Dual-Beam Additive Manufacturing for Molten Pool Cooling Control
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Solution Overview
Problem
In additive manufacturing, particularly in the directed energy deposition method, rapid cooling of hard materials can lead to cracking of shaped objects due to the toughness of the materials, and existing methods for preheating powder materials are either impractical or complicate the processing head and control system.
Innovation Solution
An additive manufacturing device with an inner light beam radiation device for melting and an outer light beam radiation device for controlled heat retention, where the power density of the outer light beam is adjusted to maintain a cooling rate of 540°C/s or less at the freezing point of the carbide binder, preventing rapid cooling and solidification.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If rapid cooling is applied to solidify the powder material after melting, then the manufacturing efficiency is improved, but cracking occurs in the shaped object due to the toughness of the hard material
Solution Approach 1:
The patent applies preliminary action by preheating the powder material before melting and controlling the cooling rate during solidification. The outer light beam preheats the powder material prior to the inner light beam melting it, and the cooling rate is controlled during solidification to prevent cracking, thus preparing the material in advance to avoid quality issues.
Solution Approach 2:
The patent changes the thermal parameters by controlling the cooling rate to be 540°C/s or less at the freezing point of the carbide binder. This parameter control is achieved by using the outer light beam to maintain temperature during solidification, transforming the rapid cooling process into a controlled slow cooling process that prevents cracking while maintaining manufacturing efficiency.
2Reliability
If a heater is used to preheat the powder material in the LMD, then the cracking is prevented, but the processing head is interfered with or the control system becomes complicated
Solution Approach 1:
The outer light beam serves multiple functions: it preheats the powder material before melting, controls the cooling rate during solidification, and prevents cracking. By using the outer light beam for multiple thermal management tasks, the patent eliminates the need for separate heaters and complex control systems, achieving multi-functionality with a single light beam system.
Solution Approach 2:
The patent merges the preheating function and the cooling rate control function into the outer light beam system. Instead of having separate heaters for preheating and separate controls for cooling rate management, the outer light beam performs both functions simultaneously, simplifying the processing head structure and control system.
3Reliability
If the cooling rate is controlled to 540°C/s or less at the freezing point of the carbide binder, then cracking is prevented, but the manufacturing time increases
Solution Approach 1:
The outer light beam continuously irradiates the molten pool during the solidification process, maintaining a controlled cooling rate without interruption. This continuous useful action ensures that the cooling rate remains at 540°C/s or less throughout the solidification, preventing cracking while minimizing the time extension through efficient energy delivery.
Solution Approach 2:
The patent utilizes the phase transition of the carbide binder from liquid to solid at its freezing point, controlling the cooling rate specifically at this transition point. By focusing control at the critical phase transition moment rather than throughout the entire process, the patent prevents cracking during the most vulnerable phase while minimizing overall manufacturing time extension.
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 effectively prevents cracking and ensures the production of high-quality shaped objects with a simple configuration by controlling the cooling rate of the molten pool, thereby enhancing the quality of additively manufactured hard materials.
Implementation Method 1
an inner light beam radiation device configured to radiate an inner light beam that heats a material at a temperature equal to or higher than a melting point of the material
Implementation Method 2
an outer light beam radiation device configured to radiate an outer light beam that heats the material at a temperature lower than the melting point
Implementation Method 3
a cooling rate of the molten pool representing a temperature drop per unit time is 540° C./s or less at a freezing point of the carbide binder included in the molten pool
Data Source
AI summary
An additive manufacturing device includes: an inner light beam radiation device of radiating an inner light beam; an outer light beam radiation device of radiating an outer light beam; and a control device. when a molten pool is irradiated with the outer light beam, the control device controls a power density of the outer light beam representing an output per unit area such that a cooling rate of the molten pool representing a temperature drop per unit time is 540° C./s or less at a freezing point of a carbide binder included in the molten pool, the molten pool being formed by irradiating a material including a hard material and a carbide binder with the inner light beam to melt the material. According to the present disclosure, the additive manufacturing device can prevent cracking and additively manufacture a high-quality shaped object with a simple configuration.