The mainstream production process for PP Honeycomb is the Extrusion-Stretching Method, an efficient, continuous, and cost-effective approach with the following steps:
- Co-extrusion of Sheet Strips: Polypropylene pellets (which may include colorants, modifiers, etc.) are fed through a precise co-extrusion die. The die simultaneously extrudes dozens or even hundreds of thin, narrow, parallel PP sheet strips (called “tapes” or “webs”) with precise spacing between them.
- Layering and Welding: Multiple layers of these extruded sheet strips are stacked on top of each other at a specific alternating angle (typically 60° or 90°). At the intersection points of each layer, localized heating and pressure are applied via precisely controlled hot rollers or ultrasonic welding devices to create strong fusion bonds, forming a dense, unexpanded “honeycomb block.”
- Expansion and Setting: This is the most critical step. The welded honeycomb block is placed on a specialized expansion machine and slowly, uniformly stretched in the direction perpendicular to the plane of the sheet strips (i.e., the direction of the cell axis). During stretching, the previously welded points are pulled apart, and the sheet strips expand, forming a regular hexagonal honeycomb cell array. The expansion ratio determines the final cell size and density.
- Heat Treatment and Post-processing: The expanded honeycomb structure contains internal stresses. To stabilize dimensions, heat treatment (heat setting) is performed. Subsequently, based on customer requirements, surface treatment (e.g., corona treatment to improve adhesive bonding), flame-retardant impregnation, or cutting into sheets of various thicknesses and widths may be carried out before final packaging.
The entire process is highly automated, enabling large-width, continuous production, ensuring product consistency and cost-effectiveness.
