PP Honeycomb has a relatively wide density range, typically from 30 kg/m³ to 150 kg/m³, with the most common range being 50-100 kg/m³. Density is determined by both cell size and cell wall thickness:
- Cell Size: Usually refers to the distance between opposite sides of the hexagon (inscribed circle diameter). Common sizes: 3mm, 4mm, 5mm, 6mm, 8mm, 10mm, 12mm, 19mm, etc. Larger cells generally mean lower density (for the same wall thickness).
- Wall Thickness: The thickness of the extruded sheet strips. Increasing wall thickness significantly increases density.
The principle for selecting the appropriate density is “use the lowest density product that meets performance requirements” to achieve lightweighting:
- Based on Load and Stiffness Requirements: For areas or requiring high flexural stiffness (e.g., floors, load-bearing partitions), choose higher density (e.g., 80-120 kg/m³) or smaller cell honeycomb, which offers higher compressive strength and shear modulus.
- Based on Skin (Face Sheet) Type: If using very thin or low-modulus skins (e.g., thin aluminum, PVC), a higher density core is needed to provide more support against skin buckling (dimpling). With high-modulus carbon fiber or thick fiberglass skins, lower density honeycomb can be paired.
- Based on Process Requirements: In vacuum infusion, excessively low density (very thin walls) may crush under vacuum pressure, requiring a denser, structurally robust core. For complex thermoforming, lower density cores bend more easily.
- Based on Budget: Generally, higher density means higher material cost.
Optimal selection often requires Computer-Aided Engineering (CAE) simulation analysis or prototype testing with supplier technical support.
