In the foundries is very important to understand and to control all the phenomena taking place at the contact (and under the action) of liquid alloy on the moulds. These phenomena are very complex, but a convenient way to treat this problem is to devide it into slices. One slice of the problem is the influence of liquid alloy on the mould. This paper is an attempt to present some aspects concerning the geometry of the contact zone between liquid alloy and mould.