One of the fastest growing parts of our oven business is ovens for powder coating. Powder coatings are the most rapidly growing coatings used today. Powder coating is the functional equivalent of liquid coating, with one notable exception: The carrying agent is eliminated, thereby also eliminating the need for mass transfer before curing. But the lack of a carrying agent increases the need for heat transfer, to fuse the powder before curing. Thus, the design of an oven to rapidly and accurately fuse and cure powder coatings requires two distinctly different heating stages.

Infrared or convection ovens alone are best at meeting the needs of one phase of these dual heating requirements. But, neither technology alone can effectively and efficiently meet all of these drying and curing requirements. Thus, the optimum drying and curing solution is often an oven that provides a combination: Infrared and convection heating technologies.

During the initial heating phase, the coating particles must be fused, gelled, or melted. The part and coating must be raised to the fusion temperature with minimal air circulation that could disturb or contaminate the coating. Electrostatically applied powder particles begin to lose their charge during heating and can be easily disturbed by vibration or airflow.

For maximum productivity during this phase, a high level of direct thermal energy is required to quickly heat the coating and part. However, temperature rise must be carefully monitored and controlled to prevent overshooting the cure temperature range which could degrade the coating or substrate.

Then during the second phase of the curing process, the part is held for a specific time at curing temperature to complete crosslinking and polymerization of the coating. Again, although exact curing temperature is unique to each powder formulation, it often falls between 200° F and
400° F.

Again, to accelerate the cure, the film or fused coating temperature should be held close to the maximum curing temperature, but not above. Temperatures above the maximum are particularly deleterious for powder coatings. Again, precise control of temperature within the curing zone is necessary for optimum coating uniformity and consistency, as well as high productivity.

Powder coated parts come in a variety of shapes and sizes. Part geometry and characteristics as well as powder formulation directly affect the oven system design. Therefore, the oven must be designed to ensure consistent and precise control of temperature, heat intensity, and airflow as well as material handling and process control.

Thermovation Engineering follows a systematic approach to the design of powder coating curing ovens. We thoroughly analyze your needs and constraints, and then design an oven that will operate efficiently and effectively to produce the optimum coating characteristics you desire at the lowest possible cost.

We know that no single heating technology, whether gas or electric, infrared or convection heating, can alone meet the complex curing requirements of powder coatings. Each has its own capabilities and limitations. Therefore, we design our ovens to incorporate just the right combination of these technologies to achieve the optimum powder coating results. Our results can be seen on every utility pole from United Lighting to every grill from Weber Stevens.

Our high efficiency ovens increase quality and productivity. Our ovens hold temperatures to within two degrees of the set point. And our ovens not only require less space, but cost less to operate than the systems they replace.

See also infrared, convection, combination, and THERMOCURE™; ovens.