If you want to produce good quality aluminum die-casting parts, you have to go through many processes and steps. Every process must pay great attention to the details and there should be no slight errors. The way of coating the aluminum castings will also affect the quality of the surface of the die-casting parts. Have an impact.
Aluminum die castings often have insufficient casting during the operation. The main reason is that the metal type conducts heat too fast, and the melting point of aluminum is low, which causes the aluminum liquid to fill the cavity in advance during the flow. Cooled down. In order to avoid the lack of casting of aluminum castings, the following issues should be noted:
1. Increase the casting temperature;
2. Perform necessary heating and insulation on the mold, or spray insulation coating inside the mold;
3. Improve the pouring system to make the casting more smooth and shorten the filling time;
4. The metal model has certain requirements on the wall thickness. If the wall thickness is too thin, then other processes, such as die casting machining, should be considered.
How to spray aluminum die castings
It is very important that the aluminum die-casting part prepares the surface quality of the metal cavity wall before coating. The new metal type must be thoroughly cleaned, degreased and rusted. The part with the draft angle must be polished with fine sand cloth. And assorted enamel (because the taper hole of CNC milling machine is microscopically stepped, not flat bevel, it is difficult to demould), the used mold must also completely remove the original coating.
The thermal insulation of the coating of aluminum die castings depends not only on the thickness of the coating, but also on the porosity of the coating itself. The porosity of the coating is largely influenced by the application conditions and methods employed. Because the degree of formation of voids in the coating is basically determined by the evaporation rate of the surface of the mold cavity contacting the carrier water, the most commonly used aluminum casting coating application method is spraying, but sometimes applying by brush coating, such as in the casting system. And in the riser area. Spraying at around 170°-200° generally achieves the best coating results, but the spray equipment and coating viscosity have an effect on the quality of the coating deposit. Therefore, depending on the viscosity of the spray equipment and paint, it is slightly biased. A little higher is the optimum spray temperature.