What is a function of a riser in a sand casting?
(a) Provide good mobility to the molten metal
(b) Prevent cavities due to shrinkage
(c) To develop holes or hollow cavities in the casting
(d) To provide differential cooling rates in specific areas of the casting
This question was addressed to me in an interview for internship.
The origin of the question is Functions of a Pattern in portion Pattern and Pattern Making of Casting-Forming-Welding I