Aluminum Alloy Die-Casting Process for MRI Cooling System Components

Aluminum Alloy Die-Casting Process for MRI Cooling System Components

MRI equipment, acting as the "precision eyes" of clinical diagnosis, experiences peak heat loads exceeding 50kW for its core components such as gradient coils and cooling pipes. Temperature control accuracy must reach ±0.2℃ to prevent image artifacts and equipment malfunctions. Aluminum alloy die-casting, with its lightweight, high density, and ability to form complex structures, has become the preferred manufacturing solution for MRI cooling system components. It meets the stringent performance requirements of medical equipment while enabling large-scale mass production, providing cost-effective core component supply support to global distributors.

I. Core Performance Requirements of MRI Cooling System Components

The strong magnetic field environment and precision imaging requirements of MRI equipment impose four core requirements on cooling system components, directly determining the selection and optimization direction of the die-casting process: **Antimagnetic and Interference-Free:** The use of non-magnetic aluminum alloys with extremely low iron content is required to avoid interfering with magnetic field uniformity (≤1ppm) and prevent image distortion.

High Density and Leak-Proof: Cooling pipes, pumps, and other components must withstand pressures exceeding 4 Bar, with porosity controlled below 1% to prevent coolant leakage and equipment damage.

Lightweight and Strength Balance: Component density must be controlled at approximately 2.7 g/cm³, reducing equipment load while meeting structural requirements of tensile strength ≥380 MPa.

Corrosion Resistance and Thermal Stability: Components must withstand corrosion from liquid helium condensate at -269℃ and disinfectants in medical environments, with a thermal expansion coefficient consistently below 23 × 10⁻⁶/℃.

II. Process Adaptation Scenarios for Low-Pressure and High-Pressure Die Casting

For the structural characteristics and performance requirements of different components in MRI cooling systems, low-pressure die casting and high-pressure die casting complement each other, achieving "dual optimization of performance and efficiency":

Low-Pressure Die Casting: The Preferred Solution for High-Density Core Components
Applicable Components: Cooling pipes, pumps, sealing valves, and other core components requiring pressure resistance and leak-proof design.

Process Advantages: Smooth, turbulent filling of the molten metal results in castings with a density exceeding 99%. After T6 Heat Treatment, tensile strength can be increased to over 380MPa, perfectly suited for sealing components requiring further machining.

Alloy Selection: Al-Si-Mg alloys A356 and A357 are preferred, with a silicon content of 5%-7%, balancing fluidity and antimagnetism to meet the extreme temperature fluctuation requirements of liquid helium cooling systems.

Key Parameters: Filling pressure 0.1-0.5MPa, mold temperature controlled at 200-250℃, single-piece production cycle 5-8 minutes, suitable for medium-batch, high-precision component production.

High-Pressure Die Casting: An efficient molding solution for complex thin-walled components.

Applicable Components: Complex structural components such as heat sinks, lightweight housings, and integrated flow channels.

Process Advantages: High-pressure, high-speed filling at 10-200MPa enables the molding of thin-walled structures with a thickness of 1.0-3.0mm and a surface roughness of Ra1.6-3.2μm. Machining allowance is only 0.1-0.3mm, allowing for assembly without secondary processing.

Alloy Selection: High-flow-rate Al-Si alloys ADC12 and 6063 are used, with iron content strictly controlled below 0.15% to ensure a balance between antimagnetism and molding precision.

Key Parameters: Injection speed 3-10m/s, mold cooling time 10-30 seconds, producing 2-3 pieces per minute, meeting annual production capacity requirements of millions of units and significantly reducing bulk procurement costs.

III. Process Optimization and Quality Control: Meeting Medical-Grade Standards

The die-casting production of MRI cooling system components requires multiple technological optimizations to meet ISO 10993 medical device material standards:
* Mold and Vacuum Technology: Utilizing modified H13 steel molds and a vacuum system designed for complex flow channels, the porosity of high-pressure die-Cast Parts is controlled below 0.5%, enabling weldability and localized heat treatment.

Precise Parameter Control: An automated system controls die-casting temperature and pressure curves, ensuring dimensional tolerances are stable within ±0.1mm, guaranteeing component interchangeability and adaptability to the assembly needs of different brands of MRI equipment.

Surface and Internal Inspection: Anodizing treatment forms a dense anti-corrosion layer, resisting corrosion from disinfectants and condensate; ultrasonic testing is used to detect internal defects, prohibiting pores larger than 0.5mm in diameter or cracks longer than 3mm.

Green Production Guarantee: Utilizing recycled aluminum alloys with over 90% recycling rate, refining technology controls the content of impurities such as Fe and Cu, reducing costs and meeting global environmental compliance requirements.

IV. Application Value and Cooperation Advantages

MRI cooling system components manufactured using aluminum alloy die-casting technology have been successfully integrated into mainstream 1.5T-3.0T MRI machines, achieving three core benefits:

Improved Equipment Stability: Gradient coil temperature is stabilized at 32±0.2℃, image artifact area is ≤2mm², and the failure rate during continuous operation is reduced by 40%;

Reduced Overall Costs: Integrated molding reduces the number of parts, lowering costs by 30%-50% compared to traditional machining. In mass production, the cost per unit can be controlled within the range of 8-15 RMB;

Adaptation to Global Needs: Supports customized design, allowing component structures to be adjusted according to the specifications of MRI equipment in different regions, meeting the medical certification requirements of markets in Europe, America, and Southeast Asia.