Shell Mold Casting

Shell Mold Casting:

A new spin on sand mold casting

Omnidex has been providing Shell Casting services to a long list of business customers for many years. We work with the industry’s best to bring you a wide range of Shell Molding solutions. If you are looking for an efficient sand mold casting method with high consistency, our Shell Mold Casting process can definitely meet your needs.

Learn more about Shell Molding

Invented in Germany during World War Two, shell casting (sometimes called shell molding) is a process similar to sand casting. It also uses temporary molds that are not reusable, but the molds are made with fine-grained, high-purity sand that is mixed with a thermosetting resin. The process offers superior dimensional accuracy across a wide range of ferrous and non-ferrous alloys.

The process of Shell Molding:

  1. The metal pattern is first heated to between 175°C (350°F) and 370°C (700°F).
  2. Fine sand mixed with a thermosetting resin is poured into the hot pattern. The heat will harden part of the sand to form a shell.
  3. The entire contraption is inverted to remove excess sand, leaving only the shell.
  4. The shell is further heated in an oven to harden, then removed from the pattern.
  5. Two or more shells are combined to form a mold.
  6. The shell mold is placed inside a frame, and surrounded with shot, sand, or gravel for metal pouring.

Pros and cons of Shell Casting:


  • Excellent dimensional accuracy (greater accuracy can be achieved using zircon sand)
  • Good surface finish
  • Can be used to produce complex shapes with fine details
  • Can use a range of ferrous or non-ferrous metals
  • Shorter project lead times
  • Can be automated for large-scale production to reduce labour cost and increase productivity
  • Minimal waste level


  • The sand resin used in shell casting is expensive and cannot be reclaimed
  • Higher equipment cost
  • Product size limited by shell molding machines
  • Additional machining needed


Shell casting is suitable for most ferrous and non-ferrous metals. Common materials include:

  • Alloy steel
  • Stainless steel
  • Carbon steel
  • Cast iron
  • Aluminum alloys
  • Copper alloys
  • Nickel alloys


Since the shell molds are made with metal patterns and special sand compounds, the shell casting process can offer excellent dimensional accuracy and tolerances. Typical tolerances for this process are around 0.005 in/in (0.127mm/mm).

Unique advantages of the shell casting process

Shell casting can be used to make complex parts with fine details and very thin sections. It also offers excellent surface finish and tight tolerances. But this is not the full extent of its capabilities.

What makes shell casting stand out from most other processes is that it can be fully mechanized and automated, and it has lower skill requirements for workers. That means this process can have reach a higher production rate and can be easily scaled for mass production. These advantages make shell casting the ideal solution for large-scale production of small to medium-sized high-precision parts. This process is often used in the manufacture of camshafts, crankshafts, gear housings and many more.

Contact us to learn more about shell casting and other metal casting process we offer. You can also learn more about Omnidex and other manufacturing processes we offer on this website.

We are always ready to help with your latest project.

Contact our Customer Service and let us know how we can help to catapult your next project to success.

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