FFF Feedstock Binder for Metal Shrinkage Control
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Solution Overview
Problem
Current fused filament fabrication (FFF) methods face challenges in producing objects from heat-resistant materials like metals, alloys, and ceramics due to limitations in binder systems, which affect the spoolability, extrudability, and final product properties such as strength and density, leading to issues like severe shrinkage and distortion during debinding and sintering.
Innovation Solution
A feedstock comprising sinterable particles and a binder composition with a polymeric compatibilizer and a polymeric binder component, including a mixture of polymers with specific glass transition temperatures, is developed to enhance spoolability, extrudability, and the final product's strength and density, allowing for the production of objects with high relative density and complex structures.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If a particle-filled filament feedstock comprising particulate material and a thermoplastic binder is used in Fused Filament Fabrication, then objects made from heat-resistant materials like metals, alloys, and ceramics can be produced, but severe shrinkage and distortion occur during debinding and sintering
Solution Approach 1:
The patent uses a composite binder system comprising a first polymer component and a second polymer component with specific glass transition temperatures. This composite binder formulation allows the feedstock to maintain structural integrity during printing while enabling controlled debinding and sintering processes that minimize shrinkage and distortion in the final heat-resistant material objects
Solution Approach 2:
The patent specifies precise parameter ranges for the binder components, including glass transition temperatures (Tg) where the first polymer has Tg ≤ 60°C and the second polymer has Tg ≥ 110°C. These parameter controls enable the binder to exhibit appropriate viscoelastic properties at different stages of processing, thereby controlling dimensional stability during debinding and sintering
2Ease of operation
If a thermoplastic binder system is used to enable spoolability and extrudability of particle-filled filament, then the feedstock can be processed through commercial 3D printing equipment, but the final object lacks high strength and density
Solution Approach 1:
The patent employs a dual-polymer binder system with specifically controlled glass transition temperatures to achieve the desired balance. The first polymer component (Tg ≤ 60°C) provides flexibility and processability at lower temperatures, while the second polymer component (Tg ≥ 110°C) ensures structural strength and stability at higher temperatures, enabling both easy handling and high final product quality
Solution Approach 2:
By combining two polymer components with complementary thermal properties, the binder system achieves both the required processability for spooling and extrusion and the structural integrity needed to produce strong, dense final objects after sintering
3Ease of operation
If the glass transition temperature of the binder is too low to ensure spoolability, then the filament can be wound onto spools, but the green body lacks sufficient strength and the binder cannot be completely removed
Solution Approach 1:
The binder system is segmented into two functional polymer components with distinct glass transition temperatures. The first polymer component (Tg ≤ 60°C) handles the spoolability requirement, while the second polymer component (Tg ≥ 110°C) ensures green body strength and facilitates complete binder removal during debinding, with each component performing its specific function
Solution Approach 2:
By carefully selecting and controlling the glass transition temperatures of the two polymer components, the patent creates a binder system that transitions from a spoolable state at lower temperatures to a structurally sound state at higher temperatures, enabling both easy handling and reliable processing
4Reliability
If the glass transition temperature of the binder is too high to ensure green body strength, then the green body maintains structural integrity, but the filament cannot be spooled and the binder cannot be completely removed
Solution Approach 1:
The binder is segmented into two polymer components with complementary thermal characteristics. The lower-Tg component enables spoolability and binder removal, while the higher-Tg component provides green body strength, allowing the system to overcome the limitations of using a single polymer with either too high or too low glass transition temperature
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 proposed feedstock enables the production of objects with high strength and density, reducing shrinkage and distortion, and allowing for the creation of complex structures with improved structural integrity and printability, suitable for commercial 3D printing equipment.
Implementation Method 1
a polymeric binder component, the polymeric binder component being selected from the group consisting of (b2-1) a polymer mixture or polymer alloy, the mixture or alloy comprising at least a first and a second polymer, the Tg of the first polymer being −20° C. or lower and the Tg of the second polymer being 60° C. or higher
Implementation Method 2
sinterable particles made of a metal, metal alloy, glass, ceramic material, or a mixture thereof
Data Source
AI summary
A feedstock for a 3D manufacturing process, in particular a Fused Filament Fabrication process. The feedstock includes (P) sinterable particles made of a metal, metal alloy, glass, ceramic material, or a mixture thereof; and (B) a binder composition including (b1) 5-15% by weight, relative to the total weight of the binder composition, of a polymeric compatibilizer, and (b2) 85-95% by weight, relative to the total weight of the binder composition, of a polymeric binder component, the polymeric binder component being selected from the group consisting of (b2-1) a polymer mixture or polymer alloy, the mixture or alloy including at least a first and a second polymer; (b2-2) one, two or more block copolymers, including at least a first polymer block and second polymer block; and (b2-3) mixtures of (b2-1) and (b2-2), wherein the amount of sinterable particles P is 40 Vol % or more of the composition.