Fiber-Reinforced Plastic Extrusion for Low-Shear Additive Manufacturing
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Solution Overview
Problem
Existing extrusion processes for additive manufacturing of fiber-reinforced plastic materials face challenges in achieving desired material strength due to limitations in screw extruder design, which often result in fiber degradation and unsheared fibers, leading to oversized 3D printing devices and difficulty in achieving required material properties.
Innovation Solution
A method and device using a conveyor screw with a length-to-diameter ratio of less than 10, limited volume in the heating zone to 5.5 cm³ or less, and a maximum rotational speed of 30 revolutions per minute, combined with controlled residence time and feed rate, to prevent fiber degradation and achieve advantageous fiber orientation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If a conventional screw extruder with long conveyor screw is used for additive manufacturing of fiber-reinforced plastic, then the device can process the material, but the fiber degrades and material strength is insufficient
Solution Approach 1:
The patent changes critical parameters of the extrusion system: reducing the length-to-diameter ratio of the conveyor screw to less than 10, limiting the heating zone volume to 5.5 cm³ or less, and controlling rotational speed to maximum 30 rpm. These parameter changes minimize shear forces and residence time, preventing fiber degradation while ensuring adequate material strength in the finished component.
Solution Approach 2:
The patent applies partial action by providing only the minimum necessary heating zone volume (5.5 cm³ or less) and using a compact conveyor screw (length-to-diameter ratio < 10). This limited configuration is sufficient for the additive manufacturing process, avoiding excessive shear forces that would degrade fibers, while still achieving complete material processing and desired component strength.
2Ease of manufacture
If a conventional screw extruder with long conveyor screw is used, then material can be processed, but the 3D printing device becomes oversized
Solution Approach 1:
The patent fundamentally changes the geometric parameters of the conveyor screw by reducing the length-to-diameter ratio to less than 10, and limits the heating zone volume to 5.5 cm³ or less. These parameter changes enable a compact extrusion device design that maintains full additive manufacturing capability while significantly reducing device size and weight compared to conventional extruders.
3Productivity
If high rotational speed is used in the conveyor screw, then extrusion efficiency increases, but shear forces increase causing fiber degradation
Solution Approach 1:
The patent optimizes the rotational speed parameter by limiting it to a maximum of 30 rpm. This controlled speed parameter achieves the necessary extrusion efficiency for additive manufacturing while maintaining shear forces at levels that prevent fiber degradation, ensuring the finished component achieves required material strength.
Solution Approach 2:
The patent applies partial action by using a relatively low rotational speed (maximum 30 rpm) that is sufficient for the compact extrusion system's productivity requirements. This limited speed prevents excessive shear forces and fiber degradation, while still achieving adequate extrusion efficiency for additive manufacturing applications.
4Reliability
If large heating zone volume is used, then complete material processing is ensured, but fiber degradation occurs due to prolonged residence time
Solution Approach 1:
The patent changes the heating zone volume parameter to 5.5 cm³ or less and controls the conveyor screw's length-to-diameter ratio to less than 10. These parameter changes reduce material residence time in the heating zone, preventing fiber degradation from prolonged exposure, while still ensuring complete thermoplastic material processing and achieving reliable extrusion for additive manufacturing.
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
This approach effectively prevents plastic material degradation and ensures long, unsheared fibers, enhancing the material strength of the finished component by controlling shear forces and fiber orientation, allowing for efficient additive manufacturing of fiber-reinforced plastic components.
Implementation Method 1
a conveyor screw of the extrusion device is used, which has a length-diameter ratio of less than 10
Implementation Method 2
heated in a heating zone of the extrusion device in order to subsequently feed the fiber-reinforced plastic material
Implementation Method 3
a material thread with (molten) fiber-reinforced plastic material for the component to be produced is extruded
Data Source
Figure 1
Figure 2
Figure 3~4
AI summary
The invention relates to a method and an apparatus for extrusion of fiber-reinforced plastic material for the additive manufacture of a component (1), wherein - the fiber-reinforced plastic material (8) is supplied to the extrusion apparatus (2) and heated in a heating zone (43) of the extrusion apparatus (2) in order to then supply the fiber-reinforced plastic material (8) to an extrusion nozzle (10) of the extrusion apparatus (2), at which a material thread comprising fiber-reinforced plastic material (8) is extruded for the component to be produced, and - in order to convey the fiber-reinforced plastic material (8) through the heating zone (43), a screw conveyor (3) of the extrusion apparatus (2) is used which has a length-diameter ratio of less than 10. A maximum of 5.5 cm3 of volume is provided in the heating zone (43) for the fiber-reinforced plastic material (8) and a speed of the screw conveyor (3) is limited to a maximum of 30 revolutions per minute.