Composites Manufacturing

Composites manufacturing builds high-strength, lightweight, corrosion-resistant parts by combining fibers and resins into tailored laminates and profiles across multiple molding and layup processes.

Overview

Composites manufacturing covers processes that combine high-strength fibers (carbon, glass, aramid) with polymer resins to create lightweight, corrosion-resistant structures. Core methods include closed-mold processes like Resin Transfer Molding (RTM) and VARTM, prepreg layup cured in autoclaves or out-of-autoclave, and continuous processes like filament winding and pultrusion. Open-mold methods such as hand lay-up, spray lay-up, and chopped fiber molding handle larger or less-critical parts at lower tooling cost.

Use composites when you need very high specific stiffness/strength, tailored fiber orientations, and complex curved shells that would be heavy or multi-piece in metal. They excel in medium volumes and larger parts where tooling cost can be spread across production. Tradeoffs: slower cycle times than high-speed plastics molding, more complex QA (voids, fiber alignment), and looser as-molded tolerances that often require secondary machining on interfaces and precision features. Process choice depends on part size, volume, structural criticality, and surface/void requirements.

Common Materials

  • Carbon fiber/epoxy prepreg
  • Glass fiber/epoxy
  • Glass fiber/polyester
  • Carbon fiber/vinyl ester
  • Aramid fiber/epoxy

Tolerances

±0.010" to ±0.030" on as-molded geometry; ±0.002"–0.005" on critical features after secondary machining

Applications

  • Monocoque chassis and body panels
  • UAV and aircraft wings and fuselages
  • Pressure vessels and composite overwrapped pressure vessels (COPVs)
  • Wind turbine blades
  • Drive shafts and tubular structures
  • Electrical cable trays and structural profiles

When to Choose Composites Manufacturing

Use composites manufacturing when you need maximum strength and stiffness per unit weight, corrosion resistance, or tailored anisotropic properties. It fits medium-volume production of structural shells, beams, and profiles where complex curvature or integration of multiple functions into one part reduces assembly and mass.

vs CNC machining

Choose composites manufacturing over CNC machining when weight reduction, corrosion resistance, and tailoring stiffness along load paths matter more than ultra-tight as-built tolerances. Machine only critical interfaces after molding to control cost and take advantage of near-net composite laminates or profiles.

vs Injection molding

Choose composites over injection molding when you need structural performance beyond what short-fiber or unfilled plastics can deliver, or when parts are large and lightly produced. Composites handle long fibers, thick sections, and large, stiff structures where injection tooling cost and press size become prohibitive.

vs Sheet metal fabrication

Choose composites instead of sheet metal when you need double-curved skins, integrated stiffeners, and high stiffness without adding ribs, brackets, and fasteners. Composites let you consolidate parts into monocoques and closed sections that are difficult or impossible to form and join in metal sheets.

vs Metal 3D printing

Choose composites over metal 3D printing when the part is relatively large, primarily loaded in tension/bending, and weight and cost per volume matter more than intricate internal metal features. Composites can deliver high-performance structures at lower material and production cost for beams, shells, and tubes.

vs Plastic 3D printing

Choose composites manufacturing over plastic 3D printing when you need repeatable structural properties, long fiber reinforcement, and production quantities beyond prototypes. Composites processes provide better mechanical performance and surface finish for real-world structural components rather than one-off mockups.

Design Considerations

  • Define primary load paths and specify fiber orientations and laminate stack-ups explicitly, not just overall thickness
  • Avoid sharp inside corners and tight radii; use generous fillets and smooth transitions to reduce stress concentrations and ease layup
  • Keep thickness transitions gradual and control ply drop-off regions to avoid print-through and local weakness
  • Separate cosmetic and structural surfaces in the drawing, with clear requirements for voids, porosity, and surface class
  • Call out only truly critical tolerances and surfaces; plan to achieve them with secondary machining rather than on the molded surface
  • Specify standard inserts, bonded hardware, and edge closeout details so the shop can design practical tooling and fixturing