Lost foam casting technology is made of polystyrene foam through the foaming process and the shape of the needed castings. It is used as a mold for molding. After filling the sand, the foam pattern does not take out the mold, and then pouring the metal into the mold to vaporize the mould to form the casting. Lost foam casting molding technology adopts dry sand for molding, which does not need the binder used in wet sand mold and resin sand mold and additives such as pulverized coal, bentonite and water. It has less demand for raw materials, saves raw materials, and the old sand can be recycled after simple treatment, so as to reduce the pollution to the environment.
Gao Chengxun and others usedtechnology to form low alloy cast iron four cylinder engine cylinder block. Figure 1 shows the pattern of lost foam casting and the form of gating system. Figure 2 shows the low alloy cast iron four cylinder block casting, with a yield of more than 95% and a process yield of more than 90%.
A company in Shandong uses lost foam casting to form a six cylinder engine cylinder block by horizontal side bottom injection process, as shown in Figure 3, for large-scale production.
The United States has the most mature technology for producing automobile cylinder block using lost foam casting technology. In 2001, Saginaw foundry of GMPT began to use lost foam casting technology to mass produce automobile cylinder block. Saginaw foundry is the most advanced and largest lost foam casting factory in the world to produce automobile cylinder blocks. Figure 4 shows the lost foam casting pattern and formed castings of six cylinder engine in Saginaw foundry.