How to Apply the Coating on the Surface Layer of Aluminum Alloy Die Castings
Spraying aluminum alloy die castings is a widespread practice. Whereas excellent coating can bring certain benefits to the product quality and function of aluminum alloy die castings, it is now important to how to spray aluminum alloy die castings. After all, if there is any omission, it can damage the high-quality effect of all coatings.
It should be understood first that the fire resistance of the coating film on aluminum alloy die castings depends not only on the thickness of the coating, but also on the porosity of the coating itself. The porosity of the plating layer is greatly affected by the selected coating specifications and methods, due to the fact that the formation level of voids in the plating layer is largely determined by the management of the transpiration rate of media water touched by the surface of the mold cavity.
Currently, there are a wide range of coating methods for aluminum alloy die casting construction coatings, that is, spraying, but sometimes painting methods are also used, such as coating for concrete pouring systems and pouring areas. When spraying aluminum alloy die castings, the ambient temperature must be outstanding. Generally, spraying around 170-200 can achieve the desired coating effect.
However, the damage of active spraying equipment and construction coating viscosity to the coating stack quality of aluminum alloy die casting construction cannot be ignored. Therefore, depending on the viscosity of active spraying equipment and construction coatings, it is necessary to appropriately improve the partial spraying ambient temperature. In addition, when the mold ambient temperature is high, the continued high temperature of the construction coating and the central media water will be significantly reflected, resulting in a very large porosity of the construction coating and promoting a certain degree of fire resistance of the aluminum alloy die casting coating.
Everyone should also consider comprehensively that excessive mold shell ambient temperatures can also cause backlash, which can lead to significant "resilience", making the coating unable to adhere to the surface of the mold cavity, resulting in reduced adhesion and service life of the coating to metal mold casting. On the contrary, when spraying at lower ambient temperatures, although the service life of the coating is relatively high, the fire resistance of the coating film will decline.
Therefore, in the entire process of spraying aluminum alloy die castings, the control of ambient temperature is indeed very important. On the premise of ensuring the successful formation of the coating, outstanding performance indicators and service life should also be guaranteed. In addition, adequate preparation should be made before coating aluminum alloy die castings, such as thorough cleaning, oil and rust removal, polishing, etc., which is conducive to improving the adhesion of aluminum alloy die casting materials.