A new milling tool for manufacturing cyclo-palloid gears in the 0.5 to 30 Module range has been developed by Ringwood-based Horn Cutting Tools Ltd (www.phorn.co.uk).

Based on the Klingelnberg design, the M279 milling system is intended for producing one-offs and small batches of components.

The cut distribution of the 12-insert tool allows a high chip volume to be achieved with a low cutting pressure.

The tool was specified by DMG Mori, which wanted a solution that would be at least 20% faster than existing solid-
carbide solutions.

A robust tool with indexable inserts was needed for taking full cuts on milling and turning machines, while also being suitable for simultaneous five-axis milling using DMG Mori’s GearMill software.

Horn’s new tool features four S279 indexable inserts (with a corner radius of 2mm) that are screwed into place on the tool’s face. These are complemented by eight tangentially secured 409 inserts.

The tool body has a diameter of 100mm; and the fact that the rows of insert edges overlap enables the system to achieve high depths of cut.

Development and testing at DMG Mori’s Pfronten facility in Germany, along with modifications to the cutting data, means that the machining of convex and concave gear-tooth flanks can be achieved with the milling tool in 5-axis simultaneous operations.

A crown wheel of Module 7.6 machined from 17CrNiMo6 was used as a trial workpiece.

The Klingelnberg cyclo-palloid gear was produced at a cutting speed of 250m/min and a feed rate of 650mm/min, with full cutter engagement; the tooth flanks were milled at a feed rate of 2,000mm/min.