True greatness is T-shaped

A key factor in the decision was the strong partner relationship, which has been contractually approved from Metalex’s side.

Advanced technology machining company Metalex Manufacturing Inc. expands its Center for Advanced Large Manufacturing with Droop+Rein T portal-type machining centers from Starrag.

The long-term partnership between US manufacturer Metalex Manufacturing Inc. and the Starrag Group has revealed a lot in common: Both are specialists in extremely large components made from aluminum, stainless steel and titanium for very challenging applications. Now the Ohio-based job shop plans to grow even more, adding a fourth Starrag machine to the mix. So what are Metalex's plans for its new Droop+Rein T six-axis portal-type machining center?


“Good things achieved and excellent things cannot be acquired without great effort and work.” This advice from the poet Hans Jakob Christoffel von Grimmelshausen around 350 years ago couldn’t be a better fit for Metalex Manufacturing Inc. from Cincinnati, Ohio, and the Bielefeld plant of the Starrag Group. This phase of their partnership may have been put on pause for many reasons, the pandemic being one of them, but now the Droop+Rein T 60 80 DT TT60 HR100 C portal-type machining center is coming into operation at the Center for Advanced Large Manufacturing, a bespoke extension of their main plant in the form of an enormous building.


It’s the biggest portal-type machining center in the Droop+Rein T product line to date: thanks to their optimal rigid construction and hydrostatic operating concept, these machines are perfectly suited to high-precision machining of extremely large workpieces with complex geometry in settings that require adherence to extremely tight tolerances. Heiko Quack, Starrag’s Bielefeld-based sales director for large projects, states that these machines “produce very flexible, efficient and precise workpieces using various materials on five axes.”

Acceptance only after intensive benchmarking

Starrag offered exactly what its American customer was looking for: Metalex was on the hunt for a machine that would satisfy not only its current production needs, but also the demands of the future, too. These are the challenges Metalex, along with its machinery suppliers, must face as a large manufacturer of top quality, complex components. Although the company already had three Starrag machine-tools at its disposal, it decided on a Droop+Rein T-product line portal-type machining center after an intensive benchmarking process. A key factor in the decision was the strong partnership, which has been contractually approved from Metalex’s side.

The machining center has a Z-axis slide feed milling unit with integrated C-axis and a wide range of milling heads. It includes two rotary tables and turning tool holders from the Dörries product range, which have been used in a Starrag machine for years and have proven to Metalex that they are reliable, productive components.

This is XXL at its finest, as a glance at the unusual dimensions of the work area shows (X: 748 in. (19,000 mm); Y: 354 in. (9,000 mm); Z: 118 in. (3.000 mm)). Here, even very large workpieces can be machined on a single setting thanks to the huge amount of space available. Extremely flexible five-axis machining is made possible by the two continuous universal fork type milling heads. They are perfect for heavy machining with up to 1,770 ft-lb (2,400 Nm) of milling torque. But it can also be used with motorized milling spindles at high speeds, which can be changed out automatically with milling spindle replacement. For even more flexible, universal work, Metalex ordered a 217 in. (5,500 mm) continuous mobile crossbar as its 6th axis (W).

Two tables for less non-productive time

The real highlight of this XXL machine is, according to sales director Heiko Quack, its specially designed table configuration with two large tables (236 in. (6,000 mm) × 315 in. (8,000 mm): “The operating personnel can work on them completely separate: One table can be used for preliminary set-up or inspection outside the work area while the other is being used for machining.”

Extra-long workpieces can be machined in a coupled tandem formation, which extends the tables to 709 in. (18,000 mm). Each table also has an integrated rotary table (diameter: 236 in. (6,000 mm)) which, thanks to the 149 hp (111 kW) main drive, also enables rotary machining of components weighing up to 200 tons. But the rotary tables can also be used as a C-axis for precision positioning when milling and drilling. Heiko Quack is convinced this machine is unique in its size, configuration and multifunctionality.

“We are already seeing very good utilization of the new machinery!”

Kevin Kummerle, CEO Metalex

Speedy aluminum milling with 18,000 rpm

The eleven machining heads Metalex ordered for its machine, create universal functionality. However, the day-to-day activities in Ohio prove that even that isn’t enough for a truly flexible manufacturer. While the machine was still being commissioned, a requirement arose for milling large aluminum rings for an aerospace customer. So, Starrag and Metalex put their heads together to look into the possibilities for high-speed machining and the highest productivity that can be achieved. The result: After successful testing, Starrag delivered and integrated a new motorized spindle (18,000 rpm) for the five-axis fork type milling head in time for production to start. “This example shows that a manufacturer, who rarely has the option to define exact specifications, can react flexibly to new requirements by using the right machine concept and the close collaboration with the machine supplier,” emphasizes the sales director. “The extra spindle allows the manufacturer to increase productivity by a huge amount when manufacturing this ring.”

But what about productivity when a machine with a head changing system and twelve machining heads suddenly has one or more machining heads added into the mix – would that lead to a rise in non-productive time? Starrag had this scenario in mind when developing this system. According to Heiko Quack, “the machining center has an electronic system for managing machining heads. I could, for example, eject an XY angular milling head in order to swap it for a fork type milling head. So Metalex can keep 30 machining heads on hand and always bring in the ones needed for a job.” And it’s paying off, because there are discussions in Ohio about adding head 13 and 14.

The robot tool change system has been rolled out at lightning speed.

Robots ensure fast tool change

The robot tool change system has been rolled out at lightning speed: Large manufacturers often need space not only for a lot of tools but also for a huge variety of tool systems. Currently, the system allows the use of tools with CAT 60, CAT 50, Capto-C8, HSK 100 or HSK 63 holders, which supply the respective machining head with the tools as and when required. Understandably, for a project of this level, which represents the largest investment in the company’s history, there is always going to be skepticism: will the expensive investment in the Center for Advanced Large Manufacturing – for which Metalex has constructed a state of the art production building with extremely low-vibration foundations weighing 7,000 tons – pay off? The investment, which cost several million US dollars, seems to have been worth it so far. At least, that’s what Heiko Quack was told when the machinery was put into action in the US: “We are already seeing very good utilization of the new machinery!” Metalex CEO Kevin Kummerle, who is already thinking about making further investments, has a similar view of things.