Competition is said to drive business. As an engineer, I therefore always enjoy reading about new developments from competitors in technical journals. Recently, fertigung announced a grinding machine designed for large dimensions, intended for the production of hob cutters. It sounded interesting at first. After reading the article, however, I was rather disappointed. Neither one thing nor the other, as we Swabians would say.

Ready to go and complete

The very first Multigrind® CB delivered to a customer is already being used to machine hob cutters. These are impressive cutting tools weighing up to 600 kilograms, with lengths of up to 600 millimetres and diameters of up to 500 millimetres.

At I.P. Huse on the Norwegian island of Herøy, such tools are used to manufacture gears for driving large, truly large winches used on cargo and container ships as well as offshore drilling platforms. The drums on which anchor chains, ship’s ropes or cables are wound can reach diameters of up to eight metres.

The machining specialists at I.P. Huse chose Haas Schleifmaschinen because we are the only grinding machine manufacturer whose machines are capable of fully machining very large gear cutting tools in a single setup. This is made possible, among other things, by a crossed double spindle arrangement, a 360‑degree swivel range on the A axis and a 320‑degree swivel range of the grinding wheel on the C axis.

Hysteresis and the "Muggaseggel"

For gears in large winches to operate reliably under heavy loads, they must be manufactured with extreme precision. This, in turn, requires highly accurate hob cutters, with tolerances of two to three micrometres.

To maintain this level of accuracy throughout the entire grinding process, we have equipped the Multigrind® CB with an intelligent integrated 3D measuring system. Our software specialists have succeeded in mathematically calibrating what is known as hysteresis. Hysteresis describes the persistence of an effect after its cause has ceased, for example when a probing system deflects more than intended, which can negatively affect the subsequent grinding operation.

That issue has now been resolved. The integrated measuring unit of the Multigrind® CB achieves repeatability of less than one micrometre. At the same time, it eliminates time‑consuming unclamping and reclamping. That is something even a Swabian can truly appreciate.

PS: A final note for all seafarers. Milling a large gear at I.P. Huse can take up to eight days. Sailing through the Panama Canal takes about eight hours. Or roughly two minutes when viewed in fast forward.