Hydraulic Bolt Tensioners

First Automated Tensioning System Helps Boost Production For Cummins Wartsila

New control and tensioning technology developed by Hydratight Sweeney for Cummins Wärtsilä (CW) cuts stud tensioning times of critical applications, such as cylinder heads and the main bearing cap studs, from over an hour to under twenty minutes on its W170 diesel engine. It also promises bolt-loading accuracy not previously attainable on any diesel engine.

Known as the Automated Multistud Tensioner (AMST) it is the first tensioning tool, which after fitting, requires no more than the press of a button to carry out the complete tensioning procedure.

With bolt tensioning speed a critical factor in avoiding production line bottlenecks, CW's plans to boost production capacity by a factor of three at its Daventry plant made the development of Hydratight Sweeney's system a priority.

Using a programmable plc controller integrated into CW's own local area network, the system automatically loads the studs to 346.6kN within an accuracy of +/- 0.06mm on stud extension.

CW's production line can assemble engines with different numbers of cylinders, so the AMST programme recognises each engine and the number of cylinder heads and main bearing caps. The system only releases the engine when all studs are tightened within the specified tolerance. It provides a failsafe process and improves the operation's repeatability for benchmarking future best practice.