First, a foam pattern and gating system are made using a molding press and aged in drying oven.
Secondly, the foam pattern and gating system are assembled into a cluster.
The cluster is then coated with a permeable refractory coating and dried under controlled conditions.
The next step is to invest the dry coated cluster in loose unbonded sand that is vibrated in and around the foam cluster.
The final step in the casting process is to pour the molten metal directly into the foam cluster, decomposing the foam in the system and replacing it with metal.
The Flask is left to cool for a period of time, depending on the type of metal that is being poured. Once enough cooling has taken place, the flask is either dumped out onto a conveyor or casting cluster is extracted before dumping sand.
Casting cleaning operations would include minimum (cutoff, grinding), heat-treat if necessary, and typical tumbling. This is similar to other casting processes, but this is one area of cost reductions. The other would be on the reduction of machining features in the casting. Dependant on the tolerances of holes, passageways, or machine stock, major savings in the process are in the reduction of machining.
While maintaining good process control over key parameters in the process, inspection could be kept down to a minimum. Process Control is a must, with proper documentation in the Lostfoam process. This starts with the raw material through the inspection process.
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What is the Lost Foam Process