Question

In sand castings, modification of bosses is done to_____

(a) have good surface finish

(b) to reduce the chances of porosity

(c) to eliminate the use of core

(d) to reduce casting yield

This question was addressed to me during an online exam.

Origin of the question is Product Design for Sand Castings topic in section Pouring – Gating Design, Melting Furnaces, Melting and Casting Quality of Casting-Forming-Welding I

Answer 1

The correct answer is (c) to eliminate the use of core

The best explanation: Bosses are mainly used to increase the sectional thickness of the housing in order to improve the strength of certain parts of casting. The modified boss or the extension of a boss to the flange eliminates the need of a core and also the undercut, which forms a less complicated design.