When it comes to additive manufacturing (AM), the U.S. Marine Corps confronts extreme versions of the opportunity and the dilemmas that many machine shops face.The opportunity: AM—particularly in metal—offers a promising way to obtain short-run parts in a hurry. For a business, the benefit is merely filling the order rapidly. But for the Marines, the benefit might be winning the battle by replacing a broken component to restore a crippled piece of equipment to use. Related Stories. But ...