The Role and Machining Process of Marine Crankshaft Forged Balance Weights

Marine crankshaft forged balance weights are key counterweight components of large crankshafts. Their core function is to balance the centrifugal inertia force and inertia torque generated by the crankshaft during high-speed rotation. By precisely calculating and configuring the mass and position of the balance weights, the unbalanced forces generated by the movement of the engine piston-connecting rod assembly can be effectively counteracted, thereby significantly reducing crankshaft vibration, additional loads, and engine noise, and improving the operational stability, reliability, and bearing life of the main engine.

Its machining process requires extremely high precision:

1. Blank preparation: Usually manufactured using the same full-fiber bending forging process as the crank arm to ensure continuous metal streamlines and excellent mechanical properties.

2. Rough machining: Milling the six faces of the balance weight to control the overall length, thickness, and width dimensions, leaving a margin for subsequent finish machining.

3. Finish machining:

   • Using the crankpin bore and main journal bore as benchmarks, precision milling the outer contour and end faces to strictly control the consistency of its overall shape with the theoretical design.

   • Drilling and reaming the connecting bolt holes between the balance weight and the crank arm. The accuracy of these holes directly affects the dynamic balance effect.

   • Machining the shoulder positioning surface that mates with the crank arm to ensure a tight fit between the mating surfaces.

4. Dynamic balance correction: After installing the balance weight on the crankshaft, the entire crankshaft is tested on a dynamic balancing machine. If there is residual unbalance, fine-tuning is required by drilling holes (weight removal) or adding balance screws (weight addition) to the balance weight until the strict balance accuracy level requirements are met.

The precision machining of this component is a core link to ensure the stable, efficient, and long-term operation of the entire crankshaft.