Breaking ranks

Highly flexible mill-turn centres

Many users of mill-turn centres from Stama are reporting time savings of up to 70% and unit cost reductions of 50%. This is all thanks to the high flexibility of the machines and their virtually negligible setup times. The integrated automation solution from Festo for loading and unloading the workpieces as well as the tool changer in the additional magazine contribute to this success.

The big advantage of machine tools from Stama is that small batch sizes and high-volume series can be processed one after the other in almost any combination. “What makes our mill-turn centres stand out is the fact that workpieces can be fully milled, turned, drilled, reamed, ground, deburred and polished on all six sides in one operating cycle,” explains Gerhard Schweicker, Sales Engineer at Stama. “With our 5-axis processing, the workpiece and tool are freely positioned and swivelled in the working space,” adds the machine expert.

Vertical part loading

“The machines from the MT series MT726-2C and MT734-2C use two tools independently in parallel. The rotating spindles enable parts to be loaded vertically,” according to Mr Schweicker. “The parts are loaded by the integrated automation solution, a linear gantry from Festo with suitable grippers,” says Jochen Boscher from the project management team at Stama. The loader and unloader places the workpiece at the processing station where it is automatically clamped. This enables optimum use of the operating cycles: while one workpiece is still being processed, the integrated automation solution can move into the processing area, unload finished parts and remove them once they have been processed, all independently of the other workpiece.

The result is shorter unit times and lower unit costs, since loading no longer needs to be done manually. Instead, the ready-to-install linear gantry is opening up new perspectives. A 4.5-metre long horizontally placed axis DGE as well as two independently working vertical axes EGC with grippers HGPL from Festo enable the workpieces to be transported directly to the working space for processing, and to be simultaneously loaded and unloaded. Festo delivers the loader and unloader to the machine complete and ready-to-install.

Tool changer reduces setup times

Stama mill-turn centres from the MT726 and MT734 series are also available with an additional magazine for holding further tools in order to significantly reduce setup times when frequent component changes are required. Here too, fully automated tool changes are carried out by a complete and ready-to-install handling solution from Festo. This tandem gripper/rotary unit comprises axes EGC, the pneumatic semi-rotary drive DRRD and the heavy-duty tool gripper HGPT. “It’s a big advantage to be able to get all the solutions we need for workpiece and tool handling from a single source during the project planning process,” emphasises Boscher. “In Festo, we have a competent development partner for all of our machine automation needs.”

Ready-to-install system solutions

When designing the system solutions for the mill-turn centres, the specialists from the Festo Technology and Application Centres were able to call on a wealth of experience gained while designing thousands of ready-to-install handling solutions. This experience is hugely valuable in projects of this kind, as it ensures the trouble-free integration of various bus systems or the I/O interface in the machine controller. Customer-specific solutions for installation interfaces and disconnection points are adapted to the requirements. In this case, the loader and unloader as well as the tool changer in the additional magazine provide a highly flexible solution as the front end can be adapted to the customer’s requirements.

“The integrated automation solution with the loader and unloader as well as the tool changer from Festo help to achieve a space-saving machine layout,” says Schweicher. “Since three quarters of our machines are used around the world, it is even more important that we work with a global partner like Festo with its extensive sales and service network. This is particularly true for China, where we as a machine tool manufacturer are experiencing especially strong growth,” adds Mr Boscher from Stama.

Stama Maschinenfabrik GmbH

Siemensstraße 23
73278 Schlierbach

Area of business: Manufacture and distribution of vertical CNC machining centres, devices, tools and measuring technology