Expandable Pattern Ceramic Shell Mold Casting for Complex Shapes

Ceramic mold casting is a casting method of pouring molten metal into ceramic molds to obtain castings. It is a kind of precision casting developed on the basis of sand casting and investment casting.

First coat the slurry on the shape of the EPS white mold. Then, a special ceramic inorganic cavity thin-walled shell is made. And then the molten metal is poured into the molded shell. When the molten metal cools and solidifies, the casting forms.

EPS white mold, cavity and castings

EPS white mold, cavity and castings


  • Ceramic cavity thin-walled shell has high strength, great refractoriness, good air permeability, smooth inner wall and precise size.
  • It can be used to produce all kinds of large high-end precision castings, such as: stainless steel and alloy steel castings with complex structure, castings with high internal and external quality requirements, large castings weighing dozens of kilograms to several tons, and several castings can be cast as a whole.
  • It is easy to be popularized and applied in expandable pattern casting, lost wax precision casting and sand casting.

Casting Gallery

EPS white molds

Cavity drying

Burnt casting cavity

Casting cavity buried box

Casting sand removal

Casting polishing

  • Compared with Expandable Pattern Casting

    There are essential differences in application modes, technological measures and casting quality between ceramic mold casting and expandable pattern casting.
    Expandable pattern casting: Pouring molten metal into white foam molds coated with paint.
    Ceramic mold casting: Pour molten metal into the clean ceramic inorganic cavity shell.

    • Advantages of Ceramic Mold Casting

      • Completely overcome the inherent defeats of traditional lost foam casting such as recarburization, porosity, carbon residue and wrinkled surfaces. It greatly improves the quality grade of all kinds of steel castings, alloy steel parts, ductile iron parts, non-ferrous alloy parts (aluminum alloy, copper alloy) produced via expandable pattern casting.
      • It can withstand high requirement tests, especially the requirements of producing ultra-low carbon alloy steel (e.g. duplex stainless steel with carbon content of 0.03% and below). Castings are basically free from recarburization, cracks, pores, slag (macro and micro) and other defects, which leads to a high spheroidization rate in ductile iron casting production.
      • High production efficiency: the coating dries quickly under high temperature and strong wind without cracking nor deformation. Compared with that of expandable pattern casting, the production efficiency is doubled. From the beginning of coating slurry, it can be poured within 2 days (only 2-3 hours for each drying).
      • Environmental protection: more than 95% of the foam plastic white mold is liquefied and recycled, and a small amount of volatile gas is easily gathered for centralized smoke removal treatment. The waste coating peeled off the surface of the casting after pouring can be crushed and reused, which makes it more environment-friendly and energy saving.
  • Compared with Lost Wax Precision Casting (Silica Sol Casting)

    Under the conditions of producing castings of the same quality, ceramic pattern casting has a lower casting cost. Featuring by flexible casting technological measures (cold iron, casting head position), it can produce large and medium casting parts and castings with complex structures.

    • Advantages of Ceramic Mold Casting

      • It can produce precision castings with a piece weight of dozens of kilograms to several tons.
      • High production efficiency. The whole process lasts only 2 days from the beginning of coating to pouring.
      • Reduced production cost, especially suitable for high alloy steel parts production.
      • This process only requires dipping in slurry without stuccoing. The shell is not easy to deform, crack, layer or peel off, which makes it have more advantages in producing large castings with a complex structure.
      • It does not require red-hot state casting. The working conditions are improved, making cold iron and other technological measures can be implemented easily and eliminate casting shrinkage cavity and porosity defeats.
      • The shell is thin and light. It only has 1/2 to 1/3 weight of the wax mold casting shell, which makes it is easy to operate and save materials.
  • Compared with Sand Casting

    Under the premise of producing castings at the same cost, ceramic pattern casting makes the quality of casting greatly improved from inside to outside.

    • Advantages of Ceramic Mold Casting

      • High precision. The dimensional accuracy of castings is improved from CT 12-14 to CT 5- 8 and the surface roughness is improved from Ra 50-100 μm to Ra 12.5-25 μm.
      • Process simplification and optimization. No sand core is required and draft angle can be ignored. Casting wall thickness is uniform, no die joint, no trimming or burring. The casting has high dimensional accuracy and low cutting and grinding workload. This advantage is more prominent when making castings with a complex structure.
      • Other casting coatings. Coatings used in sand casting, expandable pattern casting and lost wax casting are easy to be pulverized, washed and damaged due to high temperature when pouring metal liquid.
      • Coatings used in ceramic mold casting are ceramic coatings with a thickness of several millimeters, featuring by high hardness, high refractoriness, high air permeability and excellent resistance to instant cold and heat. This kind of coatings have the following benefits.
        • It ensures the casting surface and near surface are free from sand holes, pores, slag inclusion and other defects.
        • It makes the workload of subsequent welding repair and grinding be greatly reduced, especially the workload of stainless steel and high alloy steel can be reduced by nearly 90%.
        • It is easy to ensure the quality of high-end castings that have magnetic particle testing requirements.

Real Green Casting

Expandable pattern casting is recognized as "green casting in 21st century". However, the ceramic mold casting is more environmental-friendly in the following aspects.

  • Fuel gas emission

    In addition to sands used in these two processes are recycled without emission

    • Expandable pattern casting

      • In the pouring process, the polystyrene foam white mold is fully burned or vaporized by the metal liquid. Part of the flue gas is directly discharged into the atmosphere, and the other part is discharged into the atmosphere through a simple vacuum pump system treatment, resulting in certain pollution to the environment.
      • For coatings used in expandable pattern casting, when castings are taken out, it not only pollutes the dry sand but also forms dust emissions.
    • Ceramic mold casting

      • In the process of making the shell, at least 95% of the foamed solid polystyrene plastic turns into liquid polystyrene plastic, flowing out of the shell and being recycled.
      • The transition from solid to liquid is a physical process, which does not cause pollution to the environment and can be used as waste.
      • A very small amount of decomposition products are collected in the heating furnace and decomposed into CO2 and H2O in the smoke remover for emission.
  • Coating waste treatment

    • Expandable pattern casting

      • When the expandable pattern casting is finished, powdery coating wastes are mixed with dry sand, which is easy to causes dust pollution.
    • Ceramic mold casting

      • A small amount of flake coating wastes after casting cleaning are pulverized and mixed into the back-layer slurry for reuse. As a result, this process is basically pollution-free, energy saving and environment-friendly. It is a kind of green casting in real sense.

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