Biggest ever

Holroyd Precision has produced what is thought to be the biggest CNC helical profile milling system ever made, at a cost of £2.5m, on behalf of a major Chinese compressor manufacturer.

The machine is to be used for the roughing and finishing of outsize screw compressor rotors for use in the gas processing industry.Weighing in at more than 8t, the stainless steel rotors needed a special machine tool capable of handling diameters of up to 850mm with a length of up to 4.5m.

The greatest challenge involved achieving the requisite precision of movement given the enormity of the masses to be moved and the cutting forces involved requiring maximum stiffness and damping with minimum weight and friction of all axes.