Slot hole perforation

Optimised material flow and filtration efficiency

Perforated metal with slot holes is widely used for sorting, drying, and filtration due to its ability to efficiently direct air, liquid, and material flow

Slot hole perforation or elongated hole perforation is available with round-ended slot holes or square-ended rectangular holes, making it ideal for applications requiring high precision, high throughput, durability, and controlled sorting.

Depending on the application, slot hole perforation is available in various patterns, including:

  • Staggered rows for enhanced structural strength and material flow.
  • Straight rows for predictable airflow and controlled separation.
  • Herringbone and chessboard layouts for specialised sieving, sorting, or decorative purposes.

Key benefits of slot hole perforation

  • Enhanced material flow: Ideal for sorting, sieving and filtration, ensuring efficient separation of materials.
  • Optimised airflow and drying: Facilitates ventilation and moisture control in processing applications.
  • Aesthetic and functional: Combines performance with modern design for industrial and architectural uses.

Applications examples

  • Sieving and sorting: Used in grain processing, seed cleaning, and malting floors, ensuring precise separation of different materials.
  • Filtration and drying: Ideal for food processing, fodder mills, and pellet production, providing controlled airflow and efficient drying.
  • Industrial screening: Applied in recycling, bulk material handling, and separation processes, enabling effective classification of materials.
  • Ventilation and cooling: Commonly used in server cabinets, air vents, and industrial machinery, allowing optimal airflow and heat dissipation.
  • Architectural applications: Used in facades, sunscreens, and decorative panels, offering both aesthetic appeal and functional airflow control.

Technical information - Slot hole perforation

Types of slot holes

Slot hole perforation or elongated hole perforation, covers two types of holes:

  • Round-ended slot holes (LR): this hole type is also known as slot hole perforation, rectangular rounded holes, and slot, round-ended holes.
  • Square-ended rectangular holes (LC): this hole type is also known as slot hole perforation, rectangular holes, and slot, square-ended holes.

Round-ended (LR) compared to square-ended (LC)

Arrangement of holes

Slot holes (LR and LC) with a staggered pitch (Z) provide balanced open areas and structural stability. Ideal for applications requiring airflow and durability, the Z pitch configuration improves flexibility and strength.

Slot holes (LR and LC) with a rectangular (U) pitch aligned in straight, uniform rows, creating a grid-like pattern with consistent structural strength and open areas. 

Slot holes (LRD) with 45° diagonal alignment and a rectangular pitch (U) designed for efficient airflow and a structured, decorative appearance.

Slot holes (LRDD) with 45° diagonal herringbone-like alignment and a rectangular pitch (U) offer a distinct visual pattern while maintaining airflow control.

Slot holes (LR) with cross alignment and a rectangular pitch (U) forms a chessboard-like pattern, ensuring a balance between structural integrity and ventilation.

Z = Staggered pitch

U = Rectangular pitch

Slot holes 45° diagonal, rectangular pitch 
Slot holes herringbone, rectangular pitch

Slot holes cross, rectangular pitch

Beginning and end of perforated areas

Closed end pattern includes use of special tooling to create a uniform edge at the start and end of the perforated area, providing a clean, continuous look that is ideal for decorative and architectural applications. This process is more complex and may extend production time.

A semi-closed end pattern balances cost-effectiveness and visual appeal, offering a partially finished edge that improves appearance without the full expense of a closed pattern. Suitable for applications needing a moderate level of refinement.

The open end pattern is the standard option, where the perforated area begins and ends with partial or irregular rows due to the stepped perforating process. This approach is efficient and economical, ideal for non-decorative applications or areas that will be framed. However, it may lack the finished look needed for visible applications.

Closed end pattern

Semi closed end pattern

Open end pattern

Materials

Slot hole perforation are available in various materials, including: 

  • Mild steel
  • Stainless steel
  • Galvanised steel
  • Aluminium
  • Brass
  • Other alloys