The essence of laser cleaning is to irradiate a high-energy density laser beam to the surface of the workpiece, so that the dirt, oxide layer, coating or coating on the surface of the workpiece will be instantly melted, ablated, evaporated or peeled off when heated, so as to realize the cleaning of the workpiece surface. The process without damaging the substrate is an ideal choice for a new generation of industrial cleaning technology!
The concept of laser cleaning in foreign countries originated earlier, and can remove everything from thick rust layers to fine particles on the surface of objects. Since the 21st century, China has invested a lot of manpower and material resources to strengthen the research on laser cleaning technology. With the development of advanced laser technology, lasers have achieved leap-forward development in terms of energy output, wavelength range, laser quality, and energy conversion efficiency .
The development of lasers also promotes the rapid development of laser cleaning technology in my country. Laser cleaning technology has also become an indispensable cleaning technology in high-end manufacturing fields such as industry, ships, aerospace, etc., including the removal of rubber dirt on the surface of tire molds, and the surface of gold film. Removal of contaminants and high-precision cleaning in the microelectronics industry.
The removal of rust, paint, oil and oxide layer on metal surfaces is the most widely used field of laser cleaning. Due to the differences in important parameters such as wavelength and power of different lasers, different materials and stains have different requirements for laser wavelength and power. In actual cleaning work, different laser cleaning methods should be selected according to the actual situation.
After a large number of experimental verifications, MOPA lasers and compound lasers are the most widely used lasers in the laser cleaning market, followed by carbon dioxide lasers, ultraviolet lasers, and continuous lasers that are used in a small amount.
MOPA pulsed laser cleaning
Satisfy the surface cleaning of various materials
The resonator of a MOPA fiber laser system is itself a fiber. MO (Master Oscillator) is the master oscillator, which is a low-power laser. Generally, a laser with an appropriate wavelength is selected. The low-power laser LD (laser Diode) can directly modulate the output parameters through the driving current, and then couple the signal light generated by the LD into the PA (Power Amplifier) power amplification system through the pigtail to amplify the signal light.
MOPA laser is the most widely used type of laser cleaning. Since the MOPA fiber laser system can be amplified strictly according to the seed signal source coupled into the system, the relevant characteristics of the laser such as center wavelength, pulse waveform and pulse width will not be changed. Therefore, the parameter adjustment dimension is higher and the range is wider. For different application scenarios of different materials, the adaptability is stronger, and the process window range is larger, which can meet the surface cleaning of various materials.
In addition, the MOPA laser has a high laser energy margin, which can be upgraded by improving the laser cleaning device, such as increasing the laser processing spot and cooperating with an intelligent system. It is worth mentioning that due to its excellent performance and flexible scene applicability, MOPA lasers are widely used in emerging industries such as new energy batteries.
Compound Laser Cleaning
Best choice for paint removal
Laser composite cleaning uses semiconductor continuous laser as heat conduction output, so that the attachment to be cleaned absorbs energy to generate gasification and plasma cloud, and forms thermal expansion pressure between the metal material and the attachment, reducing the bonding force between the two layers. When the laser outputs a high-energy pulsed laser beam, the vibration shock wave generated makes the attachments with weak binding force directly detach from the metal surface, thereby realizing rapid laser cleaning.
Laser composite cleaning combines continuous laser and pulsed laser functionally at the same time to form the processing characteristics of 1+1>2. Fast speed, high efficiency, and more uniform cleaning quality. For different materials, lasers with different wavelengths can be used to clean at the same time to achieve the purpose of removing stains.
At present, laser composite cleaning is widely used in the fields of ships, auto repair, rubber molds, high-end machine tools, rails, and environmental protection, etc., to effectively remove resin, paint, oil, stains, dirt, rust, coatings, coatings and oxide layers on the surface of objects.
For example, in the laser cleaning of thicker coating materials, the single laser multi-pulse energy output is large and the cost is high. The use of pulsed laser-semiconductor laser composite cleaning can quickly and effectively improve the cleaning quality without causing damage to the substrate; in aluminum In the laser cleaning of highly reflective materials such as alloys, the single laser has problems such as high reflectivity. The pulsed laser-semiconductor laser composite cleaning is used. Under the action of the thermal conduction transmission of the semiconductor laser, the energy absorption rate of the oxide layer on the metal surface is increased, so that the pulsed laser The beam can peel off the oxide layer faster, thereby improving the removal efficiency more effectively, especially the paint removal efficiency is increased by more than 2 times.
CO2 laser cleaning
The best choice for removing non-metallic materials
Carbon dioxide laser is a gas laser with CO2 gas as the working substance, which is filled with CO2 gas and other auxiliary gases (helium and nitrogen and a small amount of hydrogen or xenon), which has good directionality, monochromaticity and frequency stability. Since discharge tubes are usually made of glass or quartz materials, common CO2 lasers include glass tube CO2 lasers and metal RF tube CO2 lasers.
Based on its unique wavelength, CO2 lasers are the best choice for surface cleaning of non-metallic materials such as glue removal, coating removal, and ink removal. For example, the use of CO2 laser to remove the composite paint layer on the surface of aluminum alloy will neither damage the surface of the anodized film nor reduce its thickness. Lian Ying Laser has a wealth of laser cleaning solutions in 3C industry PCB ink cleaning, new energy power battery pole piece roller glue cleaning, and soft pack tab sealing, which can provide customized needs for customers.
UV laser cleaning
Use precision components
Ultraviolet lasers used for laser micromachining mainly include excimer lasers and all-solid-state lasers. Ultraviolet laser has short wavelength and high single-photon energy, which can directly break the chemical bonds connecting materials. The material is peeled off the surface in the form of gas or particles. The heat-affected zone generated during processing is small, which has unique advantages in micro-manufacturing, such as Semiconductor materials such as Si and GaN, optical crystals such as quartz and sapphire, and polymer materials such as polyimide (PI) and polycarbonate (PC) can effectively improve the manufacturing quality.
Ultraviolet laser is considered to be the best laser cleaning solution in the field of precision electronics. Its most characteristic fine "cold" processing technology can micro-process and treat the surface without changing the physical properties of the object, which can be widely used in communications, optics , military, criminal investigation, medical and other industries and fields. For example, the 5G era has created market demand for FPC processing. The application of UV laser machines makes it possible to perform precise cold processing of materials such as FPC.
Continuous Fiber Laser Cleaning
Remove rust from metal surfaces
The working principle of the continuous fiber laser is that the pump light emitted by the pump source is coupled into the gain medium through a mirror. Since the gain medium is a rare earth element doped fiber, the pump light is absorbed, and the rare earth ions that absorb the photon energy generate energy. Level transition and realize particle number inversion. The inverted particles pass through the resonator, transition from the excited state back to the ground state, release energy, and form a stable laser output. The biggest advantage is that it can continuously emit light.
In actual laser cleaning applications, continuous fiber lasers are rarely used, but there are also a small number of applications, such as some large steel structures, pipes, etc., due to the large volume and fast heat dissipation, the requirements for substrate damage are not high, then continuous lasers can be selected.
