Curved Composite Profile Pultrusion with Continuous Cylindrical Winding

Resolve Bottlenecks,
Find Innovative Solutions
Generate Solutions

Solution Overview

Problem

Conventional pultrusion processes for producing curved composite profiles are time-consuming and costly due to their discontinuous nature and require additional design and process engineering measures, with limitations on achievable radius and length, and face challenges in producing small radii and continuous production.

Innovation Solution

A pultrusion process where reinforcing materials are wetted with a polymer matrix, formed into a composite profile in a mold, and then continuously wound onto a cylindrical unit in a dimensionally stable state, allowing for continuous production of curved profiles with variable radii and lengths, using a pultrusion device with a forming tool and cylindrical unit that can adjust to different curvatures.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Productivity

If conventional pultrusion process is used to produce curved composite profiles, then the process can be continuously operated, but the process becomes time-consuming and costly due to discontinuous operations and additional work steps

Engineering Contradiction:
Improveproduction efficiencyVSAvoidprocess time
Core Design Contradiction:
ProductivityVSLoss of time

Solution Approach 1:

The patent implements continuous pultrusion by replacing the reciprocating forming tool with a stationary forming tool and introducing a rotating cylindrical unit that continuously winds the cured composite profile. This eliminates the stop-start nature of conventional curved profile production, allowing the pultrusion process to run continuously without interruption while maintaining the ability to produce curved profiles of various radii and lengths.

Inventive Principle:
Principle #20Continuity of useful action

2Adaptability or versatility

If radius pultrusion process with reciprocating forming tool is used, then curved composite profiles can be produced, but the smallest achievable radius is limited by the size and arrangement of the forming tool and pullers

Engineering Contradiction:
Improvecurvature radius variabilityVSAvoidminimum achievable radius
Core Design Contradiction:
Adaptability or versatilityVSManufacturing precision

Solution Approach 1:

The patent transitions from a linear reciprocating motion in one dimension to a rotational motion around a cylindrical unit, introducing a new dimensional approach. The cylindrical unit's rotation axis becomes the center of curvature, allowing the forming tool to maintain a fixed position while the composite profile naturally follows a curved path determined by the cylindrical unit's radius, thereby achieving small radii without compromising tool arrangement.

Inventive Principle:
Principle #17Another dimension (Dimensionality change)

Solution Approach 2:

The stationary forming tool combined with the rotating cylindrical unit creates a universal system that can produce curved composite profiles with various radii and lengths. The cylindrical unit serves multiple functions: it acts as the center of curvature, provides continuous winding capability, and enables production of different profile geometries without requiring tool reconfiguration, thus achieving versatility without sacrificing manufacturing precision.

Inventive Principle:
Principle #6Universality (Multi-functionality)

3Length of moving object

If radius pultrusion process is used to produce long circular arcs, then curved profiles can be formed, but the maximum achievable length is limited due to collision between the plastic profile and the forming tool

Engineering Contradiction:
Improveprofile lengthVSAvoidprocess reliability
Core Design Contradiction:
Length of moving objectVSReliability

Solution Approach 1:

Instead of moving the forming tool back and forth along a curved trajectory, the patent inverts the approach by keeping the forming tool stationary and moving the cured composite profile continuously past it via rotation of the cylindrical unit. This inversion eliminates the collision problem entirely, as the forming tool remains fixed in space while the profile is wound onto the rotating unit, allowing production of arbitrarily long curved profiles without risk of collision.

Inventive Principle:
Principle #13The other way round (Inversion)

4Adaptability or versatility

If additional design and process engineering measures are implemented for curved profile production, then curved composite profiles can be produced, but the device complexity increases

Engineering Contradiction:
Improvecurved profile production capabilityVSAvoidprocess complexity
Core Design Contradiction:
Adaptability or versatilityVSDevice complexity

Solution Approach 1:

The patent merges the curing and winding operations into a single integrated step. The cylindrical unit serves dual purposes: it acts as both the winding drum and the curing chamber (through heating elements or UV lamps integrated into the cylinder). This consolidation eliminates the need for separate curing and winding processes, reducing device complexity while maintaining the capability to produce curved profiles efficiently.

Inventive Principle:
Principle #5Merging (Combining)

Applied Scientific Principles

This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.

Function Achieved in This Case

Enables the cost-effective and time-efficient production of curved composite profiles with virtually any desired radius and length, reducing deformation and stress, and allowing for seamless winding and cutting of segments, suitable for applications like bicycle rims.

Implementation Method 1

the wetted reinforcing materials are formed into a composite profile in the forming tool and cured to a dimensionally stable state

Methodology Applied
Scientific EffectCuring: Chemical Bonding

Implementation Method 2

the dimensionally stable, cured composite profile is continuously wound onto a cylindrical unit as part of the pultrusion device

Methodology Applied
Scientific EffectFriction: Friction

Data Source

PatentEP4065352B1Pultrusion method and pultrusion device for producing curved composite profiles
Publication Date: 2025.10.15 FRAUNHOFER GESELLSCHAFT ZUR FORDERUNG DER ANGEWANDTEN FORSCHUNG EV
  • EP4065352B1 patent drawingFigure 1a~1b
  • EP4065352B1 patent drawingFigure 2a~2b
  • EP4065352B1 patent drawingFigure 2c~2d

AI summary

The invention relates to a pultrusion method in which, in order to produce curved composite profiles (2), reinforcing materials are wetted with a polymer matrix material and the wetted reinforcing materials are pulled through a shaping tool (1) by means of a pultrusion device. In addition, the wetted reinforcing materials are shaped in the shaping tool (1) to form a composite profile (2) and cured in a dimensionally stable manner. After exiting the shaping tool (1), the dimensionally stably cured composite profile (2) is continuously wound on a cylindrical unit (3) as part of the pultrusion device