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Overspray: what it is and how to reduce it in coating systems | Cefla Finishing

Written by Cefla Finishing | May 9, 2023 10:29:44 AM

In the coating systems industry, process efficiency is now an increasingly strategic priority, both from an economic standpoint and in terms of sustainability. Managing paint consumption is one of the most critical aspects, as it directly affects operating costs, the quality of the final result, and the environmental impact of the entire process.

In this article, we at Cefla Finishing provide an overview of overspray and the latest solutions for improving the performance of coating systems and reducing waste.

What is overspray in coating systems and how does it affect performance?

In coating systems, overspray refers to the portion of the coating material that, during the spraying phase, fails to adhere properly to the surface of the workpiece and is dispersed within the booth or the exhaust system. 

From a physical standpoint, this phenomenon is linked to the dynamics of atomized particles: the paint is sprayed in droplets of varying sizes which, due to the exit velocity, air turbulence, and the distance between the spray gun and the surface, may deviate from the ideal trajectory and fail to reach the target.

Among the main factors contributing to overspray formation are excessive atomization energy, suboptimal airflow distribution within the system, and application parameters that are not perfectly balanced with respect to the type of paint and the workpiece being treated. The result is a reduction in transfer efficiency – that is, the amount of paint actually transferred to the substrate – which directly impacts system performance in terms of material consumption, finish quality, and process stability.

For this reason, overspray control is a key factor in the design and optimization of industrial coating systems.

Overspray control system: the solution from Cefla Finishing

In coating plants, overspray control also involves the use of systems designed to effectively manage the behavior of the coating material during the spraying phase.

This is where the “Airsphere” air diffusion plenum comes in, a solution developed and patented by us at Cefla Finishing to optimize operating conditions inside the machine. The system is designed to ensure uniform and controlled air distribution, reducing turbulence and creating a stable environment for paint application. This improves spray quality, promotes more uniform coating on the workpiece, and increases transfer efficiency.

Integrating such solutions into coating systems therefore allows for a structural approach to addressing overspray, improving overall process performance and reducing material waste.

How to reduce overspray: some operational tips

In addition to implementing advanced equipment solutions, reducing overspray also requires proper management of application parameters and operating conditions. In fact, certain measures can help optimize the spraying process and improve overall efficiency:

  • Selecting the nozzle size: it is essential to choose the most appropriate size based on the type of paint and the desired application result. In many cases, a larger nozzle size allows for operation at lower working pressures, thereby reducing product waste.
  • Adjusting the atomizing air flow: keeping the atomizing air flow at the minimum necessary level helps limit the energy imparted to the paint particles, thereby reducing the risk of them veering off course and minimizing overspray.
  • Optimization of ventilation parameters: it is recommended to minimize the plenum and exhaust air flow rates to prevent excessive turbulence inside the cabin.
  • Setting the spray area: it is important to configure the spray area precisely via the machine’s display, limiting it to only what is strictly necessary for the part being painted to avoid unnecessary overspray.
  • Spray gun positioning: keeping the spray guns as close as possible to the surface of the workpiece improves paint transfer and reduces the amount of paint lost to the environment.
  • Spray mode: whenever possible, it is preferable to use the “all” mode (back-and-forth) rather than the “front” mode (one-way), as it ensures more uniform distribution and greater control over the deposit.

Conclusion and Cefla Finishing's key role

Reducing overspray is now a key strategy for improving the efficiency of coating systems, optimizing material consumption, and ensuring consistently high quality standards over time. Addressing this issue involves not only adjusting process parameters but also adopting advanced technological solutions and an integrated design approach capable of balancing all the factors that influence the application phase.

This is precisely the direction we at Cefla Finishing are taking, designing and manufacturing turnkey coating and finishing systems for the international market, with customized solutions that combine technological innovation, efficiency, and sustainability. 

Contact us to find out how to optimize your coating system!