Lost foam casting (LFC) is a new technology with precise forming, no need eps mould ,no parting line on the surface, no sand hole, no edge, less tolerance and less manufacturing step. Comparing the traditional casting technology, LFC has many advantages. The LFC applied widely especially in the auto and pipe industry in condition of the EPS lost foam casting
is easy carving and fast foaming. Here, let us introduce the requirement for EPS mould production. Other information about casting ,please refer to the relevant books.
EPS mould casting requirement: products density rang 16-25 g/L, smooth surface, small beads, less air hole, no edge; .
Presently there are two ways to make samples:
1. the first way is block cutting ; With CNC cutter or manual way, The block will be cut ,carved and bonded for required shape. Owing to high requirement of lost foam. The block must have very good fusion with less air holes inside. The method is mainly used in small quantity , lower accuracy , large workpiece Foam casting.
2. Mould forming is fast,big quantity and most popular way. Manufacture must pay attention to the double contractility between EPS material and casting material. EPS shrinkage rate is 0.4-0. 8%. The product of the Semi auto or manual eps foam machine is better on smooth surface with no step and deformation in the ejection site because of no ejectors. Both forming methods require small size beads, 0.2 ~ 0.80 mm (the original beads <=1/9 ~ 1/10 the minimum wall thickness) It require even beads ,So the SPJ90 pre-expander is recommended because it is the high standard equipment with small size chamber.
After we finish the EPS mould, it will go to the step of EPS coating (increase strength and rigid)and casting.