Quote from Lyneham Lad...
"A looong while ago I was tasked with writing the draft structural servicing schedule for the Tornado. Apart from many meetings at Warton and MoD MB, I was despatched to Turin to see how the wing planks were produced at the Aeritalia factory. Large billets of aluminium were fed into CNC machines where >85% was machined away to form the top and bottom wing planks. Huge hoppers were situated underneath the CNC stations to take the swarf away for recycling."
Even longer ago I saw the production of the BAC 1-111. The wing skins were made in just that way, too...starting with large billets of aluminium alloy and machined away to form the structure, then they were shot peened until the required curve was obtained. Again, all the swarf was recycled. I can see how 3D printing is attractive as an alternative, but I do wonder about the quality control of such methods.