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Shell Moulding Vs No Bake

Shell Moulding Vs No Bake : Which is best for valve Bodies

Valve bodies are among the most critical components in fluid control systems, requiring high dimensional accuracy, superior surface finish, and excellent mechanical properties. In foundry manufacturing, two popular processes are commonly used for producing valve body castings — Shell Moulding and No-Bake (Air Set) moulding. Both methods have unique strengths and are suited for specific casting requirements. Let’s explore the differences and understand which process is best suited for valve body production.

1. Overview of Shell Moulding Process

Shell moulding is a precision casting process that uses resin-coated sand and heated metal patterns to form thin, rigid mould shells. These shells are then assembled to create the mould cavity.

Key Features -

  1. Uses resin coated sand (RCS)
  2. Thin mould walls (6–12 mm)
  3. Ideal for medium to small castings
  4. Excellent dimensional accuracy and smooth surface finish
  5. Fast cycle time and repeatability

Advantages for Valve Bodies -

  1. Produces valve bodies with high precision and low machining allowance
  2. Smooth internal surfaces, reducing turbulence in flow
  3. Less sand usage, making it cost-efficient for medium-scale production
  4. Suitable for complex cores and intricate passages

Overview of No-Bake (Air Set) Process

The No-Bake process, also known as the air-set process, uses chemically bonded sand that cures at room temperature without heat. It is commonly used for larger and heavier castings or components requiring strong moulds.

Key Features -

  1. Uses resin and hardener binder system
  2. Room temperature curing
  3. Strong moulds with excellent dimensional stability
  4. Suitable for large and heavy sections

Advantages for Valve Bodies -

  1. Ideal for large valve bodies exceeding 50–60 kg
  2. Capable of handling complex geometries and thicker sections
  3. High strength moulds reduce distortion in heavy castings
  4. Allows easy core assembly and handling

3. Comparative Analysis

Feature Shell Moulding No-Bake (Air Set)
Casting Size Small to Medium Medium to Large
Surface Finish Excellent (3.2–6.3 µm Ra) Good (6.3–12.5 µm Ra)
Dimensional Accuracy Very High Moderate
Tooling Cost High (metal pattern) Moderate (wood/metal pattern)
Production Rate High Low to Medium

Best Suited For Precision castings, thin-walled valve bodies Large, heavy, or complex valve bodies.

4. Which Process Should You Choose for Valve Bodies?

The choice between Shell Moulding and No-Bake depends on your valve design, size, and application -
If your valve body requires tight tolerances, smooth finish, and thin walls, Shell Moulding is the ideal choice.
If your valve body is large, heavy, or requires multiple core assemblies, the No-Bake process offers better handling and structural integrity.
In many modern foundries, both processes are integrated — allowing flexibility to produce a wide range of valve castings depending on size and design.

5. Raysons’ Expertise

At Raysons Shell Cast, we offer both Shell Moulding and No-Bake casting solutions under one roof. This dual capability enables us to supply valve bodies from 500 grams to 150 kilograms, maintaining top-quality standards across all sizes.
With advanced simulation tools, controlled sand systems, and ISO-certified processes, we ensure leak-proof, high-strength, and precision-engineered valve castings trusted by leading manufacturers across India and abroad.

Conclusion

Both Shell Moulding and No-Bake processes have distinct benefits. For high-precision and smaller valve bodies, Shell Moulding is superior, while No-Bake is ideal for large or complex valves. Partnering with a foundry that offers both ensures the best process selection, consistent quality, and cost-effectiveness — all delivered under one roof.