Q1: The taper provided on pattern for its easy & clean withdrawal from the mould is termed as the __________ allowance.

ANS:C - draft

The taper provided on a pattern for its easy and clean withdrawal from the mold is termed as the draft allowance. Explanation:

1. Draft: In patternmaking and casting processes, the draft refers to the slight taper or angle added to the vertical surfaces of a pattern. This taper is designed to facilitate the removal of the pattern from the mold cavity without causing damage to the mold or the casting.
2. Purpose: The primary purpose of providing draft on a pattern is to prevent the pattern from becoming stuck in the mold during the casting process. Without draft, the pattern may bind or drag against the mold walls, leading to defects in the casting or damage to the mold.
3. Angle: The draft angle is typically measured in degrees and is applied uniformly to all vertical surfaces of the pattern. The specific angle of draft depends on factors such as the type of casting material, the complexity of the part, and the characteristics of the molding material.
4. Benefits:
   • Easy Withdrawal: Draft allows the pattern to be easily and cleanly withdrawn from the mold cavity without causing disruption to the mold surfaces or the casting.
   • Reduced Friction: The taper reduces friction between the pattern and the mold walls, minimizing the risk of damage to both the pattern and the mold.
   • Improved Surface Finish: Proper draft helps to achieve smoother and more uniform surfaces on the casting by preventing drag marks or tearing during pattern removal.
5. Application: Draft is essential in various casting processes, including sand casting, investment casting, and die casting. It is a fundamental aspect of pattern design and plays a crucial role in the success of the casting process.