Holroyd has been commissioned by MAN Turbomaschinen AG to produce three sets of the largest screw rotors ever made. According to Holroyd’s press release, the project is an international effort to produce rotors that will measure 816 mm x 4 m and weighing more than 4 tons. The rotors will be produced on a Holroyd 8A milling machine, which can produce components up to 800 mm in diameter. As both the manufacturer of the machine tool and the sub-contract supplier of the components produced on it, Holroyd can direct the machine’s development to match market requirements. The company estimates that it will take two weeks for the machine to rough cut each rotor form from then solid forged stainless steel blanks. Rotors will then be heat treated to relieve metal stress and then finish milled. In addition, the rotor’s surface curves will be blended using the first stage machine tooling.