Thermoplastic carbon-fiber composites combine high-strength carbon reinforcements with melt-processable polymers. Yet matching the right fiber format to the right resin—and choosing the best molding route—can make or break part performance. Here is a concise, U.S.-style guide to the five processes that are actually running in factories today.

1. Melt-Impregnated Tape Production

Goal: create fully-wetted, unidirectional prepreg tapes for automated lay-up.

How it works: tension-controlled fiber tows pass through a molten resin bath, then through heated dies and nip rollers that drive resin into every filament. The key is filament spreading—wider, flatter tows mean faster, more uniform impregnation. Finished tapes are slit to width and spooled for later use.

2. Extrusion-Injection Molding

Best for: high-volume, short-fiber parts like brackets, housings, and wear surfaces.

Process snapshot: chopped carbon fiber, PA66 (or another high-performance nylon), coupling agents, and additives are dry-blended, melt-compounded in a twin-screw extruder, pelletized, dried, and then injection molded. Watch the temperature window: too low and viscosity skyrockets; too high and the resin behaves like a Newtonian fluid, offering no further viscosity drop.

3. Compression Molding

Ideal for: medium-to-large parts that need balanced mechanical properties without the cost of autoclaves.

Steps: stack pre-cut thermoplastic prepreg sheets or fiber/resin “organosheets” in a matched metal mold. Heat above the polymer’s melt point, apply pressure to squeeze resin through the fiber bed, consolidate, then cool under pressure. Result: void-free laminates with excellent fiber volume fractions.

4. FDM 3D Printing

Perfect for: prototypes, jigs, and complex lattice structures that machining can’t touch.

Fused-filament printers lay down carbon-filled thermoplastic beads layer by layer. Parts come out dimensionally accurate, but overhangs still require soluble or breakaway supports. Use high-reinforcement filaments (≥30 wt % carbon) to maximize stiffness and keep warpage low.

5. Automated Fiber Placement (AFP) & Tape Laying

Industry sweet spot: aerospace skins, spars, and curved fuselage sections.

Robotic heads heat incoming thermoplastic tape or tow just above the melt temperature, tack it onto the substrate, and immediately apply consolidation pressure. Each layer bonds in-situ, building up thickness without an autoclave. The payoff: large, contoured parts with aerospace-grade void levels and fiber alignment.