Toyota Motor Corporation has developed an airless paint atomizer that uses static electricity instead of air to replace the conventional air paint atomizers used in the vehicle body painting process. The newly developed airless painter, the first of its kind, achieves more than 95% coating efficiency (the amount of paint sprayed versus the amount that actually adheres onto the vehicle body)—the highest in the world, against the approximately 60 to 70% efficiency of conventional atomizers.
By deploying the airless paint atomizer in Toyota Group’s painting process, it is expected that the Group can reduce its CO2 emissions by about 7%. In addition, the collection device situated at the bottom of the paint booth (the area where paint is sprayed) can be made more compact. Therefore, it is able to make painting production lines more compact for the future.
Conventional air paint atomizers spray paint primarily using aerodynamic force; paint particles are scattered by the air ricocheting off the vehicle body, resulting in a coating efficiency of approximately 60 to 70%. By comparison, the new airless paint atomizer uses electricity to spray the paint (electrostatic atomization), and the statically charged particles coat in such a way that they gravitate toward the vehicle body (electrostatic painting). Electrostatic atomization and electrostatic painting technologies greatly reduce the number of atomized particles that scatter, thereby achieving a higher coating efficiency.
The tip of the airless paint atomizer features a rotating cylindrical head that optimizes the amount of paint sprayed. Approximately 600 special grooves are inserted into the tip, which is rotated to create a centrifugal force, inducing the paint to flow into the grooves and atomize through static electricity.
The unevenness of the vehicle body causes the distance between the cylindrical head and the vehicle body to fluctuate, making the electrical current unstable. However, the airless paint atomizer constantly monitors the variations in current and automatically controls the voltage, maintaining a distance of approximately 10 centimeters between the cylindrical head and the vehicle body.
Hence, electrostatic atomization and electrostatic painting under a fixed current is rendered possible, in turn preventing variation in the size of the paint particles. The result is high-quality painting.
Toyota is advancing initiatives to achieve its Plant Zero CO2 Emissions Challenge, one of the targets included in the Toyota Environmental Challenge 2050 announced in 2015. As part of this effort, it developed the airless paint atomizer and deployed it at both Takaoka and Tsutsumi Plants. Gradual deployment at other plants is planned as well as consideration of deployment among other Toyota Group companies and licensing the technology to other companies.