Gypsum Embedding Material for Rapid Heating Casting
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Solution Overview
Problem
Gypsum-based embedding materials are inadequate for rapid heating processes, particularly when used with resin patterns, as they fail to prevent cracks and breakage, and do not achieve desired dimensional accuracy and surface quality.
Innovation Solution
A gypsum-based embedding material composition comprising calcined gypsum, cristobalite, quartz, and a non-heat-expandable refractory material with specific particle diameters and blending ratios, which enhances the material's ability to withstand rapid heating without cracking and ensures a smooth, glossy surface and accurate dimensions.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If gypsum-based embedding materials are used for rapid heating processes, then treatment efficiency is improved, but cracks and breakage occur in the material
Solution Approach 1:
The patent uses a composite material system consisting of gypsum binder combined with multiple refractory materials (cristobalite, quartz, and non-heat-expandable refractory materials). This composite structure allows the embedding material to withstand rapid heating by distributing thermal stress across different components with complementary properties, preventing cracks and breakage while maintaining high treatment efficiency.
Solution Approach 2:
The patent introduces non-heat-expandable refractory materials with specific particle diameters (5 to 20 μm) to locally compensate for the heat expansion of other refractory materials. This local quality adjustment creates a balanced expansion profile within the composite material, preventing excessive expansion during rapid heating while maintaining overall structural integrity and crack resistance.
2Manufacturing precision
If heat-expandable refractory materials are used to compensate for metal contraction, then dimensional accuracy is improved, but excessive expansion causes cracks and breakage
Solution Approach 1:
The patent introduces non-heat-expandable refractory materials with specific particle diameters (5 to 20 μm) to locally compensate for the heat expansion of other refractory materials. This local quality adjustment creates a balanced expansion profile within the composite material, preventing excessive expansion during rapid heating while maintaining overall structural integrity and crack resistance.
Solution Approach 2:
The patent optimizes the particle diameter parameters of refractory materials to specific ranges (cristobalite and quartz: 5 to 20 μm, non-heat-expandable refractory materials: 5 to 20 μm) and controls their blending ratios (10 to 25 parts by mass per 100 parts by mass of main components). These parameter changes ensure appropriate heat expansion compensation without excessive expansion, maintaining dimensional accuracy while preventing cracks.
3Ease of operation
If gypsum-based embedding materials are used for high temperature casting, then operability and fluidity are improved, but casting properties at high temperature deteriorate
Solution Approach 1:
The patent creates a composite embedding material system that combines gypsum binder with multiple refractory materials (cristobalite, quartz, and non-heat-expandable refractory materials). This composite structure maintains the excellent fluidity and operability of gypsum-based materials while adding high-temperature stability through the refractory components, ensuring reliable casting properties at high temperatures.
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 effectively suppresses cracks and breakage during rapid heating, achieving a cast with desired size and surface quality, particularly suitable for dental casting and applicable to both wax and resin patterns.
Implementation Method 1
an embedding material having a coefficient of expansion to compensate for the coefficient of contraction of a metal, the embedding material containing cristobalite or quartz
Implementation Method 2
the embedding material should be the one that is capable of preventing the occurrence of cracks, breakage, or the like liable to occur by the expansion being too large in order for the embedding material to be applicable to the above-described rapid heating
Data Source
AI summary
“A gypsum-based embedding material” is provided with which favorable casting can be conducted not only in the case where a conventional wax pattern is used, but also, in particular, in the case where a resin pattern different from the conventional wax pattern in disappearance temperature and disappearance behavior is used, and with which, although being a “gypsum-based embedding material”, occurrence of cracks, breakage, or the like in a mold is suppressed even when casting is conducted by “rapid heating” excellent in treatment efficiency. The gypsum-based embedding material composition for casting comprising, as main components, calcined gypsum as a binder, cristobalite and quartz as heat-expandable refractory materials, and a non-heat-expandable refractory material having an average particle diameter of 5 to 20 μm, the blending amount of the non-heat-expandable refractory material in 100 parts by mass of the main components being 10 to 25 parts by mass.