A rolling mill in Dublin, Ireland is one of several to be equipped with Hagglunds drives, now owned by Bosch Rexroth. The drives were inroduced to cut long, costly downtime when the conventional system needed to be repaired or replaced.
Jamestown Metals is a specialist manufacturer of lead products with rolling mills in Ireland (Dublin), England (Barnsley), Wales (Ebbw Vale) and USA (Houston).
In the late 90s at its plant in Barnsley the company made the decision to install a two-high reversing mill but wanted to change the conventional drive system that was normally used to drive the work rolls because these are traditionally large dedicated gearboxes with splitter gears to the two work rolls. Experience had shown that if there are any problems with these it can take a very long time to repair or replace them causing long expensive production delays.
It was decided to use slow speed high torque hydraulic motors, one to each of the work rolls because the delivery lead times on these were very short, often held in stock. Following on from this decision a market survey was done into suitable low speed high torque motors that were available and as a result it was decided that Hagglunds motors fitted the bill providing a simple compact drive solution mounting directly on to the mill rolls with no gearboxes needed. This enabled the mill roll gap to be easily adjusted as required during the milling process.
Hagglunds could also provide the complete drive system with power unit, control system and piping. With the success of the Barnsley installation all subsequent mills, including the Dublin Mill have now been equipped with Hagglunds drives.
Rolled lead sheeting is manufactured mainly for use in the building and construction industry. The manufacture of sheet lead starts with producing an eight tonne casting from the raw materials, which are often recycled from building waste and lead acid car batteries. The hot lead billet then needs to be reduced in size to the thicknesses required in the industry. This requires a number of passes through the heavy duty reversing rolling mill typically with 250hp on each roll to do the job. After each pass the gap between the rolls is adjusted using powered screws and the rolled sheet is coiled at each end as it gets longer and longer until the correct thickness is achieved. As the billet hits the rolls the speed and torque needs to be smoothly controlled to produce a high quality sheet material in line with the high standards necessary.