Introduction
Continuous fiber reinforced thermoplastics (CFR TP) are considered one of the most promising material classes for structural lightweight applications – in aerospace, automotive engineering, and industrial technology. The reasons are well known: no autoclave, shorter process times, weldability, recyclability. However, the term "CFR TP" does not represent a uniform manufacturing reality. The way continuous fiber reinforced thermoplastic components are produced varies fundamentally depending on the process – in achievable component geometry, fiber architecture, degree of consolidation, and scalability for series production.
This article provides a technical overview of the main processes for processing continuous fiber reinforced thermoplastics – and shows which approach is suitable for which application scenarios.
The common foundation: Continuous fiber as a structural element
Before individual processes are compared, a fundamental clarification is worthwhile: The crucial difference between short-fiber and continuous-fiber reinforced thermoplastics lies not in the material, but in the achievable mechanical performance. In Europe, according to current market data, about 90% of the use of fiber-reinforced thermoplastics is accounted for by short-fiber reinforced variants – typically injection molded, with fiber lengths in the millimeter range. Continuous-fiber reinforced thermoplastics, where the fiber runs through the entire component length and fiber volume contents of 50–60% are achievable, still make up a relatively small share despite their significantly superior specific stiffness and strength.
This is exactly where the comparison begins: Which processes allow for the industrial use of this material class – and under what conditions?
Tape laying and press consolidation (Stacking & Press Consolidation)
Tape laying is one of the most established processes for continuous-fiber reinforced thermoplastics. Prepreg UD tapes are stacked in defined orientations and then consolidated under pressure and temperature in a press. The result is flat laminates with excellent fiber architecture control and consolidation quality – void contents below 1% are routinely achievable.
The strength of this approach lies in the material quality and reproducibility. The weakness lies in the geometry: Flat or slightly curved plates can be produced excellently, while complex three-dimensional components can only be made with significant effort. However, for structural plates, organ sheet semi-finished products, or raw materials for subsequent forming processes, the method is hard to surpass.
Continuous Compression Moulding (CCM)
The Continuous Compression Moulding process expands the pressing approach with a continuous process flow: Several layers of pre-impregnated tapes or fabrics are brought together in defined orientations, pass through a heating zone, and are then consolidated under pressure in a cooling zone. The result is endless profiles or laminate sheets with high-quality, reproducible structures.
CCM is particularly suitable for large-scale production of straight or slightly curved profiles – such as stringers, stiffening profiles, or structural flat profiles for aerospace or automotive applications. Void contents below 1% are documented, corresponding to the quality level of autoclaved thermoset components. The limitation lies in geometric freedom: Circular cross-sections, variable wall thicknesses, or complex hollow profiles cannot be represented with CCM.
Pultrusion and Pullwinding
Thermoplastic pultrusion is the method of choice for straight, constant profiles with a high fiber volume content in the axial direction. Continuous rovings are pulled through a heated tool, impregnated, and consolidated. The process is highly productive and cost-efficient – however, it is strictly limited to axial fiber architectures and constant cross-sections.
Pullwinding combines the pultrusion movement with an overlay winding process: While the profile is pulled through the tool, additional fibers are applied at defined angles. This allows for targeted addressing of torsional and transverse loads. The process is well-suited for pipes and profiles with defined but limited layer architecture. However, the variety of geometries remains restricted – variable wall thicknesses, short components, or complex winding geometries are difficult to realize.
Braiding
In braiding, fiber strands are intertwined on a core (mandrel) to form a textile tube, which is then consolidated – either by pressing, autoclaving, or, in the thermoplastic case, by induction or oven consolidation. The process creates a pronounced multiaxial fiber architecture with high damage tolerance and energy absorption, making it attractive for crash-relevant structures and pressure vessels.
Herone, a German company, has demonstrated that high-quality hollow profiles made of CF/PEEK with integrated functional elements can be economically produced using a combination of thermoplastic tape braiding and compression molding. The limitations of braiding lie in fiber angle control (typically ±15° to ±75°, no 0° layers without additional inserts) and in scaling to short or geometrically variable components.
