Laser cleaning systems are making their way as great alternatives to traditional surface cleaning methods likes chemical cleaning and abrasive blasting. Manufacturers who need clean metal surfaces are increasingly looking at laser cleaning as an environmentally friendly, cost-effective solution that provides more consistent results.
Whether it’s for rust, paint, oxide, or coating removal, lasers can remove contaminants without damaging the substrate. As a non-contact process, laser cleaning is a low maintenance method ideal for industrial laser cleaning applications.
There are several types of laser cleaning solutions. Knowing which one is right is not always easy. Here is an overview to help you understand the difference.
Handheld Laser Cleaners
Handheld laser cleaning systems are workstations on wheels. They’re larger than what most people expect of a handheld device, but they’re still easy to move around. The “gun” held by the operator can be positioned as needed to reach any area on large workpieces. These devices are ideal for low-volume productions where multiple parts of different shapes and sizes need to be processed.
Handheld laser cleaners come with laser configurations that can be manually selected for specific tasks, such as laser rust removal, paint removal, and corrosion removal. As with all types of laser cleaners, different configurations are needed for different contaminants, thicknesses, and substrates.
Laser safety is more complicated with handheld devices because the laser beam is not enclosed. Specific precautions need to be taken to ensure worker safety. Recommended laser safety features include a dual-action safety guard, a remote interlock, light warnings, laser safety eyewear, an isolated working area with warning signs, and training to ensure a safe usage. From a health and safety perspective, many companies forbid the use of class-4 handheld lasers in the workplace.
Manually Loaded Laser Cleaning Workstations
Laser cleaning workstations can be fully operated manually while being 100% safe for operators without PPE. Operators are responsible for loading parts into the machine and triggering the laser process. They may also need to perform other tasks depending on the type of workstation, such as opening the door, triggering table rotations, and managing fixtures.
Manual workstations can be equipped with a rotary table to meet high throughput requirements. They can be installed directly in the production line or offline.
Conveyor Laser Cleaning Machines
Laser cleaners can be installed directly on conveyors to automate contaminant removal and surface texturing before operations like welding or coating, providing complete surface preparation in a single step. Advanced features can be used to automatically manage inconsistencies in part positioning as well as process large parts with several areas that need to be cleaned.
These machines are especially useful in the automotive industry where many parts are moved from one production step to another using conveyors, such as in battery production lines. Conveyor laser cleaning machines are adjusted to fit the conveyor dimensions.
Laser cleaning systems can be mounted on robots to automate cleaning operations in robotic cells. They are equipped with advanced autofocusing systems to clean complex parts with high precision. The robot’s high freedom of movement allows the laser to clean various shapes with simple, automatic adjustments.
Robot cleaning machines can also be used to automate the cleaning of large surfaces when mounted with an ultra-high-power laser.
OEM Laser Cleaning Systems
The difference between a laser cleaning system and a laser cleaning machine isn’t always clear. Laser cleaning systems are OEM devices that can be integrated into fully custom solutions, typically with the help of a system integrator or machine builder. Laser cleaning machines, on the other hand, are predesigned solutions ready to be integrated in production lines.
Laser cleaning technology is highly versatile for industrial cleaning operations. At Laserax, we work with manufacturers to provide turnkey cleaning solutions ready to be integrated in their production lines. Here are the most important features you need to understand when choosing a laser machine.
Laser power is expressed in watts. It represents the average amount of energy released through the laser beam, as pulsed lasers are not continuously releasing energy. For cleaning applications, pulsed fiber lasers can reach high energy surges that eject contaminants with a minimal heat affected zone. A 100W watt pulsed fiber laser cleaning system, for example, can pulse laser beams with a peak power of 10,000W.
The higher the laser power, the faster the laser cleaning process. The most powerful and efficient lasers are typically multi-mode lasers, where ultra-high-power lasers can reach 3,000W of power for the most demanding applications.
Safety is never an option, so it’s definitely something you need to pay attention to when choosing a laser cleaner. Laser machines usually need a class-1 laser safety enclosure to ensure work safety and meet safety regulations all over the world, including in North America and in the European Union.
When the product is class-1 rated, no PPEs are needed. If you are using a handheld device, chances are the product is class-4 rated and requires additional PPE.
When contaminants are removed, they are vaporized into dust and fumes. These contaminants need to be extracted to protect workers and keep the work area clean. This is especially important for paint stripping applications, where hazardous substances are released in the air.
The laser fume extractor should include the following features regardless of the type of laser:
- A fume extraction nozzle positioned for source capture
- Safety measures automated through PLC communication
- The right filter and extraction units based on the types of contaminants
Multimode vs. Single Mode Lasers
Most laser cleaners on the market are multimode since they clean surfaces faster. This is because multimode lasers have a larger optical fiber core than single mode lasers. This means that the spot size is larger, and that the laser beam is pulsed over a larger surface area. Multimode lasers can also reach higher power levels and generate more energy at once than single mode lasers.
Single mode lasers, however, can both clean and texture surfaces, so they provide a complete surface preparation for bonding and coating applications. This is explained by the fact that the laser beam is better focused. By concentrating more energy in a smaller area, single-mode lasers can etch metal surfaces, leaving a texture that improves adhesion. Single-mode lasers, however, have a lower tolerance to depth variations (depth of focus), which means keeping a good focus is more complicated when processing curved surfaces.
If you are planning to use a laser cleaner mounted on a robot arm or a handheld device, you need to pay attention to the fiber cable length. A longer length gives you more freedom of movement, but it also diminishes the amount of energy (mJ) in each laser pulse. The longer the cable, the higher the energy loss.
Multimode lasers have access to longer cables, but a cable that’s too long will either slow down the cleaning process, or it will force you to choose a more powerful (and expensive) laser to maintain a good production pace.
How Does Laser Cleaning Work?
Laser cleaning removes contaminants by vaporizing them into dust and fumes through laser ablation. When the laser beam hits the surface, part of its energy is absorbed by the metal surface, and the rest is reflected.
Contaminants are ejected when they have absorbed enough energy to reach their ablation threshold. Since the ablation threshold of metal surfaces is higher than that of contaminants’, the substrate remains unaffected by the process.
More on the subject: How Does Laser Cleaning Work in 5 Steps
Industrial Applications that Benefit from Laser Cleaning
Laser cleaning is used in a wide variety of industrial applications as a surface treatment and pre-treatment of choice. There are good reasons for this: laser cleaners operate without consumables, are easy to automate, improve product quality, and provide a good return on investment.
Laser cleaning is used to:
- Prepare surfaces for laser welding, ultrasonic bonding, or other joining methods
- Remove all types of contaminants, including oxides, coatings, electrolytes, dust, and so on
- Prepare surfaces for processes like adhesive bonding and thermal spray coating by cleaning and texturing the surface
- Remove e-coating, phosphate coating, and powder coating
- Replace polluting methods like sandblasting
- And more…
Considerations When Choosing a Laser Machine
When choosing a laser cleaning machine, here is some useful information to discuss your needs with an expert.
- The surface area and geometry that needs to be cleaned
- The substrate and the type of contaminant
- The thickness of the contaminants
- The approximate cleaning time you need
- The subsequent steps in your manufacturing process
This will allow your laser provider to have a good understanding of your application and suggest a solution adapted to your needs.