Integrated Manufacturing Method and System for Fibre-Reinforced Thermoplastic Composite Components Based on Controlled Intermediate State Regulation

Abstract

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Description

TECHNICAL FIELD The present invention relates to composite material manufacturing technologies, and in particular to an integrated manufacturing method and system for continuous fibre-reinforced thermoplastic composite components based on controlled regulation of a preform intermediate state. BACKGROUND OF THE INVENTION Continuous fibre-reinforced thermoplastic composites (CFRTPs) are increasingly used in aerospace, transportation, and structural applications due to their recyclability, impact resistance, and damage tolerance. However, manufacturing complex three-dimensional loadbearing components presents fundamental challenges in existing processes. In a "fully consolidated first, then formed" approach, laminate plates are fully consolidated before secondary thermoforming. In regions with abrupt geometric features, such as flanges or rib roots, fibres cannot sufficiently rearrange during forming, leading to fibre buckling, resin cracking, interlaminar delamination, and significant degradation of mechanical properties. In a "near-net-shape placement with post-processing" approach using automated tape laying (ATL) or automated fibre placement (AFP), a preform can be laid close to the final geometry. However, if the preform is fully consolidated after placement, it loses the ability to undergo fibre rearrangement during subsequent forming. Conversely, if no consolidation is performed, the preform lacks sufficient interlaminar bonding strength to maintain its shape, making automated handling and transfer unreliable. Accordingly, there exists no effective manufacturing route that simultaneously provides sufficient shape stability for automated transfer and sufficient formability for high-quality 2026201597   03 Mar 2026 final shaping. Resolving this contradiction is critical for improving both performance and manufacturing efficiency of complex CFRTP components. SUMMARY OF THE INVENTION The present invention provides an integrated manufacturing method and system based on precise regulation of an intermediate state of a thermoplastic composite preform. The inventive concept resides in intentionally creating, during the placement stage, a partially consolidated intermediate state in which interlaminar bonding strength is sufficient to maintain a three-dimensional near-net shape and support automated transfer, while the thermoplastic matrix remains capable of full re-melting and flow during a subsequent forming stage. Such capability for re-melting and flow is evidenced by the occurrence of macroscopic fibre rearrangement during the subsequent forming stage without inducing interlaminar cracking or delamination. In one aspect, the invention provides a method for manufacturing a fibre-reinforced thermoplastic composite component, comprising: (a) forming a near-net-shape preform by placing continuous fibre-reinforced thermoplastic prepreg tapes while applying ultrasonic vibration energy and local pressure, such that partial interlaminar bonding is achieved and a preform in a partially consolidated, re-activatable intermediate state is formed; (b) transferring the preform in the intermediate state from a placement station to a heated forming tool using a robotic handling device configured to apply distributed gripping forces to avoid interlaminar shear or shape distortion; and (c) subjecting the preform to coordinated thermal and mechanical loading in the forming tool to fully melt the thermoplastic matrix, enable fibre rearrangement, and consolidate the preform into a final three-dimensional component. In another aspect, the invention provides a system configured to implement the above method, including an ultrasonic-assisted placement unit, a robotic transfer unit, a thermomechanical forming unit, and an integrated control system for coordinating the process 2026201597   03 Mar 2026 parameters across all stages. The ultrasonic-assisted placement unit is configured to perform step (a) of the method by producing a preform in the partially consolidated intermediate state. The robotic transfer unit is configured to perform step (b) by transferring the preform while applying distributed gripping forces adapted to the intermediate state. The thermomechanical forming unit is configured to perform step (c) by applying coordinated heat and pressure to complete consolidation. The integrated control system synchronises the operating parameters of the placement unit, transfer unit, and forming unit across the placement, transfer, and forming stages to ensure that the preform remains within the intended intermediate state throughout the manufacturing process. BRIEF DESCRIPTION OF THE