Sand Core Shell Structure Reducing VOC Emissions
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Conventional sand core production in sand casting processes results in high levels of volatile organic compounds (VOCs) emissions, complicates the knock-out process, and affects the dimensional stability and production efficiency, while also generating hazardous waste and increasing the risk of gas explosions due to the combustion of binder materials.
Innovation Solution
A method involving the use of a first and second binder component, where the second binder component is selectively applied to create a shell structure with minimal thickness, reducing the total binder content and emissions, and improving dimensional stability by forming a cured layer structure without hollow structures, which simplifies the knock-out process and allows for more efficient recycling of sand.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Object-generated harmful factors
If conventional binder jetting is used to create sand cores, then the sand core can be manufactured with standard binder content, but high levels of VOC emissions are generated during combustion
Solution Approach 1:
The binder system is segmented into two separate components: a first binder component mixed with sand, and a second binder component applied selectively. This segmentation allows the second component to be applied only where needed to form a cured shell, reducing total binder content and subsequent VOC emissions while maintaining structural integrity.
Solution Approach 2:
The second binder component is selectively applied to specific areas of the sand layer to create a cured shell structure. This local application ensures that binder is present only where structural support is needed, rather than uniformly throughout the entire sand core, thereby reducing overall binder content and emissions.
2Quantity of substance
If hollow plastic bodies are included within sand cores to reduce sand and binder content, then material usage is reduced, but the knock-out process becomes complicated and gas explosion risks increase
Solution Approach 1:
The invention extracts the problematic hollow plastic body concept and replaces it with a solid sand core structure that has a cured shell formed by the selective application of the second binder component. This eliminates the need for complex knock-out processes and removes gas explosion risks associated with hollow structures while still achieving reduced material content.
Solution Approach 2:
The invention converts the potential harm of gas generation from hollow structures into a benefit by using a solid sand core with a cured shell. The shell provides structural integrity without creating gas pockets, and the reduced binder content naturally decreases material usage without the complications of hollow constructions.
3Quantity of substance
If hollow structures are used in sand cores, then sand and binder content is reduced, but dimensional stability is impacted
Solution Approach 1:
The sand core is segmented into two functional zones: an inner sand region and an outer cured shell region. The shell, formed by the selective application of the second binder component, provides structural stability and dimensional accuracy, while the inner region can be optimized for material efficiency. This segmentation maintains dimensional stability without requiring hollow structures.
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 approach decreases VOC emissions, simplifies the knock-out process, maintains production efficiency, reduces hazardous waste, and enhances the dimensional stability of sand cores, while minimizing the risk of gas penetration and allowing for greater sand recycling without energy-intensive reclamation steps.
Implementation Method 1
a cured layer is created at the first sub part when the second binder component and the layer of the powder interact
Implementation Method 2
the binder material is combusted under the formation of organic emissions
Data Source
Figure 1
Figure 2
Figure 3
AI summary
A method for creating a sand core comprising the steps of mixing sand and a first binder component resulting in a powder. Supplying a layer of the powder onto a job box. The layer covering a first area. Supplying a second binder component onto the layer of powder at a first sub-part of the first area. The first sub-part comprising the supplied layer of the powder and the second binder component and a second sub-part comprising the layer of the powder but no second binder component. The first sub-part enclosing the second sub-part. Wherein a cured layer is created at the first sub part. Repeating the step of supplying a layer of the powder and the step of supplying a second binder component onto the layer of powder until a full sand core with a shell comprising a plurality of cured layers is created.