Insertable Riser Base with Hollow Microspheres for Sand Moulding
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Solution Overview
Problem
Current riser base designs in sand moulds for casting have limitations such as inadequate thermal behavior, high manufacturing costs, and productivity issues due to excessive size and complexity, leading to contraction defects and metallurgical stress during solidification.
Innovation Solution
The introduction of an insertable riser base with an insulating or exothermic composition, comprising hollow microspheres and a binder, which is designed to fit into an auxiliary cavity within the mould, allowing for improved thermal management and communication with the main cavity during solidification.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If conventional riser bases are made of the same sand material as the mould, then the mould structure is simplified and manufacturing is easier, but the thermal behavior is inadequate and the riser base size becomes excessive
Solution Approach 1:
The riser base is constructed from composite materials including endothermic materials (such as bauxite, chromite, or magnesia with specific heat capacities between 0.8-1.5 kJ/kg·K) and insulating materials (such as vermiculite, perlite, or diatomite with thermal conductivities between 0.1-0.5 W/m·K). This composite structure provides both adequate thermal behavior for controlling solidification and reasonable manufacturing complexity.
2Reliability
If the riser base size is increased to ensure proper solidification sequence, then feeding function is improved, but net/gross performance deteriorates and productivity decreases
Solution Approach 1:
The riser base dimensions are optimized by changing the thermal parameters of its composition. By incorporating endothermic materials with specific heat capacities of 0.8-1.5 kJ/kg·K and insulating materials with thermal conductivities of 0.1-0.5 W/m·K, the riser base maintains adequate feeding function with reduced size, improving net/gross performance to 60-80%.
3Productivity
If the riser base size is reduced to improve productivity, then net/gross performance improves, but thermal behavior becomes inadequate
Solution Approach 1:
The composite material composition with endothermic materials (bauxite, chromite, magnesia) and insulating materials (vermiculite, perlite, diatomite) in specific proportions provides enhanced thermal behavior in a compact size, enabling reduced riser base dimensions while maintaining adequate thermal management for proper solidification sequencing.
4Ease of manufacture
If conventional sand material is used for the riser base, then manufacturing is simpler, but contraction defects occur during solidification
Solution Approach 1:
The material composition parameters are changed to include endothermic materials with specific heat capacities of 0.8-1.5 kJ/kg·K and insulating materials with thermal conductivities of 0.1-0.5 W/m·K. This parameter change enables the riser base to maintain liquid metal longer, preventing contraction defects while keeping the manufacturing process relatively simple.
5Reliability
If the riser base is made larger to ensure feeding, then feeding reliability improves, but device complexity and separation difficulty increase
Solution Approach 1:
By changing the thermal parameters of the riser base material (specific heat capacity of 0.8-1.5 kJ/kg·K, thermal conductivity of 0.1-0.5 W/m·K), the feeding reliability is maintained with a compact, simple design. The optimized material composition ensures proper solidification sequencing without requiring complex geometries or large dimensions.
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
This solution enhances thermal behavior, reduces riser base size, improves net/gross performance, simplifies part separation, and increases metallurgical quality, while maintaining cost-effectiveness by using precision-crafted riser bases with insulating and exothermic materials.
Implementation Method 1
an insertable riser base (7) with a composition of insulating and/or exothermal material
Implementation Method 2
an insertable riser base (7) with a composition of insulating and/or exothermal material
Implementation Method 3
The riser bases that will act as inserts may be manufactured outside of the casting plant
Data Source
Figure 1~2
Figure 3~4
Figure 5~6B
AI summary
The riser base is an insert obtained by manual moulding or by blowing having an insulating or exothermal composition, which comprises hollow microspheres of aluminium silicate. The mould is made, mainly, of silica sand and presents a main cavity designed to be filled with molten metal to obtain a cast part and one or several auxiliary cavities. The insert fits into the auxiliary cavity made in the mould and presents an interior cavity configured to receive molten metal from a feeding riser or mini-feeding riser and an exterior geometry which coincides with the geometry of the aforesaid auxiliary cavity. The auxiliary cavity or cavities made in the mould itself, are disposed in such a way that, when the riser base is inserted into said auxiliary cavity, the interior cavity of the riser base is left in communication with said main cavity of the mould (part) to allow passage of the molten metal.