Microwave Sand Moulding Box for Uniform Hardening
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Solution Overview
Problem
The existing methods for drying and hardening large 3D printed foundry molds and cores using microwaves face challenges due to inhomogeneous microwave fields, leading to uneven hardening and difficulty in targeting individual layers, especially in large-scale production.
Innovation Solution
A device with a microwave chamber coextensive with the mold box, featuring microwave-emitting ceiling and wall components, a RF seal, and optional vacuum systems, allowing for a directed microwave field and controlled hardening of 3D printed foundry molds and cores by moving the mold box relative to the microwave source.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If conventional microwave chambers with chaotic microwave fields are used for drying and hardening large foundry molds, then the entire mold can be treated simultaneously, but the microwave field distribution is inhomogeneous leading to uneven hardening
Solution Approach 1:
The microwave chamber is divided into multiple independently controllable microwave zones (first and second microwave devices) that can be controlled separately. This allows different regions of the large foundry mold to receive customized microwave energy, ensuring uniform hardening across the entire mold volume even when the mold is very large.
Solution Approach 2:
Different regions of the mold can receive different microwave power levels and exposure times through the independently controllable microwave zones. This enables tailored hardening for specific areas of the mold, ensuring that all regions achieve the desired hardening quality regardless of the mold's overall size.
2Productivity
If microwave treatment is applied to large foundry molds produced by 3D printing, then production efficiency improves, but the chaotic microwave field makes it difficult to target individual layers for hardening
Solution Approach 1:
The microwave chamber is segmented into multiple independently controllable zones that can target specific layers or regions of the 3D-printed mold. This allows selective hardening of individual layers while maintaining overall production efficiency, as each zone can be independently activated and controlled.
Solution Approach 2:
The microwave devices can be controlled in periodic sequences, activating different microwave zones at different times to systematically harden different layers of the mold. This periodic activation pattern enables precise layer-by-layer hardening control while maintaining efficient production throughput.
3Device complexity
If the mold box and microwave chamber are separate entities, then the microwave field distribution becomes chaotic with multiple reflections, but integrating them simplifies the system
Solution Approach 1:
The mold box and microwave chamber are merged into a single integrated unit where the mold box forms part of the microwave chamber structure. This integration eliminates the interface between separate components, reducing chaotic reflections and simplifying the overall system while maintaining precise microwave field control through the integrated design.
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 efficient and targeted hardening of large foundry molds and cores with reduced risk of self-extinguishing reflections, allowing for quick production of large individual pieces without disassembly, and decoupling 3D printing and microwave treatment for improved process efficiency.
Implementation Method 1
microwave devices (100, 200) are provided in the ceiling plate (30) and optionally in the walls (30) of the chamber (10), which emit microwaves directly into the mold box (10, 210) and onto the 3D-printed foundry mold (20, 220)
Implementation Method 2
treating the green foundry mold (20, 220) directly with microwaves
Implementation Method 3
the ceiling plate (30) seals the mold box (10, 210) against high-frequency microwaves by means of a circumferential high-frequency (HF) seal (35)
Implementation Method 4
The green sand mold is subjected to a vacuum so that gases and vapors produced during drying do not lead to undesirable cavities
Data Source
Figure 1~1A
Figure 2
Figure 3
AI summary
The invention relates to a method and a device for producing casting moulds, known as sand moulds and cores. The sand mould is built up by 3D printing in a moulding box, wherein the moulding box is substantially equivalent to the microwave oven space in respect of microwave characteristics. The microwaves are radiated from the cope surface of the moulding box onto the casting mould so that a homogeneous microwave field is ensured, in which there are no reflections or overlapping of the microwaves. In this way a casting mould built up by 3D printing can be cured by means of microwaves, without cold spots appearing at some points in the moulding box and in the casting mould as a result of microwave extinction.