DRAWINGS Figure 1 illustrates an overall layout of an ultrasonic placement and thermoforming integrated manufacturing system. Figure 2 illustrates a block diagram of the integrated control system. Figure 3 illustrates an ultrasonic placement head. Figure 4 illustrates a placement operation state. Figure 5 illustrates a tension control system. Figure 6 illustrates a near-net-shape preform. Figure 7 illustrates a robotic transfer unit and a thermo-mechanical forming tool. Figure 8 illustrates a process flow of the manufacturing method. Reference Numerals in these figures: 2026201597   03 Mar 2026 2 - Primary feeder 3 - Weight-suspended tension control device 4 - Fibre tape conveying roller system 5 - Secondary feeder 6 - Ultrasonic layup head 7 - Rotating platform 8 - Five-axis gantry machine tool 10 - Robot-specific suction cup 11 - Thermo-mechanical forming tool 12 - Cutting device 13 - Double pressure roller 14 - Ultrasonic generator 15 - Pressure roller cylinder 16 - Suction cup mounting plate 17 - Suction cup 18 - Auxiliary roller 19 - Tensioned roller 20 - Weight pan 2026201597   03 Mar 2026 21 - Integrated control system DETAILED DESCRIPTION OF EMBODIMENTS System Overview With reference to Figures 1 and 2, an ultrasonic placement and thermoforming integrated manufacturing system is illustrated. The system comprises: •       a tape roll (1); •      a primary feeder (2); •      a weight-suspended tension control device (3); •      a fibre tape conveying roller system (4); •      a secondary feeder (5); •      an ultrasonic layup head (6); •       a rotating platform (7); •      a five-axis gantry machine tool (8); • a robotic handling device including a robot-specific suction cup (10); • a thermo-mechanical forming tool (11); and • an integrated control system (21) as shown in Figure 2. The system is configured to regulate a preform within a defined intermediate-state window throughout placement, transfer, and forming. For the purposes of this specification, the term "intermediate-state window" refers to a controlled parameter range defining acceptable limits of interlaminar bonding strength and matrix re-activatability, such that: 1. the preform maintains three-dimensional geometric stability under ambient handling conditions; and 2026201597   03 Mar 2026 2. the thermoplastic matrix remains capable of complete re-melting and macroscopic fibre rearrangement under subsequent forming conditions. Integrated Control System With reference to Figure 2, the integrated control system (21) comprises: • a central processor; • input interfaces receiving data from ultrasonic parameters, tension sensors, robot position feedback, and forming temperature / pressure sensors; and • output interfaces sending control signals to the placement unit, robotic transfer unit, and forming unit. The control system continuously monitors whether the preform remains within the intermediate-state window and adjusts operating parameters accordingly to maintain the intended state throughout the manufacturing process. The monitoring may be performed indirectly through measured ultrasonic energy input, tape tension values, robotic gripping force parameters, and forming temperature-pressure profiles, each being associated with predetermined acceptable ranges corresponding to the intermediate-state window. Ultrasonic Placement Stage With reference to Figures 1 and 3, continuous fibre-reinforced thermoplastic prepreg tapes are unwound from the tape roll (1) and fed through the primary feeder (2) and secondary feeder (5) to the ultrasonic layup head (6). The tapes are conveyed via the fibre tape conveying roller system (4) and guided by an auxiliary roller (18) and a tensioned roller (19) toward the ultrasonic layup head (6), which is mounted on the five-axis gantry machine tool (8). The ultrasonic layup head (6) comprises: an ultrasonic generator (14); 2026201597   03 Mar 2026 • a double pressure roller (13); and • a pressure roller cylinder (15). During placement, ultrasonic vibration energy generated by the ultrasonic generator (14) and local compaction pressure applied through the double pressure roller (13) are synchronously applied to the tape. As schematically illustrated in Figure 4, this induces localised softening or partial melting of the thermoplastic matrix at interlaminar interfaces, without causing full bulk consolidation. The ultrasonic vibration amplitude, contact pressure applied by the pressure roller cylinder (15), and energy dwell time are controlled within predetermined ranges to achieve partial interlaminar bonding only. This controlled regulation produces a partially consolidated intermediate preform, in which interlaminar bonding is sufficient to maintain shape integrity during handling, yet limited enough to permit complete re-melting and fibre rearrangement during subsequent forming. Tension Regulation