The first step in Lost Foam Casting for the production of expanded polystyrene (foam) the finished pattern (some pieces easily-moldable foam are glued together to make the intricately shaped pattern). The foam pattern is immersed in a liquid slurry containing ceramic platelets, dries to form a heat-resistant ceramic thin model. In casting, sand is poured around the pattern a mechanical support for the thin ceramic layer to provide.
The ceramic mold is permeable to gas, and so the foam goes through the ceramicmold vaporized, but the molten aluminum stays and eventually cools. When the metal becomes solid, it is removed from the sand, and the ceramic is removed from the casting. The sand can be used in the process to re-also SMD continuously increasing efficiency, reducing costs and helping the environment. The challenge is in the lost foam casting process perfectly dried refractory ceramic coating on the foam has reached the appropriate thickness uniformly on every surface. Slurry will have low viscosity (the property of resistance to flow of fluid) flow easily into each narrow channel and passages, and drain out so as to leave behind a surface coating of the correct thickness. The slurry may not ultra-high-viscosity flow into narrow features, or might not drain out, thus resulting in undesirable “bridging.” However, could slurry of ultra-low viscosity and sag slough along vertical surfaces when the recently-dipped foam pattern is hung to dry on a rack, resulting in uneven thickness. Such buildup may retard the migration of gas in which the coating is too thick, resulting in defect which engulfs the molten metal and gas bubble traps. Conversely, where the coating is too thin, could quickly the gas migration entice some of the molten metal to jut out like a peninsula; this can cool and “skin over,” resulting in defect. Accordingly, the consistency of the slurry flow characteristics, called rheology, control. In addition, for optimum performance, various slurry needed for different-shaped patterns.
GM Powertrain-Massena is played repeatedly lost performance quality foam solutions without any cause erratic readily ascertainable; However, the experience showed that using fresh batch of coating Cerami correct quality problems. This showed that the coating was important attributes were not detected with conventional measurement systems. Such uncertainty led ultimately to the application for a grant to do research to minimize the rate of waste through improvements coating (the project received a grant from the USDOE NICEEE # DE-FG41-01R110926 [such support from USDOE not constitute an endorsement by USDOE of the views expressed in this article], and grants from NYSERDA # 6412) – The project included various industries involved with lost foam coating, universities, consultant coating, and federal and State governments.