Supplied to the Naval Group in Osborne, South Australia, a Droop+Rein gantry milling machine is the largest machine ever to be put into operation in Australia.

With X, Y and Z axes traverses of 14,000mm x 13,000mm x 3,500mm, plus an 11m rotary table to permit turning operations in the same set-up, the five-axis giant, supplied by Starrag Group, will be used to machine hull elements and other high-precision components for the Royal Australian Navy (RAN)’s Attack class submarines.

The order for the machine comes after the Federal Government selected French company Naval Group to deliver a fleet of 12 regionally superior submarines, to be built in a modern construction yard in Osborne. The Future Submarine Program will deliver Australia a capability that can be built, operated and maintained with sovereignty, which maximises opportunities for Australian industry throughout all phases of the programme.

As the design of the Attack class progresses, the Naval Group is continuing to deliver on a commitment to achieve this through its pool of suppliers. This pool now includes the Starrag Group, which was selected to supply a Droop+Rein G 110TT HR100 C vertical gantry machine, capable of handling both large hull elements and high-precision components for submarine construction.

To deliver this important equipment, Starrag is collaborating with machine tool manufacturer H&H Machine Tools Australia, based in Campbellfield, Victoria. The company will manufacture key components, supply qualified personnel to help install the gantry, and provide technical support for the entire life cycle of the machine, securing an enduring role in servicing and maintenance in the future. Starrag will provide H&H with the necessary expertise through on-site training and quality control, transferring critical skills and sovereign ability to Australian industry.

The contract was awarded following a complex selection process. Noting its many years of experience and its extensive, not merely technical, expertise in handling large, complicated projects, the Starrag Group became an obvious selection for the contract. Not every machine supplier can manage an order of this magnitude from more than 15,000km away — but it was no problem for the Starrag Group, as Australian sales partner H&H would facilitate local work, ensuring that everything runs smoothly on-site. A previous project carried out in South Australia, for which Starrag supplied four machines for aircraft construction, shows a proven track record in this regard.

Precise heavy-duty cutting of large, heavy workpieces

The size and efficiency of the milling machine being supplied, which is also capable of turning components thanks to the integrated rotary table – tried and tested as part of the Dörries range of lathes from the Starrag Group – was of fundamental importance. The Droop+Rein G 110 TT HR100 C owes its high levels of precision to features such as the hydrostatic guides in all linear axes, as well as the thermosymmetrical design of the milling unit with integrated C axis.

Milling heads can be changed automatically via a head change interface. The team responsible selected five different machining heads to use in this project: the high-performance fork milling head possesses the ability to not only apply tools at any angle but it also has the necessary prerequisites for heavy-duty machining on five axes simultaneously.

Alternatively, the machine can be used with one straight and one angled 100kW milling head with a torque of 7,500Nm. A turret and a horizontal facing head are available for turning operations.

The large, multi-functional machine supplied by Starrag from its Bielefeld plant in Germany gives the operator optimum access. The operator can reach any point on the workpiece thanks to the spacious cabin, which travels along the gantry and features the latest Siemens operator panel. The cabin can reach a height of 8m and be moved towards the centre of the table.

Another decisive factor in favour of the Starrag Group was that, having already supplied machines to reference customers, the company could prove that the installed machine technology is very robust. This ensures that, with proper maintenance, the machine will be operational for the entire duration of the submarine project; the first of the Attack class submarines will be delivered in the early 2030s and continue into the early 2050s.