By Liz Stevens, writer, UV+EB Technology
At RadTech 2025, RadTech presented its 2025 Automotive Innovation Awards to Ford Motor Company and Toyota Industries Corporation for innovations in auto manufacturing that employ UV technologies. RadTech recognized Ford for its development of overspray-free paint applicator technology which uses UV for curing coatings on vehicles. Toyota was recognized for its innovation in single-layer, UV-curable hard coating for plastic glazing in autos. UV+EB Technology talked with Ford’s Chris Seubert, technical expert – coatings, and Toyota Industries Corporation’s Tetsuya Mitsuoka, group manager for PG Project, to learn more about these innovations.
Ford Precision Painting Technology
Per the 2022 Physics of Fluids article “Review of coating and curing processes: Evaluation in automotive industry,” 1 “… the automotive paint shop plant still consumes 30%–50% of the product’s total costs and is the most expensive section.” The main costs stem from the specialized booths and ovens used for the paint process, as well as the need for pretreatment, dedicated HVAC systems and VOC removal technologies. Removing paint over-spray and solvent from painting booths also adds to the costs in the paint shop plant.
Ford’s patented system is precision painting technology that dramatically reduces overspray, reduces the labor needed for masking processes, cuts the quantity of material used for coatings, facilitates specialty finishes and improves design flexibility. The technology is applicable for a variety of coatings, including paint and clear coat. “This technology can apply any paint or ink of specified viscosity,” said Chris Seubert, “assuming it is formulated for ultrasonic jetting. The system’s nozzle diameter limits the size of particles in the paint.”
Ford’s overspray-free precision coating is achieved through piezoelectric or other electronically activated elements within the ultrasonic applicator that deform to eject fluid through nozzles spaced across the face of the applicator. “The droplets that are formed and ejected move perpendicularly to the nozzle and directly toward the target substrate,” Seubert explained. “Typically, the applicator is 5 mm to 35 mm away from the target, but depending on the applicator and the size/velocity of the droplets produced, this distance can change. High-precision ejection of the droplets results in little to no overspray, and the paint/coating lands on the substrate at a specified location.”
UV curing of the coatings is a crucial aspect of the technology. “Because of the low viscosities needed to jet coatings with a standard ultrasonic applicator,” said Seubert, “we proposed the use of UV light to pin the material in place after the applicator ejects it or to generate a viscosity bump such that the paint, when it lands on the substrate, does not sag or drip and produce an unwanted visual defect.” Although any type of UV light source can produce this effect, Ford currently prefers a UV LED ring around the entire applicator. A ring around each individual nozzle could be used if the company produces a large multi-nozzle applicator.
The specifications for UV energy and its placement are broad. “The coating’s formulation would dictate the UV wavelengths used,” Seubert said. “Our patent covers all UV wavelengths and photoinitiators. As far as placement goes, the patent simply states that UV elements are used to initiate crosslinking in the jetted material. We suggested having the UV elements on the applicator head for simplicity.”
“There are at least two benefits to having the UV source as close to the applicator as possible,” Seubert continued. “First is the elimination of shadow areas, even though one benefit of overspray-free application is that the coating lands exactly where you want it. Second is the ability to adjust when the viscosity increases/pinning process starts. To prevent appearance defects like overlaps in overspray-free coatings, some material flow is necessary, so you must consider the entire process, from coating formulation to UV application.”
Seubert addressed the cost savings and other benefits from this technology. “The current two-tone process for an auto roof requires multiple workers to mask and de-mask the vehicle prior to paint application,” he said. “The overspray-free application process requires significantly less/no masking. Additionally, a reduction in overspray and the elimination of using the topcoat bell atomizers leads to a reduction in material usage.”
Ford is targeting the use of this process for special appearance packages such as two-tone roofs and other graphical elements. The technology allows for improved design flexibility. “The smaller footprint/reduced utilities required for the overspray-free process compared to current two-tone manufacturing allows the implementation of this process in programs and plants that could not implement the traditional two-tone process,” said Seubert. Ford currently is examining several unique materials for potential use in overspray-free applications.
Toyota Industries Corporation Plastic Glazing Technology
Toyota Industries Corporation has developed the first single-layer, UV-curable, high-hardness coating for plastic glazing in vehicles. The coating, which meets international standards for abrasion resistance, replaces the traditional three-layer system for windshields and windows. This simplifies the production process and cuts carbon emissions and costs to develop lighter, more efficient vehicles. The plastic glazing coating is being tested in real-world conditions on Lexus International hydrogen-powered Recreational Off-Highway Vehicles.
The coating technology uses general high-pressure mercury lamps for curing. Tetsuya Mitsuoka explained that there are significant savings in production time when producing one UV-cured glazing layer vs. producing the conventional glazing, which requires two thermoset coats (one acrylic component and one glass component) produced separately on a polycarbonate resin base, plus a single layer of glass applied using chemical vapor deposition (CVD). “Production time is drastically reduced with the new technology,” said Mitsuoka. “The conventional method requires several hours while the new method takes only a few minutes.” This method reduces CO2 emissions in the coating process by about 80% and cuts coating costs by about 40%.
This hard coating material meets Class L requirements with a single coat. To ensure that the upper coat is as hard as possible after curing, the material comprises a blend of an acrylic component for high flexibility and a glass component for hardness.
Another benefit of this new technology lies in reducing a vehicle’s weight. “The single-layer plastic glazing has a comparable weight to the conventional three-layer plastic glazing system,” Mitsuoka noted. “Polycarbonate, however, is approximately half the density of glass, which results in a lighter overall structure compared to traditional glass components.” Safety benefits also are seen, with the material’s high resistance to breakage reducing the risk of passenger ejection in accidents. “Auto design also is facilitated,” said Mitsuoka. “This material enables larger surfaces and complex shapes that are challenging to achieve with traditional glass. And transitioning from the CVD process to this coating method simplifies the production of large-area components.”
Mitsuoka explained that the most critical properties for hard coatings used in automotive plastic glazing are scratch resistance and weather resistance. “These two properties are inherently conflicting,” Mitsuoka said, “which necessitated innovative approaches leveraging materials science. Through designing the morphology of materials and solvents, and persistently addressing challenges, we finally experienced an ‘Aha!’ moment when a particular observation confirmed that the coating structure aligned perfectly with our initial design intent. By integrating this technology with the plastic glazing expertise we have cultivated over the years, we gained confidence in our ability to create a hard coating that successfully balances scratch resistance and weather resistance within a single UV-curable layer, effectively addressing our customers’ needs.”
As a result of product testing via the Lexus ROV-based customer experience program, the Toyota team is exploring ways to improve scratch resistance and weather durability.
Automakers are reaping the benefits of using UV energy curing on the auto production line, enabling them to make vehicles with superior characteristics and to make them more quickly, more economically and more sustainably.
References
- Mohammad-Reza Pendar, Frederico Rodrigues, José Carlos Páscoa, Rui Lima; Review of coating and curing processes: Evaluation in automotive industry. Physics of Fluids 1 October 2022; 34 (10): 101301. https://doi.org/10.1063/5.0109376
