Transmission troubles

From ground level it's difficult to see just how huge the streamlined units that house the transmission are and only when you see them in the workshop do you realise that the parts that are contained within are also of huge dimensions. The largest components have diameters of up to 2m and weigh up to 4.5 tons. Seeing them up close dwarfs anything else around.

Germany-based Kempten Engineering is a medium-sized company specialising in this type of work and it knows through experience how to handle the medium-sized 2,000mm x 1,400mm x 1,600mm cubic workpieces that go into making up the wind turbine transmission. The main part of the factory is 8,000m² in area and is temperature controlled to around 1°C. The second part of the factory is a further 2,000m² and an automatic pallet transport system connects the two, containing milling machines, drilling and production development machines, as well as sharpening centres and inspection equipment.

Transport of the raw and finished units from receiving to despatch also takes place with an automated transport system controlled by a central computer. Apart from making sure that the highest quality and deadlines for delivery are maintained, one of the logical requirements is the sourcing of forward technology tooling, found in Avantec milling systems.

One of the most challenging processes – and a process problem for Kempten – in manufacturing transmission cases is milling a groove in the oiling system because the operation must be carried out deep inside the housing. A solution to the conundrum was found through consultation with Avantec who provided a disk miller with the right technology from its standard range. It has a tangential face arranged with indexable inserts which produces clean slots and runs quietly in operation. The milling of three slots around the transmission case must be done carefully in order to avoid vibration.

Other milling tools had been tried on numerous occasions but failed to produce the grooves without excessive vibration. Avantec however developed a tool specifically to address this problem resulting in clean cuts using tangential indexable inserts. The 20mm groove necessary for the unit is produced in two steps with the second step running at the same speed as the first. No additional steps are required as the rpm is adapted to the feed resulting in optimal machinability and safe operation.

In the UK, Avantec products are available from Cheltenham-based Stocdon.

Stocdon
www.stocdon.co.uk