With reference to Figures 4 and 5, tape tension is regulated by a hybrid tension control system comprising: •      the primary feeder (2); • the weight-suspended tension control device (3); and •      a weight pan (20). The weight-suspended tension control device (3) applies passive gravity-based compensation through the weight pan (20), while the primary feeder (2) provides active baseline tension. The combined mechanism stabilises tape tension during changes in placement direction and curvature, preventing excessive tensile stress that could disturb the partially consolidated 2026201597   03 Mar 2026 interlaminar bonding state. Tension is continuously monitored via servo motor feedback to ensure it remains within a range compatible with the intermediate state. Intermediate Preform State As shown in Figure 6, the near-net-shape preform formed on the rotating platform (7) exhibits a partially consolidated intermediate state. In this state: • interlaminar bonding strength is sufficient to maintain geometric integrity during handling; and • the thermoplastic matrix remains capable of complete re-melting and macroscopic fibre rearrangement during subsequent forming. This intermediate state is structurally distinct from both a fully consolidated laminate and an unconsolidated layup. Robotic Transfer Stage With reference to Figure 7, the partially consolidated preform is transferred from the rotating platform (7) by a robotic handling device equipped with a robot-specific suction cup (10). The robot-specific suction cup (10) is mounted on a suction cup mounting plate (16) and includes multiple suction cups (17) distributed across the contact surface. Each suction cup (17) is independently controllable, enabling the gripping force distribution to be adapted to the local bending stiffness and curvature of the preform. This distributed gripping configuration minimises interlaminar shear stress and prevents shape distortion during lifting, transport, and positioning. A cutting device (12) may be used to trim the tape prior to transfer where required. Thermo-Mechanical Forming Stage 2026201597   03 Mar 2026 Also with reference to Figure 7, the preform is positioned within a heated forming tool of the thermo-mechanical forming unit (11). Coordinated thermal and mechanical loading is applied according to a predetermined temperature-pressure profile matched to the intermediate state of the preform. The profile is selected based on the degree of partial consolidation achieved in the placement stage to ensure complete matrix re-melting without degrading the fibre architecture. Under heating, the thermoplastic matrix fully melts, enabling fibre rearrangement and final consolidation. After controlled cooling, a consolidated composite component with uniform fibre distribution and strong interlaminar bonding is obtained. Process Coordination The overall manufacturing sequence is summarised in Figure 8, including: 1.     tape feeding and ultrasonic placement via the ultrasonic layup head (6); 2.     formation of the partially consolidated preform on the rotating platform (7); 3. robotic transfer using the robot-specific suction cup (10); and 4.     thermo-mechanical consolidation in the forming tool (11). The integrated control system synchronises: •      ultrasonic vibration parameters (14); • tension regulation parameters (2, 3, 20); •      robotic gripping forces (10, 17); and •      forming temperature-pressure parameters, 2026201597   03 Mar 2026 to ensure that the preform remains within the intermediate-state window throughout the manufacturing process. Inventive Concept Clarification While ultrasonic vibration is described as a preferred energy input mechanism, the inventive concept does not reside in the specific energy source itself. Rather, the inventive concept resides in: the deliberate creation, maintenance, and transformation of a partially consolidated intermediate state that simultaneously enables automated transportability and subsequent fibre rearrangement during forming. Alternative energy-assisted placement mechanisms may be employed provided that they generate the same intermediate-state characteristics defined herein. Functional Integration The system architecture shown in Figure 1 is not a mere aggregation of independent placement, transfer, and forming equipment. Instead, each subsystem is functionally configured and parameter-synchronised to cooperatively maintain the intermediate-state window, thereby enabling continuous, automated, high-quality manufacturing of complex load-bearing thermoplastic composite components. Industrial Applicability The invention is applicable to automated manufacturing of load-bearing thermoplastic composite components in aerospace, transportation, and industrial equipment sectors, particularly for components having complex three-dimensional geometries.

