When precision meets scale: Manufacturing a 90-tonne Kaplan runner

In hydropower engineering, size alone is never the greatest challenge. Precision is.

Every large component we manufacture must meet demanding tolerances while operating under enormous mechanical forces for decades. As components grow larger, maintaining accuracy becomes exponentially more complex. Every fraction of a millimetre matters.

One of our latest manufacturing milestones perfectly illustrates this challenge.

At Litostroj Power, we recently completed the assembly of an almost 7-metre Kaplan runner weighing 90 tonnes. Despite its extraordinary dimensions, the runner was assembled with a level tolerance of just 0.02 mm per metre, a level of precision that reflects the expertise, experience and commitment of our engineering and manufacturing teams.

Engineering beyond scale

Producing components of this size requires far more than advanced manufacturing equipment. Every stage, from engineering design and machining to welding, assembly and quality control, must be carefully planned and executed to ensure every part fits together exactly as intended.

Maintaining such tight tolerances on a component weighing 90 tonnes demands continuous measurement, rigorous inspection procedures and close collaboration between specialists across multiple disciplines.

Precision that creates long-term reliability

For hydropower equipment, precision is directly linked to performance.

Accurate assembly contributes to smooth operation, reduced vibration, higher efficiency and longer service life. Even the smallest deviation can influence the behaviour of a turbine operating under immense hydraulic forces.

That is why precision is not simply a manufacturing requirement, it is one of the foundations of reliable hydropower generation.