Partnership as a success factor US manufacturer Metalex: Successful launch of the Starrag 6-axis Droop+Rein T gantry machining centre in Cincinnati, OH

Specifications for production machines are usually peppered with technical details – and it was no different for US manufacturer Metalex Manufacturing Inc., who ordered one of the largest gantry machining centres in the Droop+Rein T series ever built from the Swiss Starrag Group. In addition, the regular customer from Ohio entered into a contractual commitment of cooperation on an equal footing.

”A 6-axis machine of these dimensions, in this milling and turning performance class, with eleven machining heads, five tool systems and over 400 tools, is not something you build every day,“ Heiko Quack, Director Sales Large Projects from the Starrag plant in Bielefeld, comments looking back.

”I also think it is important to mention that Metalex was looking for a partner to develop and implement this project together with them. They insisted that this should also be written in the contract. Metalex expected us to work together on this project, to exchange ideas, to both define the same goal and achieve it in a close partnership. This is the only way to implement such a massive project.“

Machining extremely large components in a single setup

A Droop+Rein T 60 80 DT TT60 HR100 C gantry machining centre was built for the huge new Centre for Advanced Large Manufacturing, a purpose-built extension to the main factory. It is one of the largest gantry machining centres in the Droop+Rein T series to date. Thanks to its optimum rigid design and hydrostatic guide concept, it is particularly suitable for high-precision machining of extremely large workpieces with complex geometries in a single setup, where it is important to maintain very narrow tolerances.

In the exceptionally large working area (X:19,000 mm; Y:9,000 mm; Z:3,000 mm), Metalex easily machines very large workpieces in a single setup. Highly flexible, five-axis machining is made possible by the two continuous universal fork milling heads. They are suitable for heavy machining with up to 2,400 Nm milling torque. It is also possible to use high-speed motorised milling spindles, which can be automatically changed in the version with milling spindle change. In order to be able to work even more flexibly and universally, Metalex ordered a cross beam that can be moved continuously over 5,500 mm as the sixth axis (W).

Rapid tool change: The robot tool change
system is designed for high speed and the
option to use a wide variety of tool systems.
The system currently allows the use of tools

Two tables and rotary milling machines reduce non-productive times

The machining centre has a Z-slide milling unit with integrated C-axis and a large selection of milling heads. It is also equipped with two rotary tables and turning tool holders from the Dörries product range, which have already proven to be reliable and productive components at Metalex over many years in a Starrag machine. According to sales manager Quack, one highlight is the special table design with two large tables (6,000 mm x 8,000 mm): ”The operating personnel can work separately on them – one table is used for pre-setting or measuring outside the work area and the other for machining.“

The machining of extra-long workpieces takes place in coupled tandem operation, which extends the tables to 18,000 mm. In each one, Starrag integrated a rotary table (diameter: 6,000 mm) which, thanks to the two 111 kW main drives, also enables the turning of components weighing up to 200 tonnes. The rotary table can also be used as a C-axis for precise positioning when milling and drilling.

Fast aluminium milling with a speed of 18,000 rpm

The eleven machining heads that Metalex ordered with the machine also ensure universal application possibilities. At the customer‘s request, Starrag also integrated a fork milling head with integrated motor spindle (18,000 rpm) for high-speed milling of large aluminium rings for an aerospace customer, just in time for the start of production. But Starrag also anticipated the use of other machining heads during development. Quack: ”The machining centre has an electronic management system for heads. So, for example, I remove an angle milling head XY in order to replace it with a fork milling head. Metalex can therefore keep 30 machining heads in stock and always bring in the ones needed for a job.“ The message was well received; in the US state of Ohio, heads 13 and 14 are already under discussion.

The investment in the fourth Starrag machine tool has also paid off. For example, Heiko Quack heard from the USA while the machine was still being commissioned: ”We already have a very good utilisation rate on the new machine!“ This opinion is also held by Metalex CEO Kevin Kummerle, who is already thinking about further investments.

Rapid head change: The machining centre has an electronic management system for heads. Metalex can thus keep up to 30 machining heads in stock and always bring in the ones currently needed for a job.