The manufacturing process has a direct influence on the selection of composite core materials because different production technologies place different mechanical, thermal, dimensional, and processing requirements on the core.
Common manufacturing processes include Vacuum Infusion, Resin Transfer Molding (RTM), Prepreg Processing, Compression Molding, Hand Lay-Up, Adhesive Bonding, and various automated composite manufacturing methods.
For vacuum infusion, resin permeability and flow behavior can be particularly important. A core that blocks resin flow may result in dry areas or incomplete wet-out. For this reason, manufacturers may use perforated, grooved, scored, or specially surface-treated composite core materials to improve resin distribution.
For RTM, the core may experience pressure from the mold and resin system. The material therefore needs adequate dimensional stability and compressive resistance. Core deformation during processing can negatively affect final thickness and structural accuracy.
Prepreg manufacturing introduces another requirement: temperature resistance. The core must withstand the specified curing temperature and pressure without unacceptable deformation, chemical degradation, or dimensional instability.
Adhesive bonding creates a different set of requirements. Surface condition, roughness, porosity, chemical compatibility, and bond strength can all influence the final skin-to-core interface.
Manufacturing Process vs. Core Requirement
| Manufacturing Process | Important Core Requirements |
| Vacuum Infusion | Resin flow, permeability, dimensional stability |
| RTM | Compression resistance, dimensional stability |
| Prepreg | Temperature resistance, pressure resistance |
| Compression Molding | Dimensional stability, compressive resistance |
| Hand Lay-Up | Bondability, handling, surface compatibility |
| Adhesive Bonding | Surface quality, bond strength |
| CNC Machining | Dimensional accuracy, machinability |
| Automated Kitting | Thickness consistency, cutting accuracy |
Research on foam-core sandwich structures demonstrates why the manufacturing and structural behavior of the core cannot be considered separately. For example, studies of PVC foam sandwich panels have identified skin/core delamination as a significant failure mode, emphasizing the importance of the interface as well as the core itself.
For procurement teams, this means an RFQ should never contain only the material name and thickness. A better specification would state the intended manufacturing process, resin or adhesive system, curing temperature, pressure, and any required core modifications.
For example:
PET Foam Core + Vacuum Infusion + Epoxy Resin + 20 mm Thickness + Perforated Surface
is much more useful to a supplier than:
20 mm PET Foam Core.
The first specification provides enough information for a technical supplier to determine whether the material is suitable.
For high-volume projects, buyers should also consider processing yield. A material that costs slightly more but produces less cutting waste and requires less manual preparation may have a lower total manufacturing cost.
Therefore, the best composite core materials are not necessarily those with the highest mechanical specifications. They are the materials whose mechanical properties, surface characteristics, thermal behavior, dimensions, and processing characteristics are compatible with the complete manufacturing system.
This approach can reduce production defects, improve cycle time, and create more consistent sandwich panel quality.
