Nowadays lasers are used across the manufacturing sectors for various material processing applications, from nanofabrication to surface cleaning. Laser cleaning is a technique that allows controlled removal of surface contaminants from the bulk of a material. One of the major advantages of using a laser as a tool for material processing is its ability to precisely control the energy deposition and hence the material removal process, making it an equipment of choice for cleaning or contaminant removal process.
The Process Of Laser Cleaning
It’s probably a bit blurry as to what exactly a laser does when removing rust. Here are the important facts to know regarding this new application of laser technology.
1. All materials have an ablation threshold
Laser ablation occurs when a layer of a material or a material which is deposited on a given surface is removed with the aid of a laser beam. This is actually the process behind laser rust removal on steel and other materials, Molecular bonds in the dust or rust layer are broken and ejected from the substrate. In less technical terms, you can imagine that the layer to be removed is simply vaporized by the laser beam.
A simple way to get a grasp of the importance of the laser threshold is to relate the concept of the laser threshold to one of throwing a ball over a wall. If you don’t throw the ball higher than the wall, it will obviously never make it over. Even if you repeat throwing the ball a thousand times, the ball will always fail to make it to the other side. It’s the same thing with laser derusting. You can shoot the laser beam a thousand times and as long as the energy is below the threshold necessary to impact the particular material you are working with, everything will remain the same. Now, since every material has different properties and thus different molecular bonds; there is a specific ablation threshold for each material. Therefore, to successfully remove a layer from a given material, it is important to make sure the energy transferred by the laser beam is above the ablation threshold of that particular material.
2. It is possible to remove a material in a highly selective way
Let’s continue with our analogy. Imagine there was a second, higher wall behind the first and that a ball is thrown with just enough energy to make it over the first wall, but the ball does not have enough energy to make it over the second wall. It will then bounce off the second wall and fall in between the two walls. Once again, no matter how many times you throw the ball, you will always get the same result. You will make it past the first wall, but not the second.
Since there is an ablation threshold for each material, it is possible to discriminate between two or more materials when trying to remove an undesired layer from an object. Given a sufficiently large ablation threshold difference between the materials, it is possible to select one material to be removed (the one with the lower ablation threshold), leaving the other material untouched.
For example, the rust ablation threshold is much lower than the threshold for common metals such as aluminum or steel. The same goes for paint and oil thresholds compared to the thresholds for different metals. It is this vast gap between the two values that effectively allows rust to be completely vaporized without any risk of damage to the steel underneath. There’s just not enough energy for damage to happen.
3. Strong and short power burst means faster removal
You can think of laser ablation as similar to a stone carver with a hammer and chisel, trying to carve a stone. You can use a small hammer, and do many little hits on your chisel. Or you could just as well use a bigger hammer to leverage more power, hence reducing the required number of hits and increasing the removal speed. The idea is the same for laser cleaning, except that you only want to remove a layer of material: the contaminant.
There are different methods available to remove any given layer. Either the laser beam is a continuous stream of light or it is pulsed at a given duty cycle. Even if the end result is pretty much the same; the speed of the process is quite different depending on the methodology chosen.
For a given surface area, putting the same energy in a much shorter pulse increases the power. It’s like using the bigger hammer. The pulsed laser methodology is more efficient and provide a faster removal speed than the continuous beam. While the pulsed laser beam do the cleaning faster, it also ensures that the underlying material (typically a metal) does not heat too much. See the graph above for an illustration of the differences between both processes.
4. It is consumable-free and environmentally friendly
As this method only uses a laser beam to vaporize the layer to be removed, there are literally no consumables with this cleaning technology. This is the beauty of a laser, which only needs a power plug to be set and ready to go. On top of this, as no solvents or other chemical products are used, laser ablation is one of the safest solutions available when it comes to rust removal. Hence, there’s no chemical waste to take care of. Also, there is no danger for employees while working with the laser machine as these machines are designed to meet safety standards. Employees won’t need cumbersome personal protective gear and won’t have to handle those pesky chemicals. Win-win.
5. Laser cleaning is of interest for various industrial processes
Removing the burnt rubber residue from tire molds; giving a new life to old pipelines; cleaning pipes in nuclear power plants; and even larger projects such as removing paint from a rusty bridge are all projects that can benefit from laser cleaning technology. Thus, this technology can be used in a lot of different fields of application; the only constraint being the ability to discriminate ablation thresholds between the material to be removed and the one to be protected.
Why Laser Cleaning Is A Smart Choice?
Laser cleaning solution is the most feasible way for surface cleaning. Laser Cleaning is considered to be environmental friendly as there is no use of chemical agents and cleaning fluids as in traditional methods. The traditional Cleaning method is contact type which can damage object, resulting in improper cleaning while laser cleaning is non-contact solution. Moreover, laser can reach to difficult parts which is not possible with traditional methods. So, laser can ensure the safety of the personnel when used in dangerous places.
