Liebherr LC 280

The Liebherr LC 280 is a CNC combined gear hobbing and chamfering machine that integrates gear hobbing and the subsequent deburring and chamfering of gear tooth ends into a single machine platform. Manufactured by Liebherr-Verzahntechnik GmbH in Kempten, Germany, the LC 280 is designed for automotive transmission gear producers and industrial gearbox manufacturers who require both operations — hobbing and chamfer/deburring — in a lean, integrated process that minimizes part handling, reduces floor space, and eliminates dedicated deburring machines from the production line. With a maximum workpiece diameter of 280 mm (11.02 in), the LC 280 covers the majority of passenger car and light commercial vehicle transmission gear sizes.

The integration of hobbing and chamfering in the LC 280 is based on Liebherr's proven two-station design. In the main hobbing station, the workpiece is hobbed to finished tooth form with a conventional gear hob running at high speed with direct-drive technology. After hobbing, the workpiece is automatically transferred on the same machine table to a secondary chamfering station where a chamfering tool removes the burrs and sharp edges left on the tooth ends by the hobbing process. Tooth end chamfering is critical because sharp hobbing burrs can cause assembly problems, damage hardening equipment (furnace basket contamination), and create stress concentration points that initiate fatigue cracks in service. By integrating chamfering into the LC 280, Liebherr eliminates the dedicated deburring station, saving floor space, part handling time, and investment cost.

Both hobbing and chamfering stations on the LC 280 use direct-drive torque motors on the key rotary axes, providing the repeatability, low maintenance, and fast cycle times associated with Liebherr's direct-drive architecture. The hob spindle reaches speeds up to 4,000 RPM to support modern carbide hob grades running at cutting speeds of 200–400 m/min on steel. The workpiece spindle accommodates gears on arbors or in chucks, and a tailstock is available for shaft-type workpieces requiring additional axial support. Dry hobbing and chamfering with an appropriate chip management system is supported, simplifying coolant management in automotive production cells.

Liebherr's WOP-G (Workshop Oriented Programming for Gear Cutting) operator interface on the Siemens SINUMERIK 840D sl control manages both hobbing and chamfering programs in a unified job setup workflow. Operators enter gear parameters once and WOP-G generates the NC programs for both operations automatically. The chamfering tool path — including chamfer angle, width, and edge break geometry — is defined parametrically rather than by hand-written NC code, reducing programming time and setup errors. Integration with Liebherr's production monitoring systems allows real-time tracking of cycle times, tool life, and machine utilization across a multi-machine cell.

The LC 280 competes with the Gleason Genesis 260GX combined hobbing/chamfering machine and with stand-alone hobbers paired with separate chamfering machines. New LC 280 machines are priced between $550,000 and $800,000, reflecting the higher investment required for the integrated dual-station design. For automotive gear producers running integrated production cells, the LC 280's combination of hobbing and chamfering in one machine typically provides a positive return on the incremental investment through floor space savings, reduced material handling, and elimination of a standalone deburring machine.