Published 6/13/2011

VTL Delivers Powerful, Heavy Cuts

In addition to high horsepower and torque for heavy cuts in difficult-to-machine materials, the Powerturn 2500 C-M vertical turning lathe offers a large-capacity ATC, thermal stability and observation cameras mounted within the work zone.

Edited by: Matt Danford

Former Senior Editor, Modern Machine Shop

Shown here is the machine’s tool storage and retrieval system. A two-position tool arm loads and unloads the tools, and the next cutter automatically moves to the “ready” position for faster change times.

The VTL’s table employs a dual-drive system that provides not only high accuracy during C-axis positioning, but also sufficient horsepower and torque for heavy cuts, the company says.

Vertical turning lathes (VTLs) have always been useful for machining large, heavy parts. That’s because gravity helps keep the workpiece in place rather than acting in opposition to the clamping forces exerted by a conventional lathe chuck. By itself, however, this inherent advantage is not sufficient to satisfy the needs of many manufacturers in the energy, construction, marine equipment and other sectors in which these machines are common. Such companies are demanding higher cutting forces for aggressive machining operations that remove large amounts of material.

Toshulin, a VTL builder based in the Czech Republic city of Hulin, says such applications shouldn’t be a problem with its new Powerturn 2500 C-M, even when dealing with hardened, difficult-to-machine alloys. Scheduled for release at the EMO trade show in Hannover, Germany this September, the machine offers a table drive system and ram that deliver high levels of horsepower and torque for heavy hogging. It also offers advancements demanded by machine tool users across all sectors of industry, including features that contribute to thermal stability, automation capabilities that reduce setup time, and a layout that conserves floor space. Additionally, cameras mounted within the workzone enable operators and other personnel to closely track operations as they proceed.

Available in the United States from Pilsen Imports (Cincinnati, Ohio), the machine offers a 98-inch table. C-axis positioning via the table’s dual drive system enables users to orient parts for machining via rotating milling and drilling tools mounted in the square, 12.5-inch ram’s live spindle, which is capable of as much as 11,250 pounds of cutting force.

The table drive system offers 190 hp and 64,400 foot-pounds of torque at continuous duty (more than 237 hp and 85,500 foot-pounds duty rated), while the ram live spindle delivers 68 hp and 1,460 foot-pounds of torque at continuous duty (85 hp and 1,825 foot-pounds duty rated). The company says these levels of power are especially beneficial in helical milling operations. Additionally, the ram is designed to resist bending as it extends, which enables heavy, accurate cutting at high speed regardless of the extension level, the company says.

Complementing the powerful ram system and table drive is a thermo-symmetrically designed machine base that reduces the effects of heat on the table and workpiece. Combined with a recirculating, temperature-controlled oil system, this feature helps maintain a consistent temperature range to mediate any heat-related table inaccuracies. Consistent temperatures also aid in obtaining consistent cutting tolerance bands, the company says.

To reduce time spent loading and unloading cutting tools, the machine’s ATC can accommodate as many as 250 tools. Compatible interfaces include Sandvik Capto, Kennametal KM or HSK for both turning and live tools as well as 50-taper live tools. With the exception of special-sized tools that require a fixed location, all cutters locate in standardized carriers that fit any location on the changer. A two-position tool arm loads and unloads the tools, and the next cutter automatically moves to the “ready” position for
faster change times. The main tool adapters are located in a carousel positioned for easy access by the ram.

The layout of auxiliary components (the electrical cabinet, hydraulic unit, coolant tank and so on) is designed to minimize the machine’s footprint, the company says. Additionally, the guard system keeps chips and coolant inside the fully enclosed workzone to facilitate a clean, safe environment for operators and support personnel.

Toshulin has also added a somewhat unusual capability to the Powerturn 2500 C-M: protected, workzone-mounted cameras that enable users to closely monitor the machining process. These full-color cameras are capable of panning, tilting and zooming as required. Images are displayed on a large screen attached to the operator’s pendant.