Question

Tumbling method, for cleaning of sand and unwanted fins from the castings, can be used for thin castings with fragile or overhung segments.

(a) True

(b) False

I got this question in my homework.

The question is from Casting Cleaning in chapter Pouring – Gating Design, Melting Furnaces, Melting and Casting Quality of Casting-Forming-Welding I

Answer 1

Right choice is (b) False

The explanation is: In the tumbling method, the castings are kept in a barrel which is completely closed and then rotated on a horizontal axis at 30-40 rpm. Movement of casting removes the sand and unwanted fins. However, one precaution to be taken for tumbling is that the castings should be rigid with no frail or overhung segments, which may get knocked off during the tumbling operation.