Hydraulic Composition for Additive Manufacturing Casting Molds
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Solution Overview
Problem
Existing additive manufacturing technologies for casting molds suffer from inadequate early flexural strength development and dimensional stability, leading to defects and increased production costs due to thermal decomposition and dimensional variations.
Innovation Solution
A hydraulic composition for additive manufacturing devices comprising a specific sand-to-inorganic binder-to-polyvinyl alcohol ratio, with calcium aluminates as the primary binder, which provides enhanced early flexural strength and dimensional stability, reducing powder leakage and improving spreading and leveling.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If rapid-hardening cement is used in the hydraulic composition, then early strength development should be improved, but the patent reveals that flexural strength at early ages (within 24 hours) remains insufficient
Solution Approach 1:
The patent applies parameter changes by optimizing the sand-to-binder ratio to 4-12 (mass basis) and controlling the polyvinyl alcohol to inorganic binder ratio at 0.1-0.4 (mass basis). These specific parameter ranges transform the material properties to achieve both early flexural strength development and dimensional stability within 24 hours, resolving the contradiction between early strength and defect prevention.
Solution Approach 2:
The patent uses composite materials by combining sand, inorganic binder (calcium aluminate), and polyvinyl alcohol in specific proportions. This composite formulation creates a synergistic effect where the organic-inorganic binder system provides both early flexural strength and dimensional stability, eliminating defects associated with single-binder systems.
2Productivity
If additive manufacturing is used to produce casting molds, then preliminary model production steps are eliminated, but dimensional variations and cracking occur after molding
Solution Approach 1:
The patent addresses dimensional stability by formulating a hydraulic composition that resists cracking during dimensional changes. The composite binder system maintains structural integrity under stress, allowing complex curved geometries to be produced without cracking, thus enabling direct additive manufacturing of final-shaped molds without preliminary steps.
Solution Approach 2:
By controlling the sand-to-binder ratio (4-12) and polyvinyl alcohol to inorganic binder ratio (0.1-0.4), the material achieves optimal dimensional stability. These parameter optimizations prevent cracking and shrinkage during curing, ensuring manufacturing precision is maintained throughout the additive manufacturing process.
3Adaptability or versatility
If complex-shaped casting molds are produced, then design flexibility is improved, but cracking occurs due to dimensional variations
Solution Approach 1:
The composite binder system combining inorganic binder (calcium aluminate) and polyvinyl alcohol provides enhanced crack resistance while maintaining design flexibility. This material composition allows complex geometries to be manufactured without compromising structural integrity, as the composite formulation accommodates stress distribution in complex shapes.
Solution Approach 2:
The optimized sand-to-binder ratio (4-12) and polyvinyl alcohol to inorganic binder ratio (0.1-0.4) create a material with improved crack resistance. These parameter changes enable the production of complex-shaped molds that maintain strength and integrity even when subjected to dimensional variations during curing.
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 composition achieves high early flexural strength, dimensional stability, and efficient production of casting molds with improved surface quality and reduced defects, enabling stable and cost-effective manufacturing.
Implementation Method 1
a hydraulic composition for an additive manufacturing device, including at least sand, an inorganic binder, and polyvinyl alcohol
Implementation Method 2
a mass ratio of the sand/(inorganic binder+polyvinyl alcohol) is 4 to 12; and a mass ratio of the polyvinyl alcohol/inorganic binder is 0.1 to 0.4
Implementation Method 3
a molded article formed by carrying out solidification and layering by addition of an aqueous binder to a material obtained by incorporating 15, to 50% rapid-hardening cement into a refractory sand
Data Source
AI summary
A hydraulic composition for an additive manufacturing device, the hydraulic composition containing at least sand, an inorganic binder, and polyvinyl alcohol, wherein the hydraulic composition for an additive manufacturing device satisfies conditions (1) and (2).(1) The mass ratio of sand/(inorganic binder+polyvinyl alcohol) is 4 to 12.(2) The mass ratio of polyvinyl alcohol/inorganic binder is 0.1 to 0.4.The hydraulic composition for an additive manufacturing device also preferably satisfies condition (3).(3) The mass ratio of water/(inorganic binder+polyvinyl alcohol) is 0.30 to 1.30.