Ventilation grilles serve two key functions in the automotive sector: protection and cooling through the supply of fresh air. At the same time, they play a major role in shaping a vehicle’s appearance. As radiator grilles, they define the distinctive front-end design and protect the engine components from dirt—while ensuring controlled air circulation. Perforated grilles in the side and rear areas help dissipate hot air and add additional design accents.
Development expertise
Graepel develops and manufactures ventilation grilles made of perforated metal with high airflow capacity—offering up to 80–85% open area, depending on the design. The design is tailored to the specific application and integrates structural, material, and manufacturing requirements into a single, integrated development process.
Bionically inspired honeycomb structures and 3D forming techniques enable high airflow while maintaining a stable component structure. During the design phase, design specifications, airflow, stability, high-temperature resistance, and protective function are systematically coordinated. The goal is a functionally optimized component that operates reliably over the long term under real-world operating conditions.
In this process, manufacturing concepts—from small-batch to large-scale production—are individually tailored to customer needs in accordance with the highest automotive quality standards. Graepel’s in-house capabilities include an in-house tooling shop and a wide range of joining methods, such as aluminum stud welding and clinching, as well as laser and spot welding.
With fully controllable punching tools, Graepel enables maximum design freedom for custom perforated patterns and non-perforated areas, optimally combining design flexibility with cost-effectiveness.
Airflow and cooling capacity ensure performance and efficiency
Reliable cooling is essential for engines to operate economically and sustainably under high loads. Perforated ventilation grilles enable a defined and reproducible airflow rate through a large open cross-sectional area.
By carefully selecting suitable hole patterns, airflow is optimized without compromising the structural integrity of the component. This ensures uniform airflow to radiators and engines. Thermal peak loads can be reduced, and operational reliability is enhanced.
Protective function while allowing fluid to flow through
In addition to providing ventilation, ventilation grilles also serve a mechanical protective function. They prevent dirt, dust, insects, or small foreign objects from entering sensitive component areas.
The design of the hole diameter involves balancing high airflow with sufficient protective effectiveness. Larger perforations increase the open area but reduce the barrier effect. Smaller perforations improve protection but increase flow resistance. The key is to tailor the hole size, web width, and open area to the specific application.
Thermal and mechanical requirements
Ventilation grilles are often exposed to high temperatures, vibrations, and dynamic loads. The choice of material (steel, aluminum, or stainless steel), sheet thickness, web width, and degree of forming are designed to ensure sufficient rigidity, control thermal deformation, and maintain the specified airflow capacity over the long term.
Coating and Material
Coatings such as cathodic electrocoating (KTL) or powder coating provide corrosion protection. For finely perforated structures, the coating thickness must be taken into account in the design, as it can slightly affect the effective hole cross-sectional area.
The material and sheet thickness determine hole fineness, web-to-hole ratio, burr formation, and formability. A coordinated tool and process design is therefore essential for consistent component quality.
With Graepel DuraVent, Graepel offers a proprietary process for ventilation grilles that combines high airflow with exceptionally durable corrosion protection. A key feature is the uniform coating even on the cut edges of the perforated sheet. This significantly reduces corrosion susceptibility in these structurally sensitive areas.
