Reactive Polymer Fused Deposition Manufacturing for Layer Adhesion
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Solution Overview
Problem
Conventional additive manufacturing methods using polymers face challenges with large macroscopic distortions, low adhesion between deposition layers, and limited z-strength due to thermal gradients and the inability to print functional components without localized heating, which restricts the scalability and flexibility of large-scale polymer extrusion.
Innovation Solution
The use of cross-linking hybrid polymers that exhibit both thermoplastic and thermoset properties, allowing for deposition and subsequent chemical bonding across layers, enabling enhanced inter-layer adhesion and z-strength through a process involving partial cross-linking during deposition and extensive cross-linking after deposition, facilitated by reactive agents and optional electromagnetic alignment.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If conventional thermoplastics are used for additive manufacturing with localized heating, then manufacturing flexibility is improved, but macroscopic distortions increase due to large thermal gradients
Solution Approach 1:
The patent changes the material parameter from conventional thermoplastics to cross-linking hybrid polymers that can be deposited at lower temperatures and then cross-linked to achieve final bonding. This parameter change allows out-of-the-box printing without severe thermal gradients, maintaining both manufacturing flexibility and dimensional accuracy
Solution Approach 2:
The patent utilizes a two-stage phase transition process: first depositing the hybrid polymer in a thermoplastic state that allows flow and bonding, then cross-linking to achieve final structural integrity. This phase transition approach eliminates the need for severe localized heating during deposition, reducing thermal distortion while maintaining process flexibility
2Strength
If high molecular weight thermoplastics are used to increase mechanical strength, then z-strength is improved, but melt viscosity increases making extrusion difficult
Solution Approach 1:
The patent changes the material from high molecular weight thermoplastics to cross-linking hybrid polymers with carefully controlled molecular weight and functionality. These hybrid polymers achieve high z-strength through cross-linking rather than relying solely on high molecular weight, enabling easier extrusion while maintaining strength
Solution Approach 2:
The patent uses cross-linking hybrid polymers that combine thermoplastic processability with thermoset strength characteristics. This composite material approach allows the material to be extruded at lower viscosities while developing high z-strength through subsequent cross-linking, resolving the contradiction between strength and processability
3Ease of manufacture
If conventional thermoplastics are used for additive manufacturing, then ease of deposition is improved, but adhesion between deposition layers deteriorates resulting in delamination
Solution Approach 1:
The patent changes the material from conventional thermoplastics to cross-linking hybrid polymers that form chemical cross-links between deposited layers. This parameter change maintains ease of deposition through thermoplastic behavior while dramatically improving inter-layer adhesion through chemical bonding, preventing delamination
Solution Approach 2:
The patent replaces purely mechanical inter-layer bonding (reliance on physical interlocking and cooling adhesion) with chemical bonding through cross-linking. This substitution maintains deposition ease while significantly enhancing inter-layer adhesion strength, eliminating delamination issues
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 enables rapid out-of-the-box printing with minimal part distortion and improved z-strength, allowing for the production of functional components with enhanced mechanical properties comparable to engineering materials, such as aluminum, and the incorporation of second-phase reinforcements like carbon fibers.
Implementation Method 1
cross-linking hybrid polymers that act both as thermoplastics and thermosets. These polymers can be melt processed and readily form networks of chemical bonds that span z-layers, significantly increasing bonding between deposition layers and z-strength
Implementation Method 2
Fused deposition manufacturing (FDM) requires that a layer maintains tolerance immediately after deposition along with a structural bond to subsequent layers. This structural bond is formed by physically pushing the polymer melt into the previous layer
Data Source
AI summary
Methods and compositions for additive manufacturing that include reactive or thermosetting polymers, such as urethanes and epoxies. The polymers are melted, partially cross-linked prior to the depositing, deposited to form a component object, solidified, and fully cross-linked. These polymers form networks of chemical bonds that span the deposited layers. Application of a directional electromagnetic field can be applied to aromatic polymers after deposition to align the polymers for improved bonding between the deposited layers.