To reduce vehicle weight, enhance the range of new energy vehicles, and lower manufacturing costs for emerging automakers, integrated die-casting technology has seen increasing practical application. However, adopting this technology requires heavier molds. If traditional automotive design structures are followed, a significant amount of imported hot-work mold steel would be needed, substantially increasing production costs. To address this, die-casting mold technology introduced a mold core sleeve—a sleeve within the mold frame that houses insert blocks in contact with the product surface. This approach significantly reduces material costs.

Mold Core Sleeve

Since the mold core sleeve also comes into contact with molten aluminum, materials such as P20 forged parts or 718 forged steel are selected. These materials offer high hardness and wear resistance, effectively resisting abrasion from plastics, rubber, and other materials, thereby extending the mold's service life. Additionally, they exhibit excellent toughness, maintaining stability under high-impact conditions. Furthermore, these mold steels provide outstanding corrosion and heat resistance, ensuring reliable performance even in harsh environments such as high temperatures and humidity. Through heat treatment processes like quenching, stress relieving, and nitriding, the material's durability is further enhanced.

Mold Core Sleeve

The mold core sleeve internally requires the assembly of over 100 insert blocks, imposing extremely high machining precision requirements. Once assembled, it forms a complete mold; any internal gaps would significantly increase defect rates in die-cast products. The typical dimensions of a mold core sleeve fall within a range of 2000mm × 2000mm in length and width, and 450–850mm in height. However, the precision requirements demand a parallelism of ±0.05mm, a flatness of ±0.02mm for each cavity surface, an internal frame tolerance of 0.02–0.05mm, and additional specifications for gating surfaces. Through continuous research, our company has refined a specialized machining process for mold core sleeves, delivering qualified products to customers.

Deep-cavity Machining of the Fixed Mold Core Sleeve

The fixed mold core sleeve involves deep-cavity machining with a depth of 684.5mm. To overcome challenges in machining quality and efficiency for deep cavities, we adopted specialized vibration-damping tool holders. Operators inspect tool runout after clamping to ensure high-efficiency machining. This solution addresses issues such as tool deflection during deep-cavity machining, small cutting depths, and difficulties in maintaining dimensional accuracy, ultimately meeting the required product specifications.