Linkable Thermoplastic Binder for Binder Jetting
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Solution Overview
Problem
Existing binder jet 3D printing technologies face challenges in achieving suitable green strength for handling during post-printing processes and in removing chemical binders without generating char residue or metal oxides.
Innovation Solution
The use of a linkable thermoplastic binder, comprising a first and second polymer strand with functional groups that non-covalently couple, providing improved green strength and enabling clean removal in inert or vacuum conditions.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Object-generated harmful factors
If conventional chemical binders are used in binder jet printing, then the green body can be formed, but the binder cannot be removed without generating char residue or metal oxides
Solution Approach 1:
The patent changes the chemical composition parameters of the binder by using thermoplastic polymers with specific functional groups (carboxyl, hydroxyl, amine, or thiol) that enable clean decomposition. The binder is formulated to decompose completely into volatile products at controlled temperatures without leaving char residue or metal oxides, resolving the contradiction between binder removal cleanliness and harmful residue generation.
Solution Approach 2:
The patent employs inert or vacuum conditions during the heating process to remove the binder. By conducting the decomposition in an inert atmosphere or vacuum environment, the thermoplastic binder decomposes cleanly without oxidizing to form metal oxides or char residue, thereby achieving complete binder removal without harmful byproducts.
2Strength
If conventional binders are used, then printing can be performed, but suitable green strength for handling during post-printing processes is not achieved
Solution Approach 1:
The patent uses composite binder systems combining thermoplastic polymers with specific functional groups that provide both adequate green strength and clean removability. The composite formulation includes polymers like polyacrylic acid, polyvinyl alcohol, or their copolymers, which create sufficient bond strength between metal powder particles while maintaining ease of handling during post-printing operations.
Solution Approach 2:
The patent optimizes the molecular weight, concentration, and functional group composition of the thermoplastic binder to achieve the optimal balance between green strength and handling ease. By controlling the binder's physical and chemical parameters, the green body achieves sufficient structural integrity for post-printing operations while the binder remains removable without harmful residues.
3Object-generated harmful factors
If thermoplastic binders are used, then clean removal is achieved, but green strength may be insufficient without crosslinking
Solution Approach 1:
The patent introduces functional groups (carboxyl, hydroxyl, amine, or thiol) as intermediaries that mediate between the thermoplastic polymer chains and the metal powder particles. These functional groups form coordination bonds or hydrogen bonds that provide sufficient green strength while the thermoplastic nature allows clean removal without char residue, resolving the contradiction between strength and clean removability.
Solution Approach 2:
The patent modifies the chemical parameters of the thermoplastic binder by incorporating specific functional groups that enable reversible bonding. These functional groups allow the binder to provide adequate green strength through coordination chemistry while maintaining the ability to decompose cleanly at elevated temperatures, achieving both strength and clean removal without crosslinking limitations.
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
The linkable thermoplastic binder enhances the green strength of the green body metal part, allowing for stable handling during post-printing processes, and ensures clean removal without char residue or metal oxides, resulting in a consolidated metal part with properties similar to the original metal powder.
Implementation Method 1
the first and second functional groups non-covalently couple the first polymer strand with the second polymer strand
Implementation Method 2
heating the green body part above a first temperature to remove at least a portion of the linkable thermoplastic binder
Implementation Method 3
heating the brown body part above a second temperature to sinter the powder to generate the part
Data Source
AI summary
A binder solution configured for use in binder jet printing is provided. The binder solution may include a primer, a surfactant, and a linkable thermoplastic binder comprising a first polymer strand and a second polymer strand, wherein the first polymer strand comprises a first functional group and the second polymer strand comprises a second functional group, and wherein the first and second functional groups are configured to non-covalently couple at least a portion of the second polymer strand with at least a portion of the first polymer strand; wherein the first polymer strand and the second polymer strand are both polymer strands of the same thermoplastic polymer, and wherein the first polymer strand further comprises the second functional group and the second polymer strand further comprises the first functional group.