Printed headline: Painting the Future
As the global airline fleet matures, metal-heavy legacy aircraft are reaching the end of their useful lives. In their place, an abundance of newer composite material-laden airframes are entering service. These new materials bring different—and at times complex—repair demands from nose to tail. This is also the case for the paint used for aircraft coatings, with new developments taking place both outside and inside the airframe.
Daniel Bencun, global director for aerospace coatings at PPG, which supplies coatings to OEMs and in the aftermarket to most airlines and paint shops worldwide, says more extensive use of composite materials is changing industry and customer requirements, typically centered on weight reduction. “Composites are lighter than metals and provide opportunities to save weight on the aircraft,” he says. “They also can be molded, which gives OEMs the opportunity to redesign and make complex parts in less time and with different mounting structures.”
The growth of 3D printing using composites and metals is having a significant impact, Bencun adds. “Material that has been 3D-printed has a very rough surface that needs to be protected but also smoothed for aesthetics. Aluminium 3D parts have shapes that require different coatings or different application techniques,” he notes.
Turnaround times in the supply chain have also necessitated process changes, according to Kathleen Matz, project marketing manager at Germany-based paint manufacturer Mankewiecz. “Everything has to be faster and more accurate for the customer,” she says. “The products must be applied and repaired in a way that is safe as houses for series production. No airline can afford unexpectedly long turnaround times.”
Ecological concerns, with a focus on ensuring better safety for both the environment and technicians handling the paints, have also affected the product development process over the past decade. Dangerous chemicals such as chromates are gradually being reduced by coatings developers. However, a downside of this is the reduced protection for aluminium surfaces from oxidation, which has led to the growing development of pretreatments and other solutions by the industry’s big names such as AkzoNobel, Sherwin-Williams, PPG and Mankewiecz.
Mankewiecz’s Matz says the company has included water-based products in its paint offerings for decades, and these have become as safe and durable as their solvent-based predecessors. More recently, this has extended to structural parts found on aircraft. “In the field of structural parts, we are deeply engaged in the development of chromate-free systems for corrosion protection, and this topic will continue to be high on our agenda in the future too,” she says.
Sherwin-Williams has also factored environmental considerations into its product lines, recently expanding its chrome-free offerings, including pre-treatments and several chrome-free epoxy primers. “These promote better sustainability without compromising performance or productivity,” says Julie Voisin, global marketing manager for aerospace.
Companies such as Sherwin-Williams are looking more closely at interior painting, which Voisin says is very different from exterior work, including disparities in labor and materials costs, but just as demanding. “There is an equal difference in the environments an exterior coating must withstand compared to an interior coating,” Voisin says. “Exterior paint is battered by sunlight, hydraulic fluids, jet fuel and extreme weather, whereas the interior must be designed to contend not only with flammability requirements but also human interactions—perspiration, food, lipstick, and luggage banging away at the interior.”
MRO providers are looking to use these new products to capitalize on increased demand for painting, resulting from the growing size of the global fleet and greater industry customization. An increasing number of MRO shops are adding paint services, one of which is Magnetic MRO, which commenced aircraft painting in 2015 from its hangar in the Estonian capital of Tallinn.
The past four years have seen a steady flow of narrowbody painting work, with Magnetic performing around 20-25 complete aircraft paintings annually. Typically, the company says simpler end-of-lease painting jobs can be finished in four days, while more complex chemical stripping and full painting into dedicated airline livery takes 7-9 days.
The Estonian MRO has also proactively looked at innovations in its paint processes, citing the main challenge of aircraft painting as the need for quicker aircraft turnarounds. “The aircraft industry is booming faster than technicians and painters around it, so the workforce is one of the main challenges as well,” says Rihards Priedkalns, painting manager at Magnetic MRO.
These new innovations include virtual reality technology, which Magnetic MRO is both testing and providing in areas such as aircraft livery visualization. Having opened an expanded paint facility in late 2017, Magnetic equipped the hangar with custom docking systems tailored to serve different types of aircraft. “These are a much better solution than flying carpets or boom-lifts, as they provide complete access to every aircraft zone, reducing time spent [on] preparation and painting,” Priedkalns says.
Sherwin-Williams sees future paint developments centering on four specific areas—productivity, weight reduction, environmental improvements and customer experience. This view is shared by PPG’s Bencun, who says the company is basing its research and development activities on producing lighter, more environmentally friendly products, with better health and safety properties and more cost-effective applications.
He also sees automated technology playing a role, particularly in boosting productivity. “Typically, the need to boost productivity creates a gap for a new method of painting that triggers development of application technology,” Bencun says. “We have seen this recently with some customers implementing more automated processes such as spray capabilities.”
“The automation of manufacturing processes is certainly the biggest driver for major developments in the coming years,” says Mankewiecz’s Matz, who cites the automatic mixing and application of coatings with robots, laser technology and additive manufacturing as some of the areas in which paint automation is a key driver.
While automated concepts such as robotics are becoming more omnipresent, Magnetic MRO’s Priedkalns doesn’t see the technology entering into the painting segment at aftermarket level on a wide scale anytime soon. “In aviation, only a few factories use paint robots for simple parts painting, like wings before installation on aircraft,” he says. “It might be [in the far future for OEM] paint facilities, but it will not pay off in aftermarket painting due to huge aircraft size and costs of implementation.”
Instead, he expects ultraviolet paints to become more prevalent in the sector, taking their place alongside existing basecoat and clearcoat systems, citing the efforts of Airbus, which is testing UV coatings on aircraft. “This technology will be the next step to reduce aircraft ground times due to painting,” he says, with reduced turnaround times also a factor. “UV technology allows paints and clearcoats to dry out in
5 min. without losing any gloss or appearance,” he adds.