Also, laser Cleaning removes various impurities on the surface achieving a degree of cleanliness that cannot be achieved by traditional method. Surely, Laser cleaning is an alternative of traditional abrasive and chemical process used in heavy industries such as aerospace and ship building. The process can be made cost-effective in coating removal by the use of laser solution. Hence choosing laser cleaning is a smart choice.
Where Does Laser Cleaning System Work?
1. Surface profiling and rust removal in steel fabrication:
Conventional rust removal and descaling operations involve the use of physical methods such as blasting, polishing, scraping devices, extra blows, and wire brushes. Chemical methods such as alkali descaling and acid descaling (pickling) can also be used for scale removal. However, these methods are very abrasive and result in environmental pollution and damage to the substrate metal. To avoid these disadvantages, laser cleaning has become the preferred method for rust removal and descaling operations. The rust/scale is removed by directing a laser beam with high peak power and repetition rates on the rusted layer. The laser must be fired in short pulses to avoid damage to the substrate being worked on. The rust rapidly absorbs the energy of the laser beam, resulting in increased temperature levels. Once the temperature is sufficiently high, the rust melts and eventually vaporizes. Using pulsed fiber lasers is the preferred option since it provides greater control over power, wavelength, and pulse duration, allowing the rust/ scale to vaporize without any damage to the underlying material. The laser cleaning process can also be applied to surface profiling. Before protective coatings can be applied to fabricated steel parts for preservation and protection from corrosive action, their surfaces must be clean and free from all contaminants.
2. Anode assembly cleaning:
The aluminum smelting industry uses carbon blocks as “sacrificial” anodes in the production of primary aluminum. The quality of the anode has an impact on the environmental, economic, and technological aspects of aluminum production.
A small percentage of cell power is devoted to overcoming the electrical resistance of prebaked anode. The presence of dirt and other contaminants will increase the anode’s electrical resistance, resulting in the consumption of more cell power. The presence of contaminants also reduces the lifespan of the anode by increasing its rate of consumption during the smelting process. From the standpoint of efficiency, it is necessary to clean and remove all surface contaminants from anode assemblies before they are used in aluminum smelting operations. In addition, anode assemblies are valuable tools that can be reused, but only after executing a thorough and careful treatment of its main components—under specific conditions. Laser cleaning meets the specific conditions under which anode assemblies can be treated for reuse.
3. Adhesive bonding preparation for metals:
To increase process stability, surface adhesion, and better seam quality, the surface of the metallic materials to be joined must be prepared before the application of welding and other joining techniques. Laser cleaning is suitable for adhesive bonding preparation since it removes oxides and other contaminants such as grease and oxides that reduce the strength of adhesive bonds. It is particularly suitable for applications involving curved or flat surfaces or parts with certain limitations for highly complex 3D geometries.
4. Pretreatment for brazing and welding:
Laser cleaning has also proven effective in pretreatment applications for welding and brazing. Before aluminum and steel materials are used for welding purposes in shipbuilding, precision tool manufacturing, automotive, and other related industries, their surfaces must first be prepared. Laser weld preparation is one of the many applications of laser cleaning and helps to remove ferrous and nonferrous metals, lubricants, and other contaminants from metal and aluminum surfaces in preparation for high-quality welds. It also ensures smooth and pore-free brazed seams. Apart from welding and brazing preparation, lasers can also be used to remove weld residues such as residual flux and oxide materials as well as thermal stains from finished weld joints. This cleaning method is particularly beneficial for stainless steel parts since laser light suspends grain boundaries, ensuring that weld seams are passivated—thus increasing corrosion resistance.
5. Partial de-coating:.
Laser cleaning is particularly effective in applications that require the partial removal of paint or coatings from finished surfaces. It can be used on virtually all surface types, whether chemically anodized, oxidized, or organic. Laser cleaning can be used to de-coat solar panels and remove paint in the automotive and aerospace industries while maintaining the integrity of the primer substance .In de-coating applications, fiber lasers are the preferred option. They obviate the need for masking by precisely removing the layer of coating in the specified area, thus eliminating some of the challenges inherent in partial de-coating applications.
6. Selective paint removal:
Selective paint removal represents one of the many applications of laser cleaning. In the automobile and aerospace industry, it is sometimes necessary to remove the top layer of paint while maintaining the primer. This is often the case when the top weathered coatings on vehicles need to be thoroughly removed before the application of a new paint finish. Since the top layer of paint is physically and chemically different from the underlying primer, the power and frequency of the laser can be set to a frequency that only removes the top layer of paint. The primer remains intact since the laser has no mechanical, chemical or thermal effect on it. This ensures the maintenance of the primer’s corrosion resistance ability. When bare metal-to-metal contact is required for electrical continuity between parts, the laser cleaning process is preferred since it saves time and materials while improving the quality of the finished surfaces.
