CERAMIC MOLDING AND ITS ADVANTAGES , DISADVANTAGES

In ceramic molding, a thick slurry, consisting of specially developed ceramic aggregates and a liquid chemical binder (alcohol based silicon ester) is poured over the reusable split and gated metal pattern which is usually mounted on a match plate. The slurry fills up all cavities and recesses by itself and no ramming or vibration of the mold is required. The pattern is withdrawn after it sets in about 3 to 5 minutes. The ceramic mass is then removed from the flask. treated with a hardener to promote chemical stabilization and heated to about 980*C in a furnace to remove the liquid binder. The mold is then ready for pouring molten metal.

Advantages of this Process are :

1. Highest precision and extremely high finish are obtained.

2. Suitable for all types of cast metals including highly reactive metals such as titanium and uranium.

3. The castings do not normally require any riser, venting or chilling as the cooling rate is very slow.

4. Any ordinary pattern of wood, metal or epoxy resin may be employed.

5. Highly suitable for precision parts which include forging dies, dies for plastic molding , dies for drawing, extrusion , diecasting, patterns for shell molding, impellers of pumps having very narrow passages, parts for aircrafts, atomic reactors etc.

Disadvantages Of Ceramic Molding are :

1. Impractical to control dimensional tolerances across the parting line to the same tolerance as within one-half of the mold.

2. The process is expensive as the mold materials are high in cost and expendable.

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