Zhuji HYozma Import & Export Co.Ltd.

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  • High quality, ferrous & non-ferrous, investment castings
  • Precision Investment Castings
  • Lost Wax Castings

Investment castings in Steel, Aluminum and Copper alloys for aerospace, defense, auto parts, medical, electronic and precision engineering applications

Investment Casting Process

The manufacture of castings involves high technology, numerous skills and a lot of experience ~ and there is no substitute for experience! HYozma Castings have built up a wealth of experience, knowledge and skill which are used with the latest equipment and technology to produce high quality castings, whether for medical and aerospace applications or for transportation & general engineering purposes.

For development purposes we can produce wax models for design discussions or cast metal prototypes using our own Rapid Prototyping machine.

This section describes the fascinating “Lost-Wax” process which combines several high technology disciplines.

The HYCAST Process


The first stage of the HYCAST process is to produce an exact replica (or “pattern”) of the required casting. This is made by injecting wax into a die.

Aluminum dies are used, which are economical to make and easily modified if design changes are required. Loose pieces may be used to form any undercuts and internal detail.

Die and wax pattern


The wax pattern is assembled onto a wax feeder system. Each assembly or “tree” may have just one large pattern or many small patterns.

Assembly of wax pattern


The wax assembly is dipped into the Silica Sol slurry.

This is the most important coating as the metal will lie next to it when poured into the mould.

Dipping the assembly into Silica Sol slurry


Whilst the thin coating is still wet, sand particles are dropped onto the wet surface, to build up a thicker coat. After drying, this coating process (or “investment” process) is repeated several times, building a shell mold.

Sand-spraying & shell built


After the final shell mould is dried, the wax is melted out in a steam autoclave, hence the name “lost-wax process”. The moulds are fired at over 1000°C to remove any remaining wax and to strengthen the mould.

Dewax and firing


Molten metal is poured into the moulds whilst they are still hot, enabling the metal to run into thin wall sections.

Pouring the metal


After cooling, the shell mould is broken away and each casting is cut away from the feeder system.

Shell & part removal


The castings are carefully fettled, blasted and heat-treated. Setting operations may also be required. Material testing, x-ray, dye penetrant or machining can then be carried out, if this is required.

Finishing & secondary operations


Testing and inspection


Packing & delivery