Diamond Burnishing

[VicParticipant @vic]

[Michael GilliganParticipant @michaelgilligan61133]

! SHINY !

MichaelG.

[gerry maddenParticipant @gerrymadden53711]

I actually experimented with diamond ball burnishing on wind turbine pitch bearing raceways (55~60HRC) a number of years ago, for some tribological benefits. It did a very good job indeed.

Unfortunately, due to the size of the bearings (around 3~4m diameter) by the time we had completed one pass on one raceway, equivalent to around 3km of travel, the tool was worn out and had to be replaced. They weren’t cheap tools!

Gerry

[Nigel Graham 2Participant @nigelgraham2]

The tool may have been costly but what was the cost of the bearing otherwise, in proportion, and its replacement earlier than planned should the diamond not have done its excellent work?

A somewhat similar form of burnishing was being used early in the last Century – I don’t know when it was invented – in the manufacture of copper tubes by electro-plating onto a former, followed by using an agate burnisher along the outside. I am not sure what that did, though it would have had a work-hardening effect.

[gerry maddenParticipant @gerrymadden53711]

Its a good point Vic. Unfortunately the wind industry is now as cost-conscious as the auto industry and even a 100Eu onto a bearing costing 50000Eu has to be justified. In the case of the diamond ball burnisher, if I recall correctly the tooling cost was probably in the region of 1000Eu or so. Prior testing of the unburnished bearing had already demonstrated adequate life in its chosen application and therefore at that stage a life enhancement was not needed. But at least the burnishing process had been trialled, so for the next application (that would undoubtedly be more highly stressed), the life improvement benefits of burnishing would probably justify the cost.

Gerry

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