The current technical difficulties of integrated die-casting are mainly reflected in four aspects: large die-casting machine, no heat treatment aluminum alloy material formulation, die-casting mold design, vacuum die-casting process.
(1) Large die-casting machine
Large die-casting machine industry has a high entry threshold, with high requirements for theory, experience and manufacturing process. At the same time, the development cycle of large die-casting machine is very long, with large initial investment and high cost (1 die-casting machine needs 138,579,900 USD on average). Integrated die casting requires die casting machine clamping force at least greater than 6000 t (the clamping force of traditional high pressure die casting is usually below 5000 t).
(2) Heat treatment-free high-pressure casting alloy
The composition and process of heat treatment-free alloy materials are complex and have high technical requirements, among which the design of alloy material composition is the core technical barrier to the development of heat treatment-free alloy. Commonly used die-casting aluminum alloys are Al-Si system, Al-Mg system, Al-Si-Cu system and Al-Si-Mg system. The main composition ratio affects the mechanical properties such as strength and hardness of the alloy, and also affects the casting properties such as fluidity and solidification.
(3) Die-casting moulds
Integrated die casting has higher requirements for die strength and toughness, requiring impact toughness and tempering stability, good thermal conductivity and fatigue resistance, small coefficient of thermal expansion, and high temperature oxidation resistance. Die casting needs high speed filling and high speed solidification, in die casting die temperature, vacuum, forming scheme, process parameters and post-treatment requirements are higher.
(4) Die-casting process
Integrated die-casting is a vacuum die-casting process with a high vacuum control system, which requires high precision sensors to control the vacuum extraction process. The process flow is mold closing, pouring, vacuum opening, cavity vacuum venting, press injection, mold opening, taking parts, spraying, mold closing again, etc.