Internal Woven Reinforcement Network for Additive Manufacturing
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Solution Overview
Problem
Extrusion-based additive manufacturing processes, such as fused deposition modeling, face challenges in achieving sufficient strength between layers (z-direction) in printed parts due to the bonding of molten material to previously solidified material, leading to weaker interlayer connections compared to the strength within the print plane (x-y plane).
Innovation Solution
The method involves creating an internal woven reinforcement network by knitting loops as each layer is printed, which extends above the part surface, allowing for the formation of a tensioned structure within the part. This is achieved by using a pre-fabricated starter piece with loops, where additional loops are knitted and printed around, and the completed part is heated to apply tension to the reinforcement network, solidifying it in place.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If layers are printed by extruding molten material onto previously solidified material, then the printing process can be completed efficiently, but the interlayer strength (z-direction) is insufficient compared to in-plane strength (x-y plane)
Solution Approach 1:
The patent combines thermoplastic material with a knitted reinforcement network to create a composite structure. The reinforcement network is integrated within the printed part and placed under tension to provide enhanced interlayer strength while maintaining the lightweight benefits of the thermoplastic material.
Solution Approach 2:
The knitted reinforcement network is prepared and positioned within the part before the final printing is complete. The network is tensioned and secured in place during the printing process, so that when the part is finished, the reinforcement is already in its functional state to provide enhanced strength.
2Adaptability or versatility
If support structures are added to underhanging portions, then the part can be printed with complex geometries, but the device complexity and manufacturing time increase
Solution Approach 1:
The knitted reinforcement network serves multiple functions simultaneously: it provides structural reinforcement, acts as a tensioning mechanism, and can be integrated with support structures. This multi-functionality reduces the need for separate complex support systems while maintaining the ability to print complex geometries.
3Strength
If the part material is heated to apply tension to the reinforcement network, then the interlayer strength is enhanced, but the energy consumption increases
Solution Approach 1:
The part material is heated to a specific temperature range to enable tensioning of the reinforcement network. This controlled parameter change allows the material to become sufficiently pliable to accommodate the tensioned network, then cools to lock the reinforcement in place. The energy input is localized and temporary, only required during the tensioning phase.
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 significantly enhances the interlayer strength of printed parts by creating a tensioned internal woven reinforcement network, providing strength comparable to or exceeding that of metal structures while maintaining the lightweight benefits of thermoplastic materials, and allowing for the printing of larger parts by securing components together.
Implementation Method 1
extruding a viscous, flowable thermoplastic or filled thermoplastic material from a print head... The extruded flow of material is deposited as a sequence of roads onto a substrate, where it fuses to previously deposited material and solidifies upon a drop in temperature
Implementation Method 2
the completed part is heated to a temperature where the material is flowable, and a force is applied to pull the starter piece and the course of loops in opposite directions from each other, thereby placing the internal woven reinforcement network into tension
Implementation Method 3
The part is cooled to a temperature where the thermoplastic material solidifies such that the internal woven structure remains in tension
Data Source
AI summary
A method of producing a part printed in a layer-wise manner includes providing a pre-fabricated starter piece with a first course of loops and printing a layer of a part by extruding one or more flowable thermoplastic materials about the existing course of loops such that an upper surface of the layer is at a selected height on the existing course of loops. The method includes knitting a next course of loops to the existing course of loops to form a portion of an internal woven reinforcement network, and printing a next layer of the part by extruding one or more flowable thermoplastic materials about the next course of loops such that an upper surface of the next layer is at a selected height on the next course of loops, wherein the next course of loops extends above the structure being printed and may function as an existing course of loops for subsequent knitting steps. The method includes repeating the knitting and printing steps to create an internal woven reinforcement network within the printed part until the part is completed. The starter piece and the course of loops extending from the second end of the completed part are engaged and heated to a temperature where the material is flowable. The reinforcement network is then placed into tension by applying a force to pull the starter piece and the course of loops in opposite directions from each other. The part is cooled to a temperature where the thermoplastic material solidifies such that the internal woven structure remains in tension.