The die casting mold gating system determines the flow path and state of the metal liquid filling, and plays an important role in reducing the pores and impurities of the die casting and obtaining a dense structure. Therefore, the choice of gating system form is crucial. In order to minimize the flow of molten metal, the die structure is compact, and the center gate is used for pouring. The process has the advantages of short flow, uniform pressure transfer, synchronous filling sequence, uniform temperature field distribution, smooth exhaust gas, and easy slag discharge, and can avoid the eccentric pressure of the cavity in the die casting process and facilitate the quality of the die casting.
Different from ordinary die castings, the rotor structure of micro-motors appears to be simple, but the wall thickness differs greatly. The wall thickness of the end rings, the blades and the guide strips are thin and thin. If the mold design is unreasonable, it will lead to shrinkage, loosening, porosity, as well as guide bars and insufficient shaping of the fan blade.
The rotor parts shown have two end rings at each end. The lengths are 12mm and 6mm, respectively. The 6mm end ring is the first design: Tian Fuxiang, male, born in 1951, professor.
For the feed gate end, a 12 mm end ring was placed at the bottom of the cavity.
During die casting, the aluminum liquid fills the top of the cavity first. Therefore, the bottom of the cavity requires a good exhausting capacity. Otherwise, defects such as blowholes and filling dissatisfaction may occur due to insufficient exhaust gas. Therefore, an exhaust port with a width of 18 mm and a depth of 0.1 mm was opened at the bottom of the illustrated mold cavity. At the same time, the method of inserting inserts and inserting sleeves in the moving and fixed molds is used to facilitate the discharge of gas during the die casting process, thereby solving the problems of the blowholes of the castings, reducing the wastes caused by the blowholes, and improving the qualification rate of the die castings. By designing the vulnerable parts on the mold cavity as the illustrated inserts and inserts, the tool steel can be saved, and the inserts and the inserts can be easily manufactured. By replacing the inserts and inserts, the update cost of the mold is reduced.
The die-casting process and its die CAD system can shorten the design cycle, reduce costs, and improve product competitiveness, which has received widespread attention at home and abroad. Currently, there are mainly two types of system development methods that are developed. One is based on general-purpose mechanical CAD/CAM software development, such as UG and Pro/Engineei in the United States; the other is based on the visual programming language in Windows environment to write CAD core programs. The components outside the core program are developed by other professional software. Pro/E is a three-dimensional CAD/CAM software developed by PTC and integrates part design, product assembly, mold development, numerical control processing, sheet metal design, casting design, and modeling CAD/CAM integration. A die casting mold was put forward to realize CAD meter, reverse engineering, automatic measurement, mechanism simulation, stress analysis and product data management. For these functional modules of Pro/E, a new method based on Pro/E for die-casting mold CAD is proposed.
1 Design Principles and Design Contents of Die Casting Dies Die casting die is an important process equipment for die casting production. The advantages and disadvantages of die casting die design directly affect the shape, size, strength, surface quality, etc. of die castings, so die casting die design should meet the following requirements: Principle: Adapt to various technological requirements of die-casting production, and obtain die castings that meet the requirements of drawings.
A high degree of emphasis is placed on the design and calculation of the gating system to minimize the consumption of cast alloys for castings.
The use of standardized components as much as possible to shorten the design and manufacturing practice shows that the mold exhaust effect and die casting quality are good, the castings are detected by the X-ray machine, the bar and the end ring metal organization are more compact, non-porous, and the surface appearance is smooth, no Cold septum and other defects.
2 Mold working principle When the mold is in the fully open position, the stacked rotor core is placed in the cavity. During die-casting, the aluminum liquid in the material cylinder is pushed from the sprue through the runner in the push of the die casting machine and injected into the cavity at the inward gate. After leaving the mold for 12s, the mold is opened. Under the action of the push rod of the die casting machine, the workpiece is ejected by the top plate 21 through the pins 3, 4. When the mold is closed, the top plate is reset by the reset lever 23 .
3 Process parameters Die casting process parameters include shot pressure, filling rate, die casting temperature, cavity temperature, mold retention time and so on.
The specific pressure has a great influence on the ability of the molten metal to fill the cavity, the strength and compactness of the casting. A higher specific pressure can increase the strength and compactness of the casting, but a higher specific pressure will reduce the service life of the die casting mold, increase the tendency of sticking, and significantly reduce the elongation of the casting. This process than the pressure is set to 52MPa filling rate is an important factor affecting the quality of the appearance of the casting. The flow rate of the molten metal at the ingate is set within the range of 20 m/s.*C.
In die-casting production, keeping the mold temperature constant can increase the quality of castings, production efficiency and service life of the mold. Model temperature control range is 200~250.0. Retention time is about 3s per millimeter for the average wall thickness of the casting. The rotor retention time should be properly selected according to the rotor model. The retention time is too short and will affect the quality of the rotor die casting. Too long will affect the production. effectiveness. Casting time is 12s. 4 conclusions The production practice shows that the die-casting die has a reasonable structure, reliable exhaust gas, flexible and convenient operation, no need to use the rotor chip for heating, long spindle life, good casting quality and high production efficiency.