we cast plenty of parts in low pressure die casting and one of the common problems we face is inclusion/ oxide entrapment on the top face of the casting which is formed on the upper half of the die cavity. , we use mesh filters on the gate but problem is not eliminated.
thanks in advance
Are you sure it is inclusions/oxides in the metal? From the picture it looks like a gas problem. Are you using any means of de-gassing the metal prior to filling the die?