Clean Technology Lasers: A New Tool in Surface Pre-Treatment for Superior Coating Adhesion

July 26, 2023
Laser systems remove corrosion, grease, residue and existing coatings from metal surfaces quickly as well as surface condition, with less preparation and less-than-traditional techniques.
Laser Photonics
Laser Photonics2

Most aircraft MROs understand the value of pretreating the metal surfaces of parts to remove corrosion, grease, residue, old coatings, or to roughen the surface of metals prior to coating. By ensuring the items are cleaned down to bare metal, aircraft MROs can avoid costly warranty issues that result when coatings peel, flake, bubble, or otherwise fail prematurely. The surface conditioning, cleaning, and profiling of jet engine parts may also be required to perform specific maintenance in accord with their operation specifications as FAA Certified Repair Stations.

Unfortunately, the traditional techniques used for this purpose – such as sandblasting, dry ice blasting, and chemical stripping – are messy and require expensive consumables, as well as substantial time for preparation and cleanup. These methods are also drawing scrutiny from regulators like the EPA and OSHA since they can pose risks to the environment and applicators.

Today, a more effective alternative is utilizing industrial-grade, precision laser-based systems that can remove paint, contaminants, rust, and residues with a high-energy laser beam that leaves the substrate unaffected. Preparation and cleanup time are minimal, and the low-maintenance equipment can last decades.

According to Vincent Galiardi, owner of Galiardi Laser Clean, a surface cleaning operator based in St. Charles County, Missouri, many people are surprised to learn that clean technology lasers are the most cost-effective, efficient, and safest method of industrial surface preparation.

“Many people are unfamiliar with the use of lasers to pretreat metal surfaces,” says Galiardi. “When I do a demonstration, at first the people in attendance are skeptical. But after I use the laser to treat a small area, everyone starts talking and getting excited. By the end, when I let them try the equipment, everyone is having a good time and saying how great the laser works.”

Given its effectiveness pretreating metal surfaces, industrial laser systems are increasingly being used by MROs. Technicians can use mobile handheld units or the systems can be integrated into automated inline processing lines. With significant advantages in safety and efficiency, laser cleaning is poised to disrupt the surface pre-treatment market across more sectors.

Resolving Conventional Cleaning Limitations

There are many applications in aircraft MRO operations that require pre-treatment of metal surfaces prior to coating. To improve coating adhesion, residue, oil, or grease must be removed before coating application. In some cases, an MRO may seek to further enhance coating adhesion by roughening the surface.

To refurbish existing metal parts, removing the previous coating along with any corrosion is usually required to facilitate the new coating’s adhesion to the surface.

To pretreat metal surfaces, sandblasting, dry ice blasting, or chemical stripping are traditionally used as industrial cleaning processes.

Sand Blasting

Abrasive sandblasting involves forcefully projecting a stream of abrasive particles onto a surface, usually with compressed air or steam. The silica sand used in abrasive blasting typically fractures into fine particles and becomes airborne, which can cause serious or fatal respiratory disease.

When workers inhale crystalline silica, the lung tissue reacts by developing fibrotic nodules and scarring around the trapped silica particles, causing a fibrotic lung condition called silicosis. Estimates indicate that more than 1 million U.S. workers are at risk of developing silicosis and that more than 100,000 of these workers are employed as sandblasters.

In addition, particles are generated during abrasive blasting that further contribute to respiratory problems and other harmful health effects.

“When sand or any other media is used to knock off particles from a substrate, there is always a byproduct that has the potential to become airborne and inhaled,” says Galiardi. “Besides the sand, this could be the particles you’re removing – the coatings, plating, anodizing, corrosion, and even lead paint.”

“Industry has needed a cleaner, safer surface pre-treatment solution for a very long time,” adds Galiardi. “Sandblasting is inherently unsafe for operators. The silica glass used in sandblasting is toxic. An operator must wear a full HEPA suit when sandblasting to avoid breathing in particulates.”

Sandblasting also is time-consuming to clean up since the sand essentially scatters everywhere, even though it is usually considered a “fast” cleaning method.

Dry Ice Blasting

With dry ice blasting, dry ice pellets are used as the abrasive. The challenge is that dry ice blasting is often not abrasive enough to sufficiently remove paint or corrosion from the surface of metals. Since dry ice is an expensive consumable, the costs can escalate when cleaning metal surfaces in higher volumes.

Chemical Stripping

With chemical stripping, harsh, even toxic chemicals are used to strip metal-based objects of paint, rust, and other contaminants to bare metal. However, for operators, exposure to corrosive acids and noxious chemical fumes is inherently dangerous. The process can also be time-consuming to prepare the proper chemical bath, achieve the required level of cleaning, and dispose of the waste. In addition, disposing of toxic chemicals is costly and closely regulated by agencies like OSHA and the EPA.

Laser Cleaning

Laser-based systems have significant advantages over these traditional methods, including ease of use in which an operator simply points and clicks a high-energy laser beam at the surface. The substrate is not affected by the laser, and the systems do not create any mess or byproducts. The approach is eco-friendly, energy-efficient, and completes the job in half the time of traditional methods when preparation and cleanup are considered.

“In our experience, laser cleaning is as fast at removing rust or old coatings as other methods, but without the same amount of cleanup,” said Galiardi. “When we treat a surface with lasers, any fumes or dislodged particulate is extracted into a HEPA filter and the job is done. There is no media [sand, dry ice, chemicals] to replenish or clean up.”

Galiardi Laser Clean uses laser systems made by Orlando, Florida-based Laser Photonics, a leading provider of patented industrial grade CleanTech laser systems for cleaning and surface conditioning. The American-made systems function either as mobile standalone units or can be integrated into production lines.

The laser systems are available in portable and stationary models ranging from 50 to 3,000 watts (a 4,000-watt version is in development) with chamber sizes from 3’ x 3’ in size to 6’ x 12’. The systems can also be installed in manufacturing lines in cabinets or operated by a robotic arm.

On top of corrosion and coating removal, the cutting-edge laser blasting technology can be utilized by MRO professionals to clean aircraft fixtures, perform selective paint removal on rivets, and more. The technology was developed to match and exceed strict industry standards.

With clean laser technology, there is now an environmentally friendly alternative to abrasive blasting and chemical stripping for surface pretreatment, conditioning, and profiling. The approach is safer for operators and highly adaptable to a wide range of MRO applications.

“As people become more aware of laser-based systems and compare them to traditional methods, they need to factor in prep and cleanup time, which can significantly impact project cost. When the improved operator safety, equipment longevity, and lower maintenance of laser systems are also considered, the clean laser technology has a much higher ROI,” says Galiardi.

The longevity of low-maintenance laser systems further adds to their value, increasing ROI, and making replacement unnecessary for decades.

“CleanTech laser systems can last for 50,000 to 100,000 hours. That’s many decades working eight-hour days. After purchase, there’s virtually no maintenance necessary,” concludes Galiardi.