ANS:A - parting

In foundry processes, "parting" refers to the application of a separation material, typically sand, between the pattern and the molding sand. The purpose of parting is to create a barrier that prevents the molding sand (often green sand) from sticking to the pattern during the mold-making process. Here's how parting works and why it's important:

1. Preventing Sticking: When creating molds for casting metal parts, a pattern is typically used to form the cavity in the sand. However, without proper precautions, the sand can stick to the pattern, making it difficult to remove after the mold is formed. This sticking can damage the pattern and result in an incomplete or flawed mold.
2. Creating a Barrier: Parting sand or material is applied to the pattern surface before it is placed in the molding sand. This creates a thin barrier between the pattern and the molding sand, preventing them from bonding together.
3. Facilitating Pattern Removal: After the mold is formed, the parting material allows for easy removal of the pattern from the mold cavity. This is essential for maintaining the integrity of the pattern for future use in additional mold-making processes.
4. Types of Parting Materials: Parting materials can vary depending on the specific requirements of the casting process. Common parting materials include parting sands (typically fine sand mixed with additives such as talc or graphite), parting compounds (such as powders or sprays), and other release agents or lubricants.
5. Application: Parting materials are applied to the pattern surface using various methods, including brushing, spraying, or dusting. Care must be taken to ensure an even and complete coverage to effectively prevent sticking.
6. Importance in Foundry Operations: Parting is a critical step in foundry operations to ensure the quality and integrity of the molds produced. Proper parting helps to avoid damage to patterns, reduces the risk of defects in castings, and improves the efficiency of the mold-making process.