Additive manufacturing with continuous fibers (AM)
Additive manufacturing with continuous fiber reinforcement – such as through systems like Anisoprint or Markforged – has received significant research attention in recent years. The principle: Continuous fibers are laid down layer by layer together with a thermoplastic matrix, thus creating fiber-reinforced components without tooling.
Design freedom is the central argument of this approach. However, the limitations are significant: fiber volume contents of 25% and porosity contents of up to 10% are documented in the literature – values that generally do not meet structural requirements in aerospace or drivetrain applications. Tensile strengths and stiffnesses are significantly lower than those of conventionally manufactured continuous fiber composites. Additive manufacturing with continuous fibers is therefore primarily a tool for prototypes, research samples, and geometrically complex small components today – not for structural series applications.
Laser-assisted thermoplastic winding (LATW) – AFP-based in-situ consolidation
Laser-assisted thermoplastic winding (LATW) – also known as the AFP process with in-situ consolidation – combines the precision of automated fiber placement with the process efficiency of thermoplastic matrices. A laser beam heats the layup position immediately before the pressing element to processing temperature; the applied tape is directly consolidated, without a subsequent autoclave step.
The process enables the production of rotationally symmetric structures – pipes, pressure vessels, shaft bodies – with precisely controllable fiber architecture, high fiber volume contents, and demonstrably low porosity contents. The layer architecture is freely selectable: axial, helical, and circumferential layers can be combined in any way, covering both torsion and pressure-loaded structures. Alformet GmbH uses this process – based on the machine technology and process know-how of AFPT GmbH – for the production of continuous fiber reinforced thermoplastic pipes and profiles, from prototype to series, without autoclave infrastructure.
Which process is suitable for continuous fiber reinforced thermoplastic pipes?
For the production of continuous fiber reinforced thermoplastic pipes and rotationally symmetric structures, winding processes – especially laser-assisted thermoplastic winding (LATW) – are the most suitable manufacturing method. They allow for a free choice of fiber architecture, high fiber volume contents, in-situ consolidation without autoclave, and are suitable for both individual parts and medium series volumes. Pultrusion and pullwinding are alternatives for straight profiles with axial-dominant loads, but offer significantly less flexibility in layer architecture.
Conclusion: No universal method – but clear strength profiles
The comparison shows: There is no universally superior manufacturing method for continuous fiber reinforced thermoplastics. Each approach has a clearly defined strength profile, determined by component geometry, layer architecture, series volume, and quality requirements.
Method | Geometry | Fiber architecture | Series suitability | Consolidation quality |
|---|---|---|---|---|
Tape laying / Pressing | Flat, slightly curved | Freely selectable | Medium | Very high |
CCM | Profiles, laminate sheets | Defined, constant | High | Very high |
Pultrusion / Pullwinding | Straight profiles, pipes | Axial + limited helical | Very high | High |
Braiding | Hollow profiles, pipes | Multiaxial, no 0° | Medium | High-Very high |
AM (Continuous fiber) | Complex, tool-free | Free, but limited | Low | Low |
LATW / AFP | Pipes, Rotational bodies | Completely free | Medium–high | High-Very high |
For development teams looking to realize structural pipes, shaft bodies, or pressure vessels made from continuous fiber reinforced thermoplastics, it is worthwhile to engage in discussions early on with a manufacturing partner that covers the entire spectrum – from materials to processes to qualification – from a single source.
Would you like to know which process is suitable for your specific application? Talk to the team at Alformet.
📚 Sources:
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CompositesWorld – Thermoplastic composite materials and processing interactions: https://www.compositesworld.com/articles/thermoplastic-composite-materials-and-processing-interactions
CompositesWorld – Aerospace-grade compression molding: https://www.compositesworld.com/articles/aerospace-grade-compression-molding
GlobalSpec Insights – Thermoplastic composites manufacturing process advances: https://insights.globalspec.com/article/12882/thermoplastic-composites-manufacturing-process-advances
Tandfonline – Advanced manufacturing of thermoplastic tape preforms: braiding simulation, curved preforming, and consolidation (2025): https://www.tandfonline.com/doi/full/10.1080/20550340.2025.2546292
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