Question

Explain various types of pattern allowances provided on patterns giving neat sketches.

Answer 1

Pattern allowances in patterns refer to the space left around a pattern to account for material shrinkage during the casting process. There are different types of pattern allowances, such as shrinkage, draft, and machining allowances.

Step-by-step explanation:

Pattern allowances in patterns refer to the space left around a pattern to account for material shrinkage during the casting process. There are different types of pattern allowances, such as:

1. Shrinkage Allowance: This allowance compensates for the contraction of the material as it cools and solidifies. The pattern is made slightly larger than the desired final size.
2. Draft Allowance: This allowance ensures that the pattern can be easily removed from the mold. It involves adding a taper or draft angle to the pattern surfaces.
3. Machining Allowance: This allowance provides additional material for subsequent machining operations to achieve the final dimensions and surface finish.

These are just a few examples of pattern allowances, and the specific type required depends on the casting process and material being used.