solution of common casting problems

 

In the casting process of the lost wax casting method, we often encounter various casting problems, such as incomplete castings, micropores, and particles on the surface. How to solve them?

Burr or flashing edge

Improper mixing rate of water and investment powder, or store investment powder in awrong way. Over timed mising and vacuum (more than 8-9mins. Temp rises too fast in the burnout oven.

Incomplete casting items

Truck of wax tree is too small, incompletely-burnt wax mould. Flask temp is too low while casting, metal temp is too low while casting, or insufficient weight of metal.

Unsmooth surface of casting items

Incompletely-burnt wax mould with carbonaceous materials inside investment mould, temp of burnout oven is too high.

With tiny holes on the surface

Metal temp is too high, also flask temp is too high. An excess of old metal mixed in the casting metal (should be half less), put too much flux while melting.

Small particles on the surface

Oven temp is too high. There are some tiny particles in the metal, rust on the flasks.

Rough surface

Incompletely mixing of water and investment powder, improper soldering of wax tree, insufficient mixing time or over-speed temp rising of flasks. Dewaxing temp is more than 150"C to corrode casting metal surface.

Remarks: casting procedure normally start from high temp metal to low temp one. Graphite has a tendency to moisture absorption before casting should be appropriate to dry.