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Huo Shan Long Xin Metal states that in aluminum alloy investment casting, dry sand is used for molding, and insulating coatings are applied to the foam molds. Since vaporization requires the absorption of a large amount of heat, the temperature at which the molten material is taken out of the furnace and the pouring temperature are higher than those in conventional sand casting, die casting, and gravity die casting. Additionally, since aluminum is a reactive metal, this leads to oxidation and absorption of gases by the aluminum alloy melt; during melting and pouring, the alloy reacts with moisture in the air, resulting in the dissolution of hydrogen and oxidation. During its cooling process, hydrogen gas tends to precipitate from the aluminum alloy melt, forming dispersed pinholes and slag pores. On the other hand, the main raw materials and auxiliary materials, as well as the melting equipment and tools, were not operated and technically controlled in a strict manner in accordance with the production process requirements throughout the production process ； If the melting equipment, raw materials and auxiliary materials, as well as the melting tools, are not properly preheated before production ； During the processes of material selection, melting, refining, aging, and pouring, there was no strict control over air absorption and oxidation in the aluminum alloy melt; moreover, improper handling during casting allowed air to enter the mold, resulting in serious casting defects ； Therefore, any oversight in even the smallest part of the entire production process can lead to negative consequences. Huo Shan Long Xin Metal mentioned common surface defects such as pinholes, gas slag pores, pin slag pores, slag pores, and slag eyes. Huo Shan Long Xin Metal stated that these defects arise mainly from unscientific and unreasonable formulation of the production processes ； The main preventive measures are as follows: ① Modify the pouring system ； Increase pouring speed ； Control pouring to prevent turbulence. ②Improve the air permeability of the coating layer and the molding sand. ③ Control the density, moisture content, and amount of foaming agent in the foam pattern. ④Ensure it is completely dry ； The paint coating has dried completely. ⑤Control the amount and quality of the foam-based adhesive used, ensuring a strong bond while doing so ； The less adhesive used, the better; at the same time, an adhesive with low outgassing must be selected.