2022.12.07
There are two types of lost foam molding machines: automatic and manual. The manual operation is controlled by the hydraulic valve of the fully automatic foam pre-expansion machine, so that the upper template, left and right templates, and front and rear templates of the molding machine are opened and closed according to the order of mold design.
The automatic lost foam molding machine follows the manual sequence. The lost foam foam machine adopts PLC to automatically control the hydraulic valve to complete the opening and closing of the mold.
Compression molding consists of two stages, steam heating and cooling to shape.
The cured pre-expanded beads are heated by steam. In about 20s-60s, the air has no time to overflow, and the pressure is generated after being heated and expanded. The sum of the pressure is greater than the steam pressure heated outside the beads. At this time, the polymer softens. After the foaming agent vaporizes, the pressure inside the cell is greater than the pressure outside, and the beads expand again, and fill the gaps between the beads to form a whole piece, forming a foamed plastic product with the same shape as the mold, which can be formed after passing through water and cooling polymerization.
The lost foam casting method first makes a foam plastic model according to the EPC process, coats it with a special paint, puts it in a special sand box after drying, fills it with dry sand, compacts it with three-dimensional vibration, and casts it in a vacuum state. The model evaporates and disappears. The model is replaced to replicate the same casting as the foam mold, the vacuum is released after condensation, and the casting is removed from the loose sand for the next cycle.
Lost foam casting process
1. Making foam plastic gasification molds (manual, mechanical);
2. Foam plastic is gasified, and the mold is combined and then dried;
3. After brushing and spraying refractory paint on the surface of foam plastic gasification mold, dry it again (must be completely dry);
4. Place the special sand box on the three-dimensional vibrating table;
5. Fill in low sand (dry sand) to vibrate and scrape;
6. Put the dried foam plastic gasification mold on the bottom sand, divide it into sand filling according to the process requirements, and scrape the box mouth after automatic vibration for a certain period of time;
7. Cover the mouth of the sand box with a plastic film, put the sprue cup on it, and connect it to the negative pressure system. After compaction, molten steel casting is carried out, the foam plastic gasification mold disappears, and molten metal takes its place;
8. After the casting is condensed, the vacuum is released and the box is turned over, and the casting is taken out for the next cycle.
Tel:
English 
