harold Maiman using ruby crystals. Since then, lasers have been developed for use across various fields. The widespread application of laser technology has significantly advanced industries such as healthcare, equipment manufacturing, precision measurement, and remanufacturing engineering, accelerating social progress.

In the cleaning industry, the application of laser technology has achieved remarkable results. Compared to traditional cleaning methods such as mechanical abrasion, chemical corrosion, and high-frequency ultrasound, laser cleaning technology offers fully automated operation. It boasts several advantages, including high efficiency, low cost, no environmental pollution, no damage to the substrate, and a wide range of applicable materials. These characteristics align with the green, environmentally-friendly processing philosophy and are regarded as the most reliable and effective cleaning method available today.

Laser cleaning provides the necessary preconditions for the inspection and processing of mechanical parts. By employing laser cleaning technology, it is possible to effectively control the surface morphology and roughness of the substrate, enhancing the performance of the material after cleaning. It is also applicable to large component manufacturing, surface treatment, and remanufacturing fields. While laser cleaning has not yet completely replaced traditional cleaning methods, it is expected that, with increased awareness of energy conservation and emission reduction in the manufacturing industry, laser cleaning will gradually become more widely adopted due to its unique advantages.

Laser Cleaning Principle

Laser cleaning utilizes the high energy density, directional control, and strong focusing capabilities of laser beams. By irradiating the surface of workpieces with high-energy laser beams, the adhesion between contaminants, rust, or coatings and the substrate is broken, or the pollutants are directly vaporized, thus cleaning the surface of the workpiece. As shown in Figure 1, when contaminants on the workpiece surface absorb the energy of the laser, they rapidly vaporize or expand due to heat, overcoming the adhesion forces between the pollutants and the substrate. As the thermal energy increases, the contaminant particles vibrate and detach from the substrate surface.

The entire laser cleaning process can be divided into four stages: laser vaporization and decomposition, laser stripping, thermal expansion of the contaminant particles, and vibration of the substrate surface, leading to the detachment of contaminants. Of course, when applying laser cleaning technology, it is essential to consider the cleaning threshold of the object being cleaned, select the appropriate laser wavelength, and achieve the optimal cleaning effect. Laser cleaning can alter the crystal structure and orientation of the substrate surface without causing damage, and it can also control the roughness of the surface, thereby enhancing the comprehensive properties of the substrate. The cleaning effect is mainly influenced by factors such as beam characteristics, the material properties of the substrate and contaminants, and the ability of the contaminants to absorb the laser energy.

Currently, laser cleaning technology includes three main types: dry laser cleaning, wet laser cleaning, and laser plasma shockwave cleaning.

1. Dry Laser Cleaning involves directly irradiating the workpiece with pulsed lasers, causing the substrate or surface contaminants to absorb energy and heat up. This results in thermal expansion or substrate vibration, leading to separation between the contaminants and the substrate. This method can be divided into two situations: one where the surface contaminants absorb the laser and expand, and another where the substrate absorbs the laser and generates thermal vibrations.
2. Wet Laser Cleaning involves applying a liquid film to the surface of the workpiece before irradiating it with pulsed lasers. The liquid film rapidly vaporizes under the action of the laser, generating a shockwave that acts on the contaminant particles, causing them to detach from the substrate. This method requires that the substrate and liquid film do not react with each other, limiting the range of applicable materials.
3. Laser Plasma Shockwave Cleaning occurs when the laser irradiates the workpiece, causing the air medium to ionize and produce a spherical plasma shockwave. This shockwave acts on the surface of the workpiece and releases energy to remove contaminants. Since the laser does not directly act on the substrate, there is no damage to the workpiece. Laser plasma shockwave cleaning technology can now remove contaminant particles as small as tens of nanometers, and it is not limited by laser wavelength.

In practical production, different experimental methods and related parameters should be selected based on specific needs to achieve optimal cleaning results. In laser cleaning, surface cleaning efficiency and quality assessment are key criteria for evaluating the effectiveness of laser cleaning technology.

Laser Cleaning Development Trends

Against the backdrop of “carbon peak” and “carbon neutrality,” laser cleaning, as a green and efficient cleaning method, is gradually gaining market acceptance and becoming a major trend in the global cleaning market. According to a report from market research company Mordor Intelligence, the global laser cleaning market is expected to reach $780 million in 2024 and grow to $1.53 billion by 2029, with a compound annual growth rate (CAGR) of 14.61% from 2024 to 2029. This trend is driven by the unique advantages of laser cleaning technology. Compared to traditional industrial cleaning methods, laser cleaning offers several key benefits:

1. Eco-Friendly: The waste generated during laser cleaning is in the form of solid powder, which is compact and virtually non-polluting. Additionally, laser cleaning does not require cleaning liquids or other chemical solutions, and its cleaning efficiency far exceeds that of chemical cleaning methods.
2. Minimal Substrate Damage: Unlike traditional mechanical cleaning methods, laser cleaning involves no physical contact with the workpiece, causing minimal damage to the substrate.
3. High Efficiency: Laser cleaning offers high efficiency and the potential for automated operation, which reduces labor costs.
4. Wide Range of Applications: Laser cleaning can handle a variety of materials and contaminants, making it versatile for many industries.

Laser Cleaning Applications

As demand for green, high-precision, and efficient cleaning solutions grows, laser cleaning technology has gained increasing attention in research and application. Currently, laser cleaning technology is being applied in fields such as microelectronics, rail transportation, aviation, cultural heritage restoration, and renewable energy. Here, we focus on the application of laser cleaning for the surface treatment of battery shells in the energy storage industry (battery shell roughening).

In battery manufacturing, surface treatment of the battery is a critical process. Previously, blue film wrapping technology was used, but this method involved plastic consumables. As plastic is flammable, it increases the risk of fires in lithium batteries. Now, there is a process upgrade that uses special coatings to achieve better insulation, anti-corrosion, and high-temperature resistance. Before coating, the battery surface needs to be roughened to improve adhesion. This roughening process is now achieved through laser scribing. Laser roughening allows for precise control of the surface roughness and can handle the specific areas of the battery poles.

The process uses the JCZ laser control system. Below is a schematic diagram of the JCZ laser control system components:

The system used in this process is the JCZ Laser Control System, which includes the following features:

• Multi-head synchronous processing: Controls up to 32 mirrors for stitching and processing.
• Supports both square and cylindrical battery roughening.
• Supports static and dynamic working modes.
• Supports void processing at the battery pole.
• Integrates with PLC and MES for automation in production lines.

Conclusion

Laser cleaning, with its eco-friendly, efficient, and precise characteristics, is driving a technological revolution across industries. As it continues to gain traction in applications such as microelectronics, aerospace, and energy storage, its future prospects remain promising, with substantial market growth expected in the coming years.