French to English Tech/Engineering Metallurgy / Casting Jewellery / mounts and settings

Les montures fabriquées par fonte doivent être débarrassées de toute trace de jonction de moule

Would this be something like a 'mould seam'? I am imagining it meaning unwanted lines or seams on the cast metal once it is taken out of the cast or mould....

but can't find conclusive evidence that this is the industry term used. Any ideas?

Thanks!