Gleason P 800G

The Gleason P 800G is a large-capacity CNC profile gear grinding machine designed for precision finishing of spur and helical gears up to 800 mm (31.5 in) in diameter. Built by Gleason Corporation in Rochester, New York, the P 800G serves heavy industrial gearbox manufacturers, wind energy gear producers, marine propulsion gear shops, and mining and process industry gearbox makers who require uncompromising accuracy on large, high-value gears. Profile (form) grinding — the method used by the P 800G — delivers the highest attainable gear quality grades (DIN 1–3 / AGMA 13–15) by dressing a grinding wheel to the exact involute tooth space profile and plunging each tooth space individually, ensuring superior surface finish and profile accuracy compared to generating methods.

The P 800G is built on a heavily ribbed cast-iron machine base with full thermal management to control spindle and bed temperature variation during extended grinding cycles. The grinding spindle is direct-driven at speeds up to 4,500 RPM, accommodating grinding wheel diameters up to 500 mm. The CNC rotary diamond dresser reshapes the wheel to precise involute profiles including topological modifications — crowning, lead taper, twist correction, and tip relief — critical for controlling gear contact patterns in large, high-load gearboxes. The workpiece table has a diameter of 800 mm with a maximum load capacity of 3,000 kg, enabling grinding of large gear blanks and shaft-mounted gears without disassembly, reducing setup time and maintaining positional accuracy.

Gleason's GEMS (Gleason Engineering and Manufacturing System) software drives the P 800G, providing an integrated workflow from gear geometry definition through grinding process planning, NC program generation, and quality data analysis. The machine connects to Gleason's closed-loop measurement system: sample gears measured on a Gleason CNC gear inspection machine automatically generate correction data that feeds back to the grinder, maintaining quality without manual operator adjustments. The Siemens SINUMERIK 840D sl control manages the six CNC axes required for profile grinding with topological modifications, including radial, tangential, axial, and tilt axes for precise wheel positioning.

The P 800G's large workpiece capacity makes it a key asset for wind turbine gearbox manufacturers, where main shaft gears, planet gears, and ring gears demand tight tolerances and smooth tooth surfaces to minimize noise and maximize fatigue life. Marine and offshore industries rely on the P 800G for grinding propulsion reduction gears and thruster gear sets. Heavy industrial sectors including cement mills, steel rolling mills, and large compressor drives use the P 800G for grinding replacement gears and new build gearsets. The machine's precision and repeatability are crucial in these sectors because the high cost and long lead times of large gear blanks make scrap unacceptable.

Competing machines in the large-capacity profile grinding segment include the Kapp Niles KNG 800 flex and Liebherr LGG 800. New Gleason P 800G machines are priced from $1,200,000 to $1,800,000 depending on configuration, automation, and metrology integration. Used P 800G machines in good condition from 2012–2020 typically trade between $600,000 and $1,000,000 when available, reflecting the machine's durability and long productive life.