In the casting and forming process of aluminum alloy die castings, defects such as pores, flow marks, scratches, dents, cracks, and undercasting are prone to occur. These defects deteriorate the appearance quality and mechanical properties of die castings. In order to avoid the above problems in the die-casting process, the structural designer needs to evaluate the plan in advance in the structural design of the die-casting part, and reasonably arrange the parts in the structural design to minimize the defects by optimizing the structure.
The design rationality of aluminum alloy die castings is related to the entire die casting process. Therefore, when designing die-casting parts, the design, structural characteristics and process requirements of the die-casting parts should be fully considered, and the defects of the designed die-casting parts during the die-casting forming process should be minimized by optimizing the design scheme, and the quality of the die-casting parts should be improved.
1) Reasonable design of wall thickness of die castings
In the structural design of aluminum alloy die castings, the wall thickness must be fully considered. In the die casting process, the wall thickness is a factor of special significance. If the designed wall thickness is too thick, there will be external surface defects such as shrinkage holes, blisters, pores, and coarse internal grains, which will reduce the mechanical properties, improve the quality of the parts, and increase the cost. If the designed wall thickness is too thin, it will lead to poor filling and forming of liquid aluminum, resulting in poor dissolution of the aluminum alloy, and defects such as difficulty in filling the surface of the casting and lack of materials, which will bring difficulties to the die-casting process.
2) Reasonable design of reinforcement ribs of die castings
Large flat or thin-walled die castings have poor strength and rigidity and are easily deformed. However, the use of reinforcing ribs can effectively prevent shrinkage and fracture of die castings, eliminate deformation, and improve the strength and stiffness of die castings. For structures such as ultra-high columns and platforms, steel bars can be used to improve stress distribution and prevent root fractures. At the same time, the reinforcing agent can promote the flow of the molten metal and improve the filling performance of the casting.
3) Reasonable design of die casting angle
The inclination angle of aluminum alloy die-casting is to reduce the friction between the casting and the cavity and facilitate the removal of the casting. Generally speaking, the outlet inclination of the outer surface of the die casting is about 1/2 of the inclination of the inner cavity outlet, but in actual design, the outlet inclination of the inner and outer surfaces of the die casting can be designed to be the same to keep the wall thickness uniform and simplify the structural design.
4) Reasonable design of machining allowance should be avoided in the design of die castings
machining, because it will destroy the dense layer on the surface of the part and affect the mechanical properties of the part. Machining also exposes internal pores in die castings, affecting surface quality and increasing part cost. When the processing of die-casting parts is unavoidable, the design with large cutting amount should be avoided as much as possible, and the structural design should be as easy as possible to process or reduce the processing area and processing cost.
5) Spraying design of aluminum alloy die castings
The surface spraying design of aluminum alloy die castings generally adopts powder spraying process. The principle is electrostatic powder spraying: the paint is mainly polarized by electrodes, and then the object to be sprayed is charged with opposite charges, and the powder is uniformly attached to the surface of the object under the action of the electric field. Features of powder spraying process: powder electrostatic spraying will not cause air pollution; powder can be recycled to reduce material consumption cost, and the coating film has good acid resistance, alkali resistance and corrosion resistance.
In the aluminum alloy die-casting process, using high-quality molds is an effective way to improve the quality and output value of die-casting; as the saying goes, sharpen the axe to win'; don't delay chopping wood - being prepared can save work time. Die casting molds are; "knives"; used to produce aluminum alloy castings. Using high-quality molds will not delay the production of castings, but will help improve the quality of castings.
Aluminum alloy die casting technology is another; "knife"; used to produce aluminum alloy castings. With the continuous improvement of skills and the need for professional development, the aluminum alloy casting industry is also constantly improving, and the die casting skills are constantly being updated. Manufacturers are committed to better die-casting skills and higher die-casting speeds, and continue to improve their die-casting skills. State-of-the-art die-casting technology always provides aluminium alloy castings of very good quality and higher production value.
Therefore, if the manufacturer wants to improve the quality and output value of aluminum alloy die-casting, using high-quality die-casting molds and leading die-casting technology is the most useful method.