Zonal Sand Compaction for Uniform Green Mold Density
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Solution Overview
Problem
The existing green sand method for producing sand casting molds struggles with achieving uniform compaction around complex models, leading to inadequate mold quality, especially for large workpieces, and often requires the use of environmentally polluting chemical binders to ensure stability.
Innovation Solution
A method and device that compact molding sand zonally, taking into account the model's contour and dimensions, using a compacting unit with movable and positionable compression cylinders, allowing for varying pressing forces and strokes to ensure optimal density, without the need for chemical binders.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Force
If a large compaction head covering the entire molding box is used to compact green sand, then the compaction force is sufficient, but the sand above the model is compressed more than the sand on the side of the model due to greater compression distance, resulting in non-uniform density
Solution Approach 1:
The compaction head is divided into multiple independently operable compaction punches (cylinders) that can be controlled separately. This segmentation allows different zones of the molding sand to receive appropriate compaction force, with punches positioned to compact sand at the model sides more effectively than sand above the model, thereby achieving uniform density throughout the mold cavity.
Solution Approach 2:
Different compaction forces and strokes are applied to different zones of the molding sand based on their specific requirements. The compaction punches are configured to apply localized compaction pressure, particularly targeting areas with the model to ensure proper density, while avoiding over-compaction of sand regions that already have adequate density.
2Stability of the object's composition
If chemical binders are added to the molding sand to produce stable molds, then mold stability is improved, but environmental pollution increases due to the use of chemical binders
Solution Approach 1:
The patent replaces chemical bonding mechanisms with mechanical compaction. By using multiple independently controlled compaction punches that apply precise mechanical pressure to the green sand, the mold achieves sufficient stability without requiring chemical binders. This mechanical compaction system substitutes for the chemical curing process, eliminating the environmental pollution associated with binder chemicals while maintaining mold integrity.
3Object-affected harmful factors
If green sand is used without chemical binders, then environmental sustainability is maintained, but homogeneous compaction of the sand to define the shape is no longer reliably possible for large molds
Solution Approach 1:
The compaction system is segmented into multiple independently operable punches that can be positioned and controlled to achieve homogeneous compaction across the entire mold cavity. This segmentation allows precise control of compaction forces in different zones, ensuring uniform density and proper shape definition even in large molds without relying on chemical binders.
Solution Approach 2:
The compaction parameters (force, stroke, sequencing) of the multiple punches are optimized to achieve homogeneous compaction of green sand. By carefully controlling the mechanical parameters of each punch, the system ensures that the green sand is uniformly compacted to define the workpiece shape accurately, maintaining environmental sustainability through binder-free operation.
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
Enables the production of high-quality sand casting molds with complex surfaces and large sizes using the green sand method, ensuring uniform density and avoiding the use of chemical binders, thus improving mold stability and environmental sustainability.
Implementation Method 1
the molding sand is compacted zonally (in some areas), taking into account the contour or the dimensions of the model
Data Source
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AI summary
The invention relates to a method for producing a casting mold for sand casting, wherein a model is positioned in a molding flask and the molding flask is filled with molding sand (green or wet sand - sand, bentonite, and water) and wherein the molding sand is compressed around the model in order to form a stable mold suitable for casting, is characterized in that the compression of the molding sand occurs in certain zones or regions, with consideration of the contour and/or the dimensions of the model. A corresponding device for using the method comprises a compression unit having a compression head having a plurality of compression cylinders.