In sand casting, what is the purpose of the pattern?

In sand casting, what is the purpose of the pattern?

• A. The pattern is used to create the mold cavity
• B. The pattern is used to cool the metal
• C. The pattern is used to remove the sprue
• D. The pattern is used to measure the finished part

Answer: (A)

In sand casting, the pattern’s job is to shape the mold cavity. The pattern is a replica of the final part, and it’s pressed into damp sand to displace it and create an impression. When you lift the pattern out, that hollow space becomes the mold cavity where molten metal is poured. This cavity determines the final shape and size of the casting, and patterns are designed with allowances (like draft and shrinkage) so the finished part comes out correctly. The other tasks—cooling the metal, trimming away a sprue, or measuring the finished part—are handled by other parts of the process, not by the pattern itself.

In sand casting, the pattern’s job is to shape the mold cavity. The pattern is a replica of the final part, and it’s pressed into damp sand to displace it and create an impression. When you lift the pattern out, that hollow space becomes the mold cavity where molten metal is poured. This cavity determines the final shape and size of the casting, and patterns are designed with allowances (like draft and shrinkage) so the finished part comes out correctly. The other tasks—cooling the metal, trimming away a sprue, or measuring the finished part—are handled by other parts of the process, not by the pattern itself.