Rotor Aluminum Casting with Temperature Gradient and Pressure Control
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Solution Overview
Problem
Current methods for casting aluminum on rotors, such as pressure casting and low-pressure casting, often result in defects like pores and shrinkage holes, which increase resistance and decrease motor efficiency.
Innovation Solution
A method that involves preheating and multi-stage heating of dies with a top-down temperature gradient and precise pressure control using an electromagnetic pump to improve feeding capacity and reduce defects, allowing for efficient casting by minimizing assembly and disassembly time and enabling one-time multi-casting.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If pressure casting is used to fill the die cavity with liquid metal at high speed under high pressure, then casting efficiency is improved, but the castings develop defects such as pores and shrinkage holes
Solution Approach 1:
The invention changes the pressure parameter from high pressure (pressure casting) to low pressure (0.03-0.06 MPa), and changes the filling speed from high speed to slow speed, thereby eliminating pores and shrinkage holes while maintaining acceptable casting efficiency
Solution Approach 2:
The die is preheated to 100-200°C before casting to prevent premature solidification and reduce shrinkage defects, and the gating system is designed with specific dimensions to control the filling process and eliminate defects
2Manufacturing precision
If low pressure casting is used to improve product quality, then casting defects are reduced, but air holes and cold shuts still occur during solidification
Solution Approach 1:
The gating system is designed with different section dimensions to control the solidification sequence, ensuring that the runner cools slower than the cavity to prevent cold shuts, while the cavity solidifies from the gating end toward the far end to prevent air holes
Solution Approach 2:
A cold well is introduced as an intermediary structure between the runner and the cavity, acting as a heat sink to control the solidification sequence and prevent defects during the casting process
3Manufacturing precision
If the die is heated and assembled three times to achieve directional solidification, then feeding capacity is improved, but production efficiency decreases
Solution Approach 1:
The die is preheated to 100-200°C before casting to establish the proper temperature gradient for directional solidification from the beginning, eliminating the need for multiple heating cycles and improving production efficiency
Solution Approach 2:
The heating temperature is optimized to 100-200°C rather than higher temperatures, which is sufficient to prevent defects while reducing energy consumption and heating time, thereby improving production efficiency
4Productivity
If multiple dies are used for casting to improve production efficiency, then casting efficiency is improved, but the complexity of the casting system increases
Solution Approach 1:
The casting system is segmented into modular components including the die, gating system, and cold well, allowing for standardized design and assembly of multiple casting stations while maintaining system simplicity
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 method enhances casting efficiency, reduces defects, and improves the quality of cast aluminum by ensuring proper feeding and solidification, resulting in higher purity and reduced production time.
Implementation Method 1
utilizing the characteristic that the pressure of the direct-current electromagnetic pump is accurately controllable
Implementation Method 2
setting heating temperatures of the top-down arranged four-section heating coil to 400℃, 450℃, 500℃ and 550℃
Implementation Method 3
heats and assembles a die in three times to realize directional solidification of aluminum
Implementation Method 4
the preheating being performed by induction heating, resistance heating, direct contact direct current resistance heating or gas heating
Data Source
Figure 1~2
Figure 3
AI summary
A method for casting aluminum on a rotor, comprising: installing casting equipment on a casting workbench and storing enough molten aluminum in the casting equipment, wherein the casting equipment comprises an heat preserving furnace and an electromagnetic pump arranged at a side of the heat preserving furnace ; assembling a plurality of rotor iron cores with a plurality of dies respectively and preheating outside the casting workbench; installing the plurality of preheated dies on a plurality of liquid outlet gates at a top end of the electromagnetic pump, wherein each liquid outlet gate is matched with a liquid inlet gate of the dies; heating and keeping the installed die in a multi-stage heating mode; controlling the pressurizing pressure of the electromagnetic pump in time-period when the electromagnetic pump is used for casting; and after completing casting, moving the plurality of dies out of the casting workbench to be cooled. According to the method for casting aluminum through the rotor, the casting efficiency is improved by reasonably distributing the heating time and the one-time multi-casting mode; the top-down temperature gradient is matched with accurate pressure control, so that the compensation capacity is improved.