Claims

1. A method for manufacturing a fibre-reinforced thermoplastic composite component, comprising:(a) placing continuous fibre-reinforced thermoplastic prepreg tapes unwound from a tape roll (1) and fed via a primary feeder (2) and a secondary feeder (5) through a fibre tape conveying roller system (4) to an ultrasonic layup head (6) mounted on a five-axis gantry machine tool (8), while applying ultrasonic vibration energy generated by an ultrasonic generator (14) and local pressure applied by a double pressure roller (13) actuated by a pressure roller cylinder (15), to form a three-dimensional near-net-shape preform on a rotating platform (7), the preform having partial interlaminar bonding and being in a partially consolidated, re-activatable intermediate state;(b) transferring the preform in the partially consolidated, re-activatable intermediate state from the rotating platform (7) to a thermo-mechanical forming tool (11) using a robotic handling device comprising a robot-specific suction cup (10) mounted on a suction cup mounting plate (16) and including multiple suction cups (17) configured to apply distributed gripping forces; and(c) applying coordinated heat and pressure to the preform in the thermo-mechanical forming tool (11) to fully melt the thermoplastic matrix, enable fibre rearrangement, and consolidate the preform into a final composite component.

2. The method according to claim 1, wherein the degree of partial interlaminar bonding achieved by the ultrasonic layup head (6) is controlled such that the preform maintains its shape at ambient temperature while permitting full matrix flow during step (c) in the thermo-mechanical forming tool (11).

3. The method according to claim 1 or claim 2, wherein step (a) includes applying controlled tape tension using a combination of active feeding by the primary feeder (2) and gravity-based passive tension regulation provided by a weight-suspended tension control device (3) including a weight pan (20).

4. The method according to any one of claims 1 to 3, wherein the robotic handling device comprises a robot-specific suction cup (10) including independently2026201597  18 Jun 2026controllable suction cups (17) configured to apply distributed gripping forces adapted to the three-dimensional geometry of the preform.

5. The method according to any one of claims 1 to 4, wherein heating in step (c) is initiated after the preform is positioned in the thermo-mechanical forming tool (11) and follows a temperature-pressure profile matched to the intermediate state of the preform.

6. A manufacturing system configured to perform the method according to any one of claims 1 to 5, comprising:an ultrasonic-assisted placement unit including a tape roll (1), a primary feeder (2), a fibre tape conveying roller system (4), a secondary feeder (5), and an ultrasonic layup head (6) comprising an ultrasonic generator (14) and a double pressure roller (13) actuated by a pressure roller cylinder (15);a robotic handling device including a robot-specific suction cup (10) mounted on a suction cup mounting plate (16) and having multiple suction cups (17);a thermo-mechanical forming unit including a thermo-mechanical forming tool (11); andan integrated control system (21) configured to coordinate ultrasonic vibration parameters, tape tension parameters, robotic gripping logic, and forming temperaturepressure parameters, wherein the ultrasonic-assisted placement unit, the robotic handling device, the thermo-mechanical forming unit, and the integrated control system are functionally configured and parameter-synchronised to cooperatively create, maintain, and transform a partially consolidated intermediate-state window throughout placement, transfer, and forming operations, such that:(i) the preform maintains sufficient geometric stability for automated transfer; and(ii) the thermoplastic matrix remains capable of complete re-melting and fibre rearrangement during subsequent forming.

7. A fibre-reinforced thermoplastic composite component produced by the method according to any one of claims 1 to 5.2026201597  18 Jun 2026The reference numerals in the claims are included for convenience and clarity only and shall not be construed as limiting the scope of the claims.

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