7. Dirt removal from metal mold surfaces:
Mold surface cleaning is a process where major maintenance bottlenecks occur as molds are usually pulled faster than they can be cleaned and made production ready. Cleaning mold plates and re-tooling are usually more tedious, time-consuming, and labor intensive than any of the other repair stages (disassembly, troubleshooting, or reassembly) combined . A new approach is needed to realize a major reduction in the time required to clean molds, to maximize tooling life, to make cleaning more systematic, consistent and predictable. Laser cleaning technology for the mold surfaces would, therefore, be a more suitable technology for this purpose.
Fascinating Features of Handheld Laser Cleaning Machine?
- Portability Redefined: Laser Cleaning System is a handheld, compact size device that allows it to operate on large and complex material surfaces with ease.
- Power-Packed System: The system delivers enough power to remove even the thicker layers of particles from the surface.
- No Complex Software: Laser Cleaning Systems comes in with easy to use control panel. Allowing users to make necessary variations without hustling with complexities of a software.
- No medium used: The only consumption required in the machine is Electricity which again depend upon the samples you want to process.
- Environment friendly: Eliminating usage of various chemicals to laser technology, along with minimal noise and dust emission the laser cleaning operation is highly environment friendly.
- Varied applications: Laser Surface Cleaning can be used in almost every sector i.e. from micro-scale to large-scale cleaning of material. Its application ranges from large commercial aircraft to micro-chips.
- It also plays an important role in fields like automobile manufacturing, military equipment, liquid crystal display cleaning, chewing gum residue removal and other related field.
- Time saving: Cleaning is precise and Selective i.e. desired area can be cleaned in lesser time making the output highly efficient.
How much does a laser rust removal machine cost?
Rust removal is one of the Convenient methods applied on metals using a 100, 200,500, 1000, 2000 Wattage Laser rust removal machine. When we have a targeted metal surface, the oxidized layer and any Rusted layer underneath absorbs the heat energy and evaporates the Corroded Rust layer from the surface directly into a gas known as sublimation.
The laser cleaning system uses the laser beam’s short pulses at high watts and cleans up rust from the metal without damaging the component. Here is a Price guide in US Dollars – Low Power laser cleaning (50W – 100W) : $70,000 – $116,000 – Mid Power laser cleaning(200W – 500W) : $160,000 – $305,000 – High Power laser cleaning (1000-2000W) : $440,000 – $700,000
How do choose the different power of the laser cleaning system?
Choosing a laser welding system is always a difficult job for an Original equipment manufacturer. Handheld held or Integrated rust removal laser of 1000 to 2000 Wattage helps the rust to evaporates. High power(1000 to 2000W)system is the most effective, precise laser cleaning solution of rust and oxidation for OEM.
Its very simple to see that the oxidation layer above the large metal surface absorbs the high watt energy and converts the solid thick rust layer directly into a gaseous state. The high wattage laser won’t affect the metal underneath, leaving a highly polished surface ready to be painted and welded.
The Laser rust cleaning system uses short pulses of laser radiations. The laser of 1000w to 2000 W power produces microplasma buries along with thermal pressure and shock waves to sublimate the rust and separate it from the metals. It won’t evaporate the human flesh.
These Lasers are 3-axis laser cleaner systems, Used for Heavy duty. These lasers are integrated into Automation to clean huge parts and where the part rotation and part handling is difficult. Automatic cleaning of metal on Curve surfaces and shapes.
The high-power Portable Laser Cleaning Machine extends cleaning from the floor to the field. An Industrial 2000 watt laser cleaning machine is applicable for the removal of rust from the metal surface. They are applied to surfaces of bridges, airplanes, heavy cars, trains, tire frame rust cleaning, laser mold cleaning.
It makes the entire rust removal process very simple and easy. Unfortunately, there is a rather large drawback, that is the cost. These lasers are specially developed, and they cost around High Power (1000W-2000W) : $440,000 – $700,000.
Laser for wattage 100 to 200 is used in slow operations where the rust removal is applicable only in a small area and where the paint is removed from the surface to apply a new paint coating over the surface. These Lasers are not recommended to integrate into automation, as their power and frequency have limitations.
High-speed cleaning of rust is not possible with this laser system. Therefore in many places, it is available as a handheld machine. These lasers are cheaper but not very cheap. The cost of 100 to 200 wattage laser cleaning is around $105,000 